Gustatory stimulus interventions for older adults with dysphagia: a scoping review

Background: Gustatory stimulus interventions have been shown to improve swallowing function in older adults with dysphagia. However, the optimal intervention strategies as well as their effects and safety remain unclear. 

Aims: To explore current evidence regarding gustatory stimulus interventions for dysphagia in older adults. 

Methods: Nine electronic databases (PubMed, Web of Science, Embase, CINAHL, Cochrane Library, China National Knowledge Infrastructure, Wanfang Database, China Science and Technology Journal Database, and Sinomed) were searched from their inception to August 2022. 

Results: This review identified 263 articles, and 15 met the inclusion criteria. The types of gustatory stimulus interventions included spicy (n = 10), sour (n = 3), and mixed (sour–sweet) stimuli (n = 2), with most studies focusing on spicy stimuli. The most frequently reported spicy stimulus was capsaicin. Further, the most commonly reported intervention frequency was thrice a day before meals for 1–4 weeks. The stimuli concentrations and dosages could not be standardized due to the among-study heterogeneity. These studies reported 16 assessment tools and 42 outcomes, which mainly included videofluoroscopy and swallowing response time respectively. More than half of the included studies reported no adverse effects of gustatory stimulus interventions. 

Conclusion and discussions: Gustatory stimulus interventions improved swallowing function in older adults with dysphagia. However, assessment tools and outcomes for dysphagia should be standardized in the future, and explore personalized interventions based on different diseases and their stages, to determine the most cost-effective interventions, and to prevent its complications.