OASIS: RetrOspective Analysis on EEGs for Identifying Seizure Susceptibility in paediatrIcs Using biomarkerS

Inclusion Criteria: * ≥2-\<18 years age. * Patients who have had a confirmed epilepsy diagnosis for ≥1+ year. * Non contributary first EEG: including routine EEG, sleep EEG (natural, melatonin induced, sleep deprived), 24-hour ambulatory EEG. * Patients who have been diagnosed with a self-limited and or focal epilepsy \[\*\] who have had a first non-contributary (no IEDS present, negative) outpatient EEG. * Patients who have been diagnosed with idiopathic generalised epilepsy \[†\] who have had a first non-contributary (no IEDS present, negative) routine EEG. * Neurodiverse patients with epilepsy can be included in the study \[‡\] * Patients with epilepsy and co-morbidities can be included in the study (anxiety, mood disorders etc) * Controls should be EEGs taken from patients who have been referred for a paroxysmal disorder, received an EEG as part of their diagnostic work up and subsequently received an alternate diagnosis. Epilepsy should have been excluded from their differential diagnosis and the alternate diagnosis should have remained stable for ≥1+ year. Exclusion Criteria: * Developmental and/or epileptic encephalopathies \[§\] * Patients with global development delay of unknown origin. * Patients with profound and multiple intellectual disabilities * Participants with a known hepatic/renal encephalopathy. * Patient diagnosed with possible NEAD and epilepsy (dual diagnosis). * Participants taking part in another Clinical Trial of an Investigational Medicinal Product (CTIMP) (qualitative/observational studies are acceptable). * Patients with any breaches of skull (plates, burr holes, shrapnel).