Noninvasive brain stimulation treatments, including transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS), reduced fatigue, pain, and psychiatric symptoms associated with multiple sclerosis (MS), according to study findings published in the journal Multiple Sclerosis and Related Disorders.
Researchers in Turkey and the United States conducted a systematic review and meta-analysis to determine whether noninvasive brain stimulation (NIBS) effectively reduced symptoms in patients with MS. They searched through databases such as MEDLINE, EMBASE, Scopus, Cochrane Center Register of Controlled Trials, and Web of Science for relevant studies published from inception until October 2022.
The systematic review and meta-analysis included 49 randomized controlled trials or quasi-experimental studies with 944 participants diagnosed with MS. The researchers used data from 44 of these 49 studies in the meta-analysis. They analyzed the efficacy of tDCS (n=33), TMS (n=9), and transcranial random noise stimulation (tRNS; n=2) compared with sham NIBS sessions in reducing MS symptoms, such as fatigue, pain, and psychiatric symptoms.
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The NIBS treatments in each of the included studies differed in terms of intensity, duration of treatment sessions, dosing parameters, and the regions of the brain targeted by the stimulation. Additionally, each patient with MS had differing baseline states of neural networks that influenced treatment outcomes.
The researchers discovered that compared with sham sessions, patients with MS who received actual tDCS treatments reported significantly decreased fatigue (effect size [ES], -0.86; 95% CI, -1.22 to -0.51; P <.0001), pain (ES, -1.91; 95% CI, -3.64 to -0.19; P =.03), and psychiatric symptoms (ES, -1.44; 95% CI, -2.56 to -0.32; P =.01). In contrast, tDCS did not improve motor performance (ES, -0.03; 95% CI, -0.35 to 0.28; P =.83) or cognition (ES, 0.71; 95% CI, -0.09 to 1.52; P =.08).
Compared with sham treatments, patients with MS who received TMS treatments reported decreased fatigue (ES, -0.45; 95% CI, -0.84 to -0.07; P =.02) and spasticity (ES, -1.11; 95% CI, -1.48 to -0.75; P <.00001). Similar to tDCS, TMS did not demonstrate the ability to improve motor performance (ES, -0.39; 95% CI, -0.95 to 0.16; P =.16).
When compared with sham treatments, tRNS, did not improve fatigue (ES, -0.28; 95% CI, -1.02 to 0.47; P =.46) or MS-related cognitive symptoms (ES, -0.04; 95% CI, -0.6 to 0.52; P =.88).
Additionally, lower disability scores (less than 3) on the Expanded Disability Status Scale (EDSS) corresponded to higher fatigue reduction after tDCS (P =.04). This correlated was noted especially after administration of stimulation intensities of 2 mA as opposed to 1.5 mA, although both intensity levels significantly reduced MS-related fatigue).
“This meta-analysis demonstrated a favorable effect of tDCS on fatigue, pain, and psychiatric symptoms, as well as a favorable effect of TMS on fatigue and spasticity,” the researchers wrote. “These findings support the idea that NIBS could be a promising alternative symptomatic therapy for patients with MS.”
This review consisted of a small number of studies, possibly due to the restriction of those only published in English. Most included studies had small sample sizes and were heterogeneous in terms of outcome measures, treatment protocols, and experimental study designs. Additionally, the findings of this review may not be generalizable outside of patients who have relapsing-remitting MS since most studies were comprised of patients with this MS subtype.
Reference
Uygur-Kucukseymen E, Pacheco-Barrios K, Yuksel B, Gonzalez-Mego P, Soysal A, Fregni F. Non-invasive brain stimulation on clinical symptoms in multiple sclerosis patients: a systematic review and meta-analysis. Mult Scler Relat Disord. Published online August 3, 2023. doi:10.1016/j.msard.2023.104927
This article originally appeared on Neurology Advisor
