Evolution into spike-and-wave activation in sleep in patients with self-limited focal epilepsies

Self-limited focal epilepsies of childhood (SeLFE), while predominantly considered benign, are known to potentially manifest with spike-and-wave activation in sleep (SWAS) in a minority of patients METHODS: The medical records of individuals diagnosed with one of the SeLFE syndromes according to the ILAE 2022 diagnostic criteria, who were followed in our center between 1989-2023, were retrospectively analyzed. At least two awake and sleep EEGs were performed during a minimum 2-year follow-up. SWAS is considered as spike and wave discharges occupying ≥50% of NREM sleep with symmetrical or mildly asymmetrical bilateral or unilateral hemispheric distribution.

Among 144 patients with SeLFE, 57(39.6%) were diagnosed with self-limited epilepsy with centrotemporal spikes (SeLECTS); 65(45.1%) with self-limited epilepsy with autonomic seizures (SeLEAS); and 22 (15.3%) with childhood occipital visual epilepsy (COVE). The mean age of seizure onset was 7.6, 5.6, and 8.5 years, respectively. Twelve (8.3%) evolved into SWAS (5 from SeLECTS, 6 from SeLEAS, 1 from COVE). Time elapsed between onset of first seizure and evolution into SWAS ranged from 5.2 to 75 months (mean: 26.8±19.8), 6.2-42.8 months (mean: 20.1±14.7 for patients with SeLECTS; 5.2-75.0 months (mean: 32.7±24.5) with SeLEAS, and 25.0 months with COVE). All except two patients had also cognitive or behavioral regression and were diagnosed as epileptic encephalopathy with spike-wave activation in sleep(EE-SWAS) and one patient was diagnosed with Landau-Kleffner syndrome.

The most recent definition of ILAE highlights that SeLFEs are no longer recognized as "benign" epilepsies. Even with a low incidence rate, clinicians should always be cautious about the risk of SWAS development in these syndromes.