Impact of carbonation on neurogenic dysphagia and an exploration of the clinical predictors of a response to carbonation.

BACKGROUND: The need for effective compensatory strategies in neurogenic dysphagia management has led to the exploration of sensory enhancement strategies (SES), such as carbonated liquids. Despite some positive findings, evidence related to the efficacy of carbonation as an SES is limited.

AIMS: To determine if carbonated thin liquids reduced dysphagia symptoms and to explore clinical factors associated with response to carbonation.

METHODS & PROCEDURES: Participants (n = 29) with neurogenic dysphagia demonstrating deep penetration or aspiration on thin liquids during videofluoroscopic swallow studies (VFSS) completed a set protocol: discrete sips of non-carbonated thin fluids (DS-NC) followed by discrete sips of carbonated thin fluids (DS-C) and then consecutive sips of carbonated fluids (CS-C). The impact of carbonation was identified through changes to swallow physiology (videofluoroscopy dysphagia scale-VDS) and depth of airway compromise (penetration-aspiration scale-PAS). Demographic variables including genetic taste type, cranial nerve function and key results from the VDS were examined for association with carbonation response using both individual parameter analysis and exploratory cluster analysis.

OUTCOMES & RESULTS: Significant (p < 0.05) improvements in PAS scores were noted in DS-C and CS-C conditions compared with DS-NC. Total VDS score was also significantly (p < 0.05) reduced (i.e., improved function) in the DS-NC condition. Individual variability in response to carbonation was noted and no clear clinical factors associated with carbonation response in the current set of parameters were identified.

CONCLUSION & IMPLICATIONS: Findings support that carbonated thin fluids sometimes result in neurogenic dysphagia symptom reduction. However, identifying the clinical characteristics of patients who may benefit from trials of carbonation needs further investigation.