The ability of sour and sweet-sour mixtures to improve swallowing in 11 nursing home residents with neurogenic oropharyngeal dysphagia was investigated using fiberoptic endoscopic evaluation of swallowing. Citric acid (2.7%) significantly reduced aspiration and penetration compared with water. Teaspoon delivery of liquids significantly reduced aspiration and penetration compared with natural cup drinking. Subjects tended to appropriately self-regulate the cup volume they consumed after the first trial. A significant increase in spontaneous dry swallows was observed after both taste stimuli. The mechanisms for improved swallowing due to citric acid are not understood but may be due to increased gustatory and trigeminal stimulation of acid to the brainstem in neurologically impaired subjects.

There is evidence that a strong, unpalatable, sour bolus improves swallowing in neurogenic dysphagia. It is not known whether other tastes may alter swallowing physiology. This study investigated the effect of moderate versus high taste concentrations (sweet, sour, salty, bitter) and barium taste samples on lingual swallowing pressure in ten healthy young adults, using a three-bulb lingual pressure array secured to the hard palate. Palatability of the samples was analyzed using the nine-point hedonic scale. Results showed that moderate sucrose, high salt, and high citric acid elicited significantly higher lingual swallowing pressures compared with the pressures generated by water. Pressures in the anterior bulb were significantly higher than those recorded from the middle or posterior bulb. There was no significant effect of palatability on lingual swallowing pressures. High salt and citric acid are known to elicit chemesthesis mediated by the trigeminal nerve. These results suggest that chemesthesis may play a crucial role in swallowing physiology. If true, dysphagia diet recommendations that include trigeminal irritants such as carbonation may be beneficial to individuals with dysphagia. However, before this recommendation more research is needed to examine how food properties and their perception affect swallowing in individuals with and without dysphagia.

This study presents the results of a blinded test of the performance of five commercial thickners. Experimental variables considered are brand of commercial thickener, type of liquid, desired thickness, and thickening time. Success of outcome is defined by a numerical rating scale comparing the consistency and taste to actual liquid samples. The findings suggest that no one commercial thickener consistently produces a desired consistency or was consistently superior regarding taste. Success in producing certain liquid consistencies and "good taste" varied according to brand, type of liquid, desired thickness, and thickening time used. It is suggested that specific recipes be developed for each brand and liquid to be thickened. Flavorings should be tested to enhance taste.

SAD in healthy women increased with changes in chemesthetic stimuli, older age, and in supertasters versus nontasters. It is unclear at this stage if increased SAD is a helpful mechanistic change (potentially protective against aspiration) or a maladaptive change (associated with aspiration). Future research should use these chemesthetic changes in bolus properties to assess if increased SAD decreases aspiration in patients with dysphagia while accounting for genetic taste differences.