First prototype of EMG-controlled power hand orthosis for restoring hand extension in stroke patients

Weakness in finger extensors is a common post-stroke deficit that can disturb hand functioning. Despite introducing several powered hand orthoses in literature, most of these devices focused on providing finger flexion. There is a little consideration for providing active hand extension in stroke patients. Moreover, in many devices, the finger extensions were restored passively by spring component. In this study, a new Electromyography (EMG)-controlled powered hand orthosis was designed to improve hand function by restoring and training hand extension in stroke patients with paretic hand. This orthosis was a glove-like device that was developed from two mechanical and electrical sections. After construction and verifying of the orthosis, its applicability was tested on two patients with Cerebrovascular accident (1 woman and 1 man) with paretic hands in an 18-session therapeutic approach. To evaluate the effectiveness of orthosis, Wolf Motor Function Test and Box and Block test were conducted before and after the training sessions. The primary assessment of the prototype was conducted on a healthy subject and three stroke patients. These evaluations showed that the new powered hand orthosis could be effective for finger extension task and training. Furthermore, after the 18-session training approach, significant improvements were seen in the scores of both Wolf and Box and Block tests. The preliminary findings suggested that the first prototype of orthosis could provide a desirable function for stroke patients with paretic hand. Moreover, it could be used as a training device in the rehabilitation of these patients.