Impact of bilingualism on cognitive outcome after stroke

Background and Purpose:  Bilingualism has been associated with slower cognitive aging and a later onset of dementia. In this study, we aimed to determine whether bilingualism also influences cognitive outcome after stroke.  Methods:  We examined 608 patients with ischemic stroke from a large stroke registry and studied the role of bilingualism in predicting poststroke cognitive impairment in the absence of dementia.  Results: A larger proportion of bilinguals had normal cognition compared with monolinguals (40.5% versus 19.6%; P<0.0001), whereas the reverse was noted in patients with cognitive impairment, including vascular dementia and vascular mild cognitive impairment (monolinguals 77.7% versus bilinguals 49.0%; P<0.0009). There were no differences in the frequency of aphasia (monolinguals 11.8% versus bilinguals 10.5%; P=0.354). Bilingualism was found to be an independent predictor of poststroke cognitive impairment.  Conclusions  Our results suggest that bilingualism leads to a better cognitive outcome after stroke, possibly by enhancing cognitive reserve.