Wideband Tympanometry: Normative Data for Young Iranian Adults

The middle ear sound transmission features can impact acoustic sounds reaching the inner ear. Wideband tympanometry (WBT) or wideband acoustic immittance is an effective and desirable measurement of conductive conditions in newborns and adults and has appropriate sensitivity to distinguish different pathologies like otosclerosis from other middle ear conflicts. Recently, there has been an increased utilization of WBT, which highlights the importance of collecting population-based normative data as a necessary step in the standardization of this test, as well as for its clinical application. This study aimed to obtain normative data on WBT in the adult Iranian ethnic.

There were 101 participants (202 ears) consisting of 53 males (57.4%) and 48 females (42.6%) in the age range of 19-29 years. The Titan WBT device (Interacoustics, Assens, Denmark) was used for WBT measurements. The broadband click was utilized as the probe tone between frequencies of 250 Hz and 8,000 Hz. All the participants underwent ear, nose, and throat assessments, pure-tone audiometry, and conventional tympanometry (226 Hz). Features like equivalent ear canal volume (Veq), tympanometric peak pressure, gradient, resonance frequency (RF), energy absorbance (EA), and admittance (Ad) were tested.

In this cross-sectional study, 202 ears were tested for WBT. EA increased by frequency enhancement; at 1 kHz and 2 kHz the EA was the most prominent; at 2,519 Hz, it started decreasing, and at 8 kHz, there was a slight increase. There was also a significant difference in the Veq and Ad between males and females. Studies have shown that the Veq may vary between male and female subjects based on body size.

In this study, normative data for the WBT were obtained from young Iranian adults with normal hearing ranges and middle ear conditions. We hope that this study and the resulting norm will provide a basis for increasing the use of WBT in Iranian diagnostic and clinical practices.