Current Role of Seizure Detection Devices in Patients with Epilepsy

There are 5 main categories of seizure detection devices used to provide more accurate seizure count and alert caregivers to ensure prompt intervention; a recent review published in Neurology assessed their mechanism of action and efficacy.

Epilepsy is associated with recurrent, unprovoked seizures, which may be life threatening. Several seizure detection modalities were developed for safety purposes in order to assist in detecting convulsive seizures, including electroencephalogram (EEG), heart rate (ECG), electrodermal activity (EDA), movement, and electromyography (EMG).

The objective of the current review was to provide a summary on the mechanisms of action and efficacy of these seizure detection modalities.

Electroencephalogram (EEG) – This is the gold standard for seizure detection. There are several EEG-based seizure detection devices. Newer, portable, and more comfortable devices include fewer electrodes and allow for longer recordings and more storage capacity. The current EEG-based devices have several limitations, such as potential artifacts with false positive results, cumbersome devices, battery life, price, and lack of regulatory approval for diagnosis and treatment.

Electrocardiogram (ECG) – Changes in heart rate are common during seizures, and rarely may be life threatening. Detecting these changes may allow prompt intervention. Currently, there are several available devices that range from a wrist watch to an implanted vagus nerve stimulator (VNS). Newer VNS models monitor heart rate and provide an electrical stimulation when a significant heart rate increase is identified. Ictal tachycardia detection is now a standard VNS feature and can trigger treatment autonomously. Several limitations are associated with ECG monitoring for seizure detection, including the potential occurrence of seizures with no change in heart rate and false positive results due to multiple potential reasons for elevated heart rate.

Electrodermal Activity (EDA) ­– Activation of the nervous system can occur during seizures, including activation of sweat glands. Watch-like devices to detect EDA can identify changes in skin conductance of electricity. Combining EDA monitoring with motion detection may improve device accuracy and further development may decrease the frequency of false alarm.

Motion Devices – Actigraphy and accelerometry may be used to identify movement and changes in the velocity/trajectory of movement, respectively. These devices may be worn on the wrist or attached to furniture such as a bed. The main limitation of these devices is high false detection rates due to deliberate movements, and the potential to miss events.

Surface Electromyography (EMG) – These devices are based on detection of electrical signal from muscles through patches attached to the skin and can identify seizure with a motor component. While these devices have fairly high sensitivity, false detection is possible due to common tasks like physical exertion.

While these devices are available for seizure detection and convenient for patients, there is significant false positive and negative rates that hinder their ability. Review authors concluded, “Future development should focus on combining multiple mechanisms of seizure detection within a single device with the ability to obtain personalized baseline data to increase the accuracy of detections while being convenient to patients and resistant to elements.” 

Reference

Atwood AC, Drees CN. Five new things: seizure detection devices. Neurol Clin Pract. Published online January 25, 2021. doi:10.1212/CPJ.0000000000001044