How aging affects visuomotor adaptation and retention in a precision walking paradigm

Amanda Bakkum,Daniel S Marigold,Shaila M Gunn

doi:10.1038/s41598-020-80916-8

Abstract

Motor learning is a lifelong process. However, age-related changes to musculoskeletal and sensory systems alter the relationship (or mapping) between sensory input and motor output, and thus potentially affect motor learning. Here we asked whether age affects the ability to adapt to and retain a novel visuomotor mapping learned during overground walking. We divided participants into one of three groups (n = 12 each) based on chronological age: a younger-aged group (20–39 years old); a middle-aged group (40–59 years old); and an older-aged group (60–80 years old). Participants learned a new visuomotor mapping, induced by prism lenses, during a precision walking task. We assessed retention one-week later. We did not detect significant effects of age on measures of adaptation or savings (defined as faster relearning). However, we found that older adults demonstrated reduced initial recall of the mapping, reflected by greater foot-placement error during the first adaptation trial one-week later. Additionally, we found that increased age significantly associated with reduced initial recall. Overall, our results suggest that aging does not impair adaptation and that older adults can demonstrate visuomotor savings. However, older adults require some initial context during relearning to recall the appropriate mapping.

Highlights

We asked whether age affects the ability to adapt to and retain a novel visuomotor mapping learned during overground walking
We divided participants into three different age groups and had them adapt to a novel visuomotor mapping induced by prism lenses while performing a precision walking task
We found that increased age significantly associated with reduced initial recall ( R2 = 0.37, coefficient = -2.41, p = 0.0001), reflected by a smaller difference in foot-placement error on the first adaptation trial between sessions

Summary

Introduction

As the world’s population ages, we need a deeper understanding of how the healthy aging process influences sensorimotor adaptation and retention Both younger and older adults are able to adapt movement in response to sensorimotor perturbations. Malone and B astian[7] showed that the healthy aging process weakened motor memories formed during split-belt treadmill walking, reflected by decreased savings of previously learned step symmetry following five-minute rest periods. In previous studies of healthy young adults, we demonstrated that the motor memory acquired after learning a novel visuomotor mapping in a precision walking paradigm is retained for at least 1 year[17,18]. We divided participants into three different age groups and had them adapt to a novel visuomotor mapping induced by prism lenses while performing a precision walking task. We tested retention of this new mapping by having participants repeat the adaptation protocol one-week later

Methods

Results

Discussion

Conclusion