Wearable Sensor System for Motor Disorder Assessment and Managing

Spasticity is a motor disorder that causes muscle stiffness and non-fluid movement. It is estimated that over 12 million people worldwide suffer from spasticity. Proper management allows patients to thrive, but if not managed it will result in permanent assisted living. Correct assessment of the severity of spasticity is crucial in selecting appropriate treatment and medication dosage, as well as in promoting the development of appropriate relief methods for spasticity. Yet, assessment of spasticity currently relies on using a perception scale that is based on the physician’s attempt to quantify and/or qualify physical experiences of moving the patient’s joints. This method is known to suffer from low sensitivity and from unacceptably high inter-rater and intra-rater variability. The ability to use a perception scale is further impaired by relying on the clinician’s working memory, as often consecutive evaluations are done within months gap. Hence, there is an urgent need to construct objective, reliable monitoring, and analyzing metrics for measuring motion dependent muscle tone for the assessment of spasticity. In this research, we demonstrate an instrumented device with force and motion sensors to enable objective quantification of the severity level of spasticity towards evidence-based medicine. We measure the force and velocity simultaneously, while also monitoring the correlation between these factors. We relate the measurements to biomechanical properties of muscles, by fitting the collected data to a modified form of Hill’s muscle model. Our system offers a quantitative tool with a reliable metric for evaluating spasticity with high accuracy at the point of care, which can enable the delivery of effective and timely treatments and improve the quality of life of the patients. Furthermore, our wearable system could be used in other applications that need objective measurements of force and motion.