Transcranial direct current stimulation improves seizure control in patients with Rasmussen encephalitis

Abstract

Aim. Rasmussen encephalitis is associated with severe seizures that are unresponsive to antiepileptic drugs, as well as immunosuppressants. Transcranial direct current stimulation (t‐DCS) is a non‐invasive and safe method tried mostly for focal epilepsies with different aetiologies. To date, there is only one published study with two case reports describing the effect of t‐DCS in Rasmussen encephalitis. Our aim was to investigate the effect of t‐DCS on seizures in Rasmussen encephalitis and to clarify its safety. Methods. Five patients (mean age: 19; three females), diagnosed with Rasmussen encephalitis were included in this study. Patients received first cathodal, then anodal (2 mA for 30 minutes on three consecutive days for non‐sham stimulations), and finally sham stimulation with two‐month intervals, respectively. Three patients received classic (DC) cathodal t‐DCS whereas two patients received cathodal stimulation with amplitude modulation at 12 Hz. Afterwards, all patients received anodal stimulation with amplitude modulation at 12 Hz. In the last part of the trial, sham stimulation (a 60‐second stimulation with gradually decreasing amplitude to zero in the last 15 seconds) was applied to three patients. Maximum current density was 571 mA/m2 using 70 mm × 50 mm wet sponge electrodes with 2‐mA maximum, current controlled stimulator, and maximum charge density was 1028 C/m2 for a 30‐minute stimulation period. Results. After cathodal stimulation, all but one patient had a greater than 50% decrease in seizure frequency. Two patients who received modulated cathodal t‐DCS had better results. The longest positive effect lasted for one month. A second trial with modulated anodal stimulation and a third with sham stimulation were not effective. No adverse effect was reported with all types of stimulations. Conclusion. Both classic and modulated cathodal t‐DCS may be suitable alternative methods for improving seizure outcome in Rasmussen encephalitis patients.

Neuronal autoantibodies in patients with Rasmussen's encephalitis

“…EPC: epilepsia partialis continua. The patients included in this study were already diagnosed and treated as patients with Rasmussen encephalitis (Tekturk et al ., ).…”

“…While two of the patients had moderate cognitive impairment, other patients were severely affected, as shown by neuropsychological testing. Demographic features and clinical, EEG, and neuroimaging findings of all patients are presented in table 1 (Tekturk et al, 2016). None of the RE patients, MS patients, or healthy controls showed positivity for any of the wellcharacterized antibodies.…”

“…In this study, we aimed to delineate antibody-mediated mechanisms as a potential source of neuronal death in RE. Since antibodies against cell surface and synapse Neuronal autoantibodies in Rasmussen's encephalitis (Tekturk et al, 2016).…”

A simple method for EEG guided transcranial electrical stimulation without models

“…The goal of using EEG to design and optimize tES is not new and it is based on the reciprocity application [1]. But the adoption remains investigational [7,8,14,38] and limited (see introduction, [9][10][11][12][13]87]).…”

“…Typically when, without a model, EEG is used to identify a target [9][10][11] or to select tES waveform [11][12][13], electrodes (often large pads) are positioned based on rules-of-thumb such as placing one electrode 'over' the region of interest and the other one at 'some distance'. Model-driven efforts on EEG guided tES have been considered with increasing sophistication and computational burden [7,14,15].…”