Electrical stimulation therapy for pain and related symptoms in multiple sclerosis: A systematic review and meta-analysis

Background: The effectiveness of electrical stimulation therapy (EST) for pain, depression, fatigue, disability, and quality of life in multiple sclerosis (MS) remains uncertain. This study aims to analyze and discuss the efficacy of various EST treatments in alleviating pain among MS patients. Methods: The primary search was conducted using PubMed, Web of Science, Cochrane Library, Embase, and the Cumulative Index of Nursing and Allied Health Literature databases until September 25, 2023. Randomized controlled trials (RCTs) including patients with MS pain receiving EST compared with other therapies were included. Pain intensity, quality of life, and neuropsychiatric symptoms were reported. The mean difference (MD) with 95 % confidence intervals (CIs) was estimated separately for outcomes to understand the mean effect size. Results: Ten RCTs containing 315 participants were included. The pooled data from 8 trials including 267 participants showed that the EST was superior in alleviating pain (MD = -1.75, 95 % CI -2.85--0.64, P = 0.002, I2=73 %) evaluated by the visual analog scale. In subgroup analysis, medium-term EST treatment showed the highest effect size compared to short-term and long-term treatment (MDmedium-term = -2.17, 95 % CI -3.51--0.84, P = 0.001, I2 = 0 %). However, no significant differences were found in terms of pain-related quality of life, depression, fatigue, and pain-related disability. No adverse events related to EST were reported. A high risk of bias was identified in three of the ten included studies. Conclusions: EST is effective and safe for alleviating pain in MS, but it should be noted that limited sample sizes and methodological issues were present in the included studies. More robust assessment criteria and high-quality RCTs are required for patients with MS. Trial registration: CRD42023406787. (https://www.crd.york.ac.uk/prospero/display_record.php?Reco rdID=406787).