Hippocampal atrophy correlates with severe cognitive impairment in elderly patients with suspected normal pressure hydrocephalus

Abstract

Measurements of hippocampal formation atrophy using MRI have been useful in distinguishing demented patients with a diagnosis of probable Alzheimer's disease from cognitively normal controls. To determine whether there is a similar relationship between hippocampal size and dementia in elderly patients suspected of normal pressure hydrocephalus (NPH), the authors obtained mini-mental status examination (MMSE) scores and MRI measurements of hippocampal size and CSF volume on 16 elderly patients whose severe ventriculomegaly and unexplained gait impairment made NPH a probable diagnosis. Hippocampal size correlated strongly with MMSE score (r = 0.75, p < 0.001); no significant MMSE correlation was found for ventricular CSF volume or extra-ventricular/ventricular CSF ratio. It was concluded that hippocampal atrophy is associated with severe cognitive dysfunction in many elderly patients with a diagnosis of NPH. As a hypothesis for further investigation, the detection of such atrophy may help identify cases where the presence of a pathology of Alzheimer's disease complicates the diagnosis of NPH.