The method applying an ultrasonic pulsed wave Doppler shift was used to measure the velocity through the pharynx of swallowed rice that had been boiled with differing water content and of imbibed water. The average vertical component of the velocity was ascertained to be around 0.1 m/s for swallowed rice below 83% of added water (zen-kayu). The average increased gradually in accordance with increase of added water by 0.15 m/s for pure water. The maximum vertical component of the velocity was found to be the highest for pure water by 0.7-0.8 m/s and as low as 0.2 m/s for zen-kayu. Namely, the vertical component of the velocity of swallowed water was faster and more dispersed compared with that of zen-kayu which drifts together with a slower velocity.
Food suitable for dysphagia might be identified by measuring the velocity through the pharynx with the method described in this report.
