Effects of Transcranial Direct Current Stimulation on Cognition, Mood, Pain, and Fatigue in Multiple Sclerosis: A Systematic Review and Meta-Analysis

Abstract

Background: The study aimed to evaluate the effects of transcranial direct current stimulation (tDCS) on cognition, mood disturbance, pain, and fatigue in people with multiple sclerosis (PwMS).Methods: A literature search was performed on articles published between January 1990 and May 2020 in Pubmed, Medline, and Web of Science using the following keywords and their abbreviation in combinations: multiple sclerosis and transcranial direct current stimulation. Mean effect size (ES) and 95% confidence interval were calculated for each domain of interest.Results: Seventeen articles with a total of 383 PwMS were included in this analysis. For cognition, a strong effect size was found for the trial administering the Symbol Digit Modalities Test (ES: 1.15), whereas trials applying the Attention Network Test showed a negative effect size of −0.49. Moderate to strong effect sizes were observed for mood disturbance (mean ES: 0.92), pain (mean ES: 0.59), and fatigue (mean ES: 0.60). Further subgroup analyses for MS-related fatigue showed that both high and low intensities of stimulation lead to nearly the same degree of favorable effects. More pronounced effects were observed in studies administering the Fatigue Severity Scale compared with studies using other fatigue measures such as the Modified Fatigue Impact Scale.Conclusion: These results provide preliminary evidence that tDCS has a favorable effect on cognitive processing speed, mood disturbance, pain, and fatigue in MS. However, the effects on cognition and fatigue vary based on the specific assessment used.

Examining the Effect of Transcranial Electrical Stimulation and Cognitive Training on Processing Speed in Pediatric Attention Deficit Hyperactivity Disorder: A Pilot Study

“…While Borragán et al (2018) reported no impact of anodal tDCS on cognitive fatigability-related PS in healthy adult subjects ( Borragán et al, 2018 ), others suggested that anodal tDCS over DLPFC improves PS of cognitive tasks in healthy adult participants ( Nelson et al, 2014 ; Sarasso et al, 2019 ) and in participants with multiple sclerosis ( Hanken et al, 2016 ; Fiene et al, 2018 ), with the impact lasting for at least 6 h ( McIntire et al, 2017 ). Given the small number of studies to date, and the heterogeneity of the methods applied and of the clinical profile of the patients, more studies are required in order to draw a more definitive conclusion ( Saiote et al, 2014 ; Chalah et al, 2017 ; Lefaucheur et al, 2017 ; Hsu et al, 2021 ).…”

The therapeutic potential of non-invasive brain stimulation for the treatment of Long-COVID-related cognitive fatigue

“…Most of the studies applied 1.5 mA or 2 mA for a duration of 15 min, 20 min, or 30 min. The stimulations were applied for three, five, or ten consecutive days (see 59 or 15 for comprehensive reviews). Before and after the stimulations, subjective trait fatigue was assessed via self-reported questionnaires.…”

“…Despite its clinical importance, there is a lack of effective therapeutic methods to alleviate fatigue. However, in recent years, numerous replicated studies, primarily conducted in people with MS, have demonstrated the efficacy of transcranial direct current stimulation (tDCS) as a promising, non-invasive, and non-pharmacological method of reducing fatigue (see 15 for a systematic review). Additionally, studies using transcranial alternating current stimulation (tACS) or transcutaneous vagus nerve stimulation (tVNS) show promising results ( 16 – 18 ).…”

On the Effects of Transcranial Direct Current Stimulation on Cerebral Glucose Uptake During Walking: A Report of Three Patients With Multiple Sclerosis

“…Such uses might strengthen long-term potentiation-like processes ( Stoykov and Madhavan, 2015 ), supporting a greater maintenance of benefits from combined therapies ( Costa-Ribeiro et al, 2016 ). Although tDCS combined with cognitive and physical training seems promising, the current results are mixed ( Sánchez-Kuhn et al, 2017 ; Steinberg et al, 2018 ; Hsu et al, 2021 ). However, tDCS group results might not mirror individual subject responses ( Wiethoff et al, 2014 ), which impedes our interpretation of the pathophysiology, treatment, and management of diseases like MS.…”