Association between neural-drive variability and motor function in middle-aged and older adults

Area of Science:

• Neuroscience
• Motor Control
• Gerontology

Background:

• Aging is associated with declines in motor function.
• Neural drive variability, originating from spinal mechanisms, influences motor performance.
• Understanding these neural factors is crucial for addressing motor deficits in older adults.

Purpose of the Study:

• To determine if neural drive variability explains motor function variance in middle-aged and older adults.
• To investigate the relationship between spinal mechanisms and performance on NIH Toolbox motor tasks.
• To assess the utility of submaximal contractions as a proxy for neural drive variability.

Main Methods:

• Review of existing literature on neural drive variability and motor function.
• Analysis of the coefficient of variation for force during submaximal contractions as a measure of neural drive variability.
• Correlation of neural drive variability measures with performance on balance, dexterity, endurance, locomotion, and handgrip strength tasks.

Main Results:

• Neural drive variability explained moderate variance in balance, dexterity, and endurance.
• Locomotion performance was linked to motor-unit discharge in calf muscles.
• Handgrip strength related to motor-unit timing in forearm-hand muscles.

Conclusions:

• Neural drive variability during submaximal contractions contributes to performance variance in dynamic motor tasks for older adults.
• Expanding the range of tasks to measure neural drive variability may enhance its explanatory power.
• Further research is needed to fully elucidate the role of neural drive in age-related motor function changes.