Use of middle ear immittance testing in the evaluation of patulous eustachian tube.

摘要

BACKGROUND: Patulous Eustachian tube is the uncommon condition of a persistently open Eustachian tube, which causes the disturbing symptoms of autophony and respiratory-synchronous tinnitus. We review this condition and propose a specific evaluation protocol that can be performed quickly and easily using standard audiologic test equipment. We have used this protocol in the evaluation of a number of patients and will discuss our findings. PURPOSE: To establish a standardized protocol for the audiologic evaluation of patulous Eustachian tube using a standard clinical tympanometer and to establish norms with respect to tympanic membrane movement during breathing tasks. RESEARCH DESIGN: Quantitative analysis of test results obtained during clinical evaluation of patients referred for suspected patulous Eustachian tube during 2008 and 2009. Study Sample: The cohort was 35 individuals including 25 patients referred for suspected patulous Eustachian tube and 10 control (normal) patients. Of the total group, 25 individuals were female, 10 were male, and the overall age range was 8 yr to 82 yr. DATA COLLECTION AND ANALYSIS: Patients underwent audiologic and otologic testing including quantitative measurement of middle ear compliance during breathing and nasal endoscopy. Two tympanometers were used to assess middle ear compliance: the Grason-Stadler Instruments Model 33 and Tympstar. Endoscopy was performed using either a Storz Endoskope Xenon Nova 175 or a Pentax EPM 1000. Results of middle ear immittance tests performed during breathing tasks were compared with results of endoscopy as well as the impressions of the examining physician. Magnitude of middle ear compliance was examined for mean and standard deviation, and the controlormal group results were compared with those of individuals complaining of symptoms suggestive of patulous Eustachian tube. RESULTS: We found that slightly greater than 75% of individual ears with patulous Eustachian tube exhibited middle ear compliance greater than 0.07 ml during breathing tasks. All ears with patulous Eustachian tube exhibited a respiratory-synchronous compliance pattern during breathing tasks. Of individual ears without patulous Eustachian tube, 97% exhibited middle ear compliance during breathing of less than 0.07 ml with no respiratory-synchronous pattern. CONCLUSIONS: Measurement of middle ear compliance during breathing appears to be a sensitive and specific tool in the examination of patulous Eustachian tube, particularly when both the magnitude of compliance and the pattern of compliance are considered.