Cognitive Decline in Patients with Chronic Hydrocephalus and Normal Aging: ‘Growing into Deficits’

BACKGROUND/AIM: To explore the theory of ‘growing into deficits’, a concept known from developmental neurology, in a series of cases with chronic hydrocephalus (CH). METHODS: Patients were selected from the Amsterdam Dementia Cohort and underwent extensive dementia screening. RESULTS: Twelve patients with CH were selected, in whom Alzheimer's disease was considered unlikely, based on biomarker information and follow-up. Mean Mini-Mental State Examination score was 24 (range 7-30). Most patients were functioning on a level of mild dementia [Clinical Dementia Rating score of 0.5 in 8/11 (66.7%) patients]. On neuropsychological examination, memory and executive functions, as well as processing speed were most frequently impaired. CONCLUSION: In our opinion, the theory of ‘growing into deficits’ shows a parallel with the clinical course of CH and normal aging when Alzheimer's disease was considered very unlikely, because most of these patients were functioning well for a very large part of their lives. The altered cerebrospinal fluid dynamics might make the brain more vulnerable to aging-related changes, leading to a faster cognitive decline in CH patients compared to healthy subjects, especially in case of concomitant brain damage such as traumatic brain injury or meningitis.