Carbonation as a sensory enhancement strategy: a narrative synthesis of existing evidence

Purpose: Sensory enhancement techniques, like other compensatory strategies, aim to reduce dysphagia symptoms. The use of carbonated liquids has been proposed as a possible sensory technique, however to date, there is limited information of its efficacy or guidance for clinical implementation. A narrative synthesis was completed to determine the quality and strength of the evidence base for use of carbonation as a compensatory strategy in dysphagia rehabilitation. Methods: From 101 articles initially identified, 14 articles met the study criteria. Eleven papers described the effects of carbonation on swallowing in healthy participants whereas three described the impact of carbonation in dysphagic populations. A narrative synthesis of papers was undertaken given the diversity of identified studies. Results: Synthesis of findings was challenging given the exploratory phase of most research activity with diverse populations described and extensive differences in research methodologies. There is currently weak, but potentially positive evidence to support using carbonation as a compensatory technique in dysphagia rehabilitation. Conclusion: Despite future potential, existing evidence fails to provide clear direction for the clinical implementation of carbonation. Validation of carbonation use with the dysphagic population requires further research with consistent, controlled methodologies, and larger cohorts of participants to inform potential for dysphagia rehabilitation. Implications for Rehabilitation The use of carbonated liquids has been proposed as a possible sensory enhancement technique which may facilitate changes to swallow physiology. However to date, there is limited information to direct clinical implementation. This paper provides a narrative synthesis of existing knowledge and highlights possible limitations of findings reported. Research to date has used disparate research methodologies in varied populations making synthesis of current findings challenging