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

Abstract

SummaryObjectiveTo investigate the effect of cathodal transcranial direct‐current stimulation (c‐tDCS) on seizure frequency in patients with drug‐resistant temporal lobe epilepsy (TLE).MethodTwenty‐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.ResultsThe 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.SignificanceResults 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.

Effect of neurostimulation on cognition and mood in refractory epilepsy

“…Other studies provide more robust seizure reduction results. A randomized‐controlled study of 29 patients showed that a single treatment of 18 total minutes of tDCS resulted in a 42.1% seizure reduction versus 17.0% reduction for the control group …”

Transcranial direct current stimulation (tDCS) in the management of epilepsy: A systematic review

“…1. Therefore, 27 original studies met inclusion criteria and were included in this systematic review, comprising nine original sham-controlled trials [20][21][22][26][27][28][29][30][31] (Table 1) and 18 uncontrolled trials and case series/reports [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] (Tables 2 and 3). Overall, studies encompassed 328 people with epilepsy of whom 253 underwent active stimulation while 75 received sham intervention.…”

“…Zoghi et al [27] investigated the effects of a distinctive tDCS protocol in a sample of adult patients with drug-resistant temporal lobe epilepsy. A 1 mA current of cathodal stimulation targeted at the affected temporal lobe was delivered in a single session consisting of two bouts of nine minutes (18 min total) spaced by a 20-minute interval.…”

“…However, there was a high variability both in the magnitude and duration of the after-effects. Taking into account four (out of eight) of the largest randomized controlled trials with drugresistant samples, for instance, a single session of cathodal tDCS led to a decrease in monthly seizure frequency at one month follow-up in two studies [26,27] while another trial that implemented a longer follow-up after an intensified protocol with 14 sessions, positive effects were detected for five weeks at most [21]. Conversely, San-Juan and coworkers reported a reduction in seizure frequency up to two months after active cathodal tDCS [31], even though the stimulation protocol was less intensewith fewer sessions and inferior current densityin comparison to that employed by Yang et al [21].…”

Genetic Polymorphisms Do Not Predict Interindividual Variability to Cathodal Transcranial Direct Current Stimulation of the Primary Motor Cortex

“…The basis for investigating inter-individual variability to c-tDCS lies in its potential use as an adjunct or alternative therapy to neurological populations such as those who experience excititoxicity such as Epilepsy and seizures as well as psychological populations such as those who experience anxiety disorders. A number of recent case reports and studies have reported improvements in seizure severity and frequency following trials of c-tDCS (Assenza et al, 2017;Lin et al, 2018;Tecchio et al, 2018;Tekturk et al, 2016;Yook et al, 2011;Zoghi et al, 2016) as well as fear response extinction in anxiety populations (Ganho-Ávila et al, 2019). With drugresistance a common problem in those who suffer seizures (Assenza et al, 2017;Tecchio et al, 2018), investigating adjunct non-invasive therapies such as c-tDCS is justified.…”