Absence of cerebral microbleeds predicts reversion of vascular ‘cognitive impairment no dementia’ in stroke

Background Cerebral microbleeds may contribute to cognitive deficits in stroke. Cognitive impairment that does not meet the criteria for dementia (cognitive impairment no dementia) is common in stroke, and patients with such impairment can revert to normal cognition. Aims and hypothesis This study examined the association between cerebral microbleeds and the reversion of cognitive impairment no dementia. Method A total of 328 Chinese patients with acute ischemic stroke admitted to the acute stroke unit of a university-affiliated regional hospital in Hong Kong participated in the study. All subjects were assessed for cognitive impairment no dementia with a neuropsychological test battery at three- and 15 months following the index stroke. Of the 180 patients with cognitive impairment no dementia at three-months poststroke, 143 (79·4%) attended the 15-month follow-up. Twenty-nine subjects had reverted from cognitive impairment no dementia to normal cognitive status (reverters), 98 were nonreverters and 16 had progressed to dementia. Results In univariate analysis, the reverters were found to be younger, less likely to have hypertension and cerebral microbleeds, and to have smaller white matter hyperintensity volumes. In multivariate analysis, the absence of cerebral microbleeds remained an independent predictor of reversion with an odds ratio of 4·3. Absence of deep cerebral microbleeds predicted the reversion of the language domain, whereas the absence of lobar cerebral microbleeds predicted the reversion of the visuomotor speed domain. Conclusions The results suggest that the absence of cerebral microbleeds may be associated with a higher likelihood of a reversible cognitive impairment in stroke patients. The mechanism of how this occurs is not well understood