Under-the-Skin Electrode Allows for Real-World Epilepsy Tracking

A landmark study funded by the Epilepsy Foundation of America demonstrates that seizures can be tracked in the home environment, giving clinicians access to data that could have a dramatic impact on future epilepsy treatment.

Novel subcutaneous electroencephalography (sqEEG) systems—consisting of a small electrode placed beneath the skin—have been proposed to help overcome this challenge, but the feasibility, acceptability and overall clinical utility of these systems had not been tested until now.

Mark Richardson, Ph.D., Paul Getty III Professor of Epilepsy at King’s IoPPN and the study’s senior author said, “It is vital that people with treatment resistant epilepsy are able to access the best possible care. This is made significantly more challenging by the fact that clinicians must rely on patient reporting to establish when episodes have taken place. Our study has been able to provide a vital and viable alternative to relying on self-reported episodes. A small tracker placed under the skin was able to detect seizures far more accurately than the participants themselves.”

sqEEG is an AI powered miniature implantable EEG for real-life epilepsy monitoring. It’s about the size of a U.K. pound coin and has a small 10 cm wire attached. Under local anesthetic, it is placed behind the ear beneath the scalp and the wire is directed to where the seizures are expected to occur.

The sqEEG wirelessly communicates with an external recorder attached with an adhesive pad behind the ear and fixed with a magnet or clip from which clinicians and researchers access the data.

The study recruited 10 adults with treatment-resistant epilepsy from King’s College Hospital and St. George’s University Hospital, both in the United Kingdom. They were then asked to record as much data as they could over the course of 15 months, while also keeping a seizure diary and keeping track of their health and fitness through a wearable fitness tracker.

“The ability to monitor seizures in the real world, accurately collecting data on the type and timing that they occur will be an invaluable tool for clinicians moving forwards, and should hopefully have a big impact on how we approach the treatment of this life-threatening condition,” stated Pedro Viana, M.D., Ph.D., senior clinical research fellow and neurologist at King’s IoPPN and the study’s lead author. “While this is an important step forwards, it’s now vital that we conduct larger trials to further validate this technology, with a view to hopefully making this available to everyone in need.”

During the study period, almost 72,000 hours of real-world brainwave data were collected, capturing 754 seizures. Participants largely reported the implant was acceptable and unobtrusive, with half recording for more than 20 hours a day.

Researchers analyzed the data and made several key observations. When comparing the electronic data to the participants’ diaries, the participants had only correctly recorded 48% of their episodes. Conversely, more than a quarter (27%) of episodes recorded in their diaries were not associated with seizure activity.

“Overall, these results demonstrate that Subscalp EEG devices are able to provide objective information about seizures and brain activity over long timeframes,” commented Benjamin Brinkmann, Ph.D., professor of Neurology at Mayo Clinic. “This technology could provide physicians and patients with new insights about long-term patterns and help optimize their epilepsy treatment.”

Epileptic seizures can broadly be divided into three separate groups; non-convulsive with preserved awareness, non-convulsive with impaired awareness, and convulsive. The participants were required to note the type of episode they experienced as well as when it took place.

Researchers again found the sqEEG system more accurately tracked the type of seizure experienced compared with the participants’ diaries.

“This study is a significant milestone for UNEEG medical. While we’ve long heard from both people living with epilepsy and their treating physicians that they are very satisfied with our system and helped improve outcome, this is the first time a study based on more than a full year of continuous EEG recordings confirms those experiences,” said Jonas Duun-Henriksen, senior director, AI and Science, at UNEEG medical. “We’ve gained valuable quantitative insights throughout the study, and we’re especially grateful for the valuable feedback from the clinicians at King’s College London—which we’ve already started incorporating into our solution to further enhance its clinical value.”

This work was supported by the Epilepsy Foundation’s Epilepsy Innovation Institute My Seizure Gauge Project.