Apathy, ventriculomegaly and neurocognitive improvement following shunt surgery in normal pressure hydrocephalus

Abstract

Introduction. Apathy – impaired motivation and goal-directed behaviour – is a common yet often overlooked symptom in normal pressure hydrocephalus (NPH). Caudate atrophy often yields apathetic symptoms; however, this structural and functional relationship has not yet been explored in NPH. Additionally, little is known about the relationship between apathy and post-shunt cognitive recovery. Methods. This audit investigated whether apathetic symptoms improve following shunt surgery in NPH, and whether this relates to cognitive response. In addition, we assessed the relationship between ventriculomegaly and apathy using the bicaudate ratio. Twenty-two patients with NPH completed the Mini-Mental State Examination (MMSE), the Apathy Evaluation Scale (AES) and the Geriatric Depression Scale (GDS) before and 3–9 months after shunt surgery. Pre-operative ventriculomegaly was correlated with pre-operative AES and GDS scores. Difference scores (post-shunt minus baseline values) for AES and GDS were correlated with cognitive outcome. Results. Greater pre-operative ventriculomegaly was associated with increased level of apathy and depression. A reduction in apathetic symptoms following shunt surgery was associated with improved performance on the MMSE. Conclusions. Apathy may be indicative of a greater degree of subcortical atrophy in NPH and may relate to functional outcome.

Keywords::

• apathy
• audit
• caudate nucleus
• cognitive function
• normal pressure hydrocephalus

Acknowledgments

The authors would like to thank the administrative staff at the Departments of Psychiatry and Neurosurgery, University of Cambridge, Addenbrooke's Hospital for their assistance.

Declaration of interest: BJS reports personal fees and share options from Cambridge Cognition, personal fees from Servier, personal fees from Lundbeck and grants from Janssen/J&J, outside the submitted work. JDP reports grants from NIHR Senior Investigator Award, grants from NIHR Cambridge Brain Injury HTC, outside the conduct of the study; CRH reports personal fees and share options from Cambridge Cognition, outside the submitted work. ZC has nothing to disclose. EED reports grants from Pinsent Darwin Fund, grants from U.S. National Institutes of Health (ORWH, NIDA, NIAAA, OD), outside the conduct of the study; KAP's PhD is funded by a grant from NIHR Biomedical Research Centre. NCK reports grants from Joint Royal College of Surgeons/Dunhill Medical Trust Fellowship, grants from Tunku Abdul Rahman Project, outside the conduct of the study; CK and GS reports grants from Janssen/J&J, outside the conduct of the study.