Motor sequencing in older adulthood: relationships with executive functioning and effects of complexity

Abstract Objective: Older adults’ motor sequencing performance is more reliant on executive functioning (EF) and more susceptible to complexity than that of younger adults. This study examined for which aspects of motor sequencing performance these relationships hold. Methods: Fifty-seven younger and 90 non-demented, community-dwelling, older adults completed selected subtests from the Delis–Kaplan Executive Function System as indices of EF and component processes (CP; graphomotor speed; visual scanning; etc.), as well as a computerized motor sequencing task (Push Turn Taptap task; PTT). The PTT requires participants to perform motor sequences that become progressively more complex across the task’s four blocks, and is designed to assess action planning, action learning, and motor control speed and accuracy. Results: Hierarchical regressions using each discrete aspect of performance as the dependent variable revealed that action planning is the only aspect of motor sequencing that is uniquely related to EF (beyond the CP composite) for both age groups. Action learning and motor control accuracy are uniquely associated with EF for older adults only, and only if the sequences are complex. Component processes do not fully account for the unique relationships between motor sequencing and EF in older adults. Conclusions: These results clarify prior findings by showing (a) more aspects of motor sequencing relate to EF for older compared to younger adults and (b) for these unique relationships, EF is only related to action during the generation of sequences that are complex. These findings further our understanding of how aging shapes the links between EF and motor actions, and can be used in evidence-based and theoretically driven intervention programs that promote healthy aging.