Contribution of Cognitive Processes to Fine Motor Reprogramming and Adaptation Processes and Effects of Musical Expertise on Motor Processes in Advanced Age

It is known that aging is associated with normative declines in both motor and cognitive processes, specifically, executive functioning. It is also known that these two processes become increasingly interdependent with advanced age. However, due to this increased interdependence between motor and cognitive processes, it remains challenging to disentangle the concurrent contributions of cognitive and motor aging. Numerous aging studies show an association between frequent cognitive stimulation and preserved cognitive abilities (e.g., enhanced executive functioning). What has been less often evaluated is whether specific skills influence cognitive and motor processes in old age. The primary objective of the current dissertation was to explore the contribution of executive functioning and musical experience to fine motor reprogramming and adaptation processes in advanced age. Firstly, we explored the involvement of three aspects of executive functioning: divided attention, response reprogramming/inhibition, and adaptation in fine motor performance of older adults. Secondly, we investigated the prediction that musical experience might provide benefits to cognitive processes involved in motor performance. To address these goals, participants overlearned repeated pairs of key presses to establish a pre-potent motor response. Participants’ performance on the pre-potent responses was compared to conflicting responses. Kinematic analyses were used to disentangle reaction time into broadly cognitive, measured by planning time (PT), and motor, measured by execution time (ET), components. The main goal of Study 1 was to investigate the contribution of cognitive and motor processes involved in fine motor reprogramming of younger and older adults. To this end, a dual-task paradigm was used to simulate the effects of cognitive aging in young adults. With the addition of a cognitive load, the ET of younger adults became more similar to that of older adults and as compared to full attention conditions. In Study 2, the same dual-task paradigm was adapted to investigate the effects of musical expertise on cognitive and motor reprogramming processes of older adults. With increased attentional load, musicians and non-musicians showed no differences in ETs. However, as opposed to musicians, non-musicians slowed down their PTs for well-learned stimuli. These findings suggest that musical experience was more beneficial to cognitive (PT) components rather than the more motor (ET) components of fine motor performance. Study 3 was designed to explore the contribution of musical experience to motor adaptation processes in older adults. In this study, previous exposure to conflict helped older musicians to adapt their motor responses, while older non-musicians failed to show motor adaptation effects with increasing conflict frequency. In conclusion, these findings provide compelling evidence that age-related declines in fine motor response reprogramming may be related to reduced cognitive capacity. These data also provide evidence for a contribution of musical experience to enhanced motor reprogramming and motor adaptation skills in older age. Notably, the observed benefits of musical experience were found in the cognitive aspects of performance and not the motor components. Together, the reported studies advance the current understanding of how cognitive processes play a role in fine motor performance. The work has implications for how to maintain or improve functional independence in late life.