Effect of Fluid Thickening with a Gum-Based Thickening Product in Older Patients with Structural or Mild Oropharyngeal Dysphagia

Background: The effect of fluid thickening in older patients with oropharyngeal dysphagia (OD) is not settled in the case of mild OD or OD caused by structural abnormalities. Objective: To assess the therapeutic effect and mechanism of action of the xanthan-gum-based thickener Tsururinko Quickly in older patients with structural OD and those with mild OD (Penetration–Aspiration Score < 3). Patients and Methods: We included 25 participants in each group (81.8 ± 7.1 vs. 77.4 ± 7.2 yr, respectively). Participants underwent videofluoroscopy (VFS) while swallowing 10 mL boluses at <50 mPa·s, 100, 200, 400, 800, and 1600 mPa·s to evaluate the safety and efficacy of swallowing and the biomechanics of the swallowing response at each viscosity level. After 30 s oral incubation, the effect of salivary α-amylase on shear viscosity was assessed using viscometer measurements. Results: (a) For the <50 mPa·s liquid series, no aspirations occurred in either group; however, 44% of patients with structural OD and 30% of patients with mild OD showed PAS 2 penetrations. (b) Fluid thickening reduced prevalence of penetrations with a maximal effect at 800 mPa·s and without affecting oral or pharyngeal residue in either group. (c) Increasing shear viscosity did not affect timing of airway protection mechanisms nor bolus kinematics. (d) Oral incubation decreased viscosity by 1.7–1.8% at 800 mPa·s. Conclusions: Fluid thickening with TQ enhances swallowing safety in older patients with structural causes of OD and those with mild OD through compensatory mechanisms and without a consistent increase in pharyngeal residue across the tested viscosity range.