Cathodal transcranial direct-current stimulation for treatment of drug-resistant temporal lobe epilepsy:A pilot randomized controlled trial

Objective: To investigate the effect of cathodal transcranial direct-current stimulation (c-tDCS) on seizure frequency in patients with drug-resistant temporal lobe epilepsy (TLE). Method: Twenty-nine patients with drug-resistant TLE participated in this study. They were randomized to experimental or sham group. Twenty participants (experimental group) received within-session repeated c-tDCS intervention over the affected temporal lobe, and nine (sham group) received sham tDCS. Paired-pulse transcranial magnetic stimulation was used to assess short interval intracortical inhibition (SICI) in primary motor cortex ipsilateral to the affected temporal lobe. SICI was measured from motor evoked potentials recorded from the contralateral first dorsal interosseous muscle. Adverse effects were monitored during and after each intervention in both groups. A seizure diary was given to each participant to complete for 4 weeks following the tDCS intervention. The mean response ratio was calculated from their seizure rates before and after the tDCS intervention. Results: The experimental group showed a significant increase in SICI compared to the sham group (F = 10.3, p = 0.005). None of the participants reported side effects of moderate or severe degree. The mean response ratio in seizure frequency was 42.14% (standard deviation [SD] 35.93) for the experimental group and 16.98% (SD 52.41) for the sham group. Significance: Results from this pilot study suggest that tDCS may be a safe and efficacious nonpharmacologic intervention for patients with drug-resistant TLE. Further evaluation in larger double-blind randomized controlled trials is warranted.