Low-frequency repetitive transcranial magnetic stimulation for seizure suppression in patients with extratemporal lobe epilepsy-A pilot study

We evaluated the effect of low-frequency repetitive transcranial magnetic stimulation (rTMS) on seizure frequency in adult patients with medically intractable extratemporal lobe epilepsy (ETLE). Seven patients with medically intractable ETLE received low-frequency rTMS at 0.9 Hz, basically two sets of 15 min stimulation per day for five days in a week, with the stimulus intensity of 90% of resting motor threshold (RMT). The number of seizures during two weeks before and after the stimulation of one week was compared. Furthermore, RMT and active motor threshold (AMT) were measured before and after rTMS for each daily session. After low-frequency rTMS of one week, the frequency of all seizure types, complex partial seizures (CPSs) and simple partial seizures was reduced by 19.1, 35.9 and 7.4%, respectively. The patients with smaller difference between RMT and AMT before rTMS had higher reduction rate of CPSs. A favorable tendency of seizure reduction, though not statistically significant, during two weeks after low-frequency rTMS was demonstrated in medically intractable ETLE patients. As far as CPSs are concerned, smaller decrease of motor threshold by voluntary muscle contraction was associated with better response to rTMS.