An investigation of taste intensity, palatability, effervescence, and sip volumes of carbonated liquid stimuli for use in videofluoroscopic studies

Purpose: Existing studies examining the effect of carbonated fluids on swallow physiology under videofluoroscopy (videofluoroscopic swallowing studies [VFSSs]) have significant variability across the fluids tested and limited consideration of the stability of the carbonation or fluid palatability. This study compared the effervescence behavior, carbonation intensity (sour, bite, bubble), palatability, and sip volumes of carbonated liquids as used in VFSSs and control samples. Method: Forty-two healthy women (20 supertasters, 22 nontasters; 20-61 years old) took sips of 4 different liquids (water, carbonated water, barium sulfate with sodium bicarbonate granules, and barium sulfate with carbonated water) across 2 time conditions (on preparation and 5 min postpreparation). The 8 conditions were presented in 100-ml amounts, in randomized order. At presentation of each fluid, participants immediately rated effervescence via visual inspection. Then after sips of each fluid, participants rated perceived intensity of sour, "bubbles" and "bite," and palatability. Sip size was derived from residual volumes. Participant perceptions of fluids were also collected. Results: The effervescence of barium sulfate with sodium bicarbonate granules, as used in the majority of published studies, was most impacted by time (p < .05), rated poorly for palatability, and had the largest impact on sip size (p < .05). Participant comments regarding the VFSS fluids were grouped in 4 themes: (a) adverse/other reactions, (b) awareness of sensory properties, (c) physiological reactions, and (d) swallow changes. Conclusions: The significant differences between liquids regarding effervescence behavior, impact of preparation time, palatability, impact on naturalistic sipping, and patient perceptions warrant consideration when testing carbonated fluids during videofluoroscopy

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

Exploring current sensory enhancement practices within videofluoroscopic swallow study (VFSS) clinics

Whilst some research evidence supports the potential benefits of sensory enhancement strategies (SES) in dysphagia management, there is limited understanding of how SES are used in clinical services and the influencing drivers involved in selection during instrumental assessment. SES include modification of temperature, flavour, texture, chemesthetic qualities and bolus size of food/fluid. This study aimed to explore the use of SES within Australian Videofluoroscopic Swallow Study (VFSS) clinics providing adult services, via a qualitative methodology. Maximum variation sampling was used to select a cross section of speech-language pathologists (SLPs) with a range of experience working within 16 VFSS clinics across metropolitan and regional settings to participate in semi-structured, focus group or individual teleconference interviews. Content analysis of interview transcripts was conducted, with four themes emerging as influencing drivers of SES use, including: Patient factors influence SES use; Clinician factors influence SES use; Trials of SES require planning and organisation, and; Organisational barriers impact on SES use. These four themes were all connected through a single integrative theme: Extensive variations of SES procedures exist across clinical settings. Findings indicate that achieving alignment of clinical purpose and implementation of practices amongst VFSS clinicians will be complex given current diversity in SES use. Organisational issues and clinician training need to be addressed, and more research is needed to provide a stronger evidence base to inform clinical practice in this emerging area of dysphagia management