A Comparative Study Between Modified Starch and Xanthan Gum Thickeners in Post-Stroke Oropharyngeal Dysphagia

Abstract

Thickeners are used in post-stroke oropharyngeal dysphagia (OD) as a compensatory therapeutic strategy against aspirations. To compare the therapeutic effects of modified starch (MS) and xanthan gum (XG) thickeners on swallow safety and efficacy in chronic post-stroke OD patients using clinical and videofluoroscopic (VFS) assessment. Patients were studied by clinical assessment (volume-viscosity swallow test, V-VST) and VFS using 3 volumes (5, 10, 20 mL) and 3 viscosities (liquid, nectar and spoon thick), comparing MS and XG. We studied 122 patients (46MS, 76XG). (A) V-VST showed that both thickeners similarly improved safety of swallow. Prevalence of safe swallowing significantly increased with enhanced viscosity (P < 0.001 vs liquid), MS: 47.83 % at liquid, 84.93 % at nectar and 92.96 % at spoon thick; XG: 55.31 % at liquid, 77.78 % at nectar and 97.84 % at spoon thick. Patients on MS reported higher prevalence of pharyngeal residue at spoon-thick viscosities. (B) VFS: increasing bolus viscosity with either thickener increased prevalence of safe swallows (P < 0.001 vs liquid), MS: 30.25 % liquid, 61.07 % nectar and 92.64 % spoon thick; XG: 29.12 % liquid, 71.30 % nectar and 89.91 % spoon thick. Penetration-aspiration scale score was significantly reduced with increased viscosity with both thickeners. MS increased oral and pharyngeal residues at nectar and spoon-thick viscosities but XG did not. Timing of airway protection mechanisms and bolus velocity were not affected by either thickener. Increasing bolus viscosity with MS and XG thickeners strongly and similarly improved safety of swallow in chronic post-stroke OD by a compensatory mechanism; in contrast only MS thickeners increased oropharyngeal residue.

Keywords: Deglutition; Deglutition disorders; Rheology; Therapy; Viscosity.