Does age-related movement variability affect visuomotor adaptation beyond cognitive factors?

What is it about?

Research over the last three decades has suggested that individuals become less able to adapt their learned movements in response to predictable changes in their bodies and environments with advancing age. The most widely accepted theory to explain this suggests that older adults are less able to develop or use cognitive strategies, such as correcting their movement during a task, to help them perform well. However, another possibility is that adaptation is affected by the simultaneous increase in movement variability with age, a relationship which has not been closely examined before. This study evaluated whether increased movement variability in older adults affects individuals' ability to adapt to predictable sensory changes. Results suggested that older adults showed more movement variability than younger adults during a visuomotor hand-eye coordination task. Across all participants, increased movement variability correlated with slower adaptation and smaller aftereffects, both signs of reduced motor learning. The hand-eye coordination task also employed sensory changes of varying magnitude, to make it more or less likely that participants would employ mental strategies. These conditions did not alter the relationship between age and task performance, suggesting that differences in adaptation with age cannot be explained fully by problems with mental strategies. Although the results show a link rather than a direct cause, they suggest that increased movement variability may contribute to age related declines in visuomotor adaptation.

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Photo by Vitaly Gariev on Unsplash

Photo by Vitaly Gariev on Unsplash

Why is it important?

Previous research into the effect of ageing on individuals' ability to adapt their movements has largely overlooked the role of increased movement variability. This study found that older adults displayed higher levels of task-related movement, and that this was linked to slower learning and weaker aftereffects, both signs of reduced adaptation. These results suggest that increased movement variability with age may be linked to the concurrent decline in motor adaptation. This challenges the theory that the age-related decline in motor adaptation is driven by a reduction in the use of cognitive strategies.