Repetitive transcranial magnetic stimulation strategies for post-stroke dysphagia: A systematic review and network meta-analysis

Objective: Repetitive transcranial magnetic stimulation (rTMS) is a promising approach in improving swallowing function after stroke. However, comparative efficacy of different rTMS protocols for post-stroke dysphagia (PSD) remains unclear.

Data sources: PubMed, Embase and Cochrane database were systematically searched for eligible random controlled trials (RCTs) from inception to 30 August 2024.

Study selection: RCTs comparing rTMS with control or head-to-head comparisons of two rTMS protocols in PSD patients.

Data extraction: Data were extracted by two independent reviewers. A network meta-analysis combining direct and indirect evidence was conducted to assess the pooled findings of RCTs with standard mean difference (SMD) with 95% credible interval (CrI).

Data synthesis: Eighteen RCTs involving 760 participants (mean age of 62.4 [range 49.7 - 74.7] years; 45.7% female) were included. Pooled data showed that high frequency (HF)/ipsilesional hemisphere (ipsi-hemi) (SMD = -0.94, 95%CrI -1.51 - -0.44), HF/bilateral hemisphere (bi-hemi) (SMD = -2.59, 95%CrI -3.50 - -1.72), HF/ipsilesional cerebellar (ipsi-CRB) (SMD = -0.79, 95%CrI -1.55 - -0.10), HF/bilateral cerebellar (bi-CRB) (SMD = -1.02, 95%CrI -1.83 - -0.29), and HF/ipsi-hemi + low frequency (LF)/contralesional hemisphere (SMD = -2.72, 95%CrI -4.12 - -1.41) rTMS all significantly improved swallowing function compared to control. For acute stroke patients, HF/ipsi-hemi rTMS had a positive effect (SMD = -1.36, 95% CrI -2.86 - -0.02); in subacute stage, HF/ipsi-hemi + LF/contra-hemi rTMS showed the best efficacy (SMD = -2.68, 95% CrI -4.26 - -1.26). However, rTMS failed to improve swallowing function in chronic stage.

Conclusions: This network meta-analysis showed that most of the rTMS protocols (HF/ipsi-hemi, HF/bi-hemi, HF/ipsi-CRB, HF/bi-CRB, and HF/ipsi-hemi + LF/contra-hemi) may improve swallowing function in patients with PSD. The HF/ipsi-hemi rTMS had a positive effect in acute stage and the HF/ipsi-hemi + LF/contra-hemi protocol seemed to have the best efficacy when applied in subacute stroke.