Electrical Stimulation of Cranial Nerves for Treating Dysphagia: A Critical Review

Dysphagia, a severe comorbidity of many neurological diseases, often lacks targeted therapies. Electrical stimulation of cranial nerves represents a novel therapeutic class. This critical review assessed the clinical effectiveness and safety of various approaches for electrical stimulation of the cranial nerves for treating dysphagia, categorized as implantable (directly targeting the nerve), minimally invasive (pharyngeal electrical stimulation), and non-invasive (transcutaneous). A critical literature review was conducted following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The PubMed database was comprehensively searched, and studies were rigorously assessed for inclusion and exclusion criteria. The Newcastle–Ottawa Scale was used to assess the risk of bias. The analysis included 15 clinical studies: four assessing vagus nerve stimulation (including implantable and transcutaneous approaches) and eleven assessing pharyngeal electrical stimulation. Most evaluated studies, particularly for pharyngeal electrical stimulation and transcutaneous vagus nerve stimulation, demonstrated significant beneficial effects on validated dysphagia outcome measures. Importantly, no long-term severe adverse effects were reported across the evaluated stimulation approaches. Cumulative evidence indicates that vagus nerve stimulation and pharyngeal electrical stimulation approaches can effectively alleviate dysphagia symptoms. The different stimulation approaches appear to be complementary, with distinct profiles rendering them suitable for different therapeutic contexts (e.g., short-term hospital-based vs. long-term at-home treatment). Consequently, they represent distinct and valuable options for individualized dysphagia therapy.