Clinical and EEG-EMG characteristics of perioral myoclonia with absence seizures

This study aimed to explore the clinical and electrophysiological characteristics and treatment prognosis of patients with perioral myoclonia with absence (POMA).

Patients with POMA were selected from our EEG database. The collected data included detailed clinical information, VEEG characteristics, and brain MRI results. Previously reported patients with POMA were also screened for inclusion in the study.

Nineteen patients were included in the study. The median seizure onset age was 5 years (range, 2-11 years), with 84.2 % (16/19) of the patients being male. POMA was VEEG monitored in 73.7 % of the patients during both wakefulness and sleep, and 63.2 % (12/19) could be induced by hyperventilation (HV). Synchronized perioral electromyography confirmed that the ictal 3-Hz discharge was time-locked with the myoclonic jerks. Twelve patients underwent VEEG follow-up, with 66.7 % achieving seizure-free with valproate (VPA) monotherapy. A review of previous reports on 15 patients with POMA revealed that 66.7 % of patients being male. Five patients experienced worsening of seizures with oxcarbazepine (OXC), carbamazepine (CBZ), or phenytoin.

POMA epilepsy, although rare, still presents distinctive characteristics. POMA tends to occur more frequently in males. 73.7 % of the patients had POMA during both wakefulness and sleep. The VEEG background is mostly normal, with rhythmic 3-Hz generalized spike and wave discharges during the ictal period that are time-locked with perioral myoclonia. Patients with POMA respond well to VPA. POMA may be misdiagnosed as focal seizures, but the use of OXC, CBZ, and phenytoin sodium for treatment should be avoided.