Development and Test of a Spasm Sensor for Hand Rehabilitation Exoskeleton

With the abnormal muscle strength caused by spasm, patients after stroke have great difficulties to regain hand function. Not only does the spasm force cause distress in rehabilitation, but the spasm type also makes an influence on rehabilitation effect. Therefore, it is vital to detect spasm force and identify spasm type, especially for device-assisted hand rehabilitation. In this article, we design a spasm sensor to detect joint spasm force and identify the spasm type. First, an elastic sensing unit with a parallel slider is introduced to eliminate mutual influence between each joint. With the principle of force detection, the joint spasm force can be measured. After that, a method of spasm type identification is proposed based on joint spasm force instead of electromyographic (EMG) signal. At last, clinical tests are carried out to show the good performance of joint spasm force measurement. Also, the accuracy of spasm type identification is tested with simulated spasm. The assistance of our sensor is shown with block lifting tests to evaluate function recovery and ensure safety in hand rehabilitation.