Abstracts

Electrical status epilepticus during sleep (ESES) consists of sleep induced paroxysmal EEG activity, lasting for months or years, which may appear continuously during sleep and is usually diffused bilaterally. Epilepsy is relatively easily controlled however the prognosis is complicated with cognitive and behavioral issues. ESES is frequently associated with behavioral disorders, hyperactivity, learning disorders and in some cases psychotic regression. This study aims to evaluate long term clinical course of patients with ESES.
Twenty two patients diagnosed with ESES were evaluated. All patients had routine EEG with stage II sleep recordings, and/or prolonged video-EEG up to 3 hours including sleep recordings. MRI was obtained in all patients, and SPECT was done in 12 patients. Follow up EEGs under different treatment regimens were evaluated along with neuropsychological data.
Seventeen cases were classified as epilepsy with continuous spike-waves during slow sleep, 3 cases were diagnosed with Landau-Kleffner Syndrome, one patient was diagnosed with benign childhood epilepsy with centro-temporal spikes, and one with progressive myoclonus epilepsy. Follow up duration ranged between 1-14 years. All patients but one had seizures, in 17 initial symtom was nocturnal seizures. Ten patients (45%) had language problems. MRI was abnormal in 9/22 patients (41%), and interictal SPECT showed hypoperfusion in various regions in 5/12 (42%). EEG showed focal epileptiform activity in 13/17 patients when ESES temporarily ceased. Carbamazepine and phenobarbital resulted in increased seizures, onset of new type of seizures and regresion in language. Vigabatrine and topiramate failed to improve EEG in long term follow up. Clobazam and clonazepam improved EEG, seizure control, behavioral and cognitive functions in [sim]70% of patients, valproate was also effective but not as much as benzodiazepines. Psychometric evaluation showed significant decrease in IQ scores during ESES.
Mental and behavioral disorders can persist even after ESES has ceased. The outcome seems to be correlated with the duration of ESES rather than the age of onset or associated seizure disorder. Therefore early recognition and effective treatment of patients with ESES are necessary for favorable outcome.