Evaluation of movement of patients with Parkinson's disease using wearable MoCap system and bilateral cyclograms

The article focuses on a method of quantifying movement of patients with Parkinson's disease (PD) using wearable motion capture (MoCap) system and bilateral cyclograms. The method uses cyclogram characteristics such as the slope, second moment of area and the area of the cyclogram to compare movements of left and right side of body. For symmetric movement, cyclogram should lie on a symmetry line passing through the origin inclined at an angle 45°. To study the body movement, measurement was performed using accelerometers (Xsens Technologies B.V.). Four accelerometers were placed on subject's arms and legs to measure accelerations in the anterior-posterior, medial-lateral and inferior-superior directions. Subjects (patients and healthy subjects) accomplished an extended Timed Up & Go Test (TUG). The data from the accelerometers were preprocessed, and then the bilateral cyclograms of two synchronized accelerations were created and evaluated. Using the cyclograms we confirmed the hypothesis that patients with PD have asymmetrical movements of the limbs. Omitting medication 24 hours before the measurement in patients with early stage PD had little effect on the synkinesias of gait. Findings suggest the possibility of the designed application of wearable MoCap system and bilateral cyclograms for use in drug therapy by evaluating postural stability via measuring accelerations. Thus, method using accelerometers and bilateral cyclograms is newly proposed for patients with PD.