O1 Prevalence and clinical associations of disproportionately enlarged subarachnoid space hydrocephalus, an imaging feature of idiopathic normal pressure hydrocephalus
Chihiro Akiba1, Bibek Gyanwali2, Steven Villaraza2, Madoka Nakajima1, Masakazu Miyajima1, Narayanaswamy Venketasubramanian2, Saima Hilal2, Christopher Chen2
1Department of Neurosurgery, Juntendo University, Tokyo, Japan; 2Memory Aging and Cognition Centre, National University of Singapore, Singapore
Correspondence: Chihiro Akiba - chihi-rocket@hotmail.co.jp
Fluids and Barriers of the CNS 2019, 16(Suppl 3):O1
Introduction: Disproportionately Enlarged Subarachnoid space Hydrocephalus (DESH) is a major imaging feature of idiopathic normal pressure hydrocephalus (iNPH). High incidence of iNPH has been reported in subjects with DESH. We aimed to investigate prevalence of DESH in Singaporean cohorts and to assume prevalence of iNPH.
Methods: A cross-sectional case–control design was used. Subjects aged 60 and over in a memory clinic and a community-based cohort were assessed for the presence of DESH, i.e. ventriculomegaly, Sylvian dilatation, and high convexity tightness and a clinical triad of iNPH, i.e. cognitive, gait and urinary symptoms. We defined subjects that fulfilled all of DESH components as DESH-group, subjects with ventriculomegaly but lacking some of other DESH components as Ventriculo-group, subjects with Sylvian dilatation but lacking some of other DESH components as Sylvian-group, and subjects with high convexity tightness but lacking some of other DESH components as Convexity-group.
Results: The prevalence of DESH was 1.1% in the memory clinic (548 subjects) and 1.0% in the community (946 subjects), which increased with age. The clinical triad was significantly more frequent in DESH-group (memory clinic/community: 50%/11%), compared to those with normal images (none/none), Sylvian-group (7%/2%), and Ventriculo-group (12%/7%). In the triad, gait disturbance was significantly more frequent in DESH-group (83%/33%) compared to those with normal images (2%/1%), Sylvian-group (14%/4%), and ventriculo-group (26%/10%).
Conclusions: The prevalence of DESH was around 1% in Singaporean cohorts. High convexity tightness was specifically associated with the clinical triad of iNPH. Gait disturbance seemed to be the most specific to DESH and high convexity tightness.