Abstracts

Rationale: Repetitive transcranial magnetic stimulation (rTMS) is a well-tolerated method for focal brain stimulation where small intracranial electrical currents are induced by a fluctuating extracranial magnetic field. When applied in low frequency (≤1 Hz), rTMS leads to suppression of cortical excitability. Recent advances enable deep brain rTMS, and stimulation of the mesial temporal structures. We adapted the deep rTMS system to test the capacity of 1 Hz stimulation, to suppress seizures in temporal lobe epilepsy (TLE). A randomized-controlled trial is in progress. We present an interim review of the safety and tolerability of the deep rTMS in patients with TLE. Methods: Patients were randomized to verum or placebo rTMS. Verum rTMS was delivered in trains of 1800 pulses at 1 Hz, at intensity of 100% motor threshold, with one train per day for 10 business days per subject. Sham rTMS delivered an audible and palpable stimulus without induced intracranial current. The following per-visit data were reviewed from all instances of verum or placebo rTMS, at baseline and subsequent to treatment: seizure diary at baseline and subsequent to treatment, EEG, and performance on the Wechsler Memory Scale or the Children's Memory Scale. Per treatment session, we also collected patient safety and tolerability questionnaires and mini-mental examination (MME) scores. Results: No serious adverse event occurred. No instance of atypical seizure, status epilepticus or epilepsy exacerbation was recorded. One subject withdrew prior to randomization and stimulation due to anxiety. One subject withdrew from the placebo arm, citing insomnia and memory deficits. The most common mild adverse events were transient headache and neck pain, which resolved in all instances within a few hours of stimulation. Neither placebo nor verum treatments adversely affected memory with insignificant increase in memory scale scores in both placebo and verum arms (10% and 18%, respectively). Interim efficacy analysis reveals an average 45% seizure frequency increase in placebo arm (n=2 patients) and a 37% seizure frequency decrease in verum arm (n=4 patients). Conclusions: 1 Hz deep rTMS appears safe and well-tolerated in patients with TLE. While too early for definitive analysis of efficacy, the initial seizure reduction is encouraging.