Abstracts

The exact diagnosis of epileptic negative myoclonus (ENM) is possible only by polygraphic recording in most cases. Characteristic features of ENM are short lapses of muscle tone (i.e. silent period). It appears in children with symptomatic and benign idiopathic focal epilepsies. Focal signs but also bilateral involvement of proximal muscle groups (more common in childhood epilepsies) can occur with it. ENM are reflex seizures (cortical reflex negative myoclonus). In many cases the sudden onset and the duration of silent period correlates with the slow waves following single spikes. Usually common antiepileptic drugs (AEDs) against focal seizures are not helpful, they might even provoke or aggravate ENM. Several publications have shown good results with Ethosuximide (ESM) for the treatment of ENM but usually dealing with smaller numbers of patients. [In addition to the patients in our study we just found three more patients in our treatment who have benefited by ESM with their ENM]. At present we report about the treatment of 10 patients with ESM. The follow-up was about 12 months at least. Patients[apos] age was between 2.3 to 18 years, average age 7.8 years. All patients had focal epilepsies: N=5 symptomatic, N=3 combination of idiopathic and symptomatic, N=1 most likely symptomatic, N=1 idiopathic. Long-term EEG-video-monitoring verified ENM including polygraphic recording. In all cases ESM was given as add-on-therapy. All patients were treated unsuccessfully before with at least two other AEDs against ENM (average number of AEDs =5). Within two weeks after the start of the therapy with ESM 8 of 10 patients (80%) became free of ENM, 1 patient (10%) had a seizure reduction of 50%. In 4 cases (40%) additional focal seizure-types were also stopped by ESM [ndash] they became complete seizure-free. After a period of 6 months 1 patient (10%) had partial relapse. ESM is the drug of choice in the treatment of ENM. In the control of ENM ESM is equally effective in treatment of benign idiopathic and of symptomatic focal epilepsies of childhood.
This study is one of the largest series demonstrating that ESM is remarkable effective in childhood focal epilepsies controlling ENM (additionally we do have at least 3 more patients who just haven[apos]t fulfilled the follow-up of one year yet). Special attention should be paid to ESM in control of ENM of symptomatic focal epilepsies due to the enormous success rate. ESM could be very successful in the control of ENM because of its special mechanism of action at thalamus[apos] voltage dependant calcium channels leading to inhibitation of thalamocortical oscillations.