The technology

The 24/7 EEG SubQ device (UNEEG Medical) is an electroencephalogram (EEG) recording device for people with epilepsy. The system is intended to monitor seizures for adults with uncontrolled epilepsy, when treatment has been adjusted and seizures remain uncontrolled or when there is a doubt about the true seizure burden being experienced. As a monitoring tool, it is intended to capture an objective count of frequency, type and circadian distribution of seizures. The implant can stay in place for up to 15 months to help identify seizures happening during daily life over a long time period.

The system consists of an EEG electrode designed for subcutaneous implantation, an external recording device and data reduction software EpiSight. The subcutaneous implant measures the EEG from 2 bipolar channels with a common reference. The device has a limited spatial coverage and lower spatial resolution than routine diagnostic EEG, which can routinely have between 12 and 64 channels. The systems software, EpiSight, has a front-end seizure detection algorithm that was developed in collaboration with the Austrian Institute of Technology (AIT). The software aims to provide continuous EEG biomarker information to support healthcare professionals in epilepsy management.


The company reports that 24/7 EEGSubQ is the first CE-marked EEG recorder for ultra-long-term monitoring of epilepsy. The system aims to help identify and manage the true seizure burden for individuals with suspected epilepsy when routine EEG and patient diaries are inadequate. The device is unobtrusive and can be used outside of hospital for people in their day-to-day life.

Current care pathway

Current standard care recommends that all adults with a new onset suspected seizure should be seen urgently (within 2 weeks) by a specialist. The diagnosis of epilepsy involves detailed history taking with the individual and any family members. If the diagnosis cannot be clearly established, further investigations will be considered. An EEG should only be considered to support a diagnosis of epilepsy in adults in whom the clinical history suggests that the seizure is likely to be epileptic in origin. If a routine EEG does not provide sufficient information, further investigations should be considered, including a sleep-deprived EEG, ambulatory EEG or video telemetry (for more information about EEG, see the NHS website).

Clinicians assess the effectiveness of anti-seizure drug therapy based on patients' seizure diary at outpatient visits every few months. If seizures are not controlled or there is diagnostic uncertainty or the treatment does not work, individuals should be referred to tertiary services within 4 weeks for further assessment. In some instances, long-term video-EEG (video telemetry) may be considered, if it is expected a 5 to 10-day monitoring period could capture seizures. The test involves a planned hospital admission over the scheduled period (between 5 to 10 days) but is not available at all centres. People may continue to need therapy adjustments as part of their follow-up consultations to better manage their condition. Neuroimaging using MRI may be used to assist in the care pathway more often in adults when seizures continue with first-line medication.

The following publications have been identified as relevant to this care pathway:

Population, setting and intended user

Epilepsy is a common neurological disorder characterised by recurring seizures. It is difficult to accurately estimate incidence and prevalence because identification is challenging, but it has been estimated to affect between 362,000 and 415,000 people in England.

The 24/7 EEG SubQ system is intended for individuals when seizures are not well controlled or if treatment does not work. It aims to provide additional information on the seizure burden to inform seizure management. The system can be used in specialist outpatient clinics by trained healthcare professionals, which may include surgeons, neurologists, clinical physiologists and neurophysiologists. The device is available in 2 variants, including a magnet (M1) and an alternative clip attachment with no magnet (C1). Clinicians should consider if either system is appropriate according to the instructions for use in the 24/7 EEG SubQ user manual. Contraindications to the system include people with other active implants such as cochlear implants, people having therapies with medical devices that deliver energy around the area of the implant and people with a hobby or profession that includes extreme pressure or risk of trauma to the device site.

The selected implant should be inserted subcutaneously with a supplied needle under local anaesthesia by a surgeon trained with the device. The outpatient procedure should take 15 to 30 minutes. Full details can be found in the 24/7 EEG SubQ company user manual for surgeons. All people who have the implant should be issued with a medical implant ID card. After around 10 days, once the stiches have healed, the recording can then begin. The company reports that a high number of people use the device as intended, with reported average recordings of 18.5 hours per day.

Follow-up care may vary from clinic to clinic. But, it is recommended the recordings are reviewed by the neurologist, with support from the neurophysiology team, for consideration in the future management plan.


Technology costs

The cost of the full system is about £13,500, including the subcutaneous implant, external device and software. Device implantation has additional costs including the local anaesthetic (costing between £5 and £23, BNF online), the anaesthetist and a trained surgeon.

Costs of standard care

Further testing may be requested. This includes long-term EEG (12 to 72 hours) at an average of £366 per test, or video telemetry EEG at a cost of around £2,000 per day (for a 5‑ to 10‑day monitoring period). Additional costs because of uncontrolled seizures might include unplanned trips to the emergency department, costing around £133 per attendance. This may result in non-elective hospital admissions that can cost between £404.17 and £2,030.88 for short stays. Follow-up neurology consultations cost about £199 per attendance. Further costs may be accrued because of therapy modifications to manage ongoing uncontrolled seizures. (National schedule of NHS costs, 2018/19).

Resource consequences

The device is currently being trialled in a research capacity at a number of NHS trusts. Adopting the device would need increased resources including surgeons and anaesthetists for implantation under local anaesthetic in an outpatient setting. The company claims that while the device cost would be in addition to standard care, it could lead to greater benefits including better clinical management and improved patient outcomes. This could result in longer-term savings by reducing unplanned admissions.

A short introductory training for healthcare professionals is provided by the company at no cost. This is expected to take 60 minutes of clinician's time, with further quick guide resources provided to support implementation. The healthcare professional is supported by the company on request for the first user. It is suggested that a surgeon do a minimum of 3 implantations before considering training other surgeons themselves in the procedure.