Objective Assessment of Rigidity in Parkinson's Disease using a Wearable Device

Rigidity is a key motor symptom of Parkinson's disease (PD). Clinical evaluation typically involves tools like the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), but such assessments have drawbacks, including their subjective nature and dependence on the expertise of the examiner. To address this, the study aimed to objectively measure rigidity using RehaBEElitation, a bee-themed serious game. This game was managed by a wearable device that features inertial and resistive light sensors The device was built using the Esp8266 microcontroller, which combines an accelerometer, gyroscope, and magnetometer, each with three axes capable of sensing hand orientation. Resistive light sensors detect the opening and closing of the hands and fingers. The device is lightweight, comfortable to use, prioritises hygiene, and is ergonomically designed. Data were collected from 5 healthy male participants and 5 PD subjects in the “on” and “off” states of medication, paired by age and gender. The participants played Phase 4 of the game for 5 minutes, or until they had completed all of the targets. The highest value of Power Spectral Density (PSD) was determined and associated with the MDS-UPDRS scale. Statistical tests were used to determine differences between groups (PD “off” vs. PD “on” vs. healthy). For all sensors and axes, the PD “off” group had the smallest power amplitude at the PSD-measured frequencies, followed by the PD “on” group and then the healthy group. On most axes, there were significant correlations between the MDS-UPDRS scores and the sensors. According to the findings, people with PD had larger impairments in muscle activity and coordination than the healthy group, indicating more rigidity.