Mechanisms underlying age-related declines in motor skill learning

Following an injury, for example older adults may need to learn to control and interact with assistive devices or may need to relearn self-care, such as dressing. Many studies, including our own work, have documented a declining ability of older adults to learn new manual motor skills. We have demonstrated the importance of spatial working memory (SWM) in the two major types of motor skill learning: sensorimotor adaptation and motor sequence learning. We found that SWM performance is predictive of the rate of motor learning in young adults for both sensorimotor adaptation and motor sequence learning. We also observed significant neural overlap between a SWM task and the early, but not late, stages of adaptation. In contrast, older adults do not engage the same brain regions as young adults do when learning new motor skills. No correlation between SWM performance and rate of sensorimotor adaptation or SWM performance and rate of motor sequence learning was found in older adults. Therefore, older adults do not successfully recruit SWM during the early stages of skill learning and rely more on cognitive processes for the control of simple actions. In contrast, for complex tasks they are less likely to engage the relevant cognitive processes. Understanding the preservation and limits of skill learning ability of older adults is, among others, critical for the develpopment of rehabilitation programs.