Tongue pressure generation during tongue-hold swallows in young healthy adults measured with different tongue positions.

Tongue-hold swallow (THS) has the potential to be a resistance exercise not only for the pharyngeal constrictor but for the tongue muscles. To elucidate the physiological mechanisms of THS, this study investigated intraoral pressure generation during THS in relation to different extents of tongue protrusion. Tongue pressure was measured by a 5-point pressure sensor sheet placed onto the hard palate of 18 healthy young subjects who performed three swallow tasks: normal dry swallow, THS with slight tongue protrusion, and THS with greater tongue protrusion. Subjects randomly repeated each task five times. Maximum range of tongue protrusion was also measured in each subject to estimate lingual flexibility. With an increase in the extent of tongue protrusion, pressure generation patterns became irregular and variable. Duration of pressure generation increased with statistical significance in the posterior circumferential parts of the hard palate (p < 0.05). Maximal magnitude and integrated value of the pressure recorded at these locations increased in eight subjects as the extent of tongue protrusion increased, but it decreased in nine. The former group showed greater lingual flexibility, while the latter group exhibited less flexibility. THS may place different amounts of load on the tongue muscles by adjusting the degree of tongue protrusion.