The cognitive syndrome of vascular dementia: Implications for clinical trials

Dementia is common among patients with cerebrovascular disease, particularl y in a setting of one or more clinically evident strokes. Prior cohort and case studies have suggested that the cognitive syndrome of vascular dementi a is characterized by predominant executive dysfunction, in contrast to the deficits in memory and language function that are typical of patients with Alzheimer disease. The course of cognitive decline may also differ between those dementia subtypes, with many, but not all, patients with vascular de mentia exhibiting a stepwise course of decline caused by recurrent stroke a nd most patients with Alzheimer disease exhibiting a gradually progressive course of decline. The findings of prior studies of the cognitive syndrome of vascular dementia must be interpreted with caution, however, because of (I)possible inaccuracies in the determination of the dementia subtype and t he loss of precision that might result from pooling heterogeneous subgroups of patients with vascular dementia, (2) difficulties inherent in identifyi ng a pattern of strengths and weaknesses in patients who are required to ha ve memory impairment and other deficits to meet operationalized criteria fo r dementia, and (3) the use of limited test batteries whose psychometric pr operties are incompletely understood. Specific questions that should be add ressed by future studies are discussed.