Objective: An objective method is presented for monitoring of positive and negative myoclonus using wearable surface EMG and 3D accelerometry in clinical and home settings. The method was validated in patients with progressive myoclonus epilepsy type 1 (EPM1).

Background: Myoclonus severity is currently evaluated in-clinic by using rating scales such as the video-recorded Unified Myoclonus Rating Scale (UMRS). These scales rely on subjective evaluation of myoclonus at one time point only. However, positive myoclonus severity can vary hourly, whereas negative myoclonus can be hard to detect. Patients struggle to rate their myoclonus severity or frequency reliably in home diaries for prolonged periods of time.

Method: The method consists of EMG and acceleration measurements for several hours or days using a wearable sensor on patient’s arm and the analysis of measurement data by using the developed algorithms: myoclonus index for quantifying the amount of positive myoclonus and number and duration of EMG silent periods for quantifying negative myoclonus. The method was used here in a baseline study with 23 EPM1 patients and in a follow-up study with 24 EPM1 patients. The method was validated against the clinical scoring, patients’ self-reporting, and videorecording.

Results: Myoclonus index and its change per year correlated strongly and significantly with the UMRS scores and its change per year in both the baseline and the follow-up study. The profile of myoclonus index values revealed variation in the myoclonus severity during the day and night, and it correlated moderately and significantly with patients’ self-reported myoclonus degree in home diaries. Number and duration of EMG silent periods were higher in patients with higher negative myoclonus severity score in UMRS.

Conclusion: With the technique, positive and negative myoclonus detection and monitoring is possible. Wearable technology allows longer measurement periods at patients’ home, revealing variation in the myoclonus severity. In the future, our technique may help symptom monitoring in clinical trials of anti-myoclonic drugs or devices and support in-clinic myoclonic symptoms assessment. The same measurement technique has been used in patients with Parkinson’s disease, as well.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/positive-and-negative-myoclonus-monitoring-using-ambulatory-surface-emg-and-3d-accelerometry/