How Common Is the Exponential Decay Pattern of Motor Skill Acquisition? A Brief Investigation

Abstract

Motor performance is classically described as improving nonlinearly with practice, demonstrating rapid improvements early in practice with stabilization later, which is commonly modeled by exponential decay functions. However, retrospective analyses of our previously collected data challenge this theoretical model of motor skill acquisition, suggesting that a majority of individual learners actually demonstrate patterns of motor improvement different from this classical model. A convenience sample of young adults, older adults, and people with Parkinson disease trained on the same functional upper-extremity task. When fitting three-parameter exponential decay functions to individual participant data, the authors found that only 13.3% of young adults, 40.9% of older adults, and 66.7% of adults with Parkinson disease demonstrated this “classical” skill acquisition pattern. Thus, the three-parameter exponential decay pattern may not well-represent individuals’ skill acquisition of complex motor tasks; instead, more individualized analysis methods may be warranted for advancing a theoretical understanding of motor skill acquisition.

Personalized practice dosages may improve motor learning in older adults compared to “standard of care” practice dosages: A randomized controlled trial

“…Typically, investigations of practice dosages assign all participants in a group to the exact same number of practice repetitions as one another. However, given the inter-individual variability of motor skill acquisition and learning ( 13 , 14 ), more personalized methods of dosing may be necessary. This study sought to investigate one such personalized method, in which practicing to or beyond one's individual practice plateau differentiates and standardizes the groups' practice dosages.…”

“…While data suggest that standard clinical dosages typically yield inadequate practice amounts to result in motor learning, the optimal number of repetitions needed to obtain a clinical benefit is not clear. What is clear, however, is that motor skill acquisition is quite variable between individuals ( 13 , 14 ), as are time scales of learning ( 15 , 16 ). Because of this inter-individual variability in motor skill acquisition and learning, it is unlikely that there is one optimal practice dose, but rather, motor practice dosages should be more personalized.…”