Bilateral Neuromodulation Outperforms Unilateral Stimulation for Swallowing Recovery After Stroke

A systematic review and meta-analysis evaluating neuromodulation interventions for adult stroke patients with dysphagia found that bilateral neuromodulation was associated with significantly greater improvements in swallowing function than unilateral stimulation across all evaluated outcomes. In primary outcome measures, bilateral stimulation produced a significant improvement on the Dysphagia Outcome and Severity Scale (mean difference = 0.97, 95% CI 0.12 to 1.82, p = 0.03) and a significant reduction on the Penetration–Aspiration Scale (mean difference = −1.32, 95% CI −2.60 to −0.03, p = 0.04), despite substantial statistical heterogeneity in the pooled primary data. Sensitivity analyses confirmed a consistent direction of effect, and GRADE evaluation established moderate certainty for these primary outcomes.

Significant functional advantages for bilateral stimulation were also observed across all secondary outcomes assessed in the review. Bilateral neuromodulation demonstrated superior outcomes on the Functional Oral Intake Scale (mean difference = 0.92, p < 0.00001), general dysphagia assessment scales (mean difference = 6.76, p < 0.00001), and the overall degree of dysphagia (mean difference = −1.09, 95% CI −1.37 to −0.80, p < 0.00001). Risk of bias was rated as low across all included randomized controlled trials.

Conducted in accordance with PRISMA guidelines, the investigation systematically searched PubMed, Scopus, and Web of Science from inception through April 2026. Seven eligible studies involving a combined total of 231 patients met inclusion criteria, comprising six randomized controlled trials and one cohort study comparing bilateral against unilateral stimulation techniques such as repetitive transcranial magnetic stimulation and transcranial direct current stimulation. Outcome data were synthesized using a random-effects model, with study quality evaluated using the Cochrane ROB2 tool for randomized trials and the Newcastle–Ottawa Scale for cohort evidence.

Post-stroke dysphagia is a frequent complication linked to heightened morbidity, mortality, and healthcare burden, with neuromodulation emerging to promote neuroplasticity and swallowing recovery. Although the study authors concluded that bilateral neuromodulation may provide greater functional improvements than unilateral approaches, they noted that substantial heterogeneity and the limited total volume of published studies warrant cautious interpretation, requiring further large-scale clinical trials to establish optimal stimulation protocols.

Subject of Research: Bilateral versus unilateral neuromodulation for post-stroke dysphagia

Article Title: Bilateral neuromodulation outperforms unilateral stimulation for post-stroke dysphagia: a systematic review and meta-analysis

Article References: Aldehri, M., Serag, I., Shaban, M. K., Alnajjar, A. Z., Sofia, T., & Alnaami, I. (2026). Bilateral neuromodulation outperforms unilateral stimulation for post-stroke dysphagia: a systematic review and meta-analysis. European Journal of Medical Research. https://doi.org/10.1186/s40001-026-05387-5

Image Credits: AI Generated

DOI: 10.1186/s40001-026-05387-5

Keywords: post-stroke dysphagia, neuromodulation, repetitive transcranial magnetic stimulation, transcranial direct current stimulation, systematic review, meta-analysis, swallowing rehabilitation, stroke recovery, Bilateral, outperforms, unilateral, stimulation