Effect of xanthan gum-based, guar gum-based, and starch-based thickeners on tongue pressure and pharyngeal residue.

OBJECTIVE

To examine the relationship between pharyngeal residue and both the oral and pharyngeal stages by observing tongue pressure and pharyngeal dynamics during the swallowing of thickened liquid prepared with starch-based, guar gum-based, and xanthan gum-based thickeners.

DESIGN

The participants were 20 volunteers without dysphagia (17 male, 3 female, 33.1 ± 8.8 years). Samples were water and liquids thickened with starch-based, guar gum-based, and xanthan gum-based thickeners, and each was 15 mL. The shear viscosity of thickened liquids was 400 mPa·s at 50 s-1. Whiteout duration and pharyngeal residue were observed by videoendoscopy, and swallowing sounds were recorded with a microphone. Tongue pressure was measured by using a multichannel sensor sheet placed on the palate. Whiteout duration, swallowing sound duration, and tongue pressure parameters were compared between the samples and the presence of pharyngeal residue.

RESULTS

The frequency of pharyngeal residue was significantly higher with starch-based samples than with water and xanthan-based samples (P < 0.05). The swallowing sound duration was significantly shorter for all of the thickened samples compared with water (P < 0.05). The tongue pressure at the posterior-circumferential for starch-based and guar gum-based samples was found to be significantly different from that for water (P < 0.05). Furthermore, when pharyngeal residue occurred, tongue pressure was significantly greater (P < 0.01), and the whiteout duration and swallowing sound duration were significantly longer (P < 0.05, P < 0.01, respectively).

CONCLUSION

Our findings suggest that the type of thickener influences both the oral and pharyngeal stages, which are associated with the occurrence of pharyngeal residue.