Abstracts

RATIONALE: Low-frequency repetitive transcranial magnetic stimulation (rTMS) is known to induce long-lasting depression of cortical excitability. A previous open pilot study showed that low-frequency rTMS treatment can reduce seizure frequency in drug-resistant epilepsy patients (Tergau et al., Lancet, 1999, 353:2209). Currently, we are performing a multicenter study to prove the antiepileptic efficacy of rTMS in a placebo-controlled single-blinded design. Results of an Interim Analysis are presented here.
METHODS: So far, 19 patients with drug-resistant epilepsy syndromes with on average at least two seizures per week were included, five patients dropped out, nine patients finished the study yet. rTMS treatment consisted of five consecutive days with daily application of 1000 pulses, 100% motor threshold intensity, using a Dantec MagPro magnetic stimulator with a round coil placed over the vertex. In each patient we performed three different types of stimulation in randomized order: 0.3Hz, 1.0Hz and, as sham stimulation, 0.6Hz. For sham stimulation we used a special coil with ineffective magnetic output. Seizure frequency was recorded in diaries four weeks before and after stimulation. There was a minimum of eight weeks between two treatment phases.
RESULTS: Overall results for periods of four weeks before and after rTMS showed a reduction in seizure frequency by on average 24.3[plusminus]24.7% and 38.0[plusminus]24.6% for 1Hz and 0.3Hz, respectively, while sham stimulation showed reduction only by 8.4[plusminus]26%. The effect was significant for 0.3Hz versus Sham (p=0.037) but failed significance for 1.0Hz (p=0.333). One patient did not respond to rTMS at all and showed increase by 20% after 1Hz. In four patients, 0.3Hz was superior to 1Hz, while the reverse was true in two patients. Two patients did not show difference between 0.3 and 1Hz. The effect lasted for one to four weeks. In none of the subjects side effects were observed.
CONCLUSIONS: The interim analysis apparently confirms the results of the pilot study and demonstrates the antiepileptic therapeutic potential of low-frequency rTMS in severe epilepsy syndromes. 0.3Hz seems to be superior to 1Hz, although there may be an interindividual difference in the optimal rTMS frequency.
[Supported by: Medtronic/Dantec Company, Duesseldorf, Germany]; (Disclosure: Materials - Magnetic Stimulators were provided by the Dantec-Medtronic Company, Duesseldorf, Germany, Royalties - Magnetic Stimulators were provided by the Dantec-Medtronic Company, Duesseldorf, Germany)