Researchers at the University of Eastern Finland have developed portable surface electromyography and a three-dimensional acceleration system that measures the onset and severity of myoclonic jolts, which are sudden muscle movements experienced by patients with progressive myoclonic epilepsy. Muscle shaking can be unpleasant, but it can also cause accidents and falls. Researchers hope the new sensors can help them understand progressive myoclonic epilepsy a little better and ultimately help develop new treatments and allow patients to track their progress.
Myoclonic movements can be stimulated by movement and can be positive or negative. A positive myoclonus usually causes spontaneous muscle contraction, while a negative myoclonus causes an alteration in muscle activation. These symptoms can be unpredictable and unpleasant, but they can also cause falls and accidents, so they pose a danger to patients.
Understanding how, why, and when these symptoms occur would be helpful for doctors and researchers to understand the condition and develop new treatments. However, methods for providing objective data are limited. Currently, the severity of myoclonic shocks is assessed by visual measurements performed by an experienced physician. This is time consuming, somewhat subjective, and only provides details about the status in a short amount of time.
Patients can provide some guidance on the severity of their symptoms, but it would be helpful for both patients and clinicians that the technology could take on the burden of controlling the disease. The latter device aims to provide data on myoclonic shocks and seems suitable for home control. It consists of usable surface electromyography and three-dimensional accelerometry sensors that are carried on the arm and provide data on the frequency and severity of the shocks.
So far, researchers have tested the technology on volunteers who carried 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 of the sensors also correlated well with assessments of the severity of symptoms performed by an experienced clinician, suggesting that they are suitable for long-term home control.
Measurement-based index that describes the variation of myoclonus symptom during measurement at home. The color black describes measurements of the extensor muscle of the fingers and measurements of the turquoise color of the biceps muscle. Image: Saara Rissanen.
Study the magazine Clinical neurophysiology: Portable monitoring of positive and negative myoclonus in progressive myoclonic epilepsy type 1