Swallowing skill training approaches and underlying motor learning principles: A scoping review

While dysphagia rehabilitation has traditionally focused on muscle strengthening, there is an increasing shift towards harnessing motor cortical plasticity to modify swallowing motor output via swallowing skill training. We reviewed current swallowing skill training approaches and framed existing evidence in the context of motor learning principles. Searches were conducted across six databases (Scopus, CINHAL, MEDLINE, PUBMED, Emcare, and Web of Science) and the grey literature. Two researchers independently screened studies for inclusion using Covidence. English publications were included without time limitations. Of 72 identified publications, 21 studies were included (15 empirical studies and 6 opinion-based papers). Four primary swallowing skill training approaches were identified, including: a) Floor of mouth surface electromyography, b) manometry, c) respiratory swallow coordination, and c) Iowa oral performance instrument. All approaches reported both improved swallowing function and patient reported outcomes. Whilst practice and feedback-related motor learning principles were incorporated in all approaches, their application varied across and within approaches. Swallowing skill training approaches can improve swallowing function and patients reported outcomes. However, to date, underlying methodologies are inconsistently described and motor learning principle are inconsistently applied. Further research is required in diverse populations to further optimise swallowing skill training outcomes.