Dementia after first stroke.

Abstract

Cognitive deficits may significantly worsen the quality of life after stroke. Our aim was to determine the frequency of dementia in a consecutive series of previously nondemented patients between the ages of 40 and 79 years at 3 months after a first ischemic stroke. All patients admitted to our department during an 18-month period who met the above criteria were visited and tested and underwent a CT scan 3 months after their stroke. Dementia was diagnosed according to criteria of the National Institute of Neurological Disorders and Stroke and AIREN, but cases with aphasia were not excluded. Of 304 patients admitted for stroke, 146 were eligible for study. Eleven refused to participate, 25 were dead at 3 months, and 110 were tested. Fifteen patients were demented (13.6%; 95% confidence interval [CI], 7.8% to 21.5%), and six had severe isolated aphasia, neglect, or memory deficit (5.4%). Excluding patients with aphasia, 5.0% of cases showed dementia (95% CI, 1.6% to 11.3%). The frequency of dementia was 24.6% (95% CI, 14.5% to 37.3%), considering only patients with supratentorial lesions and with residual deficits of elementary functions (paresis, sensory deficits) at the time of examination. Demented patients had significantly more diabetes (P<.029), atrial fibrillation (P=.032), aphasia at entry (P<.001), large middle cerebral artery infarctions (P=.001), and a more severe neurological deficit at entry (P=.003) and at 3 months (P=.001). At CT scan, demented patients had a larger mean volume of the recent lesion (P<.001) and more lesions in the frontal lobe (P=.041). An exploratory multivariate analysis selected age between 60 and 69 years (odds ratio [OR], 45.8; 95% CI, 2.9 to 726.0), diabetes (OR 59.4; 95% CI, 4.3 to 821.0), aphasia (OR, 14.8; 95% CI, 2.0 to 111.0), a large middle cerebral artery infarction (OR, 30.0; 95% CI, 2.7 to 334.0), and lesions of the frontal lobe (OR, 9.8; 95% CI, 1.3 to 72.8) as significant independent correlates of poststroke dementia. Dementia is relatively frequent after a clinical first stroke in persons younger than 80 years, and aphasia is very often associated with poststroke dementia. If aphasic patients are not considered, it may be necessary to screen a very large number of subjects to collect an adequate sample of demented cases.