Coordination of tongue pressure production, hyoid movement, and suprahyoid muscle activity during squeezing of gels.

OBJECTIVE

The aim of this study was to evaluate tongue movement and its biomechanical effects during squeezing, one of the oral strategies for processing soft foods, by tongue pressure sensors, videofluorography, and surface electromyography.

DESIGN

Fifteen healthy men (mean age, 31.0 ± 4.1 years) without dysphagia were recruited. A 0.1-mm-thick pressure sensor sheet with five measuring points, videofluorography, and surface electromyography were used for synchronous measurements of tongue pressure, hyoid movement, and suprahyoid muscles activity, respectively, while squeezing 5 mL of gels. Amplitude, duration, area, and their sequential order during initial squeezing were analyzed. Differences in hyoid position at the onset, peak, and offset of hyoid movement were also analyzed.

RESULTS

At the beginning of initial squeezing, tongue pressure at the middle area of the hard palate, hyoid movement, and suprahyoid muscle activity appeared simultaneously, followed by tongue pressure at the anterior area and then at the posterior area. When the hyoid was in an elevated position, the amplitude of suprahyoid muscle activity and tongue pressure peaked. At the end of initial squeezing, the hyoid position at the offset of hyoid excursion was superior to that at the onset. All evaluation items of tongue pressure, hyoid movement, and suprahyoid muscle activity were modulated according to the texture of gels.

CONCLUSIONS

During initial squeezing, tongue pressure, hyoid movement, and suprahyoid muscle activity were coordinated while being modulated by the food texture. At the end of initial squeezing, the hyoid was maintained in an elevated position, which might be beneficial for subsequent squeezing.