Effect of Chin Position on Swallowing Assessed by Manometry

Abstract

Objective: Evaluate the effects of chin position during swallowing in the neutral, chin-up, and chin-tucked positions using a novel high-resolution manometry (HRM) system. Method: Twenty asymptomatic volunteers were studied by HRM. We measured the maximum swallowing pressures at the velopharynx, mesohypopharynx, and upper esophageal sphincter (UES), the mean values of resting UES pressure, its length, the minimum swallowing pressure at UES, and the relaxation interval (RI) of UES, in each position. Results: In the chin-up position, in comparison with the neutral position, the maximum UES pressure (311.1 mmHg vs 214.7 mmHg; P < .01), the mean value of the resting UES pressure (67.0 mmHg vs 29.5 mmHg; P < .01), the length of the UES (44.2 cm vs 32.7 cm; P < .01), and the minimum UES pressure during the RI (−0.5 mmHg vs −6.9 mmHg; P < .01) increased and the RI (0.29 sec vs 0.63 sec; P < .01) decreased significantly. In the chin-tucked position, significant change was seen only in the minimum UES pressure during the RI (−4.5 mmHg vs −6.9 mmHg; P < .05). Conclusion: The chin-tucked position showed no change except for the increase in UES pressure during RI, and seemed to have no appreciable benefit in the facilitation of swallowing. In contrast, the chin-up position brought a marked disadvantageous effect against smooth swallowing by increasing the pressure in the region of the UES.