Abstract
The velocity of swallowed foods moving through the pharynx was measured using an ultrasonic pulsed-Doppler method. The effect of the mass of swallowed foods on velocity distribution was examined in eight subjects. Water, which dysphagia patients tend to aspirate into the trachea, and yogurt, which is suitable for dysphagia patients to swallow, were used as sample foods. The velocity spectra taken for water and yogurt passing just above the epiglottis of the pharynx were analyzed.
The maximum and mean velocities for each subject were calculated from the velocity spectra. The maximum velocity of yogurt was less than 50% of the maximum velocity of water, indicating that high-velocity food particles cause aspiration in dysphagia patients. The maximum velocity of yogurt decreased as the mass swallowed decreased from 15 to 3g. The maximum velocity of water also decreased as the mass swallowed decreased from 6 to 3g, suggesting that a small amount of food (around 3 g) is less likely to cause aspiration than a larger amount of food.
