Effect of tongue-palate contact mode on food transport during mastication

Abstract

The physiological mechanisms underlying Stage II transport (STII), during which comminuted solid food is transported from the oral cavity into the meso-pharynx for aggregation into a pre-swallow bolus, have yet to be clarified. The purpose of the present study was to investigate relationships between tongue-palate contact during mastication and incidence of STII by synchronised analysis of tongue pressure production on a hard palate and video-endoscopic (VE) images during mastication. Tongue pressure at 5 measuring points with an ultra-thin sensor sheet attached to the hard palate and trans-nasal VE images while masticating corned beef was recorded for 12 healthy subjects. All recordings were divided into 2 groups: mastication with STII and without STII. Tongue pressure duration was longer at the anterior-median part in the group with STII than in the group without STII. Integrated values of tongue pressure were greater at the anterior-median parts and posterior circumferential part in the group with STII. Integrated values of tongue pressure per second were greater in late-stage mastication than in early-stage mastication in the group with STII. These results suggest that the tongue-palate contacting at the anterior-median and post-circumferential parts of the hard palate is related with the incidence of STII.