Utilization of a wrist-mounted accelerometer to count movement repetitions

Stroke is a leading cause of disability. Lasting effects of a stroke may include limited mobility in limbs. In order to restore a reasonable amount of function in the upper extremities, extensive rehabilitation that includes multiple repetitions of practice are necessary. These practice sessions are often boring to the patient. The work we describe in this paper is a part of a larger project using the ENGAGE video gaming protocol to make these therapy sessions more engaging and effective. Instead of repeating a specific exercise, the patient plays a video game using the Nintendo Wii remote or the PlayStation EyeToy. When engaging in such non-standard motion, it becomes more difficult for the clinician to gauge how much of the required practice the patient is actually getting in each session. To help solve this problem, we have designed a simple accelerometer-based sensor node that tracks movement repetitions and helps the clinician track the patient's progress across sessions. We present results from calibration and statistical validation of this sensor node.