Multimodal Assessment of Normal Eustachian Tube Function

Objective: Evaluate normal human Eustachian tube (ET) function during swallowing and other maneuvers that open the ET using a variety of modalities including EMG of the Tensor veli palatini (mTVP), Levator veli palatini (mLVP), and submental muscles, videoendoscopy, and sonotubometry; and compare these results with ET function tests in a pressure chamber. Method: In adult volunteers surface electrodes and needle EMG electrodes were placed into the mTVP and mLVP muscles. A 45° telescope was used to video-record the ET orifice, and sonotubometry recorded the ET openings. A subset was also tested in a pressure chamber. Results: Seventeen subjects were enrolled. EMG data was recorded from both the mTVP and mLVP in 15 subjects but from only one muscle in 2 subjects. In 9 subjects ET functions tests were performed in the pressure chamber. Video recording of ET opening was consistent with the EMG activity and ET openings by sonotubometry. mTVP activity had a shorter duration but a greater amplitude than mLVP activity. mLVP activity occurs before that of mTVP and the submental muscle group. Tests conducted in the pressure chamber demonstrated ET function consistent with the multimodal test results. Conclusion: Multimodal assessment of ET openings by monitoring the EMG of the paratubal and submental muscles, video recordings of the ET, and sonotubometry with ET function testing in the pressure chamber in adult volunteers is a novel and promising method for expanding our knowledge of middle ear physiology and pathophysiology.