Slow-frequency repetitive transcranial magnetic stimulation in a patient with focal cortical dysplasia

PURPOSE: To evaluate the effect of slow-frequency repetitive transcranial magnetic stimulation (SF-rTMS) on interictal epileptiform activity and seizure frequency in a patient with medically refractory partial seizures due to focal cortical dysplasia. METHODS: A 9-cm circular coil was positioned over the area of cortical dysplasia. One hundred stimuli given at 0.5 Hz at 5% below motor threshold were given biweekly for four consecutive weeks. The EEG was recorded for 30 min before and after the first 100 stimuli. The number of seizures during the month of stimulation was compared with that of the month before stimulation. RESULTS: Stimulation was associated with a 70% reduction in the frequency of seizures and a 77% reduction in the frequency of interictal spikes. No seizures occurred during stimulation. CONCLUSIONS: SF-rTMS was safe and well tolerated in this patient. The reduction in seizures and interictal spikes associated with SF-rTMS supports the concept of SF-rTMS-induced cortical inhibition.