Changes of the EEG paroxysmal pattern during felbamate therapy in Lennox-Gastaut syndrome: a case report.

We report a case of a 43-year old woman with Lennox-Gastaut syndrome who exhibited atypical absence seizures, atonic seizures and generalized toniclonic seizures which were not controlled by antiepileptic drug (AED) treatment. Because of this, felbamate (FBM) (1800 mg per day) was progressively added to the pre-existent therapy. The patient underwent a 24-hour-video-EEG monitoring before and after 4 months of FBM therapy. Analysis of the video-EEG signal recorded during wakefulness revealed the presence of ictal activity represented by repetitive, bilateral, slow spike and wave bursts underlying atypical absence seizures; the ictal activity occurring during non-REM sleep was characterized by runs of bilateral, rapid, high-voltage spikes followed by slow spike and wave complexes corresponding to brief tonic seizures. FBM therapy induced disappearance of the EEG ictal slow, spike and wave complexes leaving rather unaffected the runs of spikes. Computerized analysis of both the EEG background activity and the sleep structure displayed a better organization of the global cerebral rhythms under FBM treatment. Our findings suggest a selective effect of FBM on the ictal atypical spike and wave pattern. The differential effect of FBM on ictal patterns may be a reflection of a different action on the excitatory and inhibitory systems.