Ischemic white matter damage and cognitive impairment

Abstract

White matter damage may play an important role in the pathogenesis of vascular dementia. White matter abnormalities are easily visualized as white matter high-intensity lesions (WML) on T2-weighted magnetic resonance images. The extent of WML may be an indicator of cognitive impairment, in particular, impairment related to frontal lobe dysfunction. However, it is unclear whether the extent of WML is an independent predictor of cognitive impairment. In patients with extensive WML, atrophy of the corpus callosum may be an important predictor of global cognitive impairment. We investigated the relationship between the extent of WML and callosal size with cognitive function in patients who had been diagnosed with lacunar stroke or no specific neurological disease. Multivariate analysis showed that only callosal size and age were significant independent predictors of mini-mental state examination scores (a measure of global cognitive function), whereas only the extent of WML was an independent predictor of the score on the verbal fluency task (a measure of frontal lobe function). Callosal atrophy may be an important predictor of global cognitive impairment in patients with WML, whereas the extent of WML per se may be related to impairment of frontal lobe function independent of callosal atrophy. White matter high-intensity lesions with callosal atrophy may indicate a severe form of white matter damage with axonal loss, the degree of which may determine the severity of global cognitive impairment. Our longitudinal study revealed an association between progression of WML and vascular risk factor status during follow up in patients with initially mild WML. Early detection of WML without callosal atrophy at a stage of subtle cognitive impairment and slowing the progression of WML to a severe form with callosal atrophy might prevent the development of dementia. (PsycInfo Database Record (c) 2023 APA, all rights reserved)