Effect of gamma-vinyl GABA on interictal spikes and sharp waves in patients with intractable complex partial seizures.

The effect of gamma-vinyl GABA (GVG) on the interictal electroencephalogram (EEG) was studied in 13 patients with intractable complex partial seizures who participated in a single-blind, add-on, multicenter clinical trial of GVG. Precise operational definitions of epileptiform paroxysms were used to evaluate records before and after 3 months and 1 year of treatment with GVG. After 3 months of treatment, six patients exhibited reduction of both epileptiform paroxysms and seizure frequency, four had no change in seizure frequency nor in the EEG, and three had a reduction in seizure frequency but no concomitant reduction of epileptiform paroxysms in the EEG. Ten patients remained in the study after 1 year of treatment. In 4 patients both seizure frequency and EEG epileptiform paroxysms continued to decrease, in 1 patient both seizure frequency and number of EEG paroxysms increased, and in the remaining 3 there was no correlation between seizure frequency and EEG changes.