Vocal Adduction Exercises for Swallowing Rehabilitation in Adults with Typical and /or Disordered Swallowing: A Scoping Review

Abstract

Background: In healthy individuals, airway protection during swallowing involves closure of the larynx at multiple levels, including adduction of vocal folds. Different vocal adduction exercises have been reported in swallowing rehabilitation, but no knowledge synthesis on them exists, to date.

Aims: This review aims to understand the extent and type of evidence on rehabilitative vocal adduction exercises and their effect on swallow physiology in adults with typical or disordered swallowing. It also presents the outcome measures and principles of rehabilitation, reported.

Methods & Procedures: The Joanna Briggs Institute, and PRISMA-ScR guidelines were used to inform this review. Electronic databases (MEDLINE (PubMed), EMBASE (Ovid), CINAHL (EBSCO) and Web of Science) and grey literature were searched from inception to March 2022 inclusive. Articles were assessed by two independent reviewers to meet the following criteria: (1) rehabilitative vocal adduction exercise, (2) which instrumentally measured impact on swallowing physiology, (3) in participants aged ≥18 years with typical and/or disordered swallowing. All types of original research were examined, with no restrictions on language or setting.

Outcome and Results: A total of 12493 records were identified for title and abstract screening. From 89 studies selected for full text review, 10 were included. In total five vocal adduction exercises, LSVT (n = 4, 40%), EMST (n = 1, 10%), singing (n = 3, 30%), supraglottic swallow maneuver (n = 1, 10%) and supraglottic swallow combined with effortful pitch glide (n = 1, 10%) were identified for swallowing rehabilitation, predominantly in adults with neurological disorders. Overall positive effect on swallowing physiology was noted. Heterogenous set of outcome measures and principles of rehabilitation were reported.

Conclusions: A diverse set of vocal adduction exercises with heterogeneous effects on swallow physiology were identified. This review offers the best available evidence on the extent and type of different rehabilitative vocal adduction exercises, with respect to instrumentally measured impact on swallowing physiology over time, to inform potential directions for future research and practice.