Intracranial pressure dynamics are not linked to aqueductal cerebrospinal fluid stoke volume

Authors: Tain RW, Alperin N.

TO THE EDITOR: A recent study by Hamilton et al. (4) proposes that aqueductal cerebrospinal fluid (CSF) stroke volume (ASV) is significantly associated with the width of the second peak of the intracranial pressure (ICP) waveform in normal pressure hydrocephalus. Existing evidence and current understanding of ICP physiology do not support a mechanistic link between aqueductal CSF flow and ICP dynamics.

Penn et al. (5) were unable to detect ICP differences between intra- and extraventricular spaces in dogs with induced hydrocephalus. Chiang et al. (3) measured CSF flow through the aqueduct in healthy and hydrocephalic patients and predicted that the pressure difference that drives the aqueductal CSF pulsation is extremely small, on the order of 0.01 mmHg, consistent with the measurements by Penn et al. Therefore it is not expected that aqueductal CSF flow either modifies or affects the shape of the ICP waveform in general, nor only its second peak.

Free full text and source: Journal of applied physiology

J Appl Physiol. 2013 Jun;114(11):1645. doi: 10.1152/japplphysiol.00357.2013.