Time: 12:05–12:55
Location: Room 205, Babcock Hall
Coffee / tea will be served starting ~11:45 outside room 205
This seminar will be presented by Elaine Lipkin, and is entitled: Rheological characterization of thickened beverages in dysphagia treatment
ABSTRACT
Dysphagia, an inability to swallow, impacts up to 60% of Americans in institutional care and is a risk factor for dehydration, malnutrition, and pneumonia. Thickened beverages are used for dysphagia treatment because they increase the duration and efficiency of swallowing. Hydrocolloids, most commonly xanthan gum and modified starch, are used to increase beverage viscosity. Clinical definitions use shear rheology to characterize thickened beverage consistency, but recent studies revealed that shear rheology has little impact on the safety of the swallow. We hypothesize that extensional viscosity describes a unique rheological response behavior with greater physiological significance to pharyngeal forces during swallowing. To better understand the relation between shear and extensional viscosity (and ultimately clinical safety), we explored a broad range of hydrocolloids to observe their effects on rheological properties. This study evaluated 12 hydrocolloids formulated at varied concentrations to achieve a shear viscosity of 300 cP at a shear rate of 30 s-1, representing a mildly thick beverage. Shear rheological tests were conducted to reveal shear thinning behavior and to ensure beverages met requirements for “mildly thick” classification. Extensional rheology was measured using a capillary break-up method to determine viscosity under extensional forces. Results show fluids with consistent shear viscosity display a range of extensional viscosity behaviors, including variation in break-up time as well as extensional viscosity. Findings from this study phase will inform the selection of hydrocolloids that represent a diverse range of rheological behaviors for further clinical assessment.
