Age-related Reductions in Manual Asymmetry with Increased Visuospatial Demands

Background: Many factors influence manual asymmetry during goal-directed motor tasks, but it is unclear how the manipulation of visuospatial information influences laterality in hand control in aging adults.
Objective: To examine age-related changes in manual asymmetry with increased visuospatial processing demands.
Methods: Twenty young (M = 20.8, SD = 3 years) and 20 older (M = 69.9, SD = 6 years) right-handed adults participated in a motor task which required pieces to be inserted into spatially mapped holes (Task 1), and a motor plus visuospatial task (Task 2), where the pieces to be inserted were not spatially mapped with the holes. Manual asymmetry was determined using the laterality quotient (LQ), which was computed using time to completion.
Results: Dominant right-hand performance was observed for Task 1 for young adults (LQ = 3.91) and older adults (LQ = 5.14), but for Task 2 a more balanced performance between the hands was found for older adults (LQ = -0.73) versus young adults (LQ = 6.53), p < 0.05.
Conclusions: The reduction in manual asymmetry in Task 2 with age is most likely due to the added demands from increased visuospatial processing, which differentially influenced movement control in older compared to young adults.