Researchers at the University of Eastern Finland have developed a wearable surface electromyography and three-dimensional accelerometry system that can measure the occurrence and severity of myoclonic jerks, which are sudden muscle movements experienced by patients with progressive myoclonic epilepsy. The muscle jerks can be unpleasant, but can also cause accidents and falls. The researchers hope that the new sensors could help them to understand progressive myoclonic epilepsy a little better, and eventually assist with developing new treatments and allow patients to track their progress.
Myoclonic jerks can be stimulated by movement, and can either be positive or negative. A positive myoclonus typically results in spontaneous muscle contraction, whereas a negative myoclonus results in impaired muscle activation. These symptoms can be unpredictable and unpleasant, but can also cause falls and accidents, meaning that they pose a hazard to patients.
Understanding how, why, and when these symptoms occur would be useful for clinicians and researchers in understanding the condition and in developing new treatments. Yet, methods to provide objective data are limited. At present, the severity of myoclonic jerks are assessed through visual measurements performed by an experienced clinician. This is time consuming, somewhat subjective, and only provides details about the condition over a short space of time.
Patients can provide some guidance as to the severity of their symptoms, but it would be helpful for patients and clinicians alike to allow technology to shoulder the burden of disease monitoring. This latest device aims to provide data on myoclonic jerks and appears to be suitable for at-home monitoring. It consists of wearable surface electromyography and three-dimensional accelerometry sensors that are worn on the arm, and which provide data on jerk frequency and severity.
So far, the researchers have tested the technology in volunteers who wore the sensors for 48 hours each. The sensors provided good agreement with the results reported by the patients themselves and showed differences in symptoms between day and night. The results from the sensors also correlated well with assessments of symptom severity performed by an experienced clinician, suggesting that they are suitable for long-term at-home monitoring.
Measurement-based index describing variation in the myoclonus symptom during at-home measurement. The black colour describes measurements from the finger extensor muscle, and the turquoise colour measurements from the bicep muscle. Image: Saara Rissanen.
Study in journal Clinical Neurophysiology: Wearable monitoring of positive and negative myoclonus in progressive myoclonic epilepsy type 1