Evolution of ohtahara syndrome to continuous spikes and waves during slow sleep in an infant

Encephalopathy with electrical status epilepticus in sleep (ESES) is defined as an age-related and self-limited electroclinical syndrome whose etiology is unknown and characterized by continuous spikes and waves during slow sleep (CSWS). Typical CSWS starts at an age of 4 to 5 years and ends by an average of 11 years. We report on an unexpected finding of CSWS in an 18-month-old male whose previous EEC at age 45 days was grossly abnormal with the presence of a burst suppression pattern during wakefulness and sleep. The patient had clinical seizures beginning day 1 of life leading to the suspicion of Ohtahara syndrome (the earliest form of epileptic encephalopathy). Patients with ESES usually have normal EEGs and functional development prior to the onset of CSWS pattern. To our knowledge, this presentation of a neonate with a history of neonatal seizures and developmental delay with an evolution to CSWS has not been described. A sleep record is strongly advised in children with epilepsy (despite the recording of awake EEG abnormalities), especially in patients with behavior or cognitive regression, to rule out the presence of CSWS.