The influence of stimulus taste and chemesthesis on tongue movement timing in swallowing.

Purpose To explore the influence of taste and trigeminal irritation (chemesthesis) on durational aspects of tongue movement in liquid swallowing, controlling for the influence of perceived taste intensity. Method Electromagnetic midsagittal articulography was used to trace tongue movements during discrete liquid swallowing with 5 liquids: water, 3 moderate concentration tastants without odor (sweet, sour, sweet-sour), and a high concentration of citric acid (sour taste plus chemesthesis). Participants were 33 healthy adults in 2 gender-balanced, age-stratified groups (under/over 50). Perceived taste intensity was measured using the Generalized Labeled Magnitude Scale (Bartoshuk, 2000; Bartoshuk et al., 2004). Tongue movement sequencing and durations of the composite tongue movement envelope and component events (rise phase, location of first movement peak, release phase) were calculated. Results No obligate sequence of tongue segment movement was observed. Overall durations and the timing of the first mov...