The goal of this retrospective study is to validate BioEP during routine adult EEG recording in an outpatient setting, using patients with a known epilepsy diagnosis. The main objectives of the study are:

• To validate BioEP during routine adult EEG recording in an outpatient setting, using patients with a known diagnosis
• To examine whether the use of BioEP could support a more efficient patient pathway to diagnosis (thus adding economic value), by reducing time to final diagnosis and/or the number of clinical appointments needed.

Inclusion Criteria:

• Adults (age 22 and above) who had a routine EEG in an outpatient setting, following a suspected seizure.
• A diagnosis of epilepsy or alternate condition has been reached. A period of at least 3 years has passed since ultimate diagnosis, which itself has remained stable.
• EEGs performed to ABRET & IFCN standards using a minimum of 19 electrodes and additional technical requirements.

Exclusion Criteria:

• Subject was not suspected of having had a seizure or epilepsy.
• Subject has a dual diagnosis of epilepsy AND non-epileptic seizures.
• Subject's final diagnosis unknown, unstable, or less than three years passed since an unchanged diagnosis was made.
• Incomplete or unreliable metadata, such as the age, sex, and treatment status at the time of the EEG recording.
• Sleep deprived EEG recordings in the outpatient setting.
• Encephalopathic subjects.
• Poor quality EEGs (multiple artefacts) that do not fulfil technical criteria for analysis.
• Known structural abnormalities or skull breaches, including historical cases, or with people with metal or plastic implants in their brain or skull.

Adult population with a diagnosis of epilepsy