Objectives/hypothesis: Describe the relationship between the magnitude of eustachian tube (ET) dilation during swallowing observed on transnasal videoendoscopy and quantified by sonotubometry.
Study design: Descriptive observational study.
Methods: Simultaneous transnasal videoendoscopic and sonotubometric recordings were done on 33 adults with no middle ear disease. Briefly, microphones were placed in the ear canals, a 45° telescope introduced through one side of the nose to visualize and record ipsilateral ET movements, and the probe from a sound generator placed in the opposite nostril. At a generated nasopharyngeal sound level, ET movements and ipsilateral microphone signals were continuously recorded while the subject performed a series of three swallows. For each swallow, relational movements among ET structures observed on video recordings and characteristics of the sonotubometry signal envelope at the ear canal were quantified at three times: swallow onset (T1), maximum soft-palate elevation (T2), and maximum ET luminal dilation (T3).
Results: A total of 99 swallows were analyzed. The average medial rotation of the ET cartilage and lateral wall over the T1-T2 interval were -32.7 ± 14.9° and 7.2 ± 25.1°, and over the T2-T3 interval were 4.6 ± 7.7° and 6.2 ± 14.6°, respectively. The transtubal sound transmission during a swallow peaked at an amplitude of 30.5 ± 35.7 mV during the 572.5 ± 292.6 ms of elevated sound-pressure time. Correlational analysis documented significant linear associations between the relational measures of ET component movements from videoendoscopy and the signal envelope measures from sonotubometry.
Conclusions: There is a direct linear relationship between the degree of ET luminal dilation visualized on videoendoscopy and represented in the sonotubometry signal envelope.
Level of evidence: NA Laryngoscope, 126:2778-2784, 2016.
Keywords: Eustachian tube; sonotubometry; swallowing; videoendoscopy.
© 2016 The American Laryngological, Rhinological and Otological Society, Inc.