Development of a Clonus Management System: A Case Study of Sit-To-Stand Learning in a Stroke Patient

This paper proposes a new clonus management system that integrates sit-to-stand (STS) learning with informatics and physical methods. Clonus is an involuntary muscle spasm, which often interferes with motor learning or the training of chronic patients. A conventional ankle-foot orthosis makes it difficult for patients to control the onset of clonus or to improve it. A new system with an original orthosis can reduce the occurrence of clonus by the physical constraint of the ankle by firmly placing the heel of the affected side on the ground. This system also provides a ground reaction force of the heel because clonus hardly occurs when the heel is placed on the ground. The system supports STS movement by linearly moving the seat up and down when users place the heel of the affected side on the ground. Using this system, users can learn how to perform the STS movement while managing their clonus. Testing its effect on a stroke patient confirmed that the system relieves the onset of clonus and reduces the frequency with which clonus occurs during STS learning. In addition, the results of continuous learning showed that the patient could perform the STS movement without the occurrence of clonus even without using the developed orthosis. Here we discuss the results from the viewpoints of human-machine interaction and the relationship between nervous and peripheral systems. The proposed clonus management system may promote the improvement of chronic patients with clonus.