Volume 1 Supplement 1

48th Annual Meeting of the Society for Research into Hydrocephalus and Spina Bifida

Open Access

Cerebrovascular pressure-reactivity in normal pressure hydrocephalus

  • ZH Czosnyka1Email author,
  • F Van Den Boogaard1,
  • M Czosnyka1,
  • S Momjian1,
  • L Gelling1 and
  • JD Pickard1
Cerebrospinal Fluid Research20041(Suppl 1):S20


Published: 23 December 2004

Clinical background

We investigated the possible relationship between vascular reactivity and the resistance to CSF outflow in a group of shunted and non-shunted NPH patients.

Materials and Methods

Sixty eight patients (47 non-shunted and 21 shunted) with NPH have been examined. During the examination ICP was measured in the ventricles (using a needle inserted into a pre-implanted Ommaya reservoir) at baseline and in response to a constant rate infusion (1.5 ml/min) of normal saline. Resistance to CSF outflow (Rcsf) was measured as an increase of ICP divided by the infusion rate. During the test, arterial pressure was monitored continuously using a Finapress finger cuff. Cerebrovascular pressure-reactivity was assessed as a moving correlation coefficient between coherent 'slow waves' of ICP and spontaneous fluctuations of arterial blood pressure (PRx index). This variable has been demonstrated previously to correlate with autoregulation of CBF [1]. Positive value of PRx reveals impaired cerebrovascular pressure-reactivity, whereas negative values indicate normal reactivity.


In non-shunted patients impaired pressure reactivity was associated with lower resistance to CSF outflow: (PRx versus Rcsf: R = -0.5; P < 0.0005). This relationship was inverted in shunted patients: PRx was positively correlated with Rcsf (R = 0.51; P < 0.03).


Cerebrovascular pressure-reactivity is disturbed in patients with normal resistance to CSF outflow, suggesting underlying cerebrovascular disease. After shunting the pressure-reactivity strongly depends on shunt function and may deteriorate when the shunt malfunctions.

Authors’ Affiliations

Academic Neurosurgery, Addenbrooke's Hospital


  1. Czosnyka M, et al: Neurosurgery. 1997, 41: 11-19. 10.1097/00006123-199707000-00005.View ArticlePubMedGoogle Scholar


© The Author(s) 2004

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.