There are 5 main categories of seizure detection devices that are used to provide a more accurate seizure count and alert caregivers to ensure immediate action. Their mechanism of action and effectiveness were evaluated in a review recently published in Neurology.
Epilepsy is associated with recurrent, unprovoked seizures that can be life-threatening. For safety reasons, various seizure detection modalities have been developed to aid in the detection of seizures, including electroencephalogram (EEG), heart rate (EKG), electrodermal activity (EDA), exercise, and electromyography (EMG).
The aim of the current review was to provide a summary of the mechanisms of action and the effectiveness of these seizure detection modalities.
Electroencephalogram (EEG) – This is the gold standard for detecting seizures. There are several EEG-based seizure detection devices. Newer, more portable and more comfortable devices contain fewer electrodes and allow longer recordings and more storage capacity. The current EEG-based devices have various limitations, e.g. These include potential artifacts with false positives, cumbersome equipment, battery life, price, and lack of regulatory approval for diagnosis and treatment.
Electrocardiogram (EKG) – Changes in heart rate are common with seizures and can rarely be life-threatening. Detecting these changes can enable immediate action. Several devices are currently available ranging from a wristwatch to an implanted vagus nerve stimulator (VNS). Newer VNS models monitor heart rate and provide electrical stimulation when a significant increase in heart rate is detected. Ictal tachycardia detection is now a standard function of VNS and can trigger treatment autonomously. There are several limitations associated with EKG monitoring to detect seizures, including the possibility of seizures occurring without changing heart rate and false positives due to several possible causes of increased heart rate.
Electrodermal Activity (EDA) – Activation of the nervous system can occur during seizures, including activation of sweat glands. Watch-like devices for detecting EDA can detect changes in the skin conductance of electricity. Combining EDA surveillance with motion detection can improve device accuracy, and further development can reduce the frequency of false positives.
Movement Devices – Actigraphy and acceleration measurement can be used to identify movement or changes in the speed / trajectory of movement. These devices can be worn on the wrist or attached to furniture such as a bed. The main limitations of these devices are high rates of false detection due to intentional movement and the possibility of missing events.
Surface Electromyography (EMG) – Based on the acquisition of the electrical signal from muscles through sites attached to the skin, these devices can identify seizures with a motor component. While these devices are fairly sensitive, false detection is possible due to common tasks such as physical exertion.
While these seizure detection devices are available and convenient for patients, there are significant false positive and negative rates that affect their ability. The review authors concluded: “Future development should focus on combining multiple seizure detection mechanisms in a single device and providing personalized base data to improve detection accuracy while being comfortable and element resistant for patients to be.”
Atwood AC, Drees CN. Five New Things: Seizure Detection Devices. Neurol Clin Pract. Published online January 25, 2021. doi: 10.1212 / CPJ.0000000000001044