Transcranial direct current stimulation for treatment of refractory childhood focal epilepsy

Abstract

Background: Cathodal transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation method for suppressing regional cortical excitability. We examine the safety and antiepileptic efficacy of cathodal tDCS in children with refractory focal epilepsy. Although a prior cathodal tDCS trial in adults with epilepsy revealed EEG improvement, neither the antiepileptic potential nor the safety and tolerability of tDCS has been tested in children.

Method: The study consisted of three phases: 1) a 4-week pre-treatment monitoring period with vital sign measures, EEG, seizure diary, and baseline quality of life (QOL) questionnaire; 2) a single treatment with 1 mA cathodal tDCS for 20 min with cathode positioned over the seizure focus and anode on the contralateral shoulder; 3) follow-ups immediately after stimulation, and at 24, 48 h, and 4 weeks after tDCS with continued seizure diary and epileptic discharge counts on EEG; the QOL questionnaire was also repeated 4 weeks after stimulation. Patients were randomized to receive either single session active or sham tDCS 1 mA, 20 min.

Results: Thirty six children (6-15 years) with focal epilepsy were enrolled, 27 in active and 9 in sham group. All patients tolerated tDCS well. No serious adverse events occurred. Active tDCS treatment was associated with significant reductions in epileptic discharge frequency immediately and 24 and 48 h after tDCS. Four weeks after treatment, a small (clinically negligible but statistically significant) decrease in seizure frequency was also detected.

Conclusion: A single session of cathodal tDCS improves epileptic EEG abnormalities for 48 h and is well-tolerated in children.

Keywords: Clinical neurophysiology; Focal seizures; Noninvasive brain stimulation; Partial seizures; Transcranial direct current stimulation.