• The technology described in this briefing is 24/7 EEG SubQ. It is a subcutaneous electroencephalogram (EEG) recording device for people with epilepsy. The system consists of an EEG electrode designed for subcutaneous implantation, an external recording device and data reduction software EpiSight.

  • The innovative aspects are that it offers ultra-long-term monitoring (30 days and over) for people with epilepsy in their day-to-day life.

  • The intended place in therapy would be in addition to standard care as an option for long-term monitoring to help manage epilepsy.

  • The main points from the evidence summarised in this briefing are from 5 studies, including 2 case studies and 3 case series with a total of 11 adults. They show that the 24/7 EEG SubQ identifies additional seizure counts and seizure pattern information to inform individual management plans.

  • Key uncertainties around the evidence are that the evidence base is small and of low methodological quality, with small sample sizes and a high risk of selection bias.

  • Experts advised that the system could improve epilepsy management for a small subgroup of people. But, there needs to be consideration of the value on a case-by-case basis with understanding of the probable location of the seizures for the correct placement of the system to capture them.

  • The cost of 24/7 EEG SubQ system is about £13,500 (excluding VAT), including the subcutaneous implant, external device and software. Additional costs include anaesthetic, anaesthetist and surgeon costs. The resource impact would be in addition to standard care when seizures remain uncontrolled and true seizure burden is not well understood.