INFLUENCE OF ALTERED TONGUE CONTOUR AND POSITION ON DEGLUTITIVE PHARYNGEAL AND UES FUNCTION

The potential influence of altered lingual position and contour during the bolus loading phase of the swallow in mediating the swallowed bol us volume-dependent regulation of upper esophageal sphincter (UES) rel axation and opening was studied in 15 healthy volunteers using simulta neous videoradiography and manometry. A maxillary dental splint modula ted tongue deformity during the early oral phase of deglutition. We ex amined the effect of the splint and swallowed bolus density on bolus v olume-dependent changes in the timing of events in the swallow sequenc e and on hypopharyngeal intrabolus and midpharyngeal pressures. Peak m idpharyngeal pressure (P = 0.001) and hypopharyngeal intrabolus pressu re (P = 0.04) were significantly reduced by the splint. The normal vol ume-dependent earlier onset of sphincter relaxation and opening was pr eserved with the splint in situ. The splint significantly delayed the onset of hyoid motion and UES relaxation and opening without influenci ng transit times or total swallow duration. Alterations in tongue cont our and position reduce intrabolus pressure and pharyngeal contraction without influencing normal bolus volume-dependent regulation of timin g of UES relaxation and opening.