Effect of a gum-based thickener on the safety of swallowing in patients with poststroke oropharyngeal dysphagia.

BACKGROUND: Increasing viscosity with thickening agents is a valid therapeutic strategy for oropharyngeal dysphagia (OD). To assess the therapeutic effect of a xanthan gum-based thickener (Nutilis Clear® ) at six viscosities compared with thin liquid in poststroke OD (PSOD) patients. METHODS: A total of 120 patients with PSOD were studied in this controlled, multiple-dose, fixed-order, and single-blind study using videofluoroscopy (VFSS). A series of boluses of 10 mL thin liquid and 2000, 1400, 800, 450, 250, and 150 mPa s viscosities were given in duplicate, interrupted in case of aspiration. We assessed the safety and efficacy of swallow and the kinematics of the swallow response. KEY RESULTS: A total of 41.2% patients had safe swallow at thin liquid which significantly increased for all viscosities from 71.9% at 150 mPa s to 95.6% at 1400 mPa s (P < .001). PAS score (3.7 ± 2.3) at thin liquid was also reduced by increasing bolus viscosity (P < .001). The prevalence of patients with aspiration at thin liquid was 17.5% and decreased at all viscosities (P < .01), except at 150 mPa s. Increasing viscosity shortened time to laryngeal vestibule closure (LVC) at all viscosities (P < .01) and reduced bolus velocity at ≥450 mPa s (P < .05). The prevalence of patients with pharyngeal residue at each viscosity 37.7%-44.7% was similar to that at thin liquid (41.2%). CONCLUSIONS AND INFERENCES: The prevalence of unsafe swallow with thin liquids is very high in PSOD. Increasing shear bolus viscosity with this xanthan gum-based thickener significantly increased the safety of swallow in patients with PSOD in a viscosity-dependent manner without increasing the prevalence of pharyngeal residue.

Reference Values for Healthy Swallowing Across the Range From Thin to Extremely Thick Liquids.

Purpose Thickened liquids are frequently used as an intervention for dysphagia, but gaps persist in our understanding of variations in swallowing behavior based on incremental thickening of liquids. The goal of this study was to establish reference values for measures of bolus flow and swallowing physiology in healthy adults across the continuum from thin to extremely thick liquids. Method A sex-balanced sample of 38 healthy adults underwent videofluoroscopy and swallowed 20% weight-to-volume concentration barium prepared in thin and slightly, mildly, moderately, and extremely thick consistencies using a xanthan gum thickener. Participants took comfortable sips and swallowed without a cue; sip volume was measured based on presip and postsip cup weights. A standard operating procedure (the ASPEKT method: Analysis of Swallowing Physiology: Events, Kinematics and Timing) was used to analyze videofluoroscopy recordings. Results The results clarify that, for thin liquid sips (10-14 ml), a single swallow without clearing swallows is typical and is characterized by complete laryngeal vestibule closure, complete pharyngeal constriction, and minimal postswallow residue. Aspiration was not seen, and penetration was extremely rare. Bolus position at swallow onset was variable, extending as low as the pyriform sinuses in 37% of cases. With thicker liquids, no changes in event sequencing, laryngeal vestibule closure, pharyngeal constriction, or postswallow residue were seen. The odds of penetration were significantly reduced. A longer timing interval until onset of the hyoid burst movement was seen, with an associated higher bolus position at swallow onset. Other timing measures remained unaffected by changes in bolus consistency. Conclusion The results include new reference data for swallowing in healthy adults across the range from thin to extremely thick liquids.

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

Erratum to: Dysphagia DOI 10.1007/s00455-014-9578-x. In the original version of this article, Fig. 1 was published incorrectly. The corrected figure is given below.

The influence of food texture and liquid consistency modification on swallowing physiology and function: a systematic review.

Texture modification has become one of the most common forms of intervention for dysphagia, and is widely considered important for promoting safe and efficient swallowing. However, to date, there is no single convention with respect to the terminology used to describe levels of liquid thickening or food texture modification for clinical use. As a first step toward building a common taxonomy, a systematic review was undertaken to identify empirical evidence describing the impact of liquid consistency and food texture on swallowing behavior. A multi-engine search yielded 10,147 non-duplicate articles, which were screened for relevance. A team of ten international researchers collaborated to conduct full-text reviews for 488 of these articles, which met the study inclusion criteria. Of these, 36 articles were found to contain specific information comparing oral processing or swallowing behaviors for at least two liquid consistencies or food textures. Qualitative synthesis revealed two key trends with respect to the impact of thickening liquids on swallowing: thicker liquids reduce the risk of penetration-aspiration, but also increase the risk of post-swallow residue in the pharynx. The literature was insufficient to support the delineation of specific viscosity boundaries or other quantifiable material properties related to these clinical outcomes. With respect to food texture, the literature pointed to properties of hardness, cohesiveness, and slipperiness as being relevant both for physiological behaviors and bolus flow patterns. The literature suggests a need to classify food and fluid behavior in the context of the physiological processes involved in oral transport and flow initiation.

Effect of bolus volume and consistency on swallowing events duration in healthy subjects.

BACKGROUND/AIMS: Swallowing is a complex function with the control of the swallowing center being located in the brain stem. Our aim in this investigation was to evaluate, in healthy volunteers, the oral and pharyngeal transit of 2 bolus volumes and 2 consistencies, and the influence of these boluses on the proportion of pharyngeal clearance duration/hyoid movement duration. METHODS: Videofluoroscopic evaluation of swallows was performed in 30 healthy volunteers, aged 29-77 years (mean 58 years). The subjects swallowed in duplicate of 5 mL and 10 mL of thick liquid barium and honey thick barium. We measured the duration of oral transit, pharyngeal transit, pharyngeal clearance, upper esophageal sphincter opening, hyoid movement, oropharyngeal transit, and the relation pharyngeal clearance duration/hyoid movement duration. RESULTS: A 10 mL bolus volume caused a longer UES opening duration than a 5 mL bolus volume, for both consistencies. The pharyngeal transit was longer for honey thick bolus consistency than for thick liquid, with both the volumes of 5 mL and 10 mL. For pharyngeal clearance, the difference was significant only with the 10 mL bolus volume. There was no difference associated with bolus volume or consistency in the relation between pharyngeal clearance duration and hyoid movement duration. CONCLUSIONS: Increase in the swallowed bolus volume causes a longer UES opening duration and an increase in bolus consistency from thick liquid to honey thick causes a longer pharyngeal transit duration. The proportion between pharyngeal clearance and hyoid movement does not change with bolus volume or bolus consistency.