Characterizing Complex Upper Limb Movements with and without Visual Feedback in Typically Developing Children
The development of upper limb movements has been primarily described through reaching movements, which may not have the complex motor planning and execution demands of many daily tasks. In this study, we introduced a complex task in which individuals had to navigate their hand from a start target through two openings in a simple maze to reach an end target. In half the trials, participants received visual feedback of their hand position, and in half of the trials they did not. Thirty-one participants ages 8 to 17 years completed the study. We found that with visual feedback, reaction time, number of speed peaks, movement time, and hand path length all decreased with age. Number of speed peaks, movement time, and hand path length were all increased without visual feedback, however, the impact of removing visual feedback was greatest on the younger children and decreased with age. Our results demonstrate that complex upper limb movements are refined across childhood and adolescence, with a decreasing reliance on visual feedback likely due to increasing feedforward control and improved ability to use proprioceptive feedback. This task can be applied to clinical populations such as cerebral palsy to assess impairments in motor planning and execution as well as determine how proprioceptive impairments contribute to complex movements. NEW AND NOTEWORTHYThis study used a novel paradigm to examine how children plan and execute complex upper limb movements, both when they have visual feedback of hand position available and when they do not. We show that with age, performance with visual feedback improves reflecting advancing motor planning and execution abilities. Older children were less impacted by removing visual feedback than younger children, likely due to improved feedforward control and use of proprioceptive feedback.