Development of a Quantitative Evaluation System for Bradykinesia Using MediaPipe Hands.

Parkinson's disease is a neurodegenerative disease characterized by slow progression and is never cured. Its symptoms include motor impairments such as bradykinesia, muscle stiffness, tremor at rest, and postural dysreflexia, as well as non-motor impairments such as depression and autonomic neuropathy. One measure to evaluate Parkinson's disease is the Unified Parkinson's Disease Rating Scale. One of the items in this scale that evaluate bradykinesia, one of the motor symptoms, is the finger tapping test. However, many of the expressions used there are subjective, and the evaluation criteria are ambiguous. Therefore, the purpose of this study was to develop a quantitative hand movement evaluation system using MediaPipe Hands, to analyze finger tapping test, and to evaluate the effectiveness of the system. With this developed system, hand movements can be analyzed by using a webcam. Hand motion was analyzed by calculating the length between hand joints, the speed of joint movement, and the angle between joints. To evaluate the accuracy of the system, we first measured the length between the joints of the fingers as the hand was moved away from and closer to the camera, and then examined the error. Then, the finger tapping test was conducted using the developed system to evaluate the bradykinesia. Accuracy evaluations have shown that MediaPipe Hands can detect hand movements with high accuracy. The finger tapping test also revealed that there was reproducibility in the magnitude of each finger movement, but not in the speed of the movement.