ObjectiveHuman eustachian tubes with known pathologic conditions of the ear were inspected endoscopically, and video recordings were made for slow-motion analysis of the pathophysiologic changes.SettingAmbulatory office in a tertiary referral center.SubjectsForty-four adults with 64 ears having pathologic conditions.InterventionsTransnasal endoscopic examination of the nasopharyngeal opening of the eustachian tube during rest, swallowing, and yawning to study the dilatory movements of the eustachian tube.Main Outcome MeasuresSlow-motion video analysis of the dilatory movements of the eustachian tube.ResultsSixty-four ears and eustachian tubes with pathologic changes were studied. Tubal function was graded on (1) the extent of lateral excursion and progression of dilatory wave as estimates of tensor veli palatini and dilator tubae muscle function, reduced function being observed in 43 tubes; (2) the degree of mucosal disease, which was significant in 48 tubes; (3) obstructive mucosal changes, which were present in 15 tubes; (4) ease and frequency of tubal dilation with maneuvers—26 tubes opened moderately, 21 opened minimally, and 11 were unable to open; and (5) patulous tubes—all 6 clinically patulous tubes showed concavities in the superior third of the tube, which is convex in normal subjects. All tubes with active pathologic conditions of the ear (otitis media with effusion, tympanic membrane retraction, draining ear, cholesteatoma) had significant abnormalities. A correlation could not be made between the severity of middle ear disease and the severity of observed eustachian tube dysfunction.ConclusionsSlow-motion endoscopic video analysis is a potentially useful technique in classifying types of pathologic changes in the eustachian tube. Additional studies of dysfunctional tubes are needed to predict outcomes in operative ear cases and to design intratubal therapy for chronically dysfunctional tubes.