Intraoral dwell time results in increased bolus temperature and decreased bolus viscosity for thickened liquids

This project investigated the effects of body temperature, saliva, and bolus dwell time on flow rate of water prethickened to nectar consistency. Ten females were given 25-mL bolus volumes of water thickened to nectar consistency, held the bolus intraorally for a specified time, and then expectorated into a cylinder. Bolus temperature and bolus flow were measured. Boluses became thinner and warmer with increasing intraoral dwell time. Knowing that the intended nectar-thick liquid consistency is not maintained once taken into the mouth has direct implications for both dysphagia diagnostic testing and rehabilitation.