A Preliminary Analysis of Tympanometric Parameters in a Local Multiethnic Population

Background: Tympanometry is a routine clinical test ordered at the Department of Otolaryngology, Ear, Nose and Throat (ENT) at Changi General Hospital (CGH). In combination with the pure tone audiogram, tympanograms aid in the diagnostic value of various middle ear disorders. However, its diagnostic value depends on the physician and audiologist's accuracy of classifying and interpreting the tympanograms. Presently, Caucasian normative values are used in the classification of tympanograms, which could be inaccurate without population specific norms. Therefore, there is a need to understand ethnic differences in tympanometry parameters in order to usefully interpret the tympanogram. Thus far, there are no local studies on the differences in tympanometric parameters among multiethnic groups. Previous studies also had conflicting results on the effects of ethnicity with direct or indirect comparison only between two ethnic groups. To our knowledge, this is the first preliminary investigation on the effects of demographic and anthropometric measurements on tympanometric parameters. Materials and Methods: 90 patients' medical charts were randomly selected and reviewed to extract demographic, anthropometric and clinical information. Tympanogram characteristics among ethnic groups were investigated using univariate and multivariate analyses. The mean ages of males and females in the study were 41.9 years ± 17.4 and 46.1 ± 19.2, respectively. Results: Gender significantly influenced ear canal volume (ECV). Chinese had marginally significant lower static admittance (SA) as compared to non-Chinese. There were, however, no effects of age or anthropometric measurements on tympanometric results. Conclusion: Further prospective large cohort analyses are warranted to expand this investigation to better elucidate differences observed in tympanometric parameters and establish population specific norms for appropriate and accurate tympanogram classifications.