Safety and Feasibility of Transcranial Direct Current Stimulation for Cognitive Rehabilitation in Patients With Mild or Major Neurocognitive Disorders: A Randomized Sham-Controlled Pilot Study

Abstract

IntroductionTranscranial direct current stimulation (tDCS) is a potentially novel strategy for cognitive enhancement in patients with mild or major neurocognitive disorders. This study aims to assess the safety and efficacy of tDCS during cognitive training on cognitive functioning in patients with mild or major neurocognitive disorders.MethodsThis study was primarily a single arm for safety, secondary a two-arm, parallel, randomized, and sham-controlled trial for potential efficacy. Patients with mild or major neurocognitive disorders were recruited. The participants and raters were blinded to the group assignment. The participants in the active arm received tDCS (anodal; F3, cathodal, Fp2, 2A, 20 min) twice daily for five consecutive days, whereas those in the sham arm received the same amount of sham-tDCS. Calculation and reading tasks were conducted in both arms as a form of cognitive intervention for 20 min during tDCS. The primary outcome was the attrition rate during the trial in the active arm, which is expected to be less than 10%. The secondary outcomes were the between-group differences of adjusted means for several cognitive scales from baseline to post-intervention and follow-up.ResultsTwenty patients [nine women (45%)], with a mean (standard deviation) age of 76.1 years participated; nine patients (45%) with minor neurocognitive disorders and 11 (55%) with major neurocognitive disorders were randomized, and 19 of them completed the trial. The attrition rate in the active arm was 0%, with no serious adverse events. Further, in the Intention-to-Treat analysis, patients in the active arm showed no statistically significant improvement compared with those who received the sham in the mean change scores of the mini-mental state examination [0.41; 95% CI (−1.85; 2.67) at day five, 1.08; 95% CI (−1.31; 3.46) at follow-up] and Alzheimer’s disease assessment scale – cognition subscale [1.61; 95% CI (−4.2; 0.98) at day 5, 0.36; 95%CI (−3.19; 2.47) at follow-up].ConclusionThese findings suggest that tDCS is safe and tolerable but causes no statistically significant cognitive effects in patients with mild or major neurocognitive disorders. Additional large-scale, well-designed clinical trials are warranted to evaluate the cognitive effects of tDCS as an augmentation to cognitive training.Clinical Trial Registrationwww.ClinicalTrials.gov, identifier NCT03050385.

Effects of multisession transcranial direct current stimulation as an augmentation to cognitive tasks in patients with neurocognitive disorders in Japan: a study protocol for a randomised controlled trial

“…Second, the long-term cognitive benefits of tDCS cannot be assessed. Our pilot study 16 indicated the short-term effects of tDCS on cognition in 10 sessions. Because the long-term cognitive effects of tDCS are uncertain, no large-scale trials have assessed these effects.…”

“…The advantage of this study is its appropriate sample size calculation for global cognition based on our previous pilot study 16 when compared with most other previous studies that lacked proper sample size calculations. Trial adherence strategies include reducing the number of hospital visits.…”

“…An estimated sample size is 46 in each group, which is based on the assumption that an estimated mean difference in ADAS-Cog from baseline to Day 5 is −1.61, and its SD is 2.7, which is based on the results of our pilot study. 16 …”

“…To be in accordance with the criteria of our pilot study. 16 7. Subjects deemed inadequate for participation by a physician in charge.…”

“…An estimated sample size is 46 in each group, which is based on the assumption that an estimated mean difference in ADAS-Cog from baseline to Day 5 is −1.61, and its SD is 2.7, which is based on the results of our pilot study. 16 Sequence generation Participants will be randomised at a 1:1 ratio to either the active or sham tDCS group using a computer-generated stratified sequence in the Electronic Data Capture (EDC) system. All data will be recorded in the EDC system, HOPE eACReSS (Fujitsu, Tokyo, Japan).…”