Experimental therapy of epilepsy with transcranial magnetic stimulation: lack of additional benefit with prolonged treatment

Abstract

-Objective: To investigate the effect of three months of low-frequency repetitive transcranial magnetic stimulation (rTMS) treatment in intractable epilepsy. Methods: Five patients (four males, one female; ages 6 to 50 years), were enrolled in the study; their epilepsy could not be controlled by medical treatment and surgery was not indicated. rTMS was performed twice a week for three months; patients kept records of seizure frequency for an equal period of time before, during, and after rTMS sessions. rTMS was delivered to the vertex with a round coil, at an intensity 5 % below motor threshold. During rTMS sessions, 100 stimuli (five series of 20 stimuli, with one-minute intervals between series) were delivered at a frequency of 0.3 Hz. Results: Mean daily number of seizures (MDNS) decreased in three patients and increased in two during rTMS-one of these was treated for only one month; the best result was achieved in a patient with focal cortical dysplasia (reduction of 43.09 % in MDNS). In the whole patient group, there was a significant (p<0.01) decrease in MDNS of 22.8 %. Conclusions: Although prolonged rTMS treatment is safe and moderately decreases MDNS in a group of patients with intractable epilepsy, individual patient responses were mostly subtle and clinical relevance of this method is probably low. Our data suggest, however, that patients with focal cortical lesions may indeed benefit from this novel treatment. Further studies should concentrate on that patient subgroup.KEY WORDS: transcranial magnetic stimulation, rTMS, epilepsy.Terapia experimental da epilepsia com estimulação magnética transcraniana: ausência de melhora adicional com tratamento prolongado RESUMO -Objetivo: investigar o efeito de três meses de estimulação magnética transcraniana repetitiva (EMTr) de baixa freqüência, na epilepsia de difícil controle. Método: Cinco pacientes (quatro homens, uma mulher, idades entre 6 e 50 anos), participaram do estudo; suas crises epilépticas não puderam ser controlados por tratamento medicamentoso e não tinham indicação cirúrgica; a EMTr foi realizada duas vezes por semana durante três meses, sendo que os pacientes anotaram o número diário de crises neste perío-do, assim como nos três meses anteriores e posteriores ao tratamento. A aplicação da EMTr foi feita no vértex com bobina circular, com intensidade 5% abaixo do limiar motor. Durante as sessões de EMTr, 100 estímulos (5 séries de 20 estímulos, com um minuto de intervalo entre as séries) foram realizadas na freqüência de 0,3 Hz. Resultados: A média diária de crises (MDC) decresceu em três pacientes e aumentou em dois durante o uso da EMTr; um destes casos foi tratado somente por um mês; o melhor resultado foi encontrado em um paciente com displasia cortical focal (redução de 43,09% na MDC). Em todo o grupo de pacientes, houve decréscimo significativo na MDC de 22,8% (p<0,01). Conclusão: Embora o tratamento prolongado com a EMTr seja seguro e tenha sido registrado decréscimo moderado da MDC em um grupo de pacientes com epilepsia de difí...

Repetitive transcranial magnetic stimulation for the treatment of refractory epilepsy

“…With regard to rTMS for the treatment of refractory epilepsy, one illustrative case report [13], 1 case series [14], 8 prospective open label studies [15][16][17][18][19][20][21][22], 6 randomized controlled trials (RCTs) [23][24][25][26][27][28] and a meta-analysis [29] were included. With regard to ictal application of TMS/rTMS, 2 illustrative case reports [30,31], 1 open label study [32] and 2 reviews [33,34] were selected.…”

Transcranial Magnetic Stimulation for Drug-Resistant Epilepsies: Rationale and Clinical Experience

“…Other single case reports [12,13,14,15] and small scale series [16,17,18,19] described the effects of TMS on various seizure types (SPS, CPS, sGTCs, myoclonias and absences) due to a wide spectrum of etiologies. Overall, results were encouraging but need to be interpreted cautiously given the uncontrolled design of these studies.…”

Low frequency (0.5Hz) rTMS over the right (non-dominant) motor cortex does not affect ipsilateral hand performance in healthy humans

“…The latter, namely repetitive transcranial magnetic stimulation (rTMS), produces cortical modulation of excitability associated to measurable effects that usually last beyond the period of stimulation. It has been widely studied as therapy for neurological and psychiatric diseases, such as epilepsy 4 , depression 5,6 , chronic pain 7 , stroke 8,9 , dystonia and other movement disorders 10 . rTMS is also a useful tool to investigate active neuroplasticity, by altering excitability and function of the stimulated cortex or its connections 11 .…”