DEVELOPMENT OF MYOCLONUS IN PATIENTS WITH PARTIAL EPILEPSY DURING TREATMENT WITH VIGABATRIN - AN ELECTROENCEPHALOGRAPHIC STUDY

In the context of a study of the effects of gamma-vinyl-GABA (GVG) on seizure occurrence and on EEG abnormalities we present three cases wit h focal epilepsy in which new clinical and EEG paroxysmal manifestatio ns were observed during GVG therapy. At that time, whereas an ameliora tion or no change in patients' habitual seizures were observed, myoclo nic jerks appeared with related changes in the EEG paroxysmal abnormal ities, represented by generalized polyspike and wave complexes. An ele ctroclinical correlation was recorded in one case. These data indicate that, although occurring rarely, it is possible to have epileptic myo clonus during GVG treatment. Mechanisms underlying these manifestation s are difficult to explain. Probably a shift in the anti/proconvulsant GABAergic balance towards the latter may compromise the therapeutic e ffect of GVG.