Corpus Callosum Integrity Loss Predicts Cognitive Impairment In Leukoaraiosis

Objective: To investigate regional white matter fibers loss in Leukoaraiosis (LA) and its relationship with cognitive impairments. Methods: Fifty-six participants with LA and 38 healthy controls underwent clinical evaluations and MR scans. Participants with LA were classified as cognitively normal (LA-NC, n = 18), vascular cognitive impairment of none dementia (LA-VCIND, n = 24), and vascular dementia (LA-VaD, n = 14) by Mini-Mental State Examination and Clinical Dementia Rating. Cognitive domains including visual-spatial, naming, attention, language, abstraction, memory, and orientation were assessed. With the use of Tract-based spatial statistics, mean fractional anisotropy (FA) of major white matter fiber tracts were compared between LA and controls and among LA groups with varying levels of cognitive impairments. Regression analyses were performed to evaluate relationships between FA values and cognitive performance. Results: Participants showed significant FA reduction in the corpus callosum (CC), bilateral corona radiata, anterior limb of the internal capsule, external capsule, posterior thalamic radiation, and superior longitudinal fasciculus compared to controls and across LA groups. The LA-VaD group showed consistent damage in the body and genu of CC compared to the LA-NC and LA-VCIND groups. A positive correlation between visual-spatial and FA reduction in right anterior corona radiates in LA-VCIND and body of CC in LA- VaD. Interpretation: We found regional fiber loss in the CC across the cognitive spectrum in patients with LA and correlations between FA and visuospatial impairment in the anterior corona radiata in patients with LA-VCIND and in the body of CC in patients with LA-VaD.