Abstracts

Small trials and case reports have had mixed results regarding the efficacy of LF-rTMS to treat epilepsy. The lack of efficacy seen in some studies may be due to less rigorous methods for selecting and targeting the ER. Thus, we studied the efficacy of stereotactically-guided LF-rTMS in carefully selected patients with well-defined ERs. This study consisted of an 8- to 12-week baseline period, a 4-week LF-rTMS period, and an 8-week follow-up (FU) period. Four subjects with refractory epilepsy were enrolled. Inclusion criteria were: at least four seizures per four-week period, one or two well-defined ERs as determined by an epilepsy surgery evaluation, and poor candidacy for resective surgery. Epilepsy surgery evaluation included scalp video-EEG monitoring, interictal FDG-PET, and epilepsy protocol MRI. Interictal MEG data was also available for two patients. The ER to be targeted with LF-rTMS was determined upon consideration of all diagnostic tests. Subjects underwent four weeks of biweekly 0.5 Hz subthreshold LF-rTMS in two 15-minute trains separated by 3 minutes. LF-rTMS was directed at the ER using frameless stereotaxy based upon the subject[apos]s MRI (N=1) or MRI + MEG (N=2). In one case, the ER was the primary motor cortex, and LF-rTMS was directed at the ER based on TMS mapping of this region. If there were two ERs (N=1), each ER received one 15-minute train per session. Subject 1 had epilepsia partialis continua involving the right hand and experienced a decrease from baseline in average seizure hours/week by 22% during the four weeks of TMS and by 62% during the FU period. Subject 2[apos]s average seizure frequency decreased by 41% during the four weeks of TMS and by 70% during the 8-week FU period. Subject 3 showed a 57% decrease in seizure frequency during the 4-week TMS period that trended back toward the baseline average seizure frequency during the FU period. Subject 4 did not show a reduction in seizure frequency. However, during the 4-week TMS period, 50% of the seizures were significantly reduced in severity. Instead of dropping to the ground followed by one-minute of hyperkinetic activity, the less severe seizures consisted of dropping to the ground followed by recovery within 1-2 seconds and no hyperkinetic activity. To our knowledge, this is the first study using MR-guided stereotaxy to direct LF-rTMS at a well-defined ER in individuals with refractory epilepsy. Using this methodology and rigorous inclusion criteria, three out of four consecutive patients had a [gt]50% reduction in seizure frequency. The fourth patient had a clinically significant reduction in seizure severity. LF-rTMS may be most useful to treat epilepsy when there is a well-defined ER that is determined by a thorough presurgical evaluation and when this region is accurately targeted with LF-rTMS. (Supported by the AAN Foundation.)