Subscalp EEG: Long-Term Seizure Monitoring
Subscalp EEG system Monitors Seizures with High Fidelity
A new subscalp electroencephalography (EEG) system shows promise in monitoring seizures with high accuracy. The device, called Minder, stores data on a smartphone app before uploading it to cloud storage.
In a recent study, the device was activated within 14 days of implantation. Participants then maintained a seizure diary, noting seizure location and demographic details. Researchers tracked patients for six months, with check-ins at 4, 6, 12, and 24 weeks post-implantation.
The primary focus of the study was to monitor adverse events during the six-month period. Secondary goals included assessing whether the device could identify normal neurophysiological signals, interictal discharges (IEDs), and seizures via one-week recordings at the 4- and 24-week marks. Researchers also compared subscalp data with patient diary entries to evaluate the device’s effectiveness in real-world scenarios.
Of the 31 individuals enrolled, 26 received implants after five withdrawals. The participants’ mean age was 45, and half were female.
The study reported 87 adverse events among 20 individuals within six months. Though, none were serious issues related to the device or implantation procedure.
Eight participants experienced 13 device-related adverse events. Eight were directly device-related, and five stemmed from the study procedure. Eleven of these were mild,and two were moderate.
Scalp pain or headaches were the most common issues, with five patients reporting eight such events. Eight of the 13 device-related adverse events resolved before the study concluded.
Researchers also noted 23 procedure-related adverse events among 12 patients. Five were directly related to the procedure, 17 were mild, and six were moderate. Six patients had 11 serious adverse events, but none were linked to the device or procedure.
The device accurately logged incidence in 44 video-monitored events from 24 enrollees at 4 and 24 weeks. Sleep spindles were noted on 23 of 23 and on 20 of 21 scalp recordings, and all chewing artifacts were present as well.
All sleep spindles, chewing artifacts, IEDs, and electrographic seizures seen on scalp recordings, including eight patients with 25 seizures, were also identified on subscalp recordings. The researchers noted that subscalp recordings offered higher clarity compared to two-channel scalp recordings.
Amy J. Halliday and colleagues compared subscalp data with diary entries and found EEG data available for 63% (377 of 600) of all diary notations, with corresponding seizures recorded for 31% of these events (115 of 377).
Halliday said that Minder’s bilateral brain coverage allows seizure lateralization, which can inform surgical eligibility and potentially open the door to curative epilepsy surgery for some patients.
Rohan Hoare added that by providing an objective measure of brain activity, the Minder system offers objective data regarding treatment efficacy, which is useful in clinical practice and could potentially assist in determining eligibility and outcomes in clinical trials.
What’s next
The Minder system may offer clinicians an objective way to measure brain activity, potentially improving treatment strategies and identifying candidates for epilepsy surgery.