Reference values for CSF outflow resistance and intracranial pressure in healthy elderly

Abstract

This study reports reference values for ICP and R(out) and should be used for comparison when investigating disorders with suspected CSF dynamic disturbances in the elderly. ICP was in the same range as that reported in the young and middle-aged. The upper limit of R(out) was higher than previously believed to be the upper limit of normal for this age group.

The European iNPH Multicentre Study on the predictive values of resistance to CSF outflow and the CSF Tap Test in patients with idiopathic normal pressure hydrocephalus

“…In this study, the mean Rout of 16 mm Hg/ml/min was well above the upper limit of normal Rout, as reported by Ekstedt,33 who found the 95th percentile of healthy individuals is 11.5 mm Hg/ml/min. According to a more recent article by Malm et al ,34 the upper limit for normality (in this case the 90th percentile) is 17.4 mm Hg/ml/min, a value surpassed by no more than 34% of our patients. The description of a normal reference interval that to such an extent overlaps with the distribution of Rout values among our patients, indicates that the contribution of the pathological factors involved in iNPH may give rise to too small changes in Rout for them to reflect disease severity in correlational analyses.…”

Spectral analysis of intracranial pressure signals recorded during infusion studies in patients with hydrocephalus

“…They obtained resting pressure values of 9.4 ± 4.6 mmHg in 151 patients at risk for normal pressure hydrocephalus (NPH). These values are lower than those found in another study on 40 healthy (no psychiatric or neurologic disorders) elderly subjects, where a median resting pressure of 11.6 mmHg was obtained while patients lied on the supine position during data recording [6]. These differences show that further research is needed to better understand CSF dynamics and to improve clinical management of patients with hydrocephalus.…”

Hydrodynamics of the Certas™ programmable valve for the treatment of hydrocephalus

“…Error bars show the 95% confidence limits. The shaded area shows the reference range (10 th to 90 th percentile) of Rout for healthy elderly [6]. …”