Therapeutic efficacy of seizure onset zone-targeting high-definition cathodal tDCS in patients with drug-resistant focal epilepsy

Objective: Epilepsy is a common neurological disease with recurrent seizures. Transcranial direct-current stimulation (tDCS) is a safe, non-invasive method used for neuromodulation. The aim of this study was to explore the efficacy of cathodal high-definition tDCS (HD-tDCS) as a noninvasive method for the treatment of patients with drug-resistant focal epilepsy (DRFE). Methods: This study was conducted as a randomized parallel and double-blind clinical trial. Twenty patients with DRFE were randomly selected through the convenience sampling method and then were divided into two groups. Ten patients received 2 mA cathodal HD-tDCS targeting the seizure-onset zone for 30 min for 2 weeks (5 consecutive days in each week and 10 days in total). Ten patients were randomized to the sham group. Seizure frequency and Interictal Epileptiform Discharges (IEDs) frequency were the primary outcome measures of this study. Quality of Life in Epilepsy Inventory (QoLIE-89) and Montreal Cognitive Assessment (MoCA) scores were used as secondary outcome measures. Results: Seizure frequency decreased significantly among the patients in the treatment group 2 weeks (Pvalue < 0.05), 1 month (P-value < 0.05), and 2 months (P-value < 0.05) after the stimulation in comparison to the sham group. Patients in the treatment group showed a decrease in the frequency of IED 2 weeks (P-value < 0.05), 1 month (P-value < 0.05), and 2 months (P-value < 0.05) after stimulation. This cathodal stimulation protocol also improved the overall QoLIE-89 score after the stimulation compared to the sham group. Conclusions: The present study showed that cathodal HD-tDCS had a positive effect on seizure frequency and IED in patients with DRFE. More evidence is required to define the optimal stimulation parameters of HD-tDCS for the treatment of epilepsy. Significance: Cathodal HD-tDCS targeting the seizure-onset zone is a promising treatment modality for patients with drug-resistant focal epilepsy. (c) 2022 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Automated summary

This study investigates the efficacy of cathodal high-definition tDCS as a noninvasive treatment for drug-resistant focal epilepsy. The results demonstrate that cathodal HD-tDCS significantly reduces seizure frequency and interictal epileptiform discharges, improves quality of life, and holds promise as a treatment modality for patients with drug-resistant focal epilepsy. Further research is needed to define the optimal stimulation parameters.