Background:
Middle ear pressure plays a vital role in the transmission of sound to the inner ear. However, limited research data exists to understand the effect of abnormal middle ear pressure on wideband absorbance (WBA) tympanometry. The purpose of the study was to evaluate WBA at peak pressure and ambient pressure in adults with abnormal positive and negative middle ear pressure and compare them with normal adult ears having normal middle ear pressure.

Material and methods:
Three groups of adults – normal middle ear pressure group (56 ears), negative middle ear pressure group (30 ears), and positive middle ear pressure group (15 ears) – in the age range 22 to 50 years were considered. WBA was measured at peak and ambient pressures across the frequencies from 250 to 8000 Hz.

Results:
WBA at peak pressure was observed to be higher than at ambient pressure in all the groups, with the difference seen mostly at low and mid-frequencies up to 2000 Hz. The negative middle ear pressure group showed the most considerable difference in mean WBA, seen between 600 Hz and 1000 Hz, followed by the positive middle ear pressure group, with a negligible difference for the normal middle ear pressure group.

Conclusions:
The study highlighted the importance of measuring WBA at peak pressure and ambient pressure. The results suggest that the comparison of WBA at peak and ambient pressures, especially from lower to mid-frequencies up to 2000 Hz, would help in differentiating abnormal negative/positive pressure from normal middle ear pressure and also between ears having negative and positive pressure.