Hydrocephalus 2017, the Ninth Annual Meeting of the International Society for Hydrocephalus and CSF disorders (Hydrocephalus Society)

© The Author(s) 2018. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. I


Introduction:
The cerebrospinal fluid (CSF) circulates through the ventricles and the cranial and spinal subarachnoid spaces that are dynamic compartments. According to MONROE-KELLIE's doctrine, the CSF is distributed constantly in compartments which interact with each other. What happen in the other compartments and the CSF flow when laterals ventricles dilate? Methods: 10 hydrocephalus patients underwent a 3T MRI with morphological and phase contrast sequences to investigate the CSF volume and its flow at the aqueductal (SVaque) and spinal (SVspine) levels. The volume of each CSF compartments lateral ventricles (LV), intracranial spaces (IV) (pontine and cerebellum cisterns) and spinal spaces (SS), were estimated by measuring the CSF area in a selected plane crossing each compartment. CSF areas measurements of each patient were normalized to show the distribution of one CSF compartment in front of another. An Heterogeneity coefficient was calculated based on the standard deviation. Results: In our population LV area presented the high heterogeneity 49%, IV heterogeneity was equal to 27% and heterogeneity for the SS was equal to 41%. Paradoxically increase of the LV compartment seems to induce an increase of the IV spaces and indeterminate change in SS which can increase or decrease a lot. SVaque was positively correlated with LV area (R = 0.63, p = 0.04) whereas SVspine presented no significant correlation with LV area. No significant correlations were measured between CSF flows and the all others areas of CSF. Conclusions: Unlike MONROE-KELLIE's doctrine, the compartments can all increase, so it's the tissue or the venous which should decrease.
Introduction: Standard automated neuroimage processing, such as FreeSurfer, has long played an important role in discovery within various patient groups. However, such standard tools can encounter difficulties when processing normal pressure hydrocephalus (NPH) patients. Methods: We present a validation of a recently developed atlas and patch based segmentation method. The method can determine the extents of the ventricular system and identify sub-components including the lateral (left and right), third, and fourth ventricles. We focus on validating the automated approach in comparison to Free-Surfer and other standard processing tools on our cohort consists of 45 NPH patients that have been manually parcellated.

Results:
We use both volumetric and overlap comparisons to evaluate our method on the 45 NPH patients. We show statistically significant improvement in accuracy at estimating the volumes of the various sub-components, over state-of-the-art methods. Conclusions: Developing methods for automated neuroimage processing is an important step for systematic evaluation of different patients groups. The high-throughput segmentation method presented and validated here enables such systematic evaluation of brains with ventriculomegaly. This method could be used to elucidate novel patterns of the ventricular system, such as disproportionate dilation of different sub-compartments in NPH patients. A secondary observation of this work is the gross inadequacies of current neuroimage processing methods for ventricle segmentation; moreover, previously reported automated evaluation of NPH patient using FreeSurfer that do not include manual review should be reviewed to ensure their validity. Introduction: Changes in craniospinal dynamic compliance have been hypothesized to be an important factor in the development of normal pressure hydrocephalus (NPH). A bioimpedance-based sensor integrated onto a drainage catheter could allow the direct monitoring of ventricular volume to be used as an additional control parameter in a smart shunt system. It may also provide further insight into craniospinal dynamics by recording the pulsation of the CSF-filled compartments. Methods: A 3-D finite element (FE) study has been conducted using COMSOL Multiphysics software on geometrical and anatomical models of the brain. Frequency dependent dielectric properties were assigned to the modelled tissues. Multiple ventricle sizes were generated. The sensor consists of a drainage catheter with six integrated ring electrodes on its surface. CSF-pulsation profiles obtained from literature were assigned to the ventricle wall boundaries. An alternating current with amplitude of 10 μA at frequencies from 1 kHz to 1 MHz was injected through the outer electrodes. The resulting current was calculated by integration of the current density and the voltage recorded at the remaining electrodes. Results: The bioimpedance signal correlates to ventricular size and the pulsatile profiles could be extracted from the measured dynamic impedance. Conclusions: The generated FE model can be used to assess the dynamic impedance properties of the CSF space and may be used to study changes in the impedance signal caused by diseases such as NPH. Future work includes the hardware implementation of the measurement system and its validation on a craniospinal bioimpedance test-bench. Fluids Barriers CNS 2018, 15(Suppl 1):4 the valve. Valve pressure was raised to the maximum of 200 mm H2O or Setting 8, when subdural hematoma (SDH) was detected. Results: A favorable response to the surgery was detected in 96.4%. Malfunction was observed in 27 (4.4%) patients. Lumbar catheterrelated; displacement in 13, disconnection in 4, and obstruction in one. Peritoneal catheter-related; disconnection in 6 and displacement in one. Obstruction of the valve was found in one patient. Complications occurred in 16 patients. Surgery-required SDH due to overdrainage was found in 10 (1.6%) patients treated by the system incorporating the conventional CHPV, and lumbar pain followed by catheter removal in 6 (1.0%). Infection occurred in 3 patients (0.5%); meningitis in 2, operative wound infection in one. Conclusions: It is safe and useful to treat iNPH by using the LP shunt system incorporating with CHPV. The use of the CODMAN CERTAS Plus valve seems to be very helpful to reduce the incidence of surgeryrequired SDH by raising valve pressure to the maximum of Setting 8.

A26
Reverse of fronto-parietal cortical perfusion on SPECT after shunting in idiopathic normal pressure hydrocephalus: a case report K. T. Chen 1  Introduction: A two-layer sign in sagittal plane has been proposed as a signature of idiopathic normal pressure hydrocephalus (iNPH) by the two-tailed view analysis using easy Z-score imaging system (eZIS) on brain perfusion SPECT. However, frontal dominant or diffuse cerebral hypoperfusion are more common. Previous studies have documented improved or normalized perfusion after a spinal tap or shunting. Here, we report a definite iNPH patient presented with a reverse of frontoparietal cortical perfusion after a shunt surgery. Methods: Case report Results: A 69-year-old woman was evaluated because of 6 months of progressive gait disturbance, urinary incontinence and memory decline. Her Japenese NPH Grading Scale-Revised (JNPHGSR) was 8 (gait:2, cognition:3, urinary:3). A brain CT revealed ventriculomegaly, periventricular lucency and disproportionately enlarged subarachnoid space. A SPECT showed a two-layer structure consisting of decreased blood flow around the corpus callosum and increased perfusion outside cingulate gyrus. A follow-up SPECT was performed 1 week after shunting. A reverse of blood flow from hyperperfusion to hypoperfusion in fronto-parietal cortical area, associated with a significant normalization of blood flow in deep nuclei was observed. The postoperative JNPHGSR was 4 (gait:1, cognition:2, urinary:1) at 1 week and 2 (gait:1, cognition:1) at 1 month, respectively. Conclusions: We reported an interesting case of perfusion inversion in an iNPH patient. We believe this finding may imply that two-layer sign represents an acute exaggerated stage based on a rapid and near total recovery in our patient; while cortical hypoperfusion could probably be a representative of preclinical or decompensated stage of iNPH. Informed consent to publish had been obtained from the patient.

Introduction:
The correlation between intra-cranial pressure (ICP) and superior sagittal sinus pressure (SSSP) has not been clearly defined in humans. At this single centre, patients with idiopathic intracranial hypertension (IIH) are investigated with 24-h ICP monitoring (ICPM) and, if there is a known sinus stenosis, catheter venography and manometry. We aim to determine the relationship of the 24-h ICPM values with SSSP. Methods: Single centre cohort of IIH patients (2010-2016) who underwent both ICPM and a single catheter manometry (under local anaesthetic) measurement of SSSP. The relationship between ICPM and SSSP, linear and nonlinear regression models were tested to compare best-fit of the data. Goodness of fit was determined by R 2 and fits were compared with F test. Results: Twenty-two patients with IIH (21 F: 1 M), mean age 36.0 ± 9.41 years (mean ± SD). The ICPM was 10.01 ± 3.40 mmHg and SSSP was 28.4 ± 9.57 mmHg. The best-fit line of ICPM and SSSP was a sigmoidal curve (R 2 = 0.67, p < 0.04), with the least-fit being linear (R 2 = 0.52, p < 0.05). Patients with ICPM 5-10 mmHg had a stable SSSP of 21 mmHg. Patients with ICPM > 13 mmHg had a mean SSSP of 37 mmHg, but with far greater variability (range 29-51 mmHg). Conclusions: Our results suggest a non-linear relationship between ICP and SSSP. There appears to be a window of ICP (10-13 mmHg) in which SSSP increases rapidly with ICP. SSSP was relatively stable when ICP was between 5 and 10 mmHg. Further research is needed to define the correlation between SSSP and ICP.
Introduction: Ventriculomegaly in the absence of raised intracranial pressure (ICP) is a known entity in adult hydrocephalus practice. The natural history is however, poorly defined. We aim to elucidate the typical demographics, characteristics and outcomes in chronic adult hydrocephalus. Methods: Cluster analysis of adults with ventriculomegaly in the absence of clinical and radiological features of raised ICP (December 2012-May 2016). Records were reviewed to determine symptoms, interventions, Evan's index, ICP monitoring and outcomes. Hierarchical agglomerative clustering with complete linkage was applied. Results: 79 patients (43 F: 36 M) with follow up 69.7 ± 42.4 months (mean ± SD). Four significantly different patient clusters with common features were identified (p < 0.005). Results are presented as: n, mean age, mean Evan's Index, predominant symptoms, median ICP (mmHg) respectively. (A) Incidental ventriculomegaly: n = 17, 39.8 years, 0.45, predominately asymptomatic, brain imaging for unrelated indication, 3.1 mmHg. (B) Decompensated hydrocephalus: n = 18, 48.3 years, 0.47, headache, GCS deterioration, cognitive issues, 14.0 mmHg.
(C) Early presenting: n = 20, 28.9 years, 0.55, headache, gait, seizures and cognitive decline, 4.0 mmHg, abnormal pulsatility commonly observed on 24-h ICP monitoring. (D) Late presenting: n = 24, 51.6 years, 0.51, headache, cognition, gait, incontinence, 1.71 mmHg. Cerebrospinal fluid (CSF) diversion resulted in symptomatic improvement in 70% and over-drainage complications in 4% in groups B-D. Endoscopic third ventriculostomy (ETV) had a high failure rate of 50% of those performed in group C (during adolescence) being later converted to shunts. Conclusions: We describe four distinct sub-types of chronic ventriculomegaly, discovered using an un-biased cluster algorithm. These phenotypes have characteristic demographics, symptoms, ICP results and outcomes. Introduction: The relationship between intracranial pulse amplitude (AMP) and mean ICP has been previously described; generally stating that AMP increases proportionally to rise in ICP. Such an increase in AMP can be observed particularly often (but not exclusively), if the rise in ICP is provoked by controlled CSF volume increase during the infusion test. We studied lower breakpoint (LB) of amplitude-pressure relationship below which pulse amplitude stays constant when ICP varies. Theoretically, below this breakpoint, the pressure-volume relationship is linear (good compensatory reserve) and above-exponential (brain compliance decreasing with rising ICP). Methods: 169 infusion tests performed in patients diagnosed for NPH (2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013) were available for analysis. Inclusion criteria: patients have been shunted and response to shunting was assessed in followup clinic; raw data of ICP digital recording (ICM+ software) were available for post hoc processing. Results: Lower breakpoint was observed in 62 patients diagnosed for NPH. Improvement in patients in whom LB was recorded was 77% versus 90% in patients where LB was not recorded (p < 0.02). In patients with detected LB, the difference between baseline ICP and LB was greater in patients who improved (improved: 4.1 ± 2.1 mmHg versus not-improved: 1.2 ± 2.7 mmHg; p < 0.02). There was no correlation between improvement and slope of amplitude-pressure characteristic above LB. Conclusions: The presence of lower breakpoint is associated with less frequent improvement after shunting in NPH. It may be interpreted that CSF dynamics of patients working on flat (linear) part of pressurevolume curve, are more frequently caused by brain atrophy and this is the component less remediable with shunting. static and pulsatile pressures have been tested simultaneously in Pressio ® 2 and Codman transducers using a standard laboratory rig. Connectivity of the systems was also assessed. Results: Long term (10 days) zero drift was less than 2 mmHg in both transducers. Temperature drift of Pressio ® 2 was low (0.2 mmHg per 20 °C). The frequency bandwidth of the Pressio ® 2 was 20 Hz (relative to Codman transducer). Absolute static accuracy of Pressio ® 2 was better than 2 mmHg over the range from − 30 to 120 mm Hg. Pulse waveform accuracy (relative to Codman) was better than 0.2 mmHg over the range from 1 to 20 mmHg. The frequency bandwidth of the Pressio ® 2 was 17 Hz (relative to Codman transducer). Temperature drift of Pressio ® 2 was low (0.2 mmHg per 20 °C). Pressio ® 2 ICP Monitor can transmit data directly to external computer without use of pressure transducer bridge amplifier with the resolution of 0.1 mmHg. It is 'ICM+' compatible. Conclusions: The new Pressio ® 2 ICP Monitor has good accuracy, low zero and temperature drift and excellent frequency properties. The monitor is comparable with Codman Express Monitor and may be, from metrological point of view, used as an alternative in clinical ICP monitoring. Introduction: The absence of spontaneous retinal venous pulsation (SVP) is believed to be an indirect sign of raised intracranial pressure (ICP) and therefore it could represent a useful tool for non-invasive assessment of ICP in patients with disturbances of CSF dynamics. We present the results of a single centre pilot study on the correlation between ICP and SVP. Methods: This is a prospective single centre study. All patients having continuous ICP monitoring who underwent neuro-ophthalmology examination were included. An SVP assessment via both fundoscopy and Spectralis OCT scanner was performed. The Spectralis OCT video recordings were assessed by two experienced neuro-ophthalmologists who were blinded to the ICP monitoring results, and the SVP was graded 0 (absent) to 3 (collapse). Results: Twenty-five consecutive patients (5 M:20F, mean age 40, range 17-72) were selected. On review of the OCT video recordings, 16 patients had bilateral SVP (grade ≥ 1). Two patients had unilateral SVP only and 3 had no SVP bilaterally. Bilateral absence of SVP has a 100% sensitivity and a specificity for 24 h median ICP ≥ 8.5 mmHg. Conclusions: Our preliminary data suggest that absence of SVP is a good indirect sign of raised median ICP. Larger prospective studies will be needed to confirm these results. Introduction: Spontaneous intracranial hypotension (SIH) is a syndrome due to a spontaneous leak of CSF from the spine. Despite many patients can improve with simple medical therapies or with epidural blood patches (EBP), numerous patients fail to respond to the above treatments and represent a great challenge for neurologists and neurosurgeons involved in their care. With our systematic review we describe the clinical and radiological presentation of this syndrome and analyze the treatment outcomes.
Methods: This is a PRISMA statement compliant systematic review of the literature. Only original studies in English language with at least 10 patients were included in this review. Results: 118 papers were selected according to the inclusion criteria. This review includes a population of 3955 patients with a mean age of 43.7 years, 37.4% male. The most common symptoms were: orthostatic headache (91%), Nausea/vomiting (38%), Neck pain/stiffness (18%) and hearing disturbances (16.1%). The most common sign on brain MRI with contrast was the typical diffuse pachymeningeal enhancement (63%). 5% of the patients had a completely normal brain MRI. Of the 722 patients with a reported lumbar puncture 63% had a low CSF opening pressure (below 60 mmH2). Only 18% of the patients improved with medical treatment, 79% underwent EBP and of these 69% improved after the first EBP. 4% had surgical treatment. Conclusions: Spontaneous intracranial hypotension (SIH) is a clinical entity with ill-defined intracranial pressure definition. Intracranial pressure monitoring should be considered in patients with atypical clinical presentation and failure to respond to EBP. Introduction: Adjustable valve settings are often modified in order to achieve symptomatic improvement in patients with CSF dynamic disturbances. The common knowledge is that increasing the opening pressure of a valve is likely to result in an increase of the intracranial pressure (ICP), however this has not been verified in vivo. We hereby show the results of such analysis in a cohort of patients with shunts undergoing continuous ICP monitoring in our centre. Methods: Retrospective review of prospectively built ICP monitor database. Patients admitted to our hospital for continuous ICP monitoring having at least one valve adjustment during their monitoring were selected. Demographics, clinical details, valve details, CT scans and ICP results were analysed. Results: Forty-three patients having a total of 78 valve setting adjustments during their continuous ICP monitoring were selected (mean age 39, 12 M). Increasing the valve setting resulted in a decrease of the median ICP in 33.3% of the cases (Mean ICP change of paradoxical response cases − 1.7 mmHg ± 1.14). Similarly reducing the valve setting resulted in an increase of the median ICP in 26.5% of the cases (Mean ICP change of paradoxical response cases 2.84 mmHg ± 2.8). Most people with paradoxical change had small ventricles on CT scan. Conclusions: Paradoxical change in ICP following adjustable valve setting change happens in a significant proportion of cases and this might have significant implications on clinical management of patients with CSF dynamic disturbances. Fluids Barriers CNS 2018, 15(Suppl 1):4 drainage hole. The goal of this device is to either flush out the proximal occlusions, or open a new hole in the VC to resume shunt flow. Methods: We first quantified occluded-VC flushing volumes and pressures using a syringe attached to an in-line pressure sensor in patients undergoing shunt-revision. Using the data, the Flusher and VC was developed. During following investigations, The Flusher was primed with sterile saline, then attached to an in-line pressure sensor connected to an implanted occluded-VC. The Flusher dome was pressed and a controlled retrograde pulse of fluid was delivered to the proximal tip of the VC. Flow and pressure data were collected, the patient then underwent routine shunt revision. Results: The Flusher successfully increased flow through 2 out of 4 occluded-VCs. In the VCs that did not resume flow, the pressure data indicated that the new drainage hole would have been opened had it been the new VC design. Conclusion: The Flusher demonstrated its ability to flush and increase flow in a non-flowing VC. The pressure measurements indicated that the new drainage hole would have opened had it been the new VC design. Introduction: Waiting time for shunt surgery at our department for patients with idiopathic normal pressure hydrocephalus (iNPH) can be up to 6 months. Andrén et al. reported that patients with iNPH deteriorate over time and that the deterioration is only partially reversible after shunt surgery. The purpose of this study was to investigate if the previously reported deterioration in clinical symptoms over time is applicable also in our patients. Methods: Gait velocity in 37 patients with iNPH was measured, using a 10-m walk test in self-chosen speed, at baseline, preoperatively (the day before surgery) and 3 months postoperatively. Median time between baseline and preoperative investigation was 6 months and between preoperative and postoperative investigation 3 months. Results: There was a significant deterioration in gait velocity between baseline and preoperative investigation from 0.66 m/s (95% CI 0.59-0.74) to 0.57 m/s (95% CI 0.49-0.65), p < 0.01. Gait velocity increased from preoperative to postoperative investigation 0.71 m/s (95% CI 0.62-0.81), p < 0.001. There was no significant difference between baseline and postoperative investigation. Conclusions: Gait function deteriorates over time in patients with iNPH. If waiting time for surgery for iNPH is long, progress of lost function may not reverse after shunt surgery. An assessment of NPH symptoms should be performed immediately preoperative for an accurate interpretation of postoperative improvement. Introduction: The shunt is accepted as an effective treatment for INPH and the shunt explicitly modifies the CSF dynamic. High Rout, high ICP amplitudes and elevated ICP, have shown good positive predictive values to select patients for shunt surgery, but not for exclusion of a patient from shunting. This indicates that the CSF dynamic disturbance is important, but that it is too complex to make single parameters reliable in patient selection for surgery. To make a holistic approach that includes multiple parameters we propose a CSF Dynamic Disturbance Scale (CSFDDS) that reflects the degree of disturbance of the system. Methods: We analysed forty-seven patients with suspected INPH that were successfully investigated with an infusion protocol using the CELDA ® infusion apparatus. The CSFDDS was defined based on Rout (0-3p), mean ICP (0-2p), ICP amplitude (0-3p) and ICP in sitting position (0-2p). Possible range 0-10p. Results: In this preliminary analysis CSFDDS varied between 0 and 9 with a mean score of 3.6 ± 2.3. Twenty-three patients were selected for shunting mean CSFDDS = 4.7 ± 2.3 compared to 2.6 ± 1.8 for the nonshunted group (p = 0.001 for the difference). Discussion: Few patients were in the upper interval of the CSFDDS, indicating that the thresholds should be lowered. The scale provided a summary of the degree of CSF dynamic disturbance, and it has potential to provide the clinician with an easily interpreted number to support the diagnosis and selection for shunting. Possible CSF dynamic parameters to add to the scale are compliance, aqueductal CSF flow and potential to reduce the ICP pulse-amplitude with shunting. Introduction: Extra cranial CSF shunts are more effective for treating non-communicating hydrocephalus in patients below the age of 1 year due to high failure rates of Endoscopic third ventriculostomy (ETV). This study determine the success rate of ETV in patients older than 1 year presenting with mechanical shunt malfunction who were shunted below 1 year of age, and evaluate different factors which determine the success rate. Methods: Thirty patients, from July 2015 to October 2016, 16 M: 14 F, aged 1-25 years (mean 9.1 years) Grouped A 1-2 years (n4), B 2-8 years (n13) and C older than 8 (n13), were clinically and radiologically assessed pre-ETV and post ETV immediately and at 1, 2 and 4 months for hydrocephalus and patency of the ventriculostomy. Results: Twenty one cases (70%) benefited from the ETV; 50% (n2) of Group A, 54% (n7) of Group B and 92% (nn12) of Group C. The mean age of successful ETV was 11 years and the failed ETV was 4.7 years. Shunted period ranged 9 months to 24 years and the mean period in successful ETV was 10 years and in failed ETV was 3.5 years. The shunt was removed in 16 case (13 success 53%) and legated and left in 2 (1 success 50%) and left untouched in 12 (7 success 30%). The mean follow up period for successful ETV was 10.5 months. Conclusions: Endoscopic third ventriculostomy is a safe and effective procedure in treating hydrocephalus in patients older than 1 year presenting with mechanical shunt malfunction, in whom shunt was implanted below the age of 1 year due to non-communicating hydrocephalus. Introduction: Volumetric evaluation of the subarachnoid space is important in various cerebrospinal fluid disorders. The task is complicated and tedious for manual raters and prone to rater bias. An additional complexity is the identification of an appropriate cortical label to parcellate the volumetric information into clinically relevant quantities. Here we present a novel approach to automatically identify and parcellate the subarachnoid space. Methods: We present a deformable model based approach that propagates an estimate of the pial surface outwards using image based forces from T1-and T2-weighted magnetic resonance (MR) acquisitions. The deformable surface also carries with it one of the 100+ Neuromorphometrics' labels from the cortical mantel. Using this approach, we are able to construct thicknes s maps of the subarachnoid space with detailed cortical labels. Results: We present subarachnoid thickness maps on a cohort comprising healthy controls and normal pressure hydrocephalus (NPH) patients. The thickness map in conjunction with the automated parcellation of the subarachnoid space demonstrates the power of the method to identify patient specific regions of change. Conclusions: Developing methods for automated neuroimage processing is an important step for expediting the clinical evaluation of patients. Clinical observations, such as disproportionally enlarged subarachnoid space in NPH, are often challenging to identify by looking at stacks of two dimensional MR images. Our method enables quantification of the subarachnoid space that could help clinicians identify specific regions of enlargements and associations with possible bottlenecks in the path of CSF flow.

A42
Introduction: There remains controversy over normal values of intracranial pressure (ICP). Papilloedema is a clinical manifestation of chronically raised ICP, often seen in idiopathic intracranial hypertension (IIH). Therefore, papilloedema may be useful for establishing normal ICP thresholds. Here we aim to compare ICP values in IIH patients who developed papilloedema and those who did not. Methods: Single centre cohort of IIH patients (2006-2016) who underwent 24-h ICP monitoring (ICPM) and ophthalmology assessments, prior to intervention. Papilloedema was graded according to the Frisén scale. An un-paired t-test compared 24-h ICPM between papilloedema and no-papilloedema groups. Fisher's exact test was used to determine predictive value of ICP. Results: 36 patients with IIH (35 F: 1 M), mean age 32.5 ± 9.49 years. Of the 25 patients with papilloedema, 6 had early disc abnormalities, 12 moderate papilloedema, 3 severe papilloedema and 4 had no grading recorded. 11 patients had no papilloedema. Patients with papilloedema had a mean median 24-h ICP of 10.4 ± 5.32 mmHg, significantly higher than the group without papilloedema (6.31 ± 3.30 mmHg) (p < 0.05). Using 24-h median ICP of 10 mmHg as a minimum cut-off predictive value, specificity = 91%, sensitivity = 48%, PPV = 92% and NPV = 44%. Conclusions: Our results suggest that a 24-h ICP of 10 mmHg or more is a good predictor for papilloedema and reflects a pathological threshold. The range varied widely suggesting papilloedema can occur at even lower pressures. These results are consistent with emerging evidence suggest that pathologically 'high' ICP is much lower than previously quoted.
Introduction: Tinnitus is a symptom commonly associated with idiopathic intracranial hypertension (IIH) and can impair quality of life. We aim to (1) determine if tinnitus correlates with intra-cranial pressure (ICP) and (2) determine symptom response after dural venous sinus stenting (DVSS) or CSF diversion with a shunt. Methods: Single centre cohort of IIH patients (2006-2016) who underwent 24-h ICP monitoring (ICPM). An un-paired t-test compared ICP and pulse amplitude (PA) values between (1) patients with and without tinnitus, and (2) patients with pulsatile tinnitus (PT) vs. subjective tinnitus (ST). Results: We identified 59 patients with IIH (56F: 3 M), mean age 39.5 ± 11.1 years, 14 of whom suffered from tinnitus. Of these 14, seven reported PT and seven reported 'ringing' , 'humming' or 'clicking' sounds (ST). Patients with tinnitus had a mean 24-h ICP and PA of 9.09 ± 5.25 and 6.05 ± 1.07 mmHg respectively. There was no significant difference in ICP nor PA between patients with tinnitus and without (p = 0.84), nor between PT vs. ST (p = 0.20). All 7 patients with PT showed symptom improvement or resolution after DVSS (n = 4), secondary DVSS (n = 2) or Shunting (n = 1). Of the 7 with ST, only 1 improved post intervention (DVSS), despite 2 patients having shunts and 5 having DVSS.
Conclusions: DVSS appears to be an effective management option for IIH patients with a clear history of pulsatile tinnitus. However, subjective tinnitus was more persistent and did not respond well to either DVSS or CSF diversion. Introduction: The lumbar puncture tap test (TT) is regularly utilised to identify shunt responsive iNPH. Testing regimes aim to identify change in function but vary significantly. This study aimed to determine if a battery of upper limb and cognitive outcome measures can identify change in iNPH patients undergoing a TT. Methods: Prospective cohort study of 74 patients undergoing a TT diagnosed with iNPH. Patients performed the Timed up and go cognition test (TUG-C), 9-hole peg test, and Montreal Cognitive Assessment (MoCA) before and after a TT. A Neurologist determined response status, patients who improved were labelled as responders. Sign-rank tests were used to analyse between groups differences. Results: Forty patients were categorised as responders, 34 nonresponders. For responders, the median change in the TUG-C (− 6.02 s p < 0.01) and MoCA (0.62 points p = 0.02) was significant. Only executive function and orientation sub scores of the MoCA showed significant change (1 point each, p = 0.03). The median 9 hole peg test change (4.33 s p = 0.14) was not significant. For nonresponders changes of 0.22 points for the MoCA (p = 0.51), 0.3 s for TUG-C (p = 0.63) and 2.58 s for the 9 hole peg test (p = 0.51) were not significant.

Conclusions:
The TUG-C can identify change following a TT and should be considered for use. Change on the MoCA, of less than 1 point, cannot be considered clinically significant. Further investigation is required regarding the ability of sub scores of the MoCA to identify change. The 9-hole peg test cannot identify change and cannot be recommended. test before and after a TT. The minimum detectable change (MDC) score for the TUG was used as the cut off value. Sign-rank tests were used to evaluate between groups differences. Results: 17 patients improved on the TUG, 27 did not improve. Significant between group differences were found for (no improvement vs. improved): sagittal sinus circumference (26.60 mm vs. 24.89 mm p < 0.01), sagittal sinus area (41.6 mm 2 vs. 34.4 mm 2 p < 0.01), sagittal sinus stroke volume (225 µl vs. 172 µl p = 0.04) and superior sagittal sinus flow percentage (47.77% vs. 38.83% p = 0.03). No differences were present for aqueduct stroke volume (140 µl vs. 140 µl p = 0.57), aqueduct net flow (0.002 ml/s vs. 0.08 ml/s p = 0.21), arterial inflow (8.29 ml/s vs. 9.31 ml/s p = 0.21) or compliance ratio (7.94 vs. 12.71 p = 0.45) Conclusions: A link between improvement in gait symptoms and sagittal sinus measurements indicates that the sagittal sinus may play a role in the manifestation of symptoms in iNPH. This may also have a role in diagnosis of iNPH. Further research is required to confirm the significance of these findings. Introduction: Epidemiological data on Normal Pressure Hydrocephalus is limited, because for the most part, knowledge is derived from indirect estimates and studies not designed specifically for this purpose. From this, incidence and prevalence data representative of the Latin American population is near null, and inexistent for our Country, so our main objective was to calculate the prevalence of NPH in Colombia. Methods: Prevalence was calculated for 7 of the Country's cities, chosen based on the number of Neurosurgical specialists in each. We used a nationwide database from the health regulation institution (SISPRO) to extract the number of cases, from 2009 to 2015, and population census information from the relevant institution (DANE). Diagnosis was established using the ICD-10 code for NPH. Overall prevalence and point prevalence for each year was calculated, standardising by age, sex and income based on health insurance regimen. Results: Total prevalence was 0.01%. It increased from 2009 to 2011 but was relatively constant in the ensuing years. Prevalence was 0.0104% for women and 0.0127% for men, and increased with age for both men and women. 73.03% of cases were seen in the middle-tohigh-income group of patients. Most were in men, even though the ratio to women varied widely Conclusions: We believe NPH prevalence is underestimated and plan to design a programme to educate upon the usage of the specific diagnostic ICD-10 code, with subsequent revaluation, as we have reason to believe its use is not generalised amongst the members of the specialty. Introduction: The Tap test has been a fundamental pillar in the diagnosis of Normal Pressure Hydrocephalus from its first description as an independent entity, and is based on the existent relationship between a positive test result and subsequent clinical improvement in the three principal manifestations of the pathology; The latter, an aspect that has been objectivised in distinct manners with the passing of time. It has been stated that the volume of CSF fluid to be extracted during the test should be between 30 and 50 cc, even though there is no explanation as to why this should be the quantity. Therefore, in our institution, we have established a practise whereby the volume of fluid extracted is based on a CSF closing pressure of 0 cm H 2 O. We are seeking to describe our experience and propose that this parameter be set as a standard in Tap test performance. Methods: A retrospective descriptive multivariate analysis, using data obtained between 2005 and 2015 from our institution, is to be carried out. Results: We have seen that an augmented Tap test sensitivity in comparison to what has been previously reported is appreciated. Conclusions: Our experience suggests that the drainage of CSF based on a pressure of 0 cm H 2 O at the time of closure increases the likelihood of a positive result for NPH. Drainage parameters can be standardised as well as individualised, by a closing pressure-guided Tap test. Introduction: Both sleep apnea syndrome (SAS) and normal pressure hydrocephalus (NPH) are responsible for falls, cognitive impairment, and urinary urgencies in elderly. Association of these conditions has been described. Our goal is to evaluate the prevalence of SAS in patients suspected of NPH. Methods: Tertiary reference center for hydrocephalus. Since 08/2015 we added to NPH evaluation one night breathing recording using a portable device (Apnealink@). Presenting symptoms were gait disorders and/or urinary incontinence and/or cognitive dysfunction, and ventriculomegaly (Evans' index > 0.3). Sleeping respiratory events were quoted using the 2012 American Academy of Sleep Medicine criteria. Clinical evaluation was based on the European iNPH scale. Decision whether shunting or not was based on symptoms, MRI findings, lumbar tap test, and lumbar CSF infusion test. When appropriate, patients were offered ventriculo-atrial shunting using a programmable valve. Improvement was defined as an increase ≥ 5 on iNPH scale.

Conclusions:
The prevalence of SAS is high among patients investigated for possible NPH. Introduction: It has been observed that some patients with idiopathic normal pressure hydrocephalus (iNPH) experience that the post-operative result is not what they expected and they experience deterioration at postoperative follow-up even though standardized tests show improvement. It has also been observed that rehabilitation possibilities for patients varies, ranging from structured rehabilitation periods, e.g. at geriatric rehabilitation units to basically no rehabilitation at all. The aim of this study was to describe the expectations patients with iNPH have on shunt treatment and how they view their own role in the rehabilitation process. Methods: A qualitative, descriptive design with manifest and inductive approach. Seven patients with iNPH were interviewed preoperatively using a semi-structured approach. Results: The informant's main expectations on shunt treatment, concerned improvements in gait, continence, cognition and a desire to become more autonomous. The informants expressed a personal responsibility for the rehabilitation process and suggested what they could contribute with in the process but also different obstacles for performing physical activities were described. Conclusions: The patient's expectations of outcome after shunt treatment should be discussed with the patient and their relatives prior to shunt surgery. The rehabilitation process needs to be discussed with the patient both pre-and postoperative in order to optimize outcome. Introduction: The main treatment of hydrocephalus is surgical diversion of CSF from the cerebral ventricles, commonly to the peritoneal cavity (ventriculo-peritoneal (VP) shunt) using a shunt. One of the major challenges in managing hydrocephalus stems from the fact that 40-60% of shunts fail within the first 2 years. In adults, 80-90% of those failures are due to peritoneal catheter malfunction. In many cases, significant intra-abdominal adhesions or scarring contributes to shunt failure. An alternative approach is to divert CSF flow to the right atrium (i.e. a ventriculo-atrial (VA) shunt). Methods: A prospective adult patient shunt outcome registry was established in January 2012 and concurrent patients enrolled. Distal shunt malfunction was confirmed by: (1) clinical deterioration in symptom control, and (2) abnormal structural or functional findings in CT/MRI scan, nuclear medicine shunt study or shunt X-ray. In April 2015, a laparoscopy-guided approach to place the distal catheter under direct visualization over the dome of the liver was initiated to attempt a reduction in distal catheter failure rates. All laparoscopically treated patients were prospectively graded regarding severity of intra-abdominal adhesions, and considered for conversion to a VA shunt after shunt failure in the presence of previously noted significant intra-abdominal adhesions. Results: We have treated 222 adult patients for hydrocephalus of different etiologies with 177 patients having a new shunt insertion (VPSI) and 51 patients presenting with an established VP shunt and in need of a shunt revision (VPSR). A total of 135 patients underwent laparoscopic-guided distal catheter placement (88 VPSI: 45 VPSR). 11 patients underwent VP to VA shunt conversion after VP shunt failures associated with significant intraabdominal adhesions. The first seven patients had surgery with fluoroscopic guidance. Patient number 7 had incorrect placement of the atrial catheter in the superior vena cava (SVC) with shunt malfunction. Transesophageal ECHO was used in the VA shunt revision of patient number 7 and the remaining three patients, all with reliable placement of the tip of the catheter 1.5-2.0 cm into the right atrium. There were no surgical complications in the VA shunt patients. Conclusions: VA shunts are a viable alternative to VP shunts for the treatment of adult patients with hydrocephalus, especially in patients with significant abdominal adhesions which affect VP shunt viability. Transesophageal ECHO is an eloquent and accurate technique that is an alternative to use of fluoroscopy to confirm position of the atrial catheter. We developed a CSF shunt SSI Prevention Bundle (SSIPB) with a 9-point checklist as a quality improvement initiative and evaluated it post-implementation. No antibiotic-impregnated catheters were used. Methods: A prospective surveillance system for SRSSI was designed based upon the CNISP protocol. Inclusion criteria included insertion or revision of any ventriculoperitoneal (VP), ventriculoatrial (VA), or lumboperitoneal (LP) shunts and exclusion criteria included patients with transcutaneous or external shunting devices or non-shunting devices, patients whose CSF was culture-positive at the time of shunt placement and if the surgery occurred > 12 months before the infection was identified. A shunt SSI was defined as having a microbe isolated from the CSF with a shunt in situ and associated with at least one of: fever (≥ 38 °C); neurological signs or symptoms; abdominal signs or symptoms or; signs or symptoms of shunt malfunction/obstruction. Denominator data was provided via an Operating Room database. Data quality measures included discussing difficult cases with an ID physician, the surveillance team and a neurosurgeon. A SSIPB with a 9-point checklist addressing pre-, peri-and post-operative care was developed by Neurosurgery and Infection Prevention and Control (IPC) and then evaluated using an uncontrolled before-after design. Differences were assessed using a x 2 or Fisher exact test as appropriate. Results: The implementation of the bundle occurred over a 24 month period to ensure a full culture change. Comparing the before-after periods of 2012-Q32015 vs. Q42015-total rates of SRSSI of 17/431 (3.94%) vs. 1/160 (0.63%) were noted (p = 0.055, two tailed). Insertion rate SRSSIs for 2012-Q32015 vs. Q42015-2016 were 12/205 (5.9%) vs. 0/66 (p = 0.04, two-tailed). Checklist compliance was completed for all procedures which allows for secondary analysis and remediation. Conclusions: We observed a 6.3-fold reduction overall and a statistically significant decrease of SRSSIs for primary shunt insertions post-implementation of a shunt SSIPB without the use of antibioticimpregnated catheters. Achieving compliance with the OR checklist was challenging; however, it has achieved significant improvements in an operative setting where SSIs are associated with high morbidity. Introduction: DESH is a powerful image marker in preoperative diagnosis of iNPH, and in the cases with DESH, postoperative improvement can be highly expected. On the other hand, their long term outcomes are not always good. Long-term outcomes were examined for definite i-NPH cases experienced by the authors. Methods: Of the cases that showed postoperative improvement, 40 cases who had been pursued for more than 1 year were investigated. Results: 2 cases were deliberately shunt removed, 4 cases died during the course, and 34 cases had continued to be shunted. The average follow-up periods of 34 patients with shunt continuation was 33.4 months. Of 34 patients, 19 cases maintained improvement, and 15 cases went backward to preoperative level or worsened. Investigation for clinical factors related to long-term outcome showed that the existence of comorbidities and termination of direct follow up were statistically significant. Main reasons for deterioration were occurrences of new problems due to exacerbations of comorbidities. Terminations of direct follow-up were mainly caused by deterioration of symptoms and entrance to the facility, but difficulty in going to the hospital due to the transfer of the doctor in charge was also one of the reasons. Conclusions: Although the presence of DESH is related to improvement immediately after surgery, the existence of comorbidities is greatly related to deterioration of long-term performance. Also, termination of direct follow-up possibly may promote deterioration in performance. Therefore, if follow-up is interrupted according to the circumstances of the doctor, it is necessary to introduce to the doctor who understands i-NPH well. Introduction: INPH is characterized by unexplained ventriculomegaly and often with increased pulsatility. We hypothesize that the cardiacrelated pulsatile flow over the cerebral aqueduct (CA), with fast systolic outflow and slow diastolic inflow, can generate net pressure effects that could source ventriculomegaly in INPH. Our hypothesis predicts a cardiac cycle averaged net pressure difference (P DIFF ) over the CA, with higher average pressure in the lateral and third ventricles. The aim of this study was to investigate these potential pressure differences arising from the nonsymmetrical CA flow in INPH.
Methods: The hypothesis is tested using (1)  For (1) typical pulsatile aqueductal flows found in healthy and INPH patients were applied to the bench aqueduct model and P DIFF was measured. For (2) we will make use of computational fluid dynamics (CFD) to calculate the pressure distributions (over the CA), based on structural MRI (area) and 2D-PCMRI (velocity) data.

Results:
The bench-test/aqueductal model verified a net P DIFF over the cardiac cycle, in the caudal direction. The effect was magnified for flow in INPH compared to flow in healthy (P DIFF : 0.18 vs. 0.04 mmHg, p < 0.01). The CFD-simulations, using the MRI-measurements, are currently under analysis and will be presented at the conference.

Conclusions:
The experimental bench-test data supported that ventriculomegaly in INPH could be caused by pressure differences introduced during each heartbeat over the CA. Identifying the cause of the ventricular enlargement will have implications for diagnosis and selection of treatment. Introduction: In hydrocephalus an important pathophysiological factor is ICP. Its regulation is primarily understood and measured in the supine position, despite patients mostly being upright and shunt over-drainage being a common complication. To fill this gap we have suggested a model, based on Davson's equation for CSF absorption, where postural ICP changes depend on hydrostatic effects in the venous system and collapse of the internal jugular veins (IJVs). The aim of this study was to investigate this relationship by simultaneous invasive measurements of ICP, venous pressure and IJV collapse in healthy volunteers. Methods: ICP (monitored via the lumbar route), central venous pressure (PICC-line) and IJV collapse (ultrasound) were assessed in eleven healthy volunteers (47 ± 10 years) in seven positions of upper-body tilt, going from supine to sitting. Hydrostatic distances were measured to adjust the pressures to the ICP reference point (auditory canal). Venous pressure and IJV collapse were inputs to the ICP prediction. Predicted and measured ICP were compared for each tilt-angle. Results: The model accurately predicted the general behavior of ICP (mean difference for all tilt-angles: 0.8 ± 3.0 mmHg, p > 0.21 for each tilt-angle), although individual variations were observed.

Conclusions:
The results support that postural ICP changes are governed by IJV collapse and venous hydrostatics. This new understanding of the ICP regulatory system in upright demands the exploration if its importance in diseases like INPH, and should be considered in the design of shunts. The results are also important for understanding the mechanisms behind head-elevation therapy of ICP in critically ill patients. Introduction: Idiopathic intracranial hypertension (IIH) is a yet not fully understood disease, which is more commonly encountered in obese, young age women. The presence of venous hypertension is often implicated as the pathophysiological origin of IIH, which is postulated to arise as a squeal to intracranial venous stenosis or intrathoracic origin (such as obesity and elevated central venous hypertension). Intracranial venous stenosis has been described in up to 90% of IIH patients. Recently, a case series examined the effect of conscious sedation (CS) and general anesthesia (GA) on endovascular venous pressure gradient measurements. Their results suggest that there is a sizable difference between measurements taken under CS and those under GA, which has an effect on the selection process of IIH patients by either overestimating or underestimating the pressure gradient. In this report, we aim to examine effect of GA of endovascular pressure gradient measurements in IIH patients as well as the decision to go on with stenting. Methods: We performed a retrospective chart review of all patients, who received endovascular transverse sinus stenting due to medical treatment refractory IIH between August 2013 and March 2017 in our institution was performed. Patients who received an endovascular venous pressure measurement during conscious sedation and under general anesthesia in the same setting were then identified. Chart analysis included: patients' demographics; anesthetic agents used in CS and GA; endovenous pressure measurements during CS, GA and after stent placement; stent type and size; and whether the decision to place the stent was revised based on the change in pressure measurements. The threshold for stenting was a pressure gradient across the transverse sinus stenosis of > 6 mm Hg. Results: We identified 12 patients who received endovascular pressure gradient measurements under CS and GA. All patients (100%) were female. The mean age was 30.7 years (SD 8.8 and rage 15-42) and the mean BMI was 40.7 (SD 10.1, range 28-63.7). Anesthetic agents used during CS were; midazolam, fentanyl and propofol and during GA; propofol and vapor anesthetic (Sevoflurane in 6 patients, Desflurane in 4 patients, and Isoflurane in 2 patients). Mean pressure gradient under CS was 21.7 mmHg (SD 8.5) and 15.8 mmHg (SD 7.9) under GA. Eight (66%) patients showed a pressure gradient reduction after initiation of GA (average 10 mmHg, range 1-20), 2 (18%) patients showed an increase of pressure gradient under GA (2 and 9 mmHg) and 2 (18%) patients had a stable gradient. Post-stenting the pressure gradient was successfully reduced to an average of 2.1 mmHg (SD 2.6). Conclusions: When performed in the same setting, endovascular pressure gradient across transverse stenosis in IIH patients performed under GA shows a sizable reduction (6 mmHg) compared with measurements taken under CS. Further studies are needed to examine the role anesthetic agents and different accompanying factors in regard to the optimal pressure gradient threshold for transverse sinus stenting in IIH patients. Introduction: The pathophysiology of iNPH is still unknown. However, there is evidence of comorbid vascular diseases. The familial occurrence of iNPH may be as high as 5-16% among Finnish elderly. The most common AD-related risk-loci do not seem to be overexpressed in iNPH. The copy number loss of SFMBT1 gene is the most potential identified genetic risk factor in iNPH among Japanese elderly. There is also a slight evidence that allelic variation of SFMBT1 gene may increase the risk of vascular diseases and diabetes potentially plausibly explaining vascular comorbidity in iNPH. We set out to investigate the copy number loss of SFMBT1 among Finnish patients with iNPH and their relatives. Methods: The study cohort consisted of 67 patients with shunt-operated iNPH and 96 relatives. The copy number loss was detected using quantitative-PCR. Results: The copy number loss in the intron 2 of the SMBT1 was identified in 10.8% of shunted iNPH patients and in 9.5% of relatives. No statistical difference was detected between the groups (p = 1).

Conclusions:
The copy number loss within intron 2 of SFMBT1 was less prevalent compared to Japan. This indicates there may be populational differences in genetics of familial iNPH. Heterogenic hypotheses and further genetic studies are needed to clarify the elusive familial aggregation and pathophysiology of iNPH. Introduction: Shunt-dependent hydrocephalus (SDHC) after aneurysmal subarachnoid hemorrhage (aSAH) is a common sequalae leading to poor neurological outcome, and predisposing to various interventions, admissions and complications. We evaluated the long-term outcome of shunted aSAH patients and the associated complications in a population-based setting. Methods: The Kuopio sIA Database includes all aSAH cases from the defined catchment population in Eastern Finland. Patients who underwent shunt surgery due to post-hemorrhagic hydrocephalus following aSAH between 1990 and 2012 were included. Medical charts, operative reports, imaging studies, and clinical follow-up evaluations were analyzed and patients were followed up till 31, December 2015. Results: From the total of 1850 aSAH patients, 275 aSAH patients with SDHC were included with a mean (SD) follow up time of 8 (7) years. The overall shunt complication rate was 33% over the followup period. Younger age (p = 0.007) and requirement of external ventricular drainage EVD (p = 0.042) during the index admission were associated with increased risk of shunt revision. The most used valve was fixed medium/high pressure (> 5 mmHg) one, fixed low pressure valves (≤ 5 mmHg) was used in 10% of cases, and valveless shunts were used in 5% of patients. Only 7% of valves were adjustable, but showing lower revision rates as compared to fixed setting valves (p = 0.042). The most common shunt complications were valve failure (13%), infection (8%), ventricular catheter obstruction (7%), with mean time to revision of 90 months (SD 33). Timing of shunting was not correlated with revision rates (p = 0.806) or with infection rates (p = 0.993). Instead, patients that underwent a shunt revision had higher risk of multiple revisions if they received their first shunt very early following the aSAH (p = 0.039). Conclusion: Long-term outcomes of shunt surgery and its complications in aSAH patient can be under-reported in a non-population based setting. Our study identified the incidence of shunt complications, also studied potential independent risk factors for complications. Age and initial requirement of EVD were associated with higher revision risk, whereas shunted aSAH patients with adjustable valve had lower risk of shunt revision in our cohort. Introduction: The pathophysiology of IIH is still unclear and no single theory fully explains the development of the raised intracranial pressure (ICP) causing the condition and resulting in headache, papilledema and vision loss. Disturbed cerebrospinal fluid (CSF) hydrodynamics affecting ICP have been suggested to affect the pathogenesis. We aim to characterize the ICP dynamics of IIH to investigate how these are affected by the disease and treatment. Methods: To define a post-treatment group (attempted weight loss and medication for at least 3 months), 35 patients diagnosed with IIH and admitted from a defined catchment area between January 1, 2000 and December 31, 2016 were reviewed. Enrollment of pre-treatment subjects, i.e. patients that receive a new diagnosis of IIH, is on-going. All demographic, clinical, medical charts and imaging findings are recorded. ICP and indicators of CSF dynamics, including ICP pulse amplitude and RAP, are calculated based on pressure measurements with a CELDA ® infusion apparatus. Volumetric analysis of white and gray matter and CSF has been performed for a subset of subject. Results: 11 subjects that had been investigated with CELDA posttreatment were included. In the pre-treatment group, 4 CELDA investigations have been completed. Preliminary results will be presented.

Conclusions:
We hope that the results will support the hypothesis that IIH patients have increased water content of grey matter and reduced intracranial compliance and that after treatment this improves.

Introduction:
Hydrocephalus is a chronic disease with multiple etiologies presenting at varying ages from birth to old age. The main treatment of hydrocephalus is surgical diversion of CSF from the cerebral ventricles, commonly to the peritoneal cavity using a shunt. One of the major challenges in managing hydrocephalus stems from the fact that 40-60% of shunts fail within the first 2 years. In adults, 80-90% of those failures are due to peritoneal catheter malfunction. Methods: A prospective adult patient shunt outcome registry was established in January 2012 and concurrent patients enrolled. Distal shunt malfunction was confirmed by: (1) clinical deterioration in symptom control, and (2) abnormal structural or functional findings in CT/MRI scan, nuclear medicine shunt study or shunt X-ray. In April 2015, a laparoscopy-guided approach to place the distal catheter under direct visualization over the dome of the liver was initiated to attempt a reduction in distal catheter failure rates. We performed a retrospective analysis of all adult patients who underwent ventrioculoperitoneal shunt insertion (VPSI) or revision (VPSR) at the FMC from January 2012 to May 2017. Fluids Barriers CNS 2018, 15(Suppl 1):4 Results: We have treated 222 adult patients for hydrocephalus of different etiologies with 177 patients having a new shunt insertions (VPSI) and 51 patients presenting with an established VP shunt and in need of a shunt revision (VPSR). A total of 177 VPSI and 91 VPSR occurred. There were 268 surgeries: 135 with laparoscopic-guided distal catheter placement (88 VPSI; 45 VPSR), and 114 with the standard surgical approach. Patients undergoing the standard surgical technique had 46.5% shunt failure at 752 days (55.4% failure at 1685 days), while patients undergoing the laparoscopic surgical technique had 27% shunt failure at 747 days. The laparoscopic surgical technique resulted in significantly lower VPSI failure rates at 2 year followup (p = 0.046 logrank test) and was protective for shunt revision (after the initial VPSI) with a hazard ratio of 0.53 compared with the standard surgical technique (p = 0.049). The laparoscopic technique was also superior to standard technique for lower failure rates after a "first VPSR". Conclusions: The initiation of a laparoscopy-guided approach to place the distal catheter under direct visualization over the dome of the liver significantly reduced shunt obstruction after a new VP shunt insertion. Introduction: Hydrocephalus is a chronic disease with multiple etiologies presenting at varying ages from birth to old age. However, the incidence of hydrocephalus is typically only described as ranging between 200 and 400 per 100,000 live births, usually with no reference to prevalence or other age ranges. Methods: A systematic review of the medical literature was performed using a search strategy for population-based studies reporting prevalence of hydrocephalus in all ages. Two reviewers independently reviewed all the abstracts, full text articles and abstracted data using standardized forms. Reported incidence of hydrocephalus and spina bifida 2008-2014 from 36 countries were obtained from The International Clearinghouse for Birth defects' database. Meta-regression was completed by data source and diagnostic method. Results: The search identified 2460 abstracts of which 148 were reviewed as full text articles and 57 met all eligibility criteria. Incidence data from 42 birth surveillance programs which included 166 million births were analyzed. Prevalence data were predominantly treatmentbased (shunt insertion) and poorly reported for adults. The mean incidence of hydrocephalus in infants was 56 per 100,000 (95% CI 43-69). The registries exclude spina-bifida-associated hydrocephalus and postnatally acquired hydrocephalus from this category. The mean incidence of spina bifida was 45 per 100,000 (95% CI 37-52). Assuming a conservative estimate that 80% of patients with spina-bifida have associated hydrocephalus, the estimated total incidence of hydrocephalus in infants approaches 109 per 100,000 (95% CI 85-133). The mean prevalence of hydrocephalus in the pediatric population (n = 25 studies) was 100 per 100,000 (95% CI 64-158). The mean prevalence of hydrocephalus in all adults less than 65 years of age (n = 7 studies) was 86 per 100,000 (95% CI 65-114). The mean prevalence of hydrocephalus in adults over 65 years of age (n = 6 studies) was 255 per 100,000 (95% CI 19-492). Prevalence increased with each decade after 65 years of age. Conclusions: The incidence of congenital hydrocephalus is reported at 109 per 100,000 from birth defects registries. The prevalence of hydrocephalus is well described in the pediatric population. The prevalence of hydrocephalus in the elderly (age over 65) is variable from one study to another with a wide range from 18 to 492 per 100,000. Inadequate information is available regarding the incidence of hydrocephalus in adults or the elderly. Further information is needed regarding the incidence and prevalence of hydrocephalus, especially in the adult and elderly patient population.  Introduction: The idiopathic normal pressure hydrocephalus (iNPH) is a disease of the elderly, and cerebrospinal fluid (CSF) shunt surgery is known to be effective. CSF tap test is useful for prediction of shunt effectiveness. We have shown that area under the curve (AUC) computed from receiver-operating characteristic curve was a high value of 0.81 in timed up-and-go test (TUG) on day 1. However, predictability of cognition tests is not well investigated. We studied the predictability of cognition tests in Otowa hospital. Methods: The shunt surgery was done in 61 patients with probable iNPH and postoperative assessment was done at 3 months after surgery. Lumbar CSF in 30 ml was removed at tap test and tests for gait and cognition were done before the tap, on day 1 and day 4. Tests for gait included TUG and 10-m walk test. Cognition tests included minimental state examination, frontal assessment battery (FAB) and trailmaking test. Positive tap test was defined as improvement of 10% or more. AUC values were computed using software of the R Foundation. Results: Positivity of cognition tests ranged from about 25% to 45% in three measures on day 1 and there was no statistical difference between day 1 and day 4. AUC values for cognition were around 0.50. Among them, FAB on day 4 was highest, but it was only 0.62. Conclusions: The predictability of cognition tests was not high enough, compared to that of gait tests. We need more sensitive test for cognition. Fluids Barriers CNS 2018, 15(Suppl 1):4 α-2 glycoprotein (LRG) in iNPH patients who underwent tap test (30 ml CSF drainage). At tap test, we separately collected CSF at the first drip (FD: 0-1 ml) and at the last drip (LD: 29-30 ml). 1 ml of VCSF was additionally collected from patients who underwent on ventriculoperitoneal shunt surgery. The levels of tau, Aβ and LRG were measured by using ELISA specific for each biomarker. Gait and cognitive function were evaluated by Timed UP & Go Test and MMSE, respectively. Results: The CSF levels of Aβ42 as well as LRG were significantly reduced in LD compared to ones in FD. Conversely, the CSF tau levels were significantly elevated in LD compared to ones in FD. Response to tap test in gait and cognitive function was closely associated with the levels of tau and LRG in LD, respectively. Conclusions: We suggested that the dynamic changes are different among measured biomarkers. The above data suggest that CSF in LD sampled in tap test likely reflects an aspect of VCSF, contributing to predicting shunt effectiveness in iNPH patients. Introduction: CSF shunting has an important role in the management of refractory idiopathic intracranial hypertension (IIH). Shunt-related complications can be a source of significant morbidity arising from multiple revision procedures. On this background, we investigated the incidence and outcomes of shunting for patients with IIH within the UK population. Methods: Patients undergoing a CSF shunting procedure with a diagnosis of IIH recorded on the UK Shunt Registry between January 1995 and 31st December 2014 were included in the analysis. Patients with more than one underlying CSF disorder diagnosis were excluded. Analysis of time to revision was performed using the Kaplan-Meier method and statistical significance determined with the log-rank test. Results: A total of 2014 patients meeting the inclusion criteria were identified, undergoing 4042 procedures across 45 centres. The majority of patients were female (1692; 84%), and median age at surgery was 31 years [IQR 23-39 years]. The commonest reasons for shunt revision included underdrainage (54%), catheter migration (12%) and disconnection (9.2%). New shunt insertions accounted for 1776 of recorded procedures, including 788 ventricular shunts and 832 lumbar shunts. Median survival of new shunts was higher for ventricular as compared to lumbar shunts (736 weeks vs. 679 weeks; p = 0.005). Conclusions: Our data suggests that new shunts inserted for IIH are associated with a long time to first revision, with the commonest reasons for this relating to mechanical failure. Furthermore, ventricular shunts have a marginally longer period to first revision compared to lumbar shunts. Evaluation of other associated operative factors will be required to determine potential underlying reasons for the observed differences.

A72
The occasional discrepancy between patient reported and clinical outcomes in idiopathic normal pressure hydrocephalus A. Junk kari 1  Introduction: Occasionally a favorable clinical disease-specific outcome does not reflect into improved generic health-related quality of life (HRQoL) in patients with idiopathic normal pressure hydrocephalus (iNPH) 1 year after the installation of the cerebrospinal fluid (CSF) shunt. Our aim was to identify factors causing this discrepancy. Methods: The 1-year HRQoL outcome of 141 iNPH patients was evaluated using the generic 15D instrument, in which the minimum clinically important change/difference on the 0-1 scale has been estimated to be ± 0.015. A 12-point iNPH grading scale (iNPHGS) was used as a clinical disease-specific outcome measure, in which one point decrease is considered to be clinically important. We identified 29 (21%) iNPH patients from our prospective study, whose HRQoL deteriorated or remained the same despite of a favorable iNPHGS outcome. We analyzed this discrepancy using patients' clinical variables and characteristics. Results: Multivariate binary logistic regression analysis indicated that a higher (worse) iNPHGS score at baseline (adjusted OR, 1.7; 95% CI, 1.3-2.3; p < 0.001), comorbid chronic pulmonary disease (40% vs. 20%; adjusted OR, 17.89; 95% CI, 3.6-89.9; p < 0.001) and any comorbid non-metastatic tumor (62% vs. 17%; adjusted OR, 11.5; 95% CI, 1.5-85.3; p = 0.017) predicted discrepancy between iNPHGS and 15D outcomes. Conclusions: Frail patients suffering from certain pre-existing comorbidities may not experience improvement in generic HRQoL despite of a favorable clinical disease-specific response. Acknowledging the comorbidity burden of the patient may help clinicians and the patients to understand the conflict between patient reported and clinical outcomes. Introduction: Idiopathic intracranial hypertension (IIH) is a rare condition affecting obese woman of childbearing age. Although IIHs pathophysiology is unknown, its profile is invariably characterised by raised intracranial pressure (ICP), papilledema and visual loss. Pulmonological disorders such as sleep apnea, and otological symptoms such as tinnitus and hearing loss have been previously reported in IIH patients. Obesity stresses the respiratory system, but otological symptoms could be directly linked to increased ICP and consequent increases in perilymphatic and venous sinus pressures. Thus, we characterized the ICPs and the presence of otological and respiratory symptoms of IIH patients in a population-based setting. Methods: A total of 35 patients with IIH diagnosis admitted from a defined catchment area between 2000 and 2016 were reviewed. All otological and respiratory symptoms were reviewed from patient records. Results: Total of 80% were females. At the time of diagnosis the mean for age was 30.1 years, for BMI 36.2 kg/m 2 , for CSF opening pressure (OP) 31.2 mmHg, and for follow-up time 4.4 years, respectively. Tinnitus occurred in 43 and 6% participants had documented hearing loss. Presentation of otological symptoms were associated with increased presence of papilledema (p = 0.045), higher BMI (37.9 vs. 34.4 kg/m 2 ) and to a poorer outcome after treatment (36% vs. 23%), but not to sex, age or OP. The patients with otological symptoms were more often shunted (44% vs. 28%) and had higher presentation of pulmonological symptoms(56% vs. 5%) (p = 0.002) as compared with patients without otological symptoms.

Introduction:
We identified a pattern of intermittent gait disturbance (IGD) observed in the early stages of idiopathic normal pressure hydrocephalus (iNPH). The purpose of this study is to clarify the temporal gait profile of IGD and explore the clinical implications of IGD. Methods: Fourteen consecutive iNPH patients with subtle short distance gait instability were treated by cerebrospinal fluid (CSF) shunting. Among these patients, seven presenting with progressive gait worsening after several minutes of gait loading were prospectively enrolled in the study. Gait and cognitive functions were evaluated by the 6-min Walk Test (6MWT) and the Mini-Mental State Examination (MMSE), respectively. Long-term follow-up (mean 49 months) of gait and cognitive function was performed in five patients. Results: All patients demonstrated features of IGD during the 6MWT, characterized by a progressive pattern of decreased gait speed and step length with increased cadence and an absence of leg pain. Postoperatively, IGD improved in all patients. Improved gait and cognitive function (MMSE range of 27-30) were well preserved during the follow-up period. Conclusions: IGD was observed in early stage of iNPH and may serve as an important clinical diagnostic marker for identifying iNPH patients with mild gait symptoms. Introduction: Spinal catheter insertion of lumboperitoneal (LP) shunt surgery for idiopathic normal pressure hydrocephalus (iNPH) is frequently associated with technical difficulties related to obesity and vertebral deformities of aging. The aim of this study is to elucidate the accuracy and safety of image-guided spinal catheter insertion by the paramedian approach (PMA) Methods: We retrospectively analyzed 39 consecutive patients with iNPH treated by LP shunting with spinal catheter insertion via the PMA. We evaluated the success rate of catheter insertion and the number of changes in puncture location. To measure accuracy of catheter insertion, both vertical and horizontal deviation of the catheter dural penetration point from the center of the inter-laminar space was evaluated. Results: The success rate for catheter insertion was 100% (39/39). The difficulty rate for catheter insertion measured by the number of changes in puncture location was 2.6% (1/39). No bloody punctures and surgical infections were observed. The accuracy of catheter insertion measured as the degree of deviation horizontally was 0.5 ± 1.9 mm and vertically 0.0 ± 2.4 mm. The rates of minor complications, including caudal catheter insertion, transient low pressure headache, and root pain, were 5.1% (2/39), 10.4% (4/39) and 0% (0/43), respectively. Subdural hematoma requiring surgery occurred in one case (2.6%). During the mean follow-up period of 36 months, spinal catheter rupture at the level of the spinous processes was not observed. Conclusions: The fluoroscopic guided PMA for spinal catheter insertion is potentially a safe, accurate, and reliable method even for use in geriatric and obese patients. Background: Idiopathic intracranial hypertension (IIH) is a rare disease with unclear pathophysiology. Dysregulated cerebrospinal fluid (CSF) hydrodynamics has been suggested to increase cerebral brain water content or cerebral blood volume resulting in transependymal flow causing interstitial brain edema. Magnetic resonance (MR) imagingbased volumetric measurements of grey, white and CSF at diagnosis and post-treatment follow-up. Methods: A total of 35 patients with IIH diagnosis admitted to the Kuopio University Hospital catchment area between 2000 and 2016 were reviewed. All demographic, clinical, medical charts and imaging findings were recorded. Brain volumes were calculated from T1 weighted MRI images by SPM 12 software. After applying all imaging requirements only three subjects were accepted for the final analysis. Results: The mean age at the time of diagnosis was 25.3 (SD 9.1) years and the mean follow-up time was 2.3 (SD 0.58) years and all were females. The mean BMI at diagnosis was 34.5 kg/m 2 , The mean CSF opening pressure at presentation was 32.4 mmHg (SD 4.2), and it reduced after treatment to 25.2 mmHg (SD 5.9). All patients were treated with acetatzolamide and weight loss, and one patient was treated with lumboperitoneal shunt. In all patients, the volume of grey Introduction: We showed therapeutic efficacy of shunt surgery for iNPH in SINPHONI and SINPHONI-2 study. Although therapeutic efficacy is important, cost-effectiveness analysis is equally valuable. Methods: Using both a set of assumptions and using the data from SINPHONI and SINPHONI-2, we estimated the total cost of treatment for iNPH, which consists of medical expenses (e.g. operation fees) and costs to the long-term care insurance system in Japan. Regarding the natural course of iNPH patients, 10 or 20% of patients on each modified Rankin Scale (mRS) show aggravation every 3 months if the patients do not undergo shunt surgery. We performed cost-effectiveness analyses for the various scenarios, calculating the quality-adjusted life year (QALY) and the incremental cost-effective ratio (ICER). Results: In the first year after shunt surgery, the ICER of VP shunt varies from 29,934 to 40,742 USD (aggravation rate 10 and 20%, respectively) and the ICER of LP shunt varies from 58,346 to 80,392 USD (aggravation rate 10 and 20%, respectively), which indicates that the shunt surgery for iNPH is a cost-effective treatment. Moreover, the total cost for iNPH patients will show a positive return on investment in as soon as 18 months (VP) and 21 months (LP). Conclusions: Because the total cost for iNPH patients will show a positive return on investment within 2 years, shunt surgery for iNPH is a cost-effective treatment and therefore recommended. Because complications naturally affect the medical expenses, more appropriate surgical technique to reduce shunt revision should be invented. (LP shunt) 61 cases, ventriculoperitoneal shunting (VP shunt) was four cases. Just 15 cases were continued and evaluated them. In comparison with aggravation of MMSE, the drop of FAB and the Kohs score was not outstanding, and there was it by improvement to maintenance in eight of 15 cases. As for the TOH to evaluate executive function, an improvement effect was poor. Conclusions: The memory decline was seen with aging, but was able to maintain the frontal lobe function. I think that it is necessary to cure at the stage when a symptom is earlier, and to intervene to maintain long-term improvement. Introduction: The aim of this study was to detect the difference in regional gray matter volume between shunt responders (SR) and shunt non-responders (SNR) in idiopathic normal pressure hydrocephalus (INPH) using voxel-based morphometry (VBM) and anatomical region of interest (ROI) analysis. Methods: The twenty-eight consecutive INPH patients were enrolled. MRI of the brain and clinical measures were performed prior to both cerebrospinal fluid removal and shunt placement. Clinical measures were re-assessed approximately 1 year after shunt surgery to assess shunt responsiveness. Twenty of the initial INPH patients were SR and the other 8 patients were SNR. Whole and regional brain gray matter volumes were detected by three-dimensional spoiled gradient echo image. Preoperative gray matter volume maps were compared between the SR and SNR groups by using VBM. In addition, anatomical ROI analyses of the regions in which gray matter volumes were significantly different among the two groups in VBM were performed to validate the results of the voxel-based analysis. Results: On a voxel-based statistical map and in anatomical ROI analysis, the volume of each thalamus in the SNR group was significantly smaller than that in the SR group. In addition, we found that the volume of bilateral thalami highly distinguished SR from SNR. Conclusions: The poor volume of the bilateral thalami might reflect the co-morbidity with other CNS diseases in SNR because this finding is common in dementing neurodegenerative diseases. The preoperative volume of bilateral thalami could predict shunt responsiveness in INPH. with LPS insertion under LA with modified NLA for last 6 years, and described their complications and outcomes. Results: Between April 2011 and March 2017, all of 372 LPS were performed with this procedure without major complication. The patients' age ranged from 55 to 95 years old with mean of 78.36 ± 6.88 (SD). In nine patients, LPS placement was failed, because of difficulty in the spinal catheter insertion. Migration of abdominal catheter was the most common complication of LPS (3.5%). But it seems to have nothing to do with the way of anesthesia. Conclusions: Our way of anesthesia provided sufficient sedation and analgesia during LP shunt procedure. And no intra-and postoperative complications due to this anesthesia resulted. As the placement of LPS is minimally invasive surgery for patients of hydrocephalus, administrations of powerful sedation or muscle relaxant agents are not necessarily required. This method may not be suitable for prolonged surgery, which can be anticipated preoperatively.  Introduction: Shunt pumping is controversial; however, no clinical evaluations of high volume tap test via shunt pumping are published. Advantage of "shunt pumping" is the non-invasiveness of the procedure. This prospective study was performed to estimate the value of high volume shunt pumping for further treatment options in patients with suspected shunt malfunction. Methods: We followed 17 patients with NPH who presented months or years after the shunt implantation with slow clinical deterioration. All patients were shunted with a gravitational and an additional "Sprung-reservoir", which is a borehole reservoir with an anti reflux valve. The shunt was pumped during an outpatient visit at least 100 times through pressing down the membrane of the reservoir resulting in release of at least 20 ml CSF. Patients and/or relative got a evaluation sheet where they had to mark the subjective changes (very good, good, marginal/none) of gait, incontinence and the overall feeling as well as the time course of these changes. Results: Pumping the shunt was possible in all cases. In 7 patients a very good improvement after pumping was seen, in 5 a good improvement and in 5 only marginal or no improvement. The improvement was observed in 8 cases within 1 h after pumping, in 4 within 1 and 3 h, and in 2 within 3-6 h. A later improvement didn´t appear. The improvements lasted in all cases more than 3 h. In 3 cases the improvement disappeared before 12 h, in 2 cases it lasted more than 12 h and in 9 more than 48 h. Conclusions: Shunt pumping can detect shunt malfunction fast and non-invasively. When the effect of pumping can be observed and how long it will last differs substantially from patient to patient. Therefore multiple evaluations are necessary after pumping. In patients with temporary improvement shunt revision should be discussed if no lower of the opening pressure is possible. In patient without clinical improvement further (invasive) investigations are recommend before excluding shunt malfunction. Introduction: Studies on iNPH focus on early assessment of probable NPH. Yet, responsiveness to shunting may be imperfect. A challenging Asian clinical subtype, characterized by a history of gait, balance and/ or cognitive impairment, with newly-diagnosed ventriculomegaly, presents late for intervention. Such late stage patients have lower functioning abilities and established dementia; responsiveness to CSF drainage is uncertain. We used diffusion tensor imaging (DTI) to characterize white matter injury patterns. Method: 10 patients with late probable NPH underwent a clinical protocol and multi-modal imaging. A full panel of DTI measures, including FA, MD, axial (L1) and radial diffusivities (L2 and L3), was examined. The DTI dataset was interrogated using both region-of-interest and whole brain tractography. demonstrated trends of axonal distortion (high MD) and stretch/compression (high axial diffusivity and tract characteristics), consistent with patterns found in classic iNPH. Conclusions: Assessment of late stage NPH is problematic. DTI may be a useful supplementary tool in identifying white matter injury patterns amenable to intervention.
Introduction: NPH patients with comorbidities such as vascular risk and neurodegenerative conditions are poor candidates for surgical intervention. Yet, this subtype represents a challenging clinical unmet need. Representative data on complex NPH patients are currently lacking. We used DTI to examine characteristics of reversible vs. irreversible injury. Method: 8 patients underwent external lumbar drainage, clinical assessment, DTI and fluid biomarkers. Inclusion criteria: participants with possible NPH and significant comorbidities, such as cardiac/vascular burden, higher-level gait disorder with cognitive impairment or neurodegenerative disease. Results: Imaging datasets from 7 participants (5 males, 2 females) were available for analysis; mean age was 72.57 years old. Mean Conclusions: Patients with complex NPH demonstrate less frequent improvement following CSF diversion. However, DTI profiles for improvement were consistent with patterns amenable to intervention seen in classic iNPH. Further cross-correlations with other imaging and fluid biomarkers for vascular, neurodegeneration and traumatic brain injury pathologies would be useful.

A86
Change of brain density distribution in CT image after shunting for hydrocephalus: a case study of two pediatric patients with achondroplasia E. J. Introduction: Incidence of shunt revision for hydrocephalus is higher in achondroplasia patients than in general population. A successful shunt insertion and reduction of ventriculomegaly are often assessed via postoperative neuroimaging. This study speculated that a change in brain density could be associated with the efficacy of shunt insertion, and set out to investigate whether such change could be evaluated in non-contrast computed tomography (CT) images of achondroplasia patients. Methods: CT images of two pediatric achondroplasia patients who had undergone shunt surgeries were subjected to analyses. Subject A (male, age = 12) had received the surgery; no further revision was required thus far. Subject B (male, age = 11), after the shunt insertion (age = 19), required repeated revisions. The post-operative CT images were acquired and subjected to the quantitative, densitometric analyses to derive the density distributions across the whole cerebrum. An averaged density distribution was acquired from normal pediatric population to act as a reference, and was compared to those of each achondroplasia patients. Results: The post-operative density distribution of subject A was similar to that of normal pediatric population. On the other hand, the postoperative density distribution of subject B did not change despite the repeated revisions, and had significantly different morphology compared to the reference distribution. Conclusions: The morphology of brain density distribution, acquired via densitometric analyses, could be associated with shunt responsiveness. Quantitative, densitometric analysis upon CT images may hold prognostic value regarding the efficacy of shunt surgery. Introduction: A reduced compliance of intracranial entities is a major physiological change in normal pressure hydrocephalus (NPH). Reduced compliances in subarachnoid space, brain parenchyma, arterial and venous systems are suspected to contribute to the development of NPH. However, the relationship between such pathological changes and the worsening of symptoms in NPH is not well understood. This study speculated that a worsened intracranial compliance could be associated with worsened symptoms of NPH, and set out to investigate the relationship via cerebrospinal fluid (CSF) infusion tests. Methods: The clinical information and data derived from infusion tests in a total of 42 patients who presented symptoms of NPH were retrospectively investigated. The intracranial compliance was evaluated by high-frequency centroid (HFC; range = 2.5-4 Hz) obtained by spectral analysis upon the baseline CSF pressure signal during infusion test. Symptom worsening is defined as a full Hakim triad, i.e. gait disturbance, cognitive deterioration, and urinary incontinence. The CSF pressure, pulse amplitude of CSF pressure (AMP) and resistance to CSF outflow (Rcsf ) was also obtained, and subjected to the statistical analyses. Results: Four patients presented the full triad, hence considered as having worse symptoms. The HFC was significantly higher in patients with worse symptoms (median = 9.57 Hz) compared to the non-full triad patients (median = 8.80 Hz), indicating decreased intracranial compliance in these patients. The diagnostic capacity for the worse symptoms was best estimated by HFC (AUC = 0. Our previous study has demonstrated that a part of subjects with AVIM (asymptomatic ventriculomegaly with features of iNPH on MRI) convert to iNPH. Here we investigated conversion rate and predictors of conversion. Methods: We conducted a prospective study of subjects with AVIM who were collected from several medical institutions/hospitals in Japan. AVIM is defined as the "ventriculomegaly with features of iNPH on MRI without objective symptoms", including subjects with subjective complaints of the iNPH triad (gait disturbance, cognitive impairment and/or urinary incontinence). We measured possible predicting factors for conversion including age, sex, education, exercise, height, weight, blood pressure, diabetes, dyslipidemia, history of mental diseases, head injury, sinusitis, smoking, alcohol, Evans index, and the presence of DESH (Disproportionately Enlarged Subarachnoid-space Hydrocephalus), and analyzed the predictive value by Chi squared test or Mann-Whitney U test. In addition, to assess the association between the number of subjective complaints and AVIM-iNPH conversion, the Cochran-Armitage test for trend was used. Results: In 2012, 93 subjects with AVIM were registered and enrolled to the study. Among them, 45 subjects were followed up for 3 years. 27 subjects were diagnosed as iNPH (11 definite, 6 probable, and 10 possible cases), while the remaining 18 subjects were still asymptomatic in 2015. None of the factors except subjective complaints of iNPH triad at baseline was associated with AVIM-iNPH conversion. Conclusions: Conversion rate from AVIM to iNPH was ~ 20% per year (27/45 per 3 years). Except subjective complaints, demographic, social and medical factors could not predict AVIM-iNPH conversion. Introduction: Based on the observation of our own cases, we examined the long-term prognosis of iNPH and the problems of its comorbidities. Methods: For a period of 10 years between 2005 and 2014, a tap test was conducted on those suspected to have probable iNPH according to the 2004 Guideline for iNPH. Subsequently, 166 cases who showed 10% or more clinical improvement were selected and V-P shunt (on 14 cases) or L-P shunt (on 152 cases) was conducted. The subjects of the current study consisted of 81 patients who were available for a followup. Modified Rankin Scale (mRS) was determined before and after, as well as 1, 2, 4, 6, and 8 years after the treatment. Results: The improvement in mRS exceeding 1 was noted in 97.6% after 1 month of treatment and in 85.0% after 1 year: the subsequent improvement was observed in 75, 74.2, 70.6, and 28.6%, after 2, 4, 6, and 8 years, respectively. Currently, an overall improvement in mRS exceeding 1 is noted in 68.8% (among 61 patients excluding those 21 who had expired). Co-morbidities included the following: Alzheimer diseases (27 cases), Parkinson disease (5 cases), benign prostatic hyperplasia (10 cases), fractures (12 cases), knee osteoarthritis (3 cases), chronic articular rheumatism (2 cases), cerebral infarction (10 cases), cerebral hemorrhage (one case), subarachnoid hemorrhage (one case) and cancer (8 cases). Conclusions: It is necessary to consider the possibility that the treatment of iNPH may not produce sufficient results due to unpredictable physiopathological conditions. Introduction: Endoscopic examination of the intra-ventricular walls is rarely performed for cases of idiopathic normal pressure hydrocephalus (iNPH) since shunting is the first treatment option for iNPH. We conducted endoscopic inspection during shunt surgery for patients with iNPH and compared the obtained findings with their pre-operative MRI data, and clinical manifestations. Methods: 16 patients (mean 76.6 years) with probable iNPH consistent with the Japanese iNPH guideline were included in this study. High-resolution MRI (T1-3D-SPGR or FIESTA) was taken pre-operatively. Intra-ventricular inspection was performed with an endoscope via a frontal burr hole during ventriculoperitoneal shunt surgery. Results: In the lateral ventricles, laceration of the septum pellucidum was found in 7 patients (44%), which was difficult to be detected by pre-operative MRI. The interspace between the bilateral mammillary bodies varied from being wide to narrow. A significant correlation was found between laceration of the septum pellucidum and the callosal angle measured by MRI. The laceration showed significant correlation with preexisting cerebral infarction and white mater change. The patterns of interspace between the bilateral mammillary bodies were correlated significantly with the width of the third ventricle, while neither significant correlation was seen with degenerative changes in MRI nor pre-operative clinical examinations. Conclusions: In iNPH, the pre-operative MRI findings of dull callosal angle and wide third ventricle were closely related to the intra-operative endoscopic findings of laceration of the septum pellucidum and wide opening between the bilateral mammillary bodies, respectively. Brain degenerative changes may be associated with the laceration of the septum pellucidum. Introduction: Imaging is fundamental in diagnosing idiopathic normal pressure hydrocephalus (iNPH), where radiological features serve diagnostical support. The aim was to assess the agreement between computed tomography (CT) and magnetic resonance imaging (MRI) for seven radiological iNPH-associated features. Methods: 354 patients received ventriculoperitoneal shunt for iNPH in Uppsala, Sweden, 2011-2015. Of those, 140 had both preoperative CT and MRI. Inclusion criteria were 1 mm isotropic voxel size or coronal reformats/scans, and scans maximum 3 months apart (n = 38). In a pilot study of 27 patients, CT and MRI were assessed for Evans' index, high convexity sulci, focally enlarged sulci, Sylvian fissures, temporal horns, callosal angle and periventricular edema. All scans were blindly assessed twice, with 6 weeks' interval. To calculate the agreement Fluids Barriers CNS 2018, 15(Suppl 1):4 Intraclass correlation (ICC) was used for continuous variables, Kappa and squared weighted Kappa for dichotomous and three stepped ordinal variables respectively. Results: The agreement between CT and MRI was good to excellent, for Evans' index, temporal horns, callosal angle and Sylvian fissures (Kappa and ICC = 0.7-0.9, p = < 0.001). The concordance was poor for periventricular edema and focally enlarged sulci (ICC = 0.2-0.4, nonsignificant). The intraobserver variability was good to excellent between consecutive CT assessments (Weighed Kappa and ICC = 0.7-0.9, p = < 0.001). Conclusions: Radiological signs associated with iNPH can be equally assessed on CT and MRI, except for periventricular edema, due to the superior soft tissue contrast of MRI. The intraobserver reliability for CT is high.

Introduction:
The aetiology of iNPH remains unclear. However, increasing evidence indicate a potential genetic component in iNPH. It was recently reported in Japan that the copy number loss in intron 2 of the SFMBT1 gene is present in 50% of patients, who present concomitantly with clinical features of iNPH together with enlarged ventricles and in 26% of shunted iNPH patients compared to 5% in healthy elderly controls. However, these results were obtained using small cohorts and have not yet been replicated outside of Japan. Interestingly, the SFMBT1 protein has been identified to be present in many structures important for the secretion, circulation, and absorption of CSF. Methods: The copy number loss in intron 2 of the SFMBT1 gene was detected using quantitative-PCR. The study cohort consisted of 936 (555 Finnish and 387 Norwegian) iNPH patients and 530 neurologically healthy elderly Finnish controls. Results: The prevalence of the copy number loss in the SFMBT1 was determined to be 11% Finnish iNPH-patients and 21% in Norwegian iNPH-patients compared to 3.7% in Finnish controls.

Conclusions:
The increased prevalence of copy number loss in intron 2 of the SFMBT1 in iNPH is now replicated in Finnish and Norwegian cohorts further emphasizing its role in the development of iNPH. Introduction: Posttraumatic hydrocephalus (PTH) is a known sequela of severe traumatic brain injury. Mental recovery and rehabilitation of patients are affected and complicated by hydrocephalus. Patients in vegetative (VS) and minimal consciousness state (MCS) pose a challenge for a surgeon to decide whom to treat. The goal of our study is to develop a reliable diagnostic criteria to differentiate PTH and atrophy. Methods: 216 patients with PTH were treated in the Burdenko Research Center. Among them 31 patients were in VS and 46 in MCS. Mean time of surgery after trauma in these groups was 5,6 ± 4,01 months. All patients were assessed according to a standard clinical assessment protocol. A new algorithm based on a complex MRI (cisternography, phase-contrast, DTI and ASL) and clinical study was proposed to distinguish PTH and atrophy. In 210 patients standard shunting procedures were made and 6 endoscopic ventriculostomies were performed in cases of proved obstruction. Results: Positive results were observed in 20 (64.5%) patients in the VS group and 30 (65.8%) patients in the MCS group. Unfavorable outcomes were observed in 11 VS patients and 16 MCS patients with a mortality rate of 9.6 and 4.3% respectively. None of the patients in these groups was treated endoscopically. In one case ventricular catheter tip was placed through the 3rd ventricle and aqueduct into the 4th ventricle with endoscopic assistance. Most of the patients had higher risk of shunt infection due to bedsores (n = 6), tracheostomy (n = 37), gastrostomy (n = 2) or both (n = 10). Clinical course was complicated by shunt infection in 8 cases-in three cases (9.6%) in VS patients and in 5 cases (10.8%) in the second group respectively. Conclusions: CSF diversion can be the necessary part of rehabilitation in patients with brain trauma sequela. However a significant number of unfavorable outcomes and absence of reliable non-invasive diagnostic methods make the clinical problem of posttraumatic hydrocephalus unsolved. A complex clinical and MRI assessment helps to state indications for surgery and sometimes to plan the procedure properly according to the individual anatomy of a patient. Introduction: Gait and balance impairments are predisposing for falls, however, falls in INPH have never been studied. The objective was to investigate falls in INPH before and after shunt surgery, compared to the general population. Methods: Shunted INPH (n = 176) were compared to age-and sexmatched population-based controls (n = 368). Falls and fear of falling (FoF) were assessed through a questionnaire regarding pre-and postoperative events. Individuals with ≥ 2 experienced falls were defined as "fallers" and those with ≤ 1 fall as "non-fallers". FoF was evaluated with a 5-item scale (graded never to always) and the Swedish falls efficacy scale (FES(S)), assessing confidence at avoiding falls in activities of daily living. Results: Comparing INPH and controls, the frequency of fallers was higher in INPH (post-and preoperatively: p ≤ 0.001). After shunting INPH fell less often (p < 0.001) and the frequency of fallers was lower (p < 0.001). INPH had more FoF and lower FES(S) than controls preand postoperatively and before surgery compared to after (all comparisons: p < 0.001). There was no difference in severity of fall-related injuries between INPH and controls. Conclusions: Falls and FoF are overrepresented in INPH. After shunt surgery, INPH feel more confident in avoiding falls and the frequency of fallers is lower. Additional interventions to avoid falls such as home safety improvements and exercise programmes should probably be considered in INPH. Introduction: Regional cerebral blood flow (CBF) has previously been studied in patients with idiopathic normal pressure hydrocephalus (iNPH) with imaging methods that require an intravenous contrast agent or expose the patient to ionizing radiation. The purpose of this study was to assess regional CBF in patients with iNPH compared to healthy controls using the non-invasive quantitative arterial spin labeling MRI technique. A secondary aim was to compare the correlation between symptom severity and CBF. Methods: Differences in regional cerebral perfusion between patients with iNPH and healthy controls were investigated using pseudo-continuous arterial spin labeling perfusion MRI. Twenty-one consecutive patients with iNPH and 21 age-and sex-matched randomly selected healthy controls from the population registry were prospectively included. The controls did not differ from patients with respect to selected vascular risk factors. Twelve different anatomical ROIs were manually drawn on coregistered FLAIR images. Holm-Bonferroni correction was applied to statistical analyses.

Results:
In iNPH patients, the perfusion was reduced in the periventricular white matter (p < 0.001), lentiform nucleus (p < 0.001) and thalamus (p < 0.01) compared with controls. Reduced cognitive function in patients correlated with lower CBF in the pons (r = 0.71, p < 0.001), cerebellum (r = 0.63, p < 0.01) and periventricular white matter (r = 0.60, p < 0.01). Conclusions: Using pseudo-continuous arterial spin labeling, we could confirm findings of a reduced perfusion in the periventricular white matter, basal ganglia and thalamus in patients with iNPH previously observed with other imaging techniques.

Conclusions:
The MMSE-total score was significantly lower in the p-iNPH group compared to u-iNPH. Inferior cognitive performance was confirmed with RAVLT and Stroop for the p-iNPH. However, the mean score for the p-iNPH was above the typical cut-off score of 24 points. Also, when comparing performance on each item on the MMSE, only orientation and recall showed any significant difference. Individuals with a total score within the non-demented range might include individuals with specific memory impairments or beginning dementia and caution should be made using the MMSE to ascertain cognitive performance. Implications: Further testing could be needed if individuals only fail the orientation and/or recall task on the MMSE even if the total score is within the non-demented range.  Introduction: During the cardiac cycle, kinetic energy is transferred to cranial compartment by arterial blood flow (ABF) leading to venous blood flow (VBF) drainage and cerebrospinal fluid (CSF) oscillations. We proposed to use phase contrast magnetic resonance imaging (PC-MRI) to determine how arterial and venous pulsatilities were transferred between extracranial and intracranial compartments. Methods: Hydrocephalus patients (n = 54) underwent PC-MRI to quantify intracranial and extracranial ABF and VBF the day before ICP monitoring with infusion tests to assess resistance to CSF outflow (Ro) using ICM+. Based on Ro value, we classified patients in potentialnon-responders (PNR, n = 22) and potential-responders (PR, n = 32) groups to shunt surgery. PC-MRI data were analysed with homemade software to extract maximal, minimal and mean values of: (i) intracranial ABF (internal carotid arteries [ICAs] + basilar artery) and VBF (straight + sagittal sinuses); (ii) extracranial ABF (ICAs + both vertebral arteries) and VBF (both jugular veins). A pulsatility index (PI = (max-min)/mean) was calculated for ABF and VBF for each intracranial and extracranial level. Results: Intracranial and extracranial arterial pulsatilities were not different between the groups. In both groups, intracranial arterial PI was smaller than extracranial arterial PI. Intracranial venous PI was not different between the two groups. The venous PI was increased at extracranial level for both groups and was significantly higher in PR group than in PNR group. Conclusions: Extracranial venous PI was impaired in PR group and seems to be an interesting MRI biomarker highlighting hydrocephalus patients with CSF dynamic alterations and could be helpful to predict shunting candidates. Introduction: Lumbar puncture (LP) is the most utilized test in the assessment of neurological disease and disorders of cerebrospinal fluid, but the variability of this single time point measure and the influence of patient position may limit its accuracy and utility. Cranial ICP monitoring (ICPM) has the advantage of direct, continuous intracranial pressure measurement and under various conditions may be considered to offer added utility, albeit through a more invasive approach. Methods: We reviewed the charts of patients undergoing ICPM at our institution between 2015 and 2017. We compared initial LP pressure measurements with subsequent cranial ICPM in patients sub classified as having suspected pseudotumor, intracranial CSF leak, or possible mixed disorders. Results: 73 patients underwent continuous ICPM procedures. Overall mean pressure was 15.5 mm Hg with LP and 11.9 mm Hg with lying ICPM (p = 0.006). Subgroup analysis demonstrated a significant difference between LP and lying ICPM pressures within the pseudotumor cerebri subgroup (p = 0.0004), but no statistical difference between the CSF leak or combined pseudotumor and CSF leak subgroups. The LP and ICPM pressures were not correlated overall (r = 0.36) or within subgroups. A positional difference between lying ICPM and sitting ICPM pressures was statistically significant in both pseudotumor and CSF leak patients (p < 0.0001). Conclusions: LP pressure measurements are limited and vary significantly from continuous ICPM. The positioning during the LP must be considered and position changes with ICPM may add value in accurately conveying pressures in patients with CSF leak, pseudotumor and mixed coexistent processes. Disease State Index (DSI) is a statistical method capable of combining data from various sources to aid clinician in differential diagnosis of dementing diseases and their progression. We evaluated performance of a DSI model aimed to predict development of clinical AD in shunted iNPH patients. Methods: 335 patients initially shunted for iNPH were followed until death or end of June 2015. In total 70 (24.6%) patients developed clinical AD during mean follow-up of 6.2 years (range 0.2-21). DSI model including symptom profile, onset age of NPH symptoms, atrophy of medial temporal lobe in CT/MRI, cortical brain biopsy, and APOE-genotype was applied. Performance was evaluated with Receiver Operating Characteristic (ROC) Curve analysis. Results: DSI model predicted development of clinical AD with moderate power (AUC = 0.75). Most effective measurement groups were cortical biopsy (AUC = 0.67), symptom profile (AUC = 0.66), and atrophy of medial temporal lobe (AUC = 0.66). Applied model had good negative predictive value, as later development of AD could have been ruled out for 54% patients with a NPV of 89.8%.

Introduction:
The CSF tap test (TT) has been established as simple, safe and inexpensive predictive INPH test. TT is recommended in the international guidelines. We hypothesized a TT placebo response as patient/relatives know that a large volume of CSF is going to be drained and an improvement to be expected. The lp may be painful, and if the test is positive, shunt surgery might be considered. The objective was to determine the magnitude of the placebo response in TT. Methods: 36 patients (15 women, 73 years) diagnosed with "possible" INPH were included. Gait velocity (6 × 10 m) was assessed before and 3 h after the TT. Patients were randomly allocated to a TT (40-50 mL CSF drained) or a sham procedure (lp without puncture). The placebo response was defined as improvement in velocity in the sham group. Results: 17 patients had the sham procedure, and 19 CSF drainage. Before TT, there were no differences in gait velocity between groups. There was a trend, however not significant, that the placebo response was different from zero (0.02 m/s (− 0.05-0.09 95% CI). Commonly used cut offs for a "positive" TT gave the following numbers: improvement ≥ 5%, 7 patients; ≥ 20%, 2; ≥ 0.1 m/s, 5 and ≥ 0.15 m/s 3 patients.

Conclusions:
The placebo response in TT is probably small. The variability of gait velocity before and after the TT may indicate that even sham patients could fulfill criteria for a "positive" TT. A more robust variable, with high test-retest reliability, could probably improve the diagnostic accuracy of the TT.

A107
Interaction between intracranial pressure and the sympathetic nervous system; a new link between the brain and the cardiovascular system S. C. Malpas 1,2 , S. J. Guild 1,2 , R. Ramchandra 1,2 1 University of Auckland, Auckland, New Zealand; 2 Millar Inc, Housten, TX, USA Correspondence: S. C. Malpas Fluids and Barriers of the CNS 2018, 15(Suppl 1):A107 Introduction: We hypothesize that cerebral perfusion pressure [measured as intracranial pressure (ICP)] is a key regulator of sympathetic nerve activity (SNA). Specifically that small changes in ICP exert a reflex control over SNA. Methods: We instrumented sheep to record renal SNA, ICP and arterial pressure. In the conscious condition a minimum of 4 days after surgery we increased ICP via infusion of artificial CSF into the lateral ventricle in a step wise fashion. The ICP infusions were repeated again after 2 h of ganglionic blocker hexamethonium. Results: The increase in ICP led to a reflex linear increase in arterial pressure even when ICP remained within normal physiological levels (0-20 mmHg) (n = 6, p < 0.01). For example: a 10 mmHg increase in ICP lead to a 6.5 ± 1.4 mmHg (n = 6) increase in arterial pressure. Ganglionic blockade significantly reduced or abolished this increase in arterial pressure, suggesting mediation by increased sympathetic nerve activity. This is supported by direct renal sympathetic nerve recordings. Conclusions: This data is supportive of the "selfish brain" hypothesis which proposes that poor brain perfusion is compensated for by chronically increased SNA and arterial pressure. Our data specifically indicate that around resting levels of ICP i.e. not markedly elevated as in the Cushing's reflex, there is a reflex control over SNA which in turn affects arterial pressure. Introduction: Idiopathic normal pressure hydrocephalus (iNPH) is a condition characterized by increased cerebrospinal fluid (CSF) volume commonly seen in elderly patients. The incidence has been reported at 1.8 cases per 100,000 and 2.2 cases per 1,000,000 individuals. Patients present with the classic triad of gait, cognitive and urinary complaints. Imaging shows ventriculomegaly as measured by Evan's index. CSF diversion procedures including shunt and endoscopic third ventriculostomy (ETV) are modalities commonly used to treat iNPH. It is important to be able to predict patient response before undergoing any of the above procedures as they are associated with risks. Many institutions utilize the lumbar puncture or CSF tap test where a large volume (40-50 cc) of CSF is drained ot the lumbar drainage trial using external lumbar catheter and draining up to 300 cc of CSF. Pre and post drainage testing includes tests of cognition and gait. The percentage improvement is calculated to determine if shunt or ETV is indicated. In our institution, the parameters tested for cognitive function are Montreal Cognitive assessment (MOCA) and Digit substitution test (DST). Gait is assessed using 10 m walk, Tinetti, Timed up and go (TUG), Dual TUG, Mini Best. Previous studies have determined the CSF tap test to be sensitive in predicting shunt response (5), while the more invasive extended lumbar drainage test is considered to have higher sensitivity and specificity (6). The aim of this study is to determine which specific parameters in the post drainage cognitive and gait assessments are most predictive of selection for shunt or other CSF diversion procedures. Methods: A retrospective review of patients admitted to The Johns Hopkins CSF disorders center for evaluation iNPH between December 2015 through May 2017 was conducted. Patients who underwent a CSF tap test and extended lumbar CSF drainage were selected for Fluids Barriers CNS 2018, 15(Suppl 1):4 analysis. Pre and post drainage tests (Independent variables) used in the analysis were as follows: Cognitive testing-MOCA, DST. Gait testing-10 m walk, Tinetti, TUG, Dual TUG, 6 min walk, MiniBEST. The dependent variable being a CSF diversion procedure-shunt or ETV. Results: Data from 31 patients was analyzed. 39% were male, 61% were female. 93.5% presented with gait dysfunction, 74.2% with cognitive complaints and 48.4% with urinary symptoms. 93.5% had ventriculomegaly (Evans index of > 3.0). In the CSF tap test group none of the patients obtained a CSF diversion procedure and none of parameters tested were statistically significant. In the External lumbar drainage group there was a statistically significant association with CSF diversion procedure (p 0.059). The parameters that were most predictive of CSF diversion procedure were 10 m walk (p 0.0039), TUG (p 0.0073) and Dual TUG (p 0.0046). Conclusions: Patients who underwent external lumbar drainage trial were more likely to obtain a CSF diversion procedure. Of the pre and post drainage tests performed, the 10 m walk, TUG and Dual TUG are most predictive of obtaining a CSF diversion procedure. Idiopathic normal pressure hydrocephalus (iNPH) is a condition characterized by increased cerebrospinal fluid (CSF) volume commonly seen in elderly patients. CSF diversion procedures including shunt and endoscopic third ventriculostomy (ETV) are modalities commonly used to treat iNPH. Results: There were 16 cases of iNPH, of whom 9 (56%) were male and 7 (44%) were female. Aged from 60 to 89 years, and the mean age was 72.9 ± 7.8 years. Disease course: 18-120 months. Clinical manifestations and disease history: All 16 cases with triad symptoms. 12 (75%) of them have a history of head trauma and 6 (37.5%) of them different bone fractures due to impaired gait disturbance. 13 (81%) of them have a history of AD diagnosis and 5 (31%) of them PD diagnosis.

Efficacy of lumbo-peritoneal shunt in elderly patients
Imaging findings: All 16 cases with head CT and/or MRI showed ventricular enlargement in a different degree. Evans index ≥ 0.3. Coronary plane of MRI display DESH in 12 cases. Reported rate of ventricular enlargement by radiological department was only 25%, in contrast, the reported rate of brain atrophy was 100%. The mean opening pressure was 145 ± 26 (Min = 90, Max = 180) mmH2O. Of them, 10 cases (62.5%) were between 70-150mmH2O and 6 cases (37.5%) were 150-200mmH2O. The mean protein containing of CSF was 0.46 ± 0.23 (Min = 0.17, Max = 1.08) g/L, a little higher than the upper normal limitation (normal: 0.15-0.45 g/L) and glucose 4.2 ± 1.2 (Min = 2.8, Max = 6.5) mmol/L. After CSF tap test, positive results of 10-m walking test were observed within 24 h in 16 cases and within 24-72 h in 14, still effective more than 72 h in 11, without effective case more than a week. The mean MMSE scores before and after Tap test and 3 months after shunt were 14.4 ± 8.4 (Min = 3, Max = 25), 18.1 ± 7.5 (Min = 6, Max = 27), and 22.2 ± 5.4 (Min = 8, Max = 28) respectively, and the difference of post-tap test MMSE and 3-month post-operation to the initial was significant (p < 0.05). The mean mRS before and after Tap test and 3 months after shunt were 3.69 ± 0.95 (Min = 2, Max = 5), 2.75 ± 0.86 (Min = 1, Max = 4), and 1.63 ± 1.26 (Min = 0, Max = 4) respectively, and the difference of post-tap test mRS and 3-month post-operation to the initial was significant (p < 0.05). The mean Evan's index before and 3 months after shunt was 0.33 ± 0.03 and 0.32 ± 0.03 respectively, the difference was significant (p < 0.05). During a followup period of 3-15 months after shunt, clinical systems improved in different degrees in all the patients. There were no operation related death and severe complications such as postoperative CNS infection, obstruction of shunt tube, over-drainage and subdural hematoma and etc. Other complications: 1 case of suspected unsmooth diversion of CSF, we continue to observe and will adjust the apparatus if the patient's symptoms progressively deteriorate. Another case of persist pain in lumbar-sacral area, partial remitted after pulling out a bit of tube that was inserted into the subarachnoid space.

Conclusions:
The results of these cases show that elderly patients with idiopathic normal pressure hydrocephalus can benefit from shunt surgery in terms of their triad symptoms and functional status. LPS is an effective procedure for iNPH with the advantages of minimal invasiveness, rapid recovery, and especially fewer and less severe complications. Introduction: CSF is a clear, water-like fluid that surrounds the CNS and fills a complex network of ventricles and cisterns. There is a rapidly growing number of medical applications that integrate virtual and/ or augmented reality (VR/AR) systems, most often as a rehabilitation tool and less often for immersive visualization. Due to its complexity, the CSF system is an excellent candidate for immersive visualization as both a teaching tool and a simulator for neurosurgical procedures. Methods: Gross anatomy of the complete CSF system was segmented from high-resolution T2-weighted MRI data. To optimize this geometry for VR systems, extensive remeshing was performed to create a low poly mesh. Fine anatomy was added though a manual process informed by additional segmentations and cadaveric measurements in the literature. The complete anatomic mesh was integrated into a 3D environment where navigational controls were added. Finally, the complete system was exported in a real-time VR platform. Results: The primary VR simulator consists of the ventricular and cortical regions of the brain, dura matter, spinal cord, coccygeal nerve and 30 dorsal and ventral nerve rootlet pairs. The secondary component Fluids Barriers CNS 2018, 15(Suppl 1):4 of the simulator is a real-time anatomical index with a 3D orientation gimbal and a MRI viewport. Conclusions: This project represents the first VR simulator of the CSF system, Neurochi ® that is equipped with navigational viewports and indices creating an immersive tool for learning and medical applications. Future work is aimed at improving navigational controls and development of a tactile interface for clinical procedure simulation, http://www.neurochi.com. Introduction: Despite the attractiveness of intrathecal drug delivery to the central nervous system (CNS), there is little information about cerebrospinal fluid (CSF) dynamics in humans with CNS disease or animal models used for preclinical research. This hinders development and optimization of intrathecal drug delivery systems. The purpose of this study was to better characterize CSF fluid dynamics in large mammalian species, including humans. Methods: Full-spine high-resolution sagittal T2-weighted magnetic resonance imaging (MRI) measurements were collected for cynomolgus monkeys (n = 8), rhesus monkeys (n = 2), Göttingen minipigs (n = 2) and adult humans (n = 10). Manual segmentation was employed to map the intrathecal geometry, which was quantified in terms of axial distribution of hydraulic diameter, wetted perimeter, cross-sectional area and total volume. CSF dynamics were quantified at 6-axial levels along the spine (foramen magnum, C2/3, C5/6, T4/5, T11/12, L3/4) using phase-contrast MRI measurements with retrospective cardiac gating. Axial distribution of CSF dynamics was quantified in terms of Reynolds and Womersley number, peak value of the mean CSF velocity, peak flow rate and stroke volume. Results: CSF dynamics in minipigs bore no relationship to humans. However, axial distribution of Reynolds number in cynomolgus and rhesus monkeys showed a similar trends to humans, although at approximately half the magnitude. Conclusions: A non-invasive method was developed to quantify CSF dynamics and geometry in large mammalian species. Correspondence to human intrathecal CSF dynamics was poor in minipig and more favorable in non-human primates. Further studies are needed to confirm these findings in a larger population and understand how CSF dynamics alterations impact intrathecal solute distribution.
Introduction: Cerebrospinal fluid (CSF) disorders remain a poorly understood entity. Patients with positional headaches that worsen upon standing are often categorized as having intracranial hypotension caused by a CSF leak. Subsequent work-up ensues and treatment through epidural blood "patching" results in improvement of the initial symptoms but can trigger intracranial hypertension. We present 5 patients with positional headaches suggestive of CSF hypotension but with high CSF opening pressures which eventually lead to the diagnosis of idiopathic intracranial hypertension treated by CSF diversion or venous sinus stenting resulting in control of their symptoms. Methods: Institutional CSF disorder database was queried and patients with clinically suspected CSF leak and CSF opening pressure greater than 15 were identified. Demographics, clinical course and imaging were reviewed, as well as method of "definitive treatment". Results: Five patients were identified with discordant CSF pressure measurements (3 males and 2 female). Average age was 42 years (range 34-48). Lumbar puncture opening pressure ranged from 17 to 47 cm H 2 0. The patients were treated with venous stenting, shunting or medically managed with Diamox. Conclusions: Patients with clinically suspected spontaneous CSF leaks presenting with high opening pressure are difficult to manage. A subset of this population may harbour underlying CSF hypertension that would cause weakening of the thecal sac, creating dural diverticula, as well spontaneous CSF leaks. Thus these patients would likely benefit from patching in addition to either CSF diversion or venous sinus stenting. Further studies to elucidate the biomechanics and pathophysiology of CSF leaks are necessary. Introduction: Many studies are ongoing to reconsider cerebrospinal fluid (CSF) physiology including its formation and absorption by using tracers. However, the movement of the tracer is not identical to the movement of water. In order to clarify the origin and turnover of water molecules in CSF, dynamic PET (positron emission tomography) study was performed using radio labeled H 2 O. Methods: Normal volunteers (n = 9, 62 ± 7.6 years) and patients with definite idiopathic normal pressure hydrocephalus (iNPH, n = 2) were included. Dynamic PET data were obtained for 15 min after intravenous bolus injection of 5 ml of saline including H 2 15 O (500 MBq). Voxels of interest (VOI) were set in the internal carotid artery (ICA), superior sagittal sinus (SSS), choroid plexus (CP), cortical gray matter (GM), white matter (WM), basal ganglia (BG), lateral ventricle (LV), Sylvian fissure (FS), and prepontine cistern (PPC) based on MR T1 (3D) images with manual corrections. The time and relative radio activity (RAA) curves of each VOI were analyzed. Results: The maximum peak radio activities of GM, WM and BG were at 22.5, 50.0 and 22.5 s after the peak in ICA, respectively. At that time, the relative peak activities of GM, WM and BG were 53, 42 and 55% of the ICA peak activity, respectively. The activities in the whole brain structures decreased gradually. On the contrary, the activity of LV increased gradually until the end of the measurement {14.5% of the ICA peak activity, 49% of the whole brain parenchyma (GM + WM + BG) activity at 12 min}. The activity curve of FS and PPC showed similar to LV. The activity curve of CP was nearly parallel and the level was 80-90% of whole brain parenchyma. The RRA of LV in iNPH tended to be lower compared to the normal control.

Conclusions:
The present study showed very fast movement of water molecules from artery to brain parenchyma and ventricular and subarachnoid CSF. Water movement into the ventricle may delay in iNPH patients.
Introduction: Post-hemorrhagic hydrocephalus (PHH) develops in approximately 20% of infants with severe intraventricular hemorrhage (IVH), indicating that critical selective mechanistic triggers downstream of the hemorrhage are required for development of this disorder. However, the specific effect of blood on the ventricular zone (VZ) is unknown. Most types of fetal-onset hydrocephalus present with loss of VZ adherens junctions formed by N-cadherin, which leads to disconnection of cells lining the ventricles. ADAM10 is a widely expressed zinc metalloprotease that principally regulates cellular adhesion and migration. In brain, ADAM10-mediated proteolysis of the N-cadherin extracellular domain disrupts cadherin-dependent homotypic intercellular interactions. We hypothesized that hyperactivity of ADAM10 is one of the underlying mechanisms causing disruption of the VZ in PHH. Methods: Newborn mouse brains were dissected and ependymal progenitor cells from the ventricular wall dissociated and plated onto coverslips where they start to differentiate as a monolayer of multiciliated ependymal cells. Five days later, three 2-h treatments were applied: (1) 25μl of blood, (2) 20 hemolytic units of α-hemolysin (an activator of ADAM10), (3) GI254023X (an inhibitor of ADAM10).
Results: Blood treatments caused significant reductions in the percentage of multiciliated ependymal cells and expression of N-cadherin, significant over-expression of ADAM10, and decreased transepithelial resistance, suggesting a defect in adherens junctions. Exposure to α-hemolysin caused similar significant decreases in N-cadherin expression. Ongoing experiments with the ADAM10 inhibitor will be presented. Conclusions: These preliminary findings suggest that over-expression of ADAM10 may mediate cleavage of N-cadherin in PHH VZ disruption.

Introduction:
The pathogenesis of post-hemorrhagic hydrocephalus (PHH) is not clear. While traditional views attribute ventriculomegaly to thrombus obstruction of cerebrospinal fluid (CSF) outflow pathways, recent studies in lissencephalic animals and humans have implicated ventricular zone (VZ) disruption as a prominent mechanism. Nevertheless, systematic studies of PHH are lacking in young animals with a gyrencephalic cortex. To test the hypothesis that VZ disruption occurs following intraventricular hemorrhage (IVH), we have analyzed tissue and CSF from our recently developed infant ferret model of PHH. Methods: PHH was induced in 14-20 day old ferrets by intraventricular injections of lysophosphatidic acid (LPA) or autologous blood; sham controls received similar injections of sterile saline. Neuroimaging (T2-weighted MRI and diffusion tensor imaging) was conducted biweekly until approximately 150 days following induction. Cisternal CSF and fixed tissue from frontal and parietal regions were analyzed using protein chemistry and immunohistochemistry for neuroepithelial/ependymal cells, neural progenitors, multiciliated ependymal cells, astrocytes, cell-adhesion molecules and one of their neuromodulators (ADAM10). Results: Within 1-2 weeks after either LPA or blood injections, mildmoderate ventriculomegaly was confined to the lateral ventricles and was most prominent in the occipital and inferior horns. PHH animals all presented with patches of denuded ependyma, VZ cells lacking cilia and radial processes, eruptions of VZ regions into the ventricle, altered cell-adhesion molecules, increased ADAM10 expression, and reactive astrocytosis in regions of VZ disruption. Conclusions: Since these findings are similar to those observed in patients with PHH, VZ disruption may play an important role in the pathogenesis of this disorder. Methods: MEDLINE (PubMed) search using terms AQP1 or AQP-1 or AQP 1 or AQP one and all non-abbreviated equivalents. Results were filtered to include neurological functions, CSF dynamics, hydrocephalus, intracranial pressure (ICP) and acetazolamide. Results: The search criteria identified 3475 papers, of which 212 studies were relating to neurological function, of which 24 implicated AQP1 to have a role in CSF dynamics and/or intracranial pressure.

Mice, rats
Conclusions: There is a growing body of evidence that AQP1 plays a significant role in ICP and CSF dynamics. The evidence suggests that increased AQP1 expression may result in increased CSF production, which may in-turn result in raised ICP. AQP1 inhibition or reduced expression appears to reduce CSF production. Therefore, AQP1 may be a putative target for non-surgical management of disorders of CSF dynamics. Results: The adjustment of the flow is achieved by a needle determines the opening area in the outlet. The cam plate is moved similar to the mechanism that is used in adjustable differential pressure hydrocephalus valves. An adjustment between an unrestricted flow down to a flow between 5 and 10 ml per hour and any flow in between these values is possible. The pathway through the shunt can be completely closed tentatively by an independent mechanism at the inlet. The cylindric titanium housing has a diameter of 16 mm and thickness of 4.5 mm. The device is 3.0 Tesla MRI safe.

Introduction:
We provide an accurate picture of how much shunt intervention contributes to the prognoses of the patients registered in nationwide epidemiological surveys who are treated for idiopathic normal pressure hydrocephalus (iNPH). Methods: We examined 1423 possible iNPH patients (581 women; mean age: 76.5 ± 6.4 years) aged 60 or older who had been diagnosed based on the clinical guidelines for iNPH following a hospital visit in 2012. Patients in whom improvement of at least one grade in the modified Rankin Scale (mRS) was achieved after intervention were considered "improved" while the remaining patients were considered "non-improved. " A shunt intervention group (n = 974) and non-intervention group (n = 449) were statistically analyzed by binomial logistic regression analysis. Our results show improvement in executive functions and visuospatial constructive abilities. There was also a significant improvement in depression. On visual side TT lead to faster and more accurate performance in sustained and selective attention tests and, on verbal side, to better logic reasoning and increased access to phonemic source. It is interesting to observe that posterior abilities seems to be positively influenced as well as anterior ones showing that improvement could include a widespread spectrum of different cerebral areas. We also noticed that affective status, albeit not varying in a relevant way, seems to be positively influenced on the depressive side and not on the anxiety one. Conclusions: iNPH patients have a selective, objective and documented enhancement of executive functions after TT. In our preliminary multidisciplinary experience ("pro-hydro" group), NPS evaluation has been crucial to refer patients for surgical treatment. In the light of these results, an in-depth and standardized NPS assessment seems to be highly valuable. Conclusions: iNPH is a complex and often misdiagnosed syndrome. A preliminary consult with a qualified specialist, a multidisciplinary evaluation and the enrolment in a dedicated study protocol such as the "prohydro", help achieving a correct diagnosis and management of iNPH patients providing a standardized patient selection criteria for VPS.  Conclusions: Diverting CSF from the lateral ventricle to the sylvian fissure using an inexpensive shunt catheter seems to be easy as microsurgical dissection of sylvian fissure is standard part of neurosurgical training22. As both ends of the shunt are intracranial, over drainage seems to be an unlikely complication. The surgical field is small and duration of procedure being short it would translate into lesser Introduction: In addition to evolution of institutional protocols including surgical technique and antibiotic prophylaxis for hydrocephalus shunt operations, antibiotic-impregnated catheters (AICs) have been shown to reduce the incidence of revision operations for infection. However, there has been concern based on anecdotal reports that AICs may lead to late infections caused by antibiotic-resistant organisms. Is there an increased incidence of late infections with AICs than with conventional catheters? There was an overall reduction in shunt infection rate using conventional catheters from 4.7 to 1.87% between the two cohorts. Bactiseal catheters significantly reduced the infection risk in both cohorts (to 3% p = 0.048 and 1.12% p = 0.006 respectively). The first cohort has been followed up long term. Importantly, there were late infections in both the conventional (from 4.7 to 5.1%) and the Bactiseal groups (from 3 to 3.3%). The beneficial effect of Bactiseal was maintained long term. Conclusions: There is a similar low incidence of late infections with both conventional and antibiotic-impregnated hydrocephalus shunt catheters. The bacteriological causes of such late infections will require a prospective multicentre study.

A140
The Results: Data from a total of 104 patients was collected and divided into those with and without a diagnoses of SA. The data included CSF pressure and polysomnogram characteristics among patients without and with IIHS (opening pressure = 25) subdivided into those with and without sleep apnea (AHI = 5). Higher opening pressures were found in subjects higher BMI (p 0.001) and SA (p 0.001). We used opening pressure as a measure of disease severity for IIHS and found no significant association between SA severity as measured by AHI. In addition, there was no correlation between opening pressure in those with more severe apnea in REM (0.9) related SA. Conclusions: There have only been a few studies looking at OSA and IIHS. Our sample includes many more variables and a much larger sample size. Our statistical analysis revealed similar results to prior studies after adjusting for age and BMI namely that there is no association between IIHS and OSA. Both conditions however are correlated with age and BMI. Future direction could include looking at multiple time points of direct intracerebral pressure monitoring in conjunction with continuous positive airway pressure use. Introduction: Obesity is a risk factor for both Idiopathic intracranial hypertension syndrome (IIHS) and sleep apnea (SA). Thus far, there are no human studies on neurochemical factor that may play a role in the susceptibility of this population to sleep disordered breathing. Leptin is well known for its adipogenic properties (3) and high levels in serum of obese individuals. Animal studies have shown that Leptin is protective against OSA and that it is deficient in the cerebrospinal fluid (CSF) of obese animals, a phenomenon known as "leptin resistance" due to poor penetration through the blood-brain barrier. (4). However, this has not been tested in humans. This project addresses the basic mechanism of OSA susceptibility in obese patients with PTC by distinguishing between those who have leptin resistance (low plasma versus CSF Leptin levels). Through this study we would like to propose alternate interventions such as intranasal leptin as a viable option for the treatment of OSA in this patient population. Our hypothesis is that patients with IIHS are more susceptible to OSA due to obesity and/or leptin resistance. Through this study we plan to explore the relationship between leptin and sleep disordered breathing in subjects with IIHS. We also plan to analyze the CSF from these subjects for evidence of leptin resistance as well as other possible neurohumoral factors which may play a role in the pathophysiology. Higher opening pressures were found in subjects with with higher BMI (p = 0.03) and SA (p = 0.05). Leptin concentrations in CSF were not correlated to the plasma level (r = 0.5; p = 0.216). CSF leptin levels were not correlated to body mass index (r = 0.14; p = 0.567). Opening pressure did not correlate with CSF leptin levels (r = 0.96; p = 0.732). Conclusions: Obesity is a risk factor for both PTC and OSA and is characterised by leptin resistance due to poor penetration through the blood-brain barrier. Leptin has been shown to be protective against OSA (5). Our pilot data demonstrates that in subjects with IIHS those with higher BMI and SA had higher opening pressures. Our analysis of leptin levels in subjects with IIHS and SA did not demonstrate a correlation between CSF and serum leptin as is seen in obesity and SA, i.e. "leptin resistance". There was also no correlation with BMI which was a surprising finding. This suggests that the neurochemical pathways associated with leptin in IIHS are unique and distinct from its role in adiposity. Sleep disordered breathing and leptin resistance in Idiopathic intracranial hypertension syndrome. Summary: The role of leptin in obesity and in the physiology of respiration has been well established. Patients with sleep apnea have been shown to be "leptin resistant" with low cerebrospinal fluid levels of leptin suggesting abnormal blood brain penetration. Elevated intracerebral pressure has also been associated with sleep disordered breathing. To date no study has looked at the relationship between neurochemical factors and sleep disordered breathing in patients with Idiopathic intracranial hypertension syndrome. We performed analysis of leptin and other adipocytokines in cerebrospinal fluid, reviewed polysomnographic and anthropometric data in patients with IIHS and SA. Our study did not demonstrate "leptin resistance" which suggests a unique role for leptin and the blood brain barrier in this population which is distinct from that seen in adiposity. Fluids Barriers CNS 2018, 15(Suppl 1):4

Sleep disordered breathing and leptin resistance in idiopathic intracranial hypertension syndrome
Battery (FAB), and Trail Making Test (TMT)-A. Gait disturbance was evaluated with 10-m reciprocating walking test. We counted a time and the number of steps, and calculated average gait speed, average step length, and cadence. Regional cerebral blood flow (rCBF) was quantified in 34 Regions-of-interest (ROIs) by 123I-IMP single photon emission computed tomography using the autoradiography method.
We assessed the relationships between improvements of clinical measures and improvement of rCBF of each ROI after LPS. Results: There were significant improvements of MMSE, FAB, gait speed, step length, and cadence after LPS. The rCBF in the left anterior thalamus, bilateral amygdala and left hippocampus significantly improved after LPS. We found significant associations between an improvement of TMT-A and increased rCBF in the left anterior thalamus, between an improvement of gait speed and increased rCBF in the left anterior thalamus and left amygdala, and between an improvement of step length and increased rCBF in the left ventrolateral prefrontal cortex, left putamen and left amygdala. Conclusions: These results might suggest that hypoperfusion in the anterior thalamus is responsible for decreases of psychomotor speed and gait speed, and that hypoperfusion in the amygdala relates to gait disturbance. Introduction: Frailty is a common clinical syndrome best conceived as an acceleration of the aging process. Frailty in elderly persons increases their vulnerability to stress, thus leading to a greater risk of disease and disability, increased use of health services and a higher risk of death. Normal pressure hydrocephalus (NPH) is well known as a treatable syndrome of the classical triad of gait disturbance, dementia, and urinary disturbance. This work is the first attempt in order to discuss hypotheses on the link between frailty and NPH, a new window of opportunity for reversible frailty. Our framework should successively address whether (i) patients suspected of NPH meet frailty criteria, (ii) hydrocephalus aggravates frailty and (iii) in what way treating NPH with a shunt insertion should be considered as reversing frailty. Methods: The objective of this work was to estimate prospectively prevalence of frailty in a cohort of 100 patients suspected of NPH. In all patients, we measured CSF hydrodynamics, in particular resistance to CSF outflow (Rout). We also measured frailty, with the Short Emergency Geriatric Assessment (SEGA) index, a simple tool to detect frailty in elderly subjects. SEGA index evaluates frailty on a 13-item scale, with each item graded either 0 (most favourable state), 1 or 2 (least favourable state), thus making it possible to classify subjects into three groups: not very frail (score ≤ 8), frail (8 < score ≤ 11), and very frail (score > 11). Results: In our cohort, mean ± SD SEGA was 8.9 ± 3.6. 63% of were not very frail (SEGA ≤ 8) and 19% very frail (SEGA > 11). There no correlation between SEGA index and Rout (cf figure). But note that patients with the lowest SEGA (less frail) were those with the lowest Rout (less CSF disorder).

A149
Conclusions: More than half of our population suspected of NPH meets frailty criteria. The concept of frailty, a precursor state to functional dependency, appears as a useful tool in gaining better knowledge of the mechanisms leading to loss of autonomy. Identification of frailty has become a major objective, notably with the aim of implementing effective preventive health policies, targeting populations at risk of dependency sufficiently upstream in the disablement process. Identification of frail patient with NPH in order to be treated with a shunt should valuable to reverse loss of autonomy and improve quality of life, but also be beneficial in terms of health economics, health system efficiency but also in terms of social protection. Introduction: The fluid pressure in the subarachnoid space is distributed evenly in the cranium and the spine thanks to Pascal Swider's law. In a supine patient (i.e. low gradient effect of gravitation on body fluids) with communicating CSF circulation, a needle inserted in the lumbar space gauges cranio-spinal fluid. During infusion tests, saline is injected though a lumbar needle to challenge intracranial fluid mechanics. The lumbar needle has per se an intrinsic resistance that has to be taken in account to measure accurately CSF hydrodynamic parameters. To avoid this, one proposes to insert two lumbar needles: one for fluid pressure measurement and one for fluid challenge. Hence the measurement is not influenced by the needle's resistance. However, it imposes the insertion of a second needles that increases the morbidity and duration of the procedure. One needle infusion study is routinely performed in our Department. We hypothesize that the lumbar needle's resistance influences the resistance to CSF outflow (Rout) but doesn't correlate with other intracranial parameters. Methods: 100 one needle lumbar infusions studies have been performed. ICM+ software was used to measure and estimate various parameters such as baseline and plateau ICP mean, ICP pulse amplitude (Amp), resistance of the needle, Rout (taking in account the needle's resistance), elastance and PVI. We performed basic statistics and Pearson's r 2 correlation between the needle's resistance and other intracranial parameters. Results: In this example of infusion study, the needle's resistance is identified by the first bump in the upper left trace. Note that the change in ICP mean doesn't influence ICP pulsatility (Amp).In our group, the mean (± SD) resistance of the needle was 1.32 ± 0.59 mmHg ml −1 min −1 . There was no correlation (i.e. r 2 ≈ 0) between the resistance of the needle vs. baseline ICP, plateau ICP, baseline ICP amp, plateau ICP amp, Rout, elastance and PVI.

A150
Introduction: A decrease in cerebral blood flow (CBF) is repeatedly observed in patients with severe symptoms of normal pressure hydrocephalus (NPH), however it is currently unclear how exactly a decrease in CBF affects the symptoms of NPH. A previous study reports that CBF is highly associated with the low-frequency centroid (LFC) of intracranial (or cerebrospinal fluid; CSF) pressure signal. This study attempted to investigate the association between CBF decrease, assessed by LFC, and the symptom presentation in NPH.

Methods:
The clinical information and data from forty-two NPH patients who had undergone CSF infusion test were retrospectively analyzed. The LFC was obtained from spectral analysis of low frequency bandwidth (0.5-2.5 Hz). Major symptoms of NPH is defined as per the Hakim triad (i.e. gait disturbance, cognitive deterioration and urinary incontinence). Results: Urinary incontinence (n = 6) was highly associated with lowered LFC during the entire phase of the infusion test (p < 0.05). The lowered LFC in patients with urinary incontinence was most prominent during the plateau phase of infusion test (p = 0.001, AUC = 0.912), followed by transient phase (p = 0.024, AUC = 0.792) and the baseline phase (p = 0.048, AUC = 0.755). The lowered LFC was not indicative of cognitive deterioration (n = 14) nor gait disturbance (n = 19). Conclusions: The urinary incontinence, which is known to be associated with lowered CBF, is also associated with lowered LFC. Correcting CBF could be effective for urinary incontinence, but not for the cognitive and gait dysfunction in NPH. Efforts should be made for combining different therapeutic options for treating varying symptoms of NPH. Introduction: Respiration modulates ICP pulse amplitude originating in cardiac beat-induced vascular pulsation (A vp ). This modulation reflects the change in craniospinal compliance during a respiratory cycle. We aimed to quantify such modulation during periods of impaired compliance as characterized by the occurrence of B-waves, and to test whether the amplitude modulation is increased in aqueduct stenosis. Methods: We developed a method for quantifying A vp while demodulating respiratory waves. With A rp denoting the amplitude of respiratory waves in the ICP time course, and AA vp the amplitude of respiratory waves in the A vp time course, we defined 'Respiratory Amplitude Quotient' as RAQ = A rp /AA vp . We determined RAQ in phases of B-wave occurrence in recordings of two patient groups presenting with Hakim's triad: 17 patients without positive response to external lumbar drainage or irresponsive to shunt therapy (non-responder, NR), and seven patients with aqueduct stenosis (AQ) confirmed by morphological changes assessed in MRI scans. We used a Mann-Whitney test to determine whether there was an association between RAQ and the diagnosis. Results: We found significant association between RAQ and independent AQ diagnosis (p = 0.0308) with RAQ lower in the AQ group. Our method proved suitable for quantifying respiratory modulation of ICP pulse amplitude originating in vascular pulsation. Conclusions: In AQ patients, respiration modulates the vascular ICP pulse amplitude significantly stronger than in NR patients. This modulation may reflect short term craniospinal compliance, which appears to be substantially reduced in aqueduct stenosis. Introduction: A serious adverse event following shunt surgery is subdural hematoma (SDH), but the use of adjustable shunts makes it possible to non-invasively treat postoperative SDH. In this study, based Introduction: To assess and classify the cerebrospinal fluid (CSF) dynamics, cardiac-and respiratory-induced pressure gradients were visualized and quantified in healthy subjects using real-time magnetic resonance (MR) imaging. Methods: Asynchronous 2D phase-contrast imaging was applied to 12 healthy subjects (10 males and 2 females, 31 ± 13 yo) at 3-tesra MRI to observe spatio-temporal distributions of total CSF velocities. Subjects were instructed to repeat 6-s respiration by audio guidance. Cardiac pulsation of each individual was recorded by electrocardiogram. Whereas respiration was monitored by a bellows-type pressure sensor. The frame rate was 4.6 image/s, resulting in acquiring approximately 256 frames during 56 s. The total velocity waveform in each voxel was separated into the cardiac-and respiratory-driven components in the frequency domain. The two components were then used to calculate the corresponding pressure gradients based on Navier-Stokes equation. After obtaining the pressure gradient components in all the voxels in the intracranial CSF space, region of interests (ROIs) were placed at the anterior cistern of the brainstem, Sylvian aqueduct, lateral ventricle, and fourth ventricle for quantitative analysis. Results: The cardiac-driven pressure gradient in caudal-to-cranial was 14.2 ± 3.05 Pa/m, while the respiratory-driven was 1.23 ± 0.46 Pa/m at the anterior cistern of the brainstem. The cardiac component was significantly and consistently higher than the respiratory in all the ROIs. Conclusions: The cardiac-and respiratory-driven CSF pressure gradients in the intracranial space were differentiated. As the scan time is only a minute, the present technique is readily applicable to patients with hydrocephalus to be compared with the healthy subjects. Introduction: Idiopathic normal pressure hydrocephalus (iNPH) is non-obstructive ventricular enlargement with normal intracerebral pressure resulting in a triad, gait difficulty, cognitive impairment and urinary incontinence. The Evans' index (EI) has been extensively used as diagnostic imaging. The EI value of 0.3 or greater is one of criteria in iNPH guideline. However, the normal EI in the Thai aging population has not been reported. Moreover, skull shapes between the Asian and Caucasian may be different. The purpose of the study is to establish normal Evans' index, lateral ventricular volume (LVV) and the correlation respect to age, modified cephalic index (mCI) in non-hydrocephalus Thai adults. Methods: Axial brain non-contrast computerized tomographic scans (NCCT) of 100 Thai mild traumatic head injury subjects (45 men, 55 women) without intracranial lesion were reviewed. The mean age was 67.25 ± 15.38(above 40 years old). EI, LVV, mCI were measured. Results: The mean value of EI in this study was 0.258 ± 0.03. The correlation coefficient of EI, LVV with respect to Age is high in 70-79 and ≥ 80 age group with the value of 0.611, 0.632 respectively. The mean value of mCI was 86.8 ± 4.5 and compatible with hyperbrachycephalic head shape. Conclusions: EI is a good indirect marker of LVV especially in patients above 70 years old. Different head shape between Caucasians and Thais may reduce optimal EI cutoff point.

A158
Chronic posttraumatic headache completely cured by ventriculo-atrial shunt: report of three cases K. Takagi 1 , K. Onouchi 2 , K. Kato 3 1 NPH Center, Kashiwa-Tanaka Hospital, Japan; 2 Department of Neurology, Kashiwa-Tanaka Hospital, Kashiwa, Japan; 3 Department of Surgery, Abiko-Seijinkai Hospital, Abiko, Japan Correspondence: K. Takagi Fluids and Barriers of the CNS 2018, 15(Suppl 1):A158 Introduction: Chronic post-traumatic headache (CPTH) is still a common complication of minor head injuries. The purpose of this study is to report three cases with long lasting CPTH completely cured by VA shunt. Methods: We have treated 728 patients with CPTH. Most of them complained headache with orthostatic nature similar to spontaneous intracranial hypotension. However, their CSF pressures were not low and their signs and symptoms improved by CSF removal in high incidence. Therefore, we applied VA shunt in 16 cases. Three cases with complete cure were reported here. Results: Case 1 was 66 yo male who suffered from whiplash injury 5 years ago. He complained orthostatic headache with many other symptoms such as memory disturbance. He received VA shunt because CSF removal improved his signs and symptoms. All of his symptoms disappeared next morning of the surgery. Case 2 was 68 yo female with orthostatic headache and other many symptoms shortly after whiplash injury 17 years ago. Because her complaints almost disappeared by CSF removal, VA shunt was applied. Her symptoms almost disappeared next morning of the surgery. Case 3 was 64 yo complaining orthostatic headache with body pain similar to fibromyalgia since whiplash injury 24 yo ago. She received VA shunt because CSF removal eliminated her signs and symptoms. Her body pain disappeared just next morning of the surgery Conclusions: These positive effects of VA shunts for CPTH without organic brain damage suggest that the involvement of CSF circulation abnormalities for the development of CPTH. Informed consent to publish had been obtained from the patients.

A159
Regional cerebral blood flow at the top of high convexity is not increased in idiopathic normal pressure hydrocephalus R. Takahashi Introduction: The purpose of this study was to elucidate the specific regional cerebral blood flow (rCBF) alterations for idiopathic normal pressure hydrocephalus (iNPH) by comparing proportional rCBF and grey matter change from those of a normal database at the same point of SPECT and MRI examinations, and to demonstrate the relationship between rCBF and the callosal angle. Methods: Thirty subjects with iNPH underwent both CBF SPECT and MRI. After normalization, voxel-wise two-samples t test between patients and 11 normal controls were conducted to compare the regional alteration in grey matter density and rCBF in addition to the correlation analysis between rCBF and the callosal angle. Results: The rCBF reduction and the grey matter decrease were seen in almost similar regions surrounding Sylvian fissure, the left parietotemporal lobe and frontal lobes whereas we did not find rCBF increase at the top of the high convexity where the increase of grey matter density was the highest. Further, the significant positive correlation between rCBF and the callosal angle was found at the top of the high convexity. Conclusions: The current study suggests the relative rCBF decrease due to compression of the top of the high convexity in iNPH. The absence of the rCBF increase with evident increase of grey matter density at the top of the high convexity might be a hallmark of iNPH. Introduction: The idiopathic intracranial hypertension (IIH) a rare and etiologically unknown disorder characterised by serious disturbances in cerebrospinal dynamics, obesity and hormonal factors. In adult populations, the IIH mostly affects obese woman of childbearing age. The IIHs conventional radiographic manifestations are non-specific, as guided by modified Dandy criteria, although several suggestive MRI findigs have been presented. Thus, we studied unorthodox magnetic resonance imaging (MRI) findings and their correlations to BMI, cerebrospinal fluid opening pressure (OP) and treatment outcome. Methods: A total of 35 patients with IIH diagnosis admitted defined catchment area between 2000 and 2016. All available demographic, clinical, medical charts and imaging findings were studied. Results: The mean age at the time of diagnosis was 30 years and the mean follow-up time was 4.4 years and 80% were females. At diagnosis, mean BMI was 36.2 kg/m 2 and mean OP was 31.2 mmHg. Treatment included acetazolamide (94%) and shunting (34%). The MRI at diagnosis showed partial or complete empty sella in 48.6%, edema of optic nerve (CNII) sheaths in 45.7%, increased tortuosity of CNII in 17.1%, flattened sclera in 28.6%, and intraocular protrusion of CNII head in 8.6% of cases. The presence of empty sella, increased tortuosity and edema of CNII, and flattened sclera correlated with higher OP at presentation, although the differences were not significant. The BMI at presentation was higher in patients with empty sella. Complete resolution of symptoms was found more often in patients with IIH-related MRI-findings (78% vs. 56%) Conclusions: Unorthodox findings in MRI are common in IIH patients. The IIH patients with empty sella on MRI had higher BMI and OP at diagnosis, whereas more severe MRI findings suggested better treatment outcomes. Unorthodox phenotypes such as presentation of empty sella are frequent in IIH and could contribute on neuroendocrinological disturbances, thus further multidisciplinary research is warranted.

A161
Cost versus benefit analysis of telemetric ICP measuring device within a shunt system: a single centre experience S. D. Thompson Introduction: The recent introduction of telemetric intracranial pressure (ICP) monitoring devices presents an opportunity to improve the treatment of patients post shunt insertion. However, these devices are not without an increase in cost, which presents a challenge to many public health services to assess the financial value of inserting such devices. Methods: A retrospective review of our in-house database of all Miethke Sensor Reservoir (SR) units inserted to date. We look at the number of occasions that patients with these devices have presented, when without this device, they would have been admitted for surgical insertion of an ICP bolt in line with our hospital policy. The SR currently costs around an additional £1700 versus our standard shunt reservoir, with an average cost of admission/surgery of £3000 for ICP monitoring at our institution. Results: 60 SR units inserted to date over a 6.5 year period, telemetrically measured ICP 105 times. A minimum of 18 ICP bolts have been prevented in this patient population due to the SR unit, resulting in a return on investment (ROI) of 53%. ICP bolts prevented in patients with an SR in place for > 6 months (n33) = 16, with an ROI of 86%. ICP bolts prevented in patients with an SR in place for > 12 months (n9) = 7, with a ROI of 137%. Conclusions: Our results suggest a cost-benefit after 12 months for the SR. We believe this highlights that there is a financial benefit to using the SR as well as a clinical one.

A162
The effect of MRI scans on implanted shunt valves with magnetically adjustable settings S. D. Thompson Introduction: The use of magnetically adjustable valves for the treatment of complex hydrocephalus has been increasing gradually since the original Hakim adjustable valve was introduced in the 1980s. However the issue of magnetic forces unintentionally adjusting valves has caused issues over the years with unintentional adjustments through contact with magnetic fields causing patients to deteriorate and require intervention. Some valves available to market, whilst being unable to be classed as 'MRI safe' due to incorporating magnets, are understood to be unlikely to adjust in an MR environment. Methods: Over a 5 month period, an attempt was made to check the shunt setting pre/post MRI for all patients undergoing an MRI with an adjustable shunt. Checks were made pre and post MRI by the same highly experienced practitioner. Results: Over the course of 5 months, 28 patients were assessed with a magnetically adjustable valve. 10 patients had a Miethke Pro-GAV