The effect of shunt surgery on neuropsychological performance in normal pressure hydrocephalus: a systematic review and meta-analysis.

We conducted a systematic review of the literature and used meta-analytic techniques to evaluate the impact of shunt surgery on neuropsychological performance in patients with normal pressure hydrocephalus (NPH). Twenty-three studies with 1059 patients were identified for review using PubMed, Web of Science, Google scholar and manual searching. Inclusion criteria were prospective, within-subject investigations of cognitive outcome using neuropsychological assessment before and after shunt surgery in patients with NPH. There were statistically significant effects of shunt surgery on cognition (Mini-Mental State Examination; MMSE), learning and memory (Rey Auditory Verbal Learning Test; RAVLT, total and delayed subtests), executive function (backwards digit span, phonemic verbal fluency, trail making test B) and psychomotor speed (trail making test A) all in the direction of improvement following shunt surgery, but with considerable heterogeneity across all measures. A more detailed examination of the data suggested robust evidence for improved MMSE, RAVLT total, RAVLT delayed, phonemic verbal fluency and trail making test A only. Meta-regressions revealed no statistically significant effect of age, sex or follow-up interval on improvement in the MMSE. Our results suggest that shunt surgery is most sensitive for improving global cognition, learning and memory and psychomotor speed in patients with NPH.The research was supported by the National Institute for Health Research (NIHR) Brain Injury Healthcare Technology Co-operative based at Cambridge University Hospitals NHS Foundation Trust and University of Cambridge. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. Katie Peterson is funded by a grant awarded to John D. Pickard from the NIHR Biomedical Research Centre. Dan Jackson is supported by the Medical Research Council Unit Programme number U105260558. George Savulich and Clare Killikelly were supported by grants awarded to Barbara J. Sahakian from Janssen/J&J. John D. Pickard reports grants from the NIHR Senior Investigator Award, the NIHR Cambridge Brain Injury Healthcare Technology Co-operative and Van Geest Grant for hydrocephalus research. Barbara J. Sahakian receives funding from the Wellcome Trust (grant 089589/Z/09/Z), the MRC/Wellcome Trust Behavioural and Clinical Neuroscience Institute (joint award G00001354), the Human Brain Project and the NIHR Cambridge Brain Injury Healthcare Technology Co-operative.This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by Springer