Abstracts

Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive method for focal brain stimulation where small intracranial electrical currents are induced by a strong fluctuating extracranial magnetic field. rTMS is generally safe, although the reported low incidence of rTMS-associated seizures raises the concern for safety and tolerability in epileptic patients. Accordingly, our aim is to estimate the risk of seizure and other adverse events (AEs) occurring during rTMS in pediatric and adult patients with epilepsy ., Using PubMed we identified 25 English language articles published from January 1990 to April 2006 where epileptic subjects were treated with rTMS. The search criteria relied on the following key words: [apos]transcranial magnetic stimulation[apos], [apos]rTMS[apos], [apos]repetitive transcranial magnetic stimulation[apos], and [apos]epilepsy[apos], or [apos]seizure[apos]. We reviewed all 25 papers and noted number of subjects, medication usage, incidence of AEs, and stimulation parameters including stimulus frequency, number of stimuli, train duration, inter-train interval, coil type, and stimulation sites. When not explicitly stated in the manuscript, we obtained the relevant information by personal communication with the authors., In 25 studies (n=208 subjects), 12 studies (n=94 subjects) applied rTMS at 100% of motor threshold (MT) or above (range 100 - 150% of MT), while 114 subjects only received rTMS with intensity below MT (range 60 - 95% of MT). Of 25 articles reporting original research with rTMS in epileptic patients, AEs were reported in 23. Of the subjects (n=201) in the 23 articles, the reported AEs are: seizure (n=3), headache (n=13), nonspecific discomfort (n=13), skin irritation (n=2), jerking arm movement (n=2), and transient visual deficit (n=1). The risk of a seizure during rTMS is three in 201 total subjects (1.5%, crude mean rate), and the risk of AEs other than seizure is 31 in 201 subjects (15.4%). Of 25 articles reporting original research with rTMS in epileptic patients, both AEs and patient age were reported in 21. In these 21 studies, 174 were adult (age [ge]18 years) and 9 were pediatric (age [lt]18 years). rTMS-associated seizure risk in adults was 1.7% (n=3 patients). Notably, none of the 9 pediatric patients had a seizure occur at time of rTMS therapy. No rTMS-related episodes of status epilepticus were reported., The risk of a seizure in epileptic patients during rTMS is small, and the risk of other AEs is comparable to that seen when rTMS is used to treat other diseases. rTMS thus appears to be a safe therapeutic tool for treatment of seizures in adults and children.,