Relation between vascular risk factors and neuropsychological test performance among elderly persons with Alzheimer's disease

BACKGROUND: Vascular risk factors increase the risk of Alzheimer's disease (AD). The mechanisms for these associations are unclear, and may be due to misdiagnosis of a vascular dementia syndrome as AD. OBJECTIVE: To examine differences in neuropsychological profile among persons diagnosed clinically with AD with and without vascular risk factors or stroke. METHODS: Community based cohort study. Individual and composite scores of neuropsychological tests at the time of clinical diagnosis of incident AD were compared among 243 persons with and without vascular risk factors or stroke. RESULTS: Among subjects with incident AD, diabetes was associated with lower performance in Delayed Recall of the Selective Reminding Test (SRT), while persons diagnosed with hypertension scored lower in consistent long term recall (CLTR) of the SRT and current smokers scored lower in Category Fluency. None of the risk factors was associated with differences in composite scores in memory, abstract/visuospatial or language domain, nor was the number of risk factors per person. Persons with stroke had a higher delayed recall score at the time of AD diagnosis. CONCLUSION: The presence of vascular risk factors among persons with clinically diagnosed AD was associated with subtle differences in neuropsychological profile at the time of diagnosis. This study needs to be replicated in samples with brain imaging, a comprehensive executive abilities battery, and pathological diagnosis of AD.