Effects of Bolus Rheology on Aspiration in Patients with Dysphagia

Abstract

Bolus manipulation is a primary treatment strategy in the management of oral-pharyngeal dysphagia. The use of thickening agents to alter bolus rheology is particularly commonplace; however, the precise effects of these alterations on swallowing remain uncertain. The purpose of our study, a prospective, double-blind clinical trial (Level 1b), was to investigate the effects of viscosity on aspiration. One hundred patients with dysphagia were prospectively evaluated with fluoroscopic swallow studies performed across three standardized and randomized conditions: thin liquid barium (THIN), liquid barium thickened with a starch-based agent (STARCH), and liquid barium thickened with a gum-based agent (GUM). Outcome measures included the prevalence of aspiration and score on the Penetration-Aspiration Scale. A total of 23 out of 100 patients exhibited 56 episodes of aspiration. Twenty patients aspirated on THIN, 15 on STARCH, and 11 on GUM bolus conditions (P<0.05, thin vs gum). There were 28 instances of aspiration on THIN, 16 on STARCH, and 12 on GUM. Mean Penetration-Aspiration Scale score ± standard deviation was 2.11 ± 2.22 for THIN, 1.76 ± 1.88 for STARCH, and 1.42 ± 1.47 for GUM conditions, respectively (P<0.001, THIN vs GUM). A clinically significant reduction in the incidence of penetration and aspiration was observed for gum-thickened barium compared with thin liquid barium.

The Influence of Food Texture and Liquid Consistency Modification on Swallowing Physiology and Function: A Systematic Review

“…The available data also lack evidence regarding the important possibility that properties of a liquid bolus other than apparent viscosity, such as density, yield stress, cohesiveness, or slipperiness (to list a few) might influence swallowing physiology and function. On this latter point, we are aware of a recent publication describing differences in the rates of occurrence of penetration–aspiration for liquids, depending on the type of thickener used (starch vs xanthangum), albeit thickened to different degrees [75]. A recent conference abstract also reports differences in residue accumulation for liquids thickened with corn-starch versus xanthangum thickeners, and attributes these differences to subjectively judged cohesive properties of the bolus [76].…”

Rheological Characteristics of Cold Thickened Beverages Containing Xanthan Gum–Based Food Thickeners Used for Dysphagia Diets

“…17 Therefore, an appropriate selection of rheological parameters is required to describe the rheological properties of a complex fluid during swallowing. The dynamic moduli (G 0 and G 00 ) of thickened fluids have been proposed as potentially relevant for swallowing.…”

Rheological aspects of dysphagia-oriented food products: A mini review

“…These thickeners may be gum based or starch based [50,51]. In this strategy, a thickening agent is added to a thin liquid (e.g., water or juices), to alter fluid consistency.…”