Objective: The aim of this study was to determine whether patients with possible Alzheimer's disease (AD) who do not meet criteria for vascular dementia but who nonetheless have clinical or radiographic evidence of cerebrovascular disease (CVD), differ in presentation or rate of progression from patients with probable AD.
Method: Baseline cognitive and functional scores were obtained from 154 patients who had either possible or probable AD. Repeat data after a 12 month interval were obtained on 73 of these patients. Baseline data and rates of progression were compared for probable AD patients and possible AD patients with evidence of co-existent CVD.
Results: The diagnostic groups did not differ at baseline with a mean mini-mental state examination (MMSE) score of 18.1. Comparison of the longitudinal data showed a mean annual drop of 4.1 points on the MMSE in both groups.
Conclusions: The patients with and without evidence of co-existent CVD did not differ either at baseline or prognostically suggesting that evidence of CVD does not affect the rate of progression in AD. However, further longitudinal studies using neuropathological criteria are warranted to determine whether such data can be interpreted in favour of including possible AD cases in clinical trials of probable AD.