Therapeutic potential of repetitive transcranial magnetic stimulation (TMS) in long COVID: a systematic review and meta-analysis protocol

The cumulative global incidence of long COVID is around 400 million individuals, yet effective treatment options remain limited. A recent systematic review published in 2025 highlighted promising results for non-invasive brain stimulation in alleviating long COVID symptoms. Given the growing use of repetitive transcranial magnetic stimulation (rTMS) for people with long COVID, a focused meta-analysis on the therapeutic effectiveness of rTMS is warranted. To address this gap, this protocol outlines the planned procedures for a systematic review and meta-analysis. A comprehensive search will be conducted across CINAHL Ultimate, MEDLINE, ScienceDirect, and Scopus. Retrieved studies will be managed using Rayyan, with two independent reviewers screening titles and abstracts, followed by full-text review. Data extraction will follow PRISMA and Cochrane guidelines using a standardised form, with dual independent extraction and reconciliation of discrepancies. Risk of bias will be assessed using Cochrane RoB 2.0. Meta-analytical procedures will include calculation of standardised effect sizes (e.g., Hedges’ g), use of random-effects models, and assessment of heterogeneity via I², Cochran’s Q, and tau². Subgroup and moderator analyses will explore variations in rTMS protocols, participant characteristics, and symptom domains. Sensitivity analyses and meta-regression will be conducted where data permit. Results will be visualised using forest and funnel plots, and the GRADE framework will be used to assess the quality of evidence.