Finger motor skills and related brain regions in patients with cognitive disorder.

BackgroundMotor impairment precede cognitive impairment and may be early biomarkers for dementia. We have previously reported an association between finger tapping and cognitive function; however, the link between finger motor movements and associated brain regions is unclear.ObjectiveIn this study, finger tapping movements were used to identify brain regions strongly associated with finger motor dexterity in individuals with Alzheimer's disease (AD) and mild cognitive impairment (MCI).MethodsThis exploratory, cross-sectional study included individuals with AD or MCI who underwent finger motor movement measurements and 3D magnetic resonance imaging (MRI). Voxel-based morphometry analysis was conducted using Statistical Parametric Mapping 12 and Computational Anatomy Toolbox 12 to assess gray matter volume. Correlations between MRI and finger motor parameters were analyzed using intracranial volume, Mini-Mental State Examination score, age, and sex as covariates.ResultsWe included 136 individuals (AD, 71; MCI, 65). The number of taps and the number of freezing calculated from acceleration significantly correlated with gray matter volume in motor and sensory regions, including the primary motor (BA4) and primary somatosensory (BA3, 1, 2) cortices. Many correlations with the left hemisphere were found in both left- and right-handed bimanual alternating tapping tasks.ConclusionsFinger motor dexterity in individuals with cognitive impairment is associated with gray matter volume in specific brain regions, with a pronounced correlation in the left hemisphere. These findings suggest that finger motor skills may be linked to structural brain changes.