Effects of bolus rheology on aspiration in patients with dysphagia

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.