As per the findings of a systematic review and meta-analysis, transcranial direct current stimulation minimized fatigue and enhanced cognitive function whereas repetitive transcranial magnetic stimulation decreased muscle spasticity in people suffering from multiple sclerosis. This study aimed to summarize the evidences on the effects of non-invasive brain stimulation on the core symptoms of multiple sclerosis (a chronic and inflammatory disorder of the central nervous system).

Researchers carried out a systematic search of articles published in PubMed, Medline, EMBASE, and Web of Science that compared the effects of active transcranial direct current stimulation or repetitive transcranial magnetic stimulation with sham intervention for the management of multiple sclerosis. For conducting this meta-analysis, a random-effects model was utilized.

For examining the effects of stimulation dose, meta-regression was utilized. For assessing the effects of different stimulation protocols, a subgroup meta-analysis was done. In total, 25 randomized controlled trials (6 repetitive transcranial magnetic stimulation and 19 transcranial direct current stimulation studies)were incorporated in this review. The transcranial direct current stimulation triggered a substantial and immediate decrease of fatigue with a large effect size.

Specifically, the subgroup assessment demonstrated that applying transcranial direct current stimulation over the left dorsolateral prefrontal cortex and bilateral S1 resulted in fatigue reductions in comparison with sham stimulation. In addition, transcranial direct current stimulation exhibited positive effects on fatigue in multiple sclerosis people with a low physical disability but not those with a high physical disability, and also enhanced cognitive functions.

Though repetitive transcranial magnetic stimulation was noted to decrease muscle spasticity, these non-invasive brain stimulation protocols depicted no further influence on multiple sclerosis-linked pain and mood symptoms. Additional high-quality studies are warranted for substantiating the therapeutic effects of different non-invasive brain stimulation protocols in multiple sclerosis, concluded the study authors.