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. A total of 31 participants aged 8-17 yr 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. The number of speed peaks, movement time, and hand path length were all increased without visual feedback. Our results demonstrate that complex upper limb movements are refined across childhood and adolescence, potentially reflecting more anticipatory planning and feedforward control. 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.<b>NEW & NOTEWORTHY</b> This 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.