Extended practice improves the accuracy and efficiency of goal-directed reaching guided by supplemental kinesthetic vibrotactile feedback

Prior studies have shown that providing task-specific vibrotactile feedback (VTF) during reaching and stabilizing with the arm can immediately improve the accuracy and efficiency. However, such studies typically evaluate performance after less than 1 hour of practice using VTF. Here we tested the effects of extended practice using supplemental kinesthetic VTF on goal-directed reaching with the arm. Healthy young adults performed a primary reaching task and a secondary choice reaction task individually and as a dual-task. The reaching task was performed under three feedback conditions: visual feedback, proprioceptive feedback, and with supplemental kinesthetic VTF applied to the non-moving arm. We compared performances before, during, and after approximately 10 hours of practice on the VTF-guided reaching task, distributed across 20 practice sessions. Upon initial exposure to VTF-guided reaching, participants were immediately able to use the VTF to improve reaching accuracy. Performance improvements were retained from one practice session to the next. After 10 hours of practice, the accuracy and temporal efficiency of VTF-guided reaching were equivalent to or better than reaching performed without vision or VTF. However, hand paths during VTF-guided reaching exhibited a persistent strategy whereby movements were decomposed into discrete sub-movements along the cardinal axes of the VTF interface. Dual-tasking capability also improved, such that the primary and secondary tasks we performed more concurrently after extended practice. Our results demonstrate that extended practice on VTF-guided reaching can yield performance improvements that accrue in a manner increasingly resistant to dual-task interference.