Influence of Habitual Tongue Posture on Tongue Pressure During Swallowing

BACKGROUND: Tongue pressure is essential for bolus transport and oral stability during swallowing and serves as a clinical marker of tongue function. Habitual tongue posture, defined as the resting position of the tongue, is associated with swallowing efficiency and craniofacial development. OBJECTIVE: This study investigated the association between habitual tongue posture and regional tongue pressure amplitudes. METHODS: We enrolled 52 healthy adult participants (26.0 [24.0-27.0] years). Habitual tongue posture was evaluated using standardised lateral cephalometric radiographs, measuring tongue-palate (T-P) and mandible-hyoid distances. Based on the mean T-P value, participants were divided into long-distance (LD) and short-distance (SD) groups. Tongue pressure during 5 mL water swallowing was measured using a tactile sensor system with five sensor points (Ch1-5). RESULTS: Intra-group analysis revealed significantly lower pressure at Ch3 (2.1 [0.7-4.5] kPa) than at Ch4 (5.6 [2.0-9.9] kPa, p = 0.0286) and Ch5 (8.1 [3.8-15.7] kPa, p < 0.0001) in the LD group. Inter-group comparisons showed that the LD group had significantly lower tongue pressure than the SD group at Ch2 (3.2 [1.5-6.5] kPa vs. 6.8 [4.6-14.7] kPa, p = 0.0018), Ch3 (2.1 [0.7-4.5] kPa vs. 10.6 [6.0-21.2] kPa, p < 0.0001), and Ch4 (5.6 [2.0-9.9] kPa vs. 9.8 [5.5-11.8] kPa, p = 0.0203). CONCLUSION: Our findings suggest that habitual low tongue posture impairs swallowing efficiency by reducing tongue pressure in certain areas, posing a risk for age-related dysphagia and swallowing difficulties.