<p>Tremor, or an involuntary and oscillatory movement of a body part, is one of the cardinal symptoms of Parkinson’s disease (PD) and can significantly affect activities of daily living in patients. Although tremor can be mitigated with anti-PD medications, medication effectiveness is mixed for patients. Therefore, daily monitoring and assessment of tremor are of interest to patients, clinicians, and researchers. While several sensors and wearable devices have been developed and introduced to the market, their high costs limit accessibility. The current study aimed to develop a tremor assessment system in the format of a mobile application and assess the reliability of the system for measuring tremor and movement speed. Self-generated tremor by healthy young adult participants were used for the research’s data collection. Participants held the portable device and conducted self-measurements by following in-app instructions in the mobile application. Resting tremors were measured while participants rested their arm on an arm of a chair, postural tremor was measured while they maintained a position against gravity, and kinetic tremor was measured during a movement task. The data collection took less than fifteen minutes. The linear and rotational motions were collected by accelerometers and gyroscopes, embedded within the mobile devices, and the results delivered to the users’ end. An assessment system, with multiple algorithms, provided a final evaluation of the tremor for participants. The process included three parts. First, calculation of root-mean-square (RMS) values at all linear and rotational directions was conducted to provide the strength of tremor. Second, fast Fourier transform (FFT) extracted the peak frequency at each direction. The powers of peaks were compared and the highest one was defined as the dominant frequency and its corresponding direction of motion. Third, hand and motion correlation analysis was used to find any coherence of tremor on 3-D motions. To test the reliability of this design, the same motion input was applied to multiple devices simultaneously. The outputs of different types of mobile devices were evaluated while considering various factors and models of mobile devices in the market (e.g., device size, weight, operating system, sampling frequency, and accuracy during the measurement). Multiple trials were conducted to test the reliability of the assessment system and the performance of the mobile app. Additionally, we added a finger tapping function was added to the app to measure movement speed, which is also affected by Parkinson’s disease. Both tremor and movement speed measurements can be used to evaluate disease progression overtime and could support an individualized medication plan.</p>

Reliability Check of an Assessment System for Parkinson’s Disease Tremor Monitoring With Portable Devices

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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