Fig. 1

Flowchart of the study population. The initial outcome 3 months postoperatively has been highlighted in grey in each prognostic group. The number of observations, ratios and percentages have been given to account for any missing data. ^aTap test evaluation based only on clinician’s judgement. ^bDescription of the performance and interpretation of tap test are found in (Table 1). ^cImprovement of any core symptoms (gait, cognition and urinary incontinence) assessed by neurosurgeon. ^dAt least 20% improvement in average gait speed, gait test task and evaluation described in (Table 1). ^eReduction in the iNPHGS total score at least by a single point. ^fAt least 0.015 improvement in 15D score. ^g1 Ventriculomegaly (congenital or unclear etiology). ^h8 VAD or CVD,7 AD, 7 AD + VAD, 3 Cognitive impairment or dementia of unspecified etiology, 3 Ventriculomegaly (congenital or unclear etiology), 3 PD (2 vascular, 1 idiopathic), 2 Drug induced parkinsonism or psychiatric condition, 2 traumatic brain injury, 1 FTD, 1 Spinal stenosis, 1 arthrosis, 1 LBD. ⁱ7 AD, 5 spinal stenosis, 3 Cognitive impairment or dementia of unspecified etiology, 3 VAD or CVD, 2 Drug induced parkinsonism or psychiatric condition, 1 LBD, 1 Vertigo. ^jPatients underwent 24-h intraventricular measurement of ICP, interpretation of the monitoring is described in (Table 1). iNPH Idiopathic normal pressure hydrocephalus, sNPH secondary normal pressure hydrocephalus, ICP intracranial pressure, VAD vascular dementia, CVD cerebrovascular disease, AD Alzheimer’s disease, PD Parkinson’s disease, iPD idiopathic PD, LBD Lewy’s bodies disease