Tolerability and Effectiveness of Cathodal Transcranial Direct Current Stimulation in Children with Refractory Epilepsy: A Case Series

Abstract

There are limited treatment options for drug-resistant epilepsy (DRE) in children. We performed a pilot study to investigate the tolerability and effectiveness of cathodal transcranial direct current stimulation (tDCS) in DRE. Twelve children with DRE of varied etiology underwent three to four daily sessions of cathodal tDCS. The seizure frequency at 2 weeks before and after tDCS was obtained from seizure diaries; clinic reviews at 3 and 6 months assessed any longer-term benefits or adverse effects. The spike wave index (SWI) was analyzed in the EEGs done immediately before and after tDCS on the first and last day of tDCS. One child remained seizure free for a year after tDCS. One child had reduced frequency of ICU admissions for status epilepticus for 2 weeks, likely due to reduced severity of seizures. In four children, an improvement in alertness and mood was reported for 2-4 weeks after tDCS. There was no benefit following tDCS in the other children. There were no unexpected or serious adverse effects in any child. Benefit was seen in two children, and the reasons for the lack of benefit in the other children need further study. It is likely that tDCS stimulus parameters will need to be tailored for different epilepsy syndromes and etiologies.

Keywords: EEG epileptiform abnormality; children; drug-resistant epilepsy; seizure frequency; transcranial direct current stimulation.

Figure 1

EEG recordings. All EEG epochs are in a bipolar double banana montage. Calibration bars in each subfigure: horizontal, 1 s; vertical, 0.2 mV. (A,B) The 15 s epochs from wake EEG recording from case 12 before tDCS showing no epileptiform activity in (A) and epileptiform discharges in the F3-C3 derivations with phase reversal at C3 (see arrowheads) in (B). (C,D) The 15 s epochs from wake EEG recordings from case 8 before (C) and after (D) tDCS. Epileptiform discharges are seen in both epochs; however, there is a reduction in the amplitude and frequency of epileptiform discharges in (D). The symbols “v v v v” are the arrowheads referred to in description of Figure 1B. The horizontal and vertical bars at the bottom right corner of each subfigure are calibration bars mentioned in the caption.

Figure 2

Line graphs showing the spike wave index percent (SWI%) before and after the first and last (third or fourth) day of tDCS in individual cases. Abbreviations: SWI: spike wave index; tDCS: transcranial direct current stimulation.