Coordination between lingual motion and pressure production during dipper/tipper type swallows

Abstract

Background: Tongue motor biomechanics during swallowing was not fully elucidated due to the technical difficulty. Objective: To evaluate the relationship between tongue motion and tongue pressure production by simultaneously measuring tongue motion and tongue pressure during water swallowing. Methods: In 12 healthy male participants (mean age, 30.8 ± 4.2 years), tongue pressure and tongue motion trajectory during dipper-and tipper-type swallows of 3 mL of water were measured using a sensor sheet system equipped with five sensing points and an electromagnetic articulography, respectively. The temporal correlation between motion of anterior/posterior tongue and tongue pressure production during swallowing was evaluated on the synchronised waveforms. Results: In the dipper-type swallow, a similar up-and-down motion pattern in vertical direction was observed among all participants before tongue pressure production. Those motion patterns were common at the anterior and posterior tongue locations with a temporal difference in some segment of tongue motion. On the other hand, tongue directly attached to hard palate with temporal synchronicity between the anterior and posterior parts. In both types of swallow, a strong temporal correlation was found between the timing of tongue-palate contact and the Onset of tongue pressure by intra-class correlation coefficients. Conclusion: From the simultaneous measurement of tongue motion and tongue pressure production, the tongue motion pattern during water swallowing and the temporal correlation between tongue motion and tongue pressure production were elucidated.

Modulation of tongue motion and tongue pressure during liquid swallowing with different bolus volumes

“…In the present study, simple vertical motion and tongue rotations were observed in P‐B2‐CS (just before the tongue contacts the palate), and these movements varied depending on tongue region and bolus volume. Tongue motion from P‐B2‐CS (just before the tongue contacts the palate) is related to the transportation of the bolus from the oral cavity to the pharynx 15 . In addition, the period from the bolus head passing through the fauces to the oesophageal entrance overlapped with start of the tongue making contact with the palate, suggesting that the generation of tongue pressure during swallowing was temporally coincident with the pharyngeal phase of swallowing 19 .…”

“…Tongue motion just before contact with the palate (between P‐B2‐CS) is related to bolus transport by the tongue 15 . Vertical and tongue rotation in the sagittal plane were observed from the tongue motion trajectory recorded by the anterior and posterior markers between the intervals P‐B2‐CS (Figure 3).…”

“…Seven time events, 15 which were common to all the participants, defined by the inflection points of tongue motion plotted with respect to time were identified and noted (Figure 2C). 15 In general, during swallowing, the tongue descends from S (the starting point) to B1 (the first trough), rises to P (the highest point of ascent), descends again to B2 (the second trough) and rises rapidly to reach CS (initial contact with the palate). After a plateau, with little change in the vertical direction for some time, the tongue descends from the CE (end of contact with the palate) and returns to R (rest point).…”

“…The vertical upward displacement of the tongue between B2 and CS is also closely related to tongue pressure 15 . The vertical displacement between B2 and CS and the maximum velocity between B2 and CS were calculated.…”

“…On the other hand, contact pressure of the tongue on the hard palate during swallowing (tongue pressure) is measured as a biomechanical effect of tongue motion by using a sensor sheet system 11–14 . Tongue pressure is recorded only for the interval during which there is contact between the tongue and the hard palate, whereas tongue motion is recorded, using EMA, only during intervals for which there is no contact between the tongue and the hard plate because the tongue stops moving during this period of contact 15 . Therefore, a comprehensive system combining EMA and the sensor sheet system was developed to record tongue motion, tongue pressure and the temporal correlation between the two during swallowing 15 …”