CLINICAL DETERMINANTS OF POSTSTROKE DEMENTIA

Background and Purpose-Frequency of poststroke dementia is high, and s troke considerably increases the risk of dementia. The risk factors fo r dementia related to stroke are still incompletely understood. We sou ght to examine clinical determinants of poststroke dementia in a large well-defined stroke cohort. Methods-The study group comprised 337 of 486 consecutive patients aged 55 to 85 years who 3 months after ischem ic stroke completed a comprehensive neuropsychological test battery an d MRI, including structured medical, neurological, and laboratory eval uations; clinical mental status examination; interview of a knowledgea ble informant, detailed history of risk factors, and evaluation of str oke type, localization, and syndrome. The DSM-III definition for demen tia was used. Results-Frequency of any poststroke dementia was 31.8% ( 107/337), that of stroke-related dementia (mixed Alzheimer's disease p lus vascular dementia excluded) was 28.4% (87/306), and that oi dement ia after first-ever stroke was 28.9% (79/273). The patients with posts troke dementia were older and more often had a low level of education, history of prior cerebrovascular disease and stroke, left hemispheric stroke (reflecting laterality), major dominant stroke syndrome (refle cting laterality and size), dysphasia, gait impairment, and urinary in continence. The demented patients were also more frequently current sm okers, had lower arterial blood pressure values, and more frequently h ad an orthostatic reaction compared with the nondemented stroke patien ts. The correlates of dementia in logistic regression analysis were dy sphasia (odds ratio [OR], 5.6), major dominant stroke syndrome (OR, 5. 0), history of prior cerebrovascular disease (OR, 2.0), and low educat ional level (OR, 1.1). When we excluded those with cerebrovascular dis ease plus Alzheimer's disease or those with recurrent stroke, the: ord er of correlates remained the same. When the patients with dysphasia ( n=30) were excluded, the correlates were major dominant syndrome (OR, 4.6) and low educational level (OR, 1.1). Conclusions-Our data suggest that a single explanation for poststroke dementia is not adequate; ra ther, multiple factors including stroke features (dysphasia, major dom inant stroke syndrome), host characteristics (educational level), and prior cerebrovascular disease each independently contribute to the ris k.