Clinical effect of cerebrovascular atherosclerosis on cognition in Alzheimer's disease

Abstract

BACKGROUND: The association between cerebrovascular atherosclerosis and Alzheimer's disease (AD) has been examined in many cross-sectional studies; however, there are few data regarding the role of cerebrovascular atherosclerosis on the longitudinal course of cognitive decline in AD. The aim of this study was to examine the progression of cognitive function in AD patients with cerebrovascular atherosclerosis compared to those without atherosclerosis over a two-year period. METHODS: Forty-seven AD patients with cerebrovascular atherosclerosis and 81 AD patients without atherosclerosis were assessed for cognitive function at the time of diagnosis and again at follow-up after two years. The cognitive functions were evaluated by neuropsychological tests including mini-mental state examination (MMSE) and clinical dementia scale (CDR). RESULTS: Repeated-measures multivariate analyses showed that there was a significant group-by-time interactions for the temporal changes of the MMSE and CDR between the two groups. The group-by-time interactions remained significant when the atherosclerotic patients were sub-classified into either an extracranial stenosis (EC) group or an intracranial stenosis(IC) group. Comparing either the EC or IC group with the non-atherosclerosis group, there were no main effects by time or group alone, but there were significant group-by-time interactions for the MMSE and CDR. CONCLUSIONS: Cognitive function worsened more in terms of progressive impairment in AD patients with cerebrovascular atherosclerosis compared to AD patients without cerebrovascular atherosclerosis, regardless of whether the atherosclerosis was extracranial or intracranial.