[Classification of idiopathic generalised epilepsies in patients over 16 years of age]

Idiopathic generalised epilepsies (IGE) are a set of electroclinical syndromes with different phenotypes. Our aim is to analyse those phenotypes in patients over 16 years of age.

We conducted a retrospective analysis of a series of patients with IGE. They were classified as childhood absence epilepsy (CAE), juvenile absence epilepsy (JAE), juvenile myoclonic epilepsy (JME), epilepsy with tonic-clonic seizures only (TCSE), epilepsy with eyelid myoclonias and absences (EMA) and pure photogenic epilepsy (PE).

We included 308 patients, the majority females (56.8%), in our study. JME was the most prevalent (40.9%), followed by TCSE (30%), JAE (10%), EMA (8.7%), CAE (7.7%) and PE (1.6%). The types of seizures presented by the most patients were tonic-clonic (89.6%), myoclonic (45.4%), absence (31.4%), reflex seizures (13.3%), eyelid myoclonias (12.6%), non-epileptic psychogenic seizures (3.6%) and status epilepticus (1.9%). They all had generalised spike-and-wave discharges in the electroencephalogram (EEG). 19.2% presented asymmetrical discharges and 28.2% showed a photoparoxysmal response. We observed differences between syndromes in polytherapy (p < 0.0001), withdrawal of therapy (p = 0.01) and being seizure-free beyond the age of 50 (p = 0.004).

JME was the most frequent. Generalised tonic-clonic seizures were the type of seizures presented by the most patients, followed by myoclonic, absent and reflex seizures. The EEG showed a photoparoxysmal response in over a quarter of the patients, and one in five displayed asymmetrical anomalies. Differences were observed according to the syndrome in polytherapy, persistence of seizures and withdrawal of treatment.