Summary of: Feeney, M. P., Stover, B., Keefe, D. H., Garinis, A. C., Day, J. E., & Seixas, N. (2014). Sources of variability in wideband energy reflectance measurements in adults. Journal of the American Academy of Audiology, 25(5), 449–461. https://doi.org/10.3766/jaaa.25.5.4
The absorbance of the middle ear can be measured by either pressurizing the system using wideband tympanometry or through a non-pressurized absorbance test. The purpose of the present study was to evaluate sources of variability in absorbance measurements measured at ambient pressure. The authors measured audiometry, tympanometry, and absorbance in a group of 112 subject annually for a period of up to 5 years. The authors also compared the baseline results from this group to a group of 24 adult’s with middle ear pathology as determined by reduced admittance 226 Hz tympanometry. The results showed there were small but statistically significant mean differences in absorbance as a function of age, sex and ear. The test retest variance for absorbance measurements was found to be about 0.1 at 1, 2 and 4 kHz which is similar to previous studies. A particularly useful finding from this study is that ears with negative middle ear pressure showed similar absorbance finding those with abnormal 226 Hz admittance tympanograms. The authors therefore recommend that it may be necessary to measure wideband absorbance in a pressurized condition such as wideband tympanometry in order to obtain an effective differential diagnosis in adults.