Widespread gray and white matter microstructural alterations in dual cognitive-motor impairment

Abstract

INTRODUCTION: Dual cognitive-motor impairment in aging is a strong predictor of dementia, yet its effects on vulnerable gray matter regions microstructure remain unexplored. METHODS: This study classified 582 individuals aged 36-90 into cognitive-motor impairment, isolated cognitive or motor impairment, and control groups. Microstructural differences in 27 temporal and motor-related gray matter regions and white matter tracts were assessed using DTI and mean apparent propagator (MAP-MRI), a technique well-suited for gray matter analysis. RESULTS: We found widespread microstructural alterations in gray and white matter among individuals with dual cognitive-motor impairment. These changes were not observed in isolated cognitive or motor impairment after multiple comparisons correction. DISCUSSION: Dual cognitive-motor impairment is associated with reduced cellular density in temporal gray matter, decreased fiber coherence, and potential demyelination in white matter tracts, suggesting widespread microstructural disruption. These findings could help understand brain aging and facilitate interventions to slow neurodegeneration and delay dementia onset.