Background and Purpose— Poststroke cognitive impairment is frequent. There are, however, few longitudinal studies examining delayed changes in poststroke cognition.

Methods— As part of a longitudinal study of incident dementia after stroke, 115 older stroke survivors (>75 years of age) without dementia were evaluated at 3 and 15 months with a detailed neuropsychological evaluation (including memory, attention, executive performance, and language).

Results— we found that 9% of older stroke patients developed incident dementia, with significant deterioration in global cognition, memory, and attention. Only the severity of expressive language performance at 3 months was associated with dementia at follow-up. Conversely, 57 patients (50%) experienced some improvement in global cognition. None of the criteria for early cognitive impairment identified people at increased risk for dementia.

Conclusions— Delayed dementia is frequent in older stoke patients, but current criteria for early cognitive impairment are not useful as predictors of cognitive deterioration. Improvement in cognition occurred in most patients.