Shared and Distinct Associations of Manual Dexterity and Gross Motor Function With Brain Atrophy

Area of Science:

• Neuroscience
• Gerontology
• Radiology

Background:

• Poor motor function is linked to brain atrophy and cognitive decline.
• The relationship between specific motor domains, brain atrophy, and influencing factors like cerebrovascular burden and physical activity requires further investigation.

Purpose of the Study:

• To investigate the associations between manual dexterity and gross motor function with brain atrophy in older adults.
• To determine if cerebrovascular burden and physical activity modify these associations.

Main Methods:

• Analysis of data from 726 participants in the Baltimore Longitudinal Study of Aging (mean age 70.6 years).
• Utilized latent growth curve modeling to assess associations between motor domains (manual dexterity, gross motor function) and brain volumes (cortical and subcortical) using MRI scans.
• Adjusted analyses for demographics, white matter hyperintensities, and physical activity.

Main Results:

• Both manual dexterity and gross motor function were cross-sectionally associated with larger white matter volumes and smaller ventricular volumes.
• Manual dexterity showed additional associations with gray matter and white matter volumes in various brain regions.
• Longitudinally, higher motor function was linked to reduced atrophy in temporal white matter and occipital gray matter, and slower ventricular enlargement.

Conclusions:

• Manual dexterity and gross motor function have both shared and distinct associations with brain atrophy in cognitively normal older adults.
• These findings highlight the importance of motor function in maintaining brain structure in aging.