Wearable system to measure asymmetry by sensing arms swing

Motor alterations produced by Parkinson’s disease (PD) are commonly evaluated by the observation of a clinical expert. In order to provide an objective assessment, we developed a cloud-based measurement system that can be attached to arms, based on accelerometers, for measuring, storing and analyzing acceleration data from the upper limbs to estimate the arms swing asymmetry.This paper presents the design of the instrument and evaluates two methods to obtain the asymmetry of arms swing; the first using an accelerometer in both wrists of the participants; the second using a pair in both arms. The system was used to evaluate the gait in 40 individuals (20 PD patients and 20 controls without motor anomalies), matched by age.We have determined that at least two accelerometers are required to measure the asymmetry of individuals, allowing us to observe significant differences (p <0.01) between PD patients and controls, although both methods correctly measure the effective acceleration (RMS) in the movement of the arms.