Limitations in differentiating vascular dementia from Alzheimer's disease with brief cognitive tests

Abstract

OBJECTIVE: To investigate the diagnostic value of brief cognitive tests in differentiating vascular dementia (VaD) from Alzheimer's disease (AD). METHOD: Fifteen patients with mild VaD, 15 patients with mild probable AD and 30 healthy controls, matched for age, education and dementia severity, were submitted to the following cognitive tests: clock drawing (free drawing and copy), category and letter fluency, delayed recall test of figures and the EXIT 25 battery. RESULTS: VaD patients performed worse than AD patients in category fluency (p=0.014), letter fluency (p=0.043) and CLOX 2 (p=0.023), while AD cases performed worse than VaD patients in delayed recall (p=0.013). However, ROC curves for these tests displayed low sensitivity and specificity for the differential diagnosis between VaD and AD. CONCLUSION: Although the performance of VaD and AD patients was significantly different in some cognitive tests, the value of such instruments in differentiating VaD from AD proved to be very limited.