Objective: A prospective multicenter phase III trial was undertaken to evaluate the performance and tolerability in the epilepsy monitoring unit (EMU) of an investigational wearable surface electromyographic (sEMG) monitoring system for the detection of generalized tonic–clonic seizures (GTCSs). Methods: One hundred ninety-nine patients with a history of GTCSs who were admitted to the EMU in 11 level IV epilepsy centers for clinically indicated video-electroencephalographic monitoring also received sEMG monitoring with a wearable device that was worn on the arm over the biceps muscle. All recorded sEMG data were processed at a central site using a previously developed detection algorithm. Detected GTCSs were compared to events verified by a majority of three expert reviewers. Results: For all subjects, the detection algorithm detected 35 of 46 (76%, 95% confidence interval [CI] = 0.61–0.87) of the GTCSs, with a positive predictive value (PPV) of 0.03 and a mean false alarm rate (FAR) of 2.52 per 24 h. For data recorded while the device was placed over the midline of the biceps muscle, the system detected 29 of 29 GTCSs (100%, 95% CI = 0.88–1.00), with a detection delay averaging 7.70 s, a PPV of 6.2%, and a mean FAR of 1.44 per 24 h. Mild to moderate adverse events were reported in 28% (55 of 199) of subjects and led to study withdrawal in 9% (17 of 199). These adverse events consisted mostly of skin irritation caused by the electrode patch that resolved without treatment. No serious adverse events were reported. Significance: Detection of GTCSs using an sEMG monitoring device on the biceps is feasible. Proper positioning of this device is important for accuracy, and for some patients, minimizing the number of false positives may be challenging.
Bibliographical noteFunding Information:
A custom-designed device for recording sEMG data was used (Fig. S1) that includes a commercial foam-backed electrode patch containing three pregelled, Ag/AgCl surface electrodes (1-cm diameter and 1 cm apart in a triangular configuration; Multi Bio Sensors, El Paso, TX, U.S.A.). Recording electrodes were placed transversely over the belly of the biceps brachii muscle with the reference electrode oriented proximally. The electrode patch adhered to the skin with an acrylic-based adhesive, and the weight of the device was supported by an arm band. The electrical components of the applied device consist of an instrumentation amplifier, filtering network, and microcontroller designed to amplify and continuously record 1-kHz sampled sEMG, analyze sEMG for potential seizure activity, and transmit potential seizure alerts via Wi-Fi to a base station (BSN) computer. See Figure S1 for an example of the sEMG signal recorded from a GTCS.
This study was funded by Brain Sentinel in San Antonio, Texas.
© 2017 The Authors. Epilepsia published by Wiley Periodicals, Inc. on behalf of International League Against Epilepsy.
- Clinical trials
- Epilepsy monitoring
- Generalized seizures
- Grand mal seizures