Reflex myoclonic epilepsy in infancy. A multicenter clinical study

Purpose: To describe the clinical and electroencephalographic (EEG) features of reflex myoclonic epilepsy in infancy (RMEI) and long-term cognitive outcome. Methods: We enrolled 31 children from 16 neuropediatric centres in Italy, who underwent clinical and video-EEG evaluation. Cognitive assessment was performed in all patients using standardized psychometric tests. Results: The age at onset ranged from 3 to 24 months of age. Seizures were characterised in all patients by symmetric myoclonic seizures (MS), triggered by sudden unexpected acoustic (38.7%) or tactile stimuli (29%) or both (29%). Spontaneous attacks were reported in 32.2% of the cases. Ictal EEG showed generalized high-amplitude 3. Hz polyspike and wave discharges, synchronous with brief rhythmic bursts of electromyographic activity. Patients were re-evaluated after a period of 7.2±5.6 years. The prognosis for seizure control was excellent in all cases and reflex MS disappeared spontaneously or after valproate treatment. The cognitive outcome was excellent in 90.3% of children. Conclusions: RMEI appears to be a variety of idiopathic generalized epilepsy with specific features that occurs in developmentally normal children.