Epileptic encephalopathy with electrical status epilepticus: An electroclinical study of 59 patients

• Long-term follow-up of patients with electrical status epilepticus in sleep are reported.
• Outcome of patients depend on the etiology, duration and early treatment response.
• Levetiracetam and clobasam are effective antiepileptic drugs in ESES.
• Hydrocephalus and thalamic lesions should be followed cautiously.

PurposeTo evaluate the electroclinical features, treatment effectiveness, and outcome of 59 patients with epileptic encephalopathy with electrical status epilepticus during sleep.MethodsMedical-files of 59 patients with electrical status epilepticus during sleep were retrospectively evaluated for data concerning: history, physical and neurological examinations, sleep and awake EEG's, psychometric tests and brain MRI.ResultsA total of 31 boys and 28 girls were identified. Patients were evaluated in two groups: symptomatic/structural and idiopathic group. There was no significant difference between the etiological groups in term of mean age at ESES onset, mean interval between the first seizure and the onset of ESES. The mean age at seizure onset was earlier in the symptomatic/structural group than the idiopathic ones. The mean follow-up time after the ESES onset was 4.5 years for all patients. The most effective antiepileptic drugs in our series were clobazam and levetiracetam. In refractory patients, steroid treatment was found effective during the early course of the disease. In the idiopathic group, cognitive decline has improved. However in the symptomatic group, patients did not respond to the treatment and cognitive deterioration did not improve in one third of the group.ConclusionThe long-term outcome of ESES is highly variable and usually depends on etiology and the duration of ESES. The most efficious antiepileptic drugs in our study are clobazam and levetiracetam.