Changes in gray matter volume associated with gait speed and muscle mass in older adults with mild cognitive impairment.

BackgroundMild cognitive impairment (MCI) is an early stage of cognitive decline between normal aging and dementia. Gait speed, a key marker of physical function, has been associated with both cognitive decline and brain atrophy. Sarcopenia, characterized by age-related loss of muscle mass and function, has also been linked to structural brain changes.ObjectiveTo investigate the associations between sarcopenia, its individual components and regional gray matter volume (GMV) in older adults with MCI.MethodsThis cross-sectional study included 234 older adults with MCI. Sarcopenia, gait speed, handgrip strength, and appendicular skeletal muscle mass index (ASMI) were assessed according to the 2019 Asian Working Group for Sarcopenia criteria. Brain T1-weighted magnetic resonance imaging was analyzed using voxel-based morphometry. Voxel-wise group comparisons were performed to identify GMV differences after adjustment age, sex, comorbidity, depressive symptoms, nutritional status, and total intracranial volume.ResultsSlower gait speed was significantly associated with lower GMV in the bilateral putamen and left superior frontal cortex. Lower ASMI was associated with higher GMV in the left inferior temporal cortex. No significant GMV differences were found by sarcopenia status or handgrip strength.ConclusionsSlower gait speed is associated with reduced GMV in motor-related brain regions, indicating early brain structural changes in older adults with MCI. Although lower ASMI was associated with higher GMV, this finding should be interpreted cautiously. These findings highlight the complex interactions between physical function and brain structure, emphasizing gait speed as a potential indicator of brain health in older adults with MCI.