Partial epilepsy with tonic seizures during sleep: Seizure prognosis in 6 patients

Burst of fast (10-20, 20-25 c/s) rhythmic activity during stage I and II of NREM sleep (tonic seizures) has been recorded in patients suffering from Lennox-Gastaut syndrome or severe partial epilepsies. We describe clinical, neuropsychological, EEG, brain CT findings and seizure evolution in 6 patients with partial epilepsy in which sleep EEG recordings disclosed numerous tonic seizures during stages I and II NREM. Electroclinical (interictal frontal focus in 5 patients, involvement of frontal lobes during diurnal seizures in 5 patients), brain CT (enlargement of left silvian fissure in 2 patients) and interictal neuropsychological finding (impairment of cognitive frontal functions in 2 out of 4 patients) indicated a frontal origin of this kind of partial epilepsy. During a follow-up period of 6-36 months, generalized convulsive fits and partial complex seizures without tonic and/or clonic motor components were well controlled in 6 and 2 patients respectively. Partial complex seizures with tonic and/or clonic manifestations (3 patients), drop attacks (3 patients) and tonic seizures during sleep (all patients) were resistant (frequency ≥ 10/month) to antiepileptic treatment. Nonetheless, tonic seizures during sleep did not constitute a relevant clinical problem in 5 patients. Three out of 5 patients who received sodium valproate on polytherapy regimen, had hyperammoniemic encephalopathy with stupor, vomiting and flapping tremor. In conclusion, the study of the seizure semeiology in patients suffering from partial frontal epilepsy with tonic fits during sleep is important to recognize pharmacoresistant and diabiliting seizures. Antiepileptic polytherapy including sodium valproate should be cautiously considered in these patients.