Home-Use Synergy-Alleviating System.

This project develops a simple home-use training system for people with upper limb motor impairment that measures the strength of abnormal synergy expressions applied to the fingers and provides visual feedback so that the user can strive to reduce the involuntary movement of distal joints. Most neurological disorders, including stroke, originate from damage to the corticospinal tract (CST). A significant recovery of motor impairment necessitates the restoration of the CST, while the reliance on alternative tracts including the reticulospinal tract (RST) enhances abnormal synergy expressions, degrading arm/hand dexterity. An intentional effort to restore preferential use the CST would be expected to retrieve and expedite joint individuation and arm/hand dexterity. Indeed, the efficacy of the so-called synergy-alleviating exercises which are considered to promote preferentially using the CST has been evidenced by several studies. Through repeated efforts to reduce involuntary co-activation using this system, the abnormal synergy would be alleviated and CST integrity would be strengthened, leading to improvement in the overall motor function. The system provides proprioceptive and visual feedback to the central nervous system so that the user tries to correct motor commands to distal joints. The interactive training program motivates the user to achieve a certain number of repetitions for a training session so that neural plasticity can occur.