The effectiveness of anodal tDCS and cognitive training on cognitive functions in multiple sclerosis; a randomized, double-blind, parallel-group study.

BACKGROUND

Forty to 70% of patients with multiple sclerosis (MS) suffer from cognitive impairment during their illness. Only a few studies have examined the effects of anodal transcranial direct current stimulation (a-tDCS) along with cognitive training on cognitive performance in MS patients. This study aims to determine whether multi-session a-tDCS with or without cognitive training impacts cognitive performance in MS.

METHODS

Eighty MS patients received a-tDCS, cognitive training, a-tDCS plus cognitive training, and sham for ten consecutive daily sessions. Cognitive function (including episodic memory, attention, and inhibitory control, working memory, and visuospatial skill) was measured at baseline, week 4, and week 12 after the intervention.

RESULTS

All cognitive functions significantly improved after the intervention compared to the sham condition. This effect also showed persistence during follow-up for some cognitive tasks in the a-tDCS and a-tDCS combined cognitive training groups. Although the cognitive training group experienced an immediate improvement in attention and inhibitory control, the difference was not significant at follow-up. Also, there were no significant differences between these three groups in cognitive scores after the intervention.

CONCLUSION

a-tDCS alone and a-tDCS paired with or without cognitive training as compared to sham appears to be a promising therapeutic option for cognitive performance in MS patients.