Effects of repetitive transcranial magnetic stimulation on spike-and-wave discharges

Aim of this study was to evaluate the effect of 5Hz-suprathreshold repetitive transcranial magnetic stimulation (rTMS) on the duration of the spike-and-wave discharges (SWDs) in a patient presenting idiopathic absence seizures. At the moment of the study the patient presented a mild blunting of consciousness due to the high frequency of absences and EEG recordings showed sub-continuous, generalized, symmetrical and synchronous 3c/s SWDs, petit mal status. Trains of 10 stimuli (120% resting motor threshold) were delivered at 5Hz frequency at the beginning of the SWDs. 5Hz-rTMS trains significantly changed the EEG activity by reducing the duration of SWDs without changing the intervals between two consecutive discharges. rTMS had not significant after-effects on the epileptic activity and patient's clinical status. Despite the limitations of a single case report, our neurophysiological findings suggest that 5Hz-suprathreshold rTMS delivered in short trains induces a transitory interference of the ongoing epileptic activity.