UBC Theses and Dissertations
Clinical application of the Interacoustics REFLWIN system wideband reflectance machine in the assessment of the eustachian tube. Kenny, Stéfane Pascal Van Neste
Objective: Eustachian tube function remains an area of middle ear analysis in which suitable clinical tests are lacking. Eustachian tube malfunction has been linked to pathology of the middle ear such as otitis media with effusion. Wideband reflectance (WBR) is a new clinical technique which determines the ratio of sound energy that enters the middle ear to that which reflects back into the ear canal. This technique could provide information regarding Eustachian tube function that other tympanometric measures do not. Design: Measures of WBR were taken in 50 Chinese and Caucasian young adult subjects before and after performing Valsalva and Toynbee manoeuvres. Subjects were students or affiliates of the University of British Columbia. Data were analysed based on static and dynamic power absorbance measures, power absorbance tympanograms, 226 Hz tympanograms and 1000 Hz tympanograms provided by the Interacoustics REFLWIN wideband reflectance system. Baseline measurements were compared between gender and ethnicity. Similarities to measurements using other clinical WBR devices were also analysed. Finally, comparisons were made on each variable between baseline and post-manoeuvre state. Results: Baseline results were comparable with previous wideband reflectance research in this subject population. Notable differences were observed between the current study and a previous version of the same device. Differences between the current system and the Mimosa Acoustics system were minimal. For both the Valsalva and Toynbee manoeuvres significant shifts in middle ear pressure were indicated by changes in tympanometric peak pressure and power absorbance tympanogram peak pressure. However, dynamic power absorbance did not differ between baseline and either manoeuvre state. Conclusion: The current version of the Interacoustics REFLWIN system provides comparable estimates of WBR to the other major clinical system available on the market. The measures of wideband reflectance did not offer information regarding Eustachian tube function in addition to that already provided by measures of tympanometry following physical manoeuvres. However, the equivalent performance of wideband reflectance to tympanometry shows that it can be used to evaluate Eustachian tube function in the same manner as tympanometry. There is still a need to devise a clinical test to accurately distinguish between healthy and pathological Eustachian tubes.
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