[The study of tongue pressure during swallowing liquid in healthy adults]

To investigate the tongue pressure (TP) produced by tongue-hard palate contact in the process of normally swallowing liquid in healthy adults.

Thirteen adult male subjects were recruited to perform a single swallow of 5 ml water when sitting with upright position. The tongue pressure sensor sheet was used to monitor TP as a result of tongue-hard palate approximatation in the anteriomedian, midmedian, posteriomedian and circumferential parts, and the swallowing sound was recorded by microphone. The temporal sequence of TP at each measured part was obtained after setting the swallowing sound as the reference time. Also, the total duration, pre-peak duration, post-peak duration, maximum magnitude and integrated value of TP were recorded and compared among the measured parts.

TP was produced from anterior to posterior along the midline of hard palate during normal swallowing of water [Ch1: (-0.40 ± 0.22) s, Ch2: (-0.36 ± 0.21) s, Ch3: (-0.24 ± 0.18) s], with the circumferential TP [Ch4: (-0.38 ± 0.23) s, Ch5: (-0.40 ± 0.23) s] occurring nearly to the anteriomedian one (P > 0.05). Before the swallowing sound (P < 0.05), TP at each part reached a peak synchronously [Ch1: (-0.12 ± 0.24) s, Ch2: (-0.16 ± 0.22) s, Ch3: (-0.13 ± 0.21) s, Ch4: (-0.16 ± 0.23) s, Ch5: (-0.17 ± 0.23) s] in a rapid manner (P > 0.05), then decreased gradually until disappeared simultaneously [Ch1: (0.32 ± 0.23) s, Ch2: (0.27 ± 0.21) s, Ch3: (0.23 ± 0.16) s, Ch4: (0.33 ± 0.31) s, Ch5: (0.33 ± 0.29) s] (P > 0.05) after the swallowing sound (P < 0.05). The TP related parameters (the total duration of TP:Ch1: (0.72 ± 0.20) s, Ch2: (0.63 ± 0.16) s, Ch3: (0.47 ± 0.17) s, Ch4: (0.70 ± 0.35) s, Ch5: (0.73 ± 0.29) s; the pre-peak duration of TP: Ch1: (0.28 ± 0.21) s, Ch2: (0.20 ± 0.16) s, Ch3: (0.12 ± 0.10) s, Ch4: (0.21 ± 0.22) s, Ch5: (0.23 ± 0.21) s; the post-peak duration of TP: Ch1: (0.44 ± 0.23) s, Ch2: (0.43 ± 0.18) s, Ch3: (0.36 ± 0.18) s, Ch4: (0.49 ± 0.25) s, Ch5: (0.50 ± 0.23) s; the maximum magnitude of TP: Ch1: (13.80 ± 7.73) kPa, Ch2: (12.40 ± 6.51) kPa, Ch3: (10.26 ± 7.15) kPa, Ch4: (12.16 ± 5.38) kPa, Ch5: (13.08 ± 5.05) kPa; the integrated value of TP: Ch1: (4.99 ± 3.69) kPa×s, Ch2: (4.25 ± 2.13) kPa×s, Ch3: (2.88 ± 1.87) kPa×s, Ch4: (4.32 ± 3.47) kPa×s, Ch5: (4.63 ± 2.49) kPa×s were significantly smaller in the posteriomedian part among all the five parts measured. No laterality was found in TP produced at the circumferential parts of the hard palate (P > 0.05).

The TP at each part coordinates precisely during swallowing. The effective measurement of TP by tongue pressure sensor sheet will facilitate the evaluation of oral swallowing and the diagnosis of dysphagia simply and non-invasively.