Under-the-skin electrode allows for real-world epilepsy tracking

New research from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London in partnership with the Mayo Clinic and UNEEG medical, has found that an electronic device placed under the scalp is an effective and feasible means of accurately tracking epilepsy.  

In a landmark study, published in Epilepsia and funded by the Epilepsy Foundation of America, researchers demonstrated that seizures can be tracked in the home environment, giving clinicians access to data that could have a dramatic impact on the way in which epilepsy is treated in the future.  

Tracking epileptic seizures over time is challenging and relies upon a person keeping a subjective diary. It is an unreliable format, as people with epilepsy can experience seizures without realising, due to impairment of consciousness and memory loss, or might misinterpret several symptoms as seizures when they are not. This is particularly important for those with treatment resistant epilepsy, who have ongoing seizures despite treatment with anti-seizure medication – known to occur in around a third of people with epilepsy. 

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

sqEEG is an AI powered miniature implantable EEG for real life monitoring of people with epilepsy.  It is about the size of a UK pound coin and has a small 10cm wire attached. Under local anaesthetic, 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 are able to access the data. 

This study recruited 10 adults with treatment resistant epilepsy from King's College Hospital and St. George's University Hospital. 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 via a wearable fitness tracker.  

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

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

Professor Mark Richardson, 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.” 

Epileptic seizures can broadly be divided into three separate groups; nonconvulsive with preserved awareness, nonconvulsive with impaired awareness, and convulsive. The participants were required to note down the nature of the type of episode they experienced as well as when it took place. Researchers again found that the sqEEG system was able to more accurately track the type of seizure experienced versus the participants’ diaries.  

Dr. Pedro Viana, Senior Clinical Research Fellow and Neurologist at King’s IoPPN and the study’s lead author said, “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. 

“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.” 

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

Jonas Duun-Henriksen, Senior Director AI & Science at UNEEG medical said, “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. 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. 

Ends 

For more information, please contact ioppn-pr@kcl.ac.uk 

Real-world epilepsy monitoring with ultra-long-term subcutaneous electroencephalography: A 15-month prospective study (DOI.org/10.1111/epi.18566) (Viana, Richardson et al) was published in Epilepsia 19 July 2025 https://onlinelibrary.wiley.com/doi/10.1111/epi.18566 

Copyright free images available on request/uploaded 

Notes for editors 

More information about the procedure can be found in Djurhuus BD, Viana PF, Ahrens E, Nielsen SS, Srinivasan HL, Richardson MP, et al. Minimally invasive surgery for placement of a subcutaneous EEG implant. Front Surg. 2023; 10:130434 

About King’s College London  

King’s College London is amongst the top 35 universities in the world and 5th best in the UK (QS World University Rankings 2026), and one of England’s oldest and most prestigious universities.  With an outstanding reputation for world-class teaching and cutting-edge research, King’s maintained its sixth position for ‘research power’ in the UK (2021 Research Excellence Framework). 

King's has more than 33,000 students (including more than 12,800 postgraduates) from some 150 countries worldwide, and 8,500 staff. 

For nearly 200 years, King’s students and staff have used their knowledge and insight to make a positive impact on people, society and the planet. Focused on delivering positive change at home in London, across the UK and around the world, King’s is building on its history of addressing the world’s most urgent challenges head on to accelerate progress, make discoveries and pioneer innovation. Visit the website to find out more about Vision 2029, which sets out bold ambitions for the future of King’s as we look towards our 200th anniversary.  

World-changing ideas. Life-changing impact: kcl.ac.uk/news    

The Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s is a leading centre for mental health and neuroscience research in Europe. It produces more highly cited outputs (top 1% citations) on psychiatry and mental health than any other centre (SciVal 2021), and on this metric has risen from 16th (2014) to 4th (2021) in the world for highly cited neuroscience outputs. In the 2021 Research Excellence Framework (REF), 90% of research at the IoPPN was deemed ‘world leading’ or ‘internationally excellent’ (3* and 4*). World-leading research from the IoPPN has made, and continues to make, an impact on how we understand, prevent and treat mental illness, neurological conditions, and other conditions that affect the brain. 

www.kcl.ac.uk/ioppn | Follow @KingsIoPPN on Twitter, Instagram, Facebook and LinkedIn 

About UNEEG medical 

#UNEEGmedical #UltraLongTermEEG 

@: https://www.linkedin.com/in/jonasduunhenriksen/  

We break new ground in epilepsy. UNEEG medical A/S is an entrepreneurial and ambitious company specializing in providing the epilepsy community with more accurate knowledge of seizures to support improvement in epilepsy care, ultimately aiming at improving patients’ quality of life. Our unique subcutaneous EEG solution for remote monitoring of brain activity was CE marked in 2019. 

CAUTION – Investigational device in the US. Limited by Federal law to investigational use. 

UNEEG medical was founded in 2005 in Denmark and now has subsidiaries in Germany, the UK, Austria and the US. UNEEG medical currently employs about 40 people representing various cultures, backgrounds, skills, and years of experience. 

About Mayo Clinic 

Mayo Clinic is the largest integrated, not-for-profit medical group practice in the world. We're building the future, one where the best possible care is available to everyone — and more people can heal at home. Our relentless research turns into earlier diagnoses and new cures. That's how we inspire hope in those who need it most. 

At Mayo Clinic, experts work together to solve the most challenging unmet needs of patients. Our history of innovation dates back almost 150 years, when brothers Will and Charlie Mayo pioneered an integrated, team-based approach to medicine. Today, that trailblazing spirit drives innovations like Mayo Clinic Platform — which powers new technologies to change how care is delivered to all. 

Our unwavering drive to create better medical care has earned Mayo Clinic more top rankings for high-quality patient care than any other health care organization. In fact, Mayo Clinic has more specialties ranked in the top three than any other hospital in the nation. 

www.mayoclinic.org  

About the Epilepsy Foundation 

For more than 50 years, the Epilepsy Foundation has shone a light on epilepsy by promoting awareness and understanding, advocating for laws that matter to people with epilepsy, and funding epilepsy research.  

The mission of the Epilepsy Foundation is to improve the lives of people affected by epilepsy through education, advocacy, research, and connection. For more than five decades, the Epilepsy Foundation and our network of nearly 50 partners have helped to: 

• Connect people to treatment, support and resources; 

• Fund innovative research and the training of specialists; and 

• Educate the public about epilepsy and seizure first aid. 

www.epilepsy.com