Furthermore, in a primary care setting, tympanometry can be helpful in making the diagnosis of otitis media by demonstrating the presence of fluid build up in the middle ear cavity.

In infants under 4 months of age, research has shown a 1000 Hz tone yields more accurate results.

The instrument measures the reflected sound and expresses it as an admittance or compliance, plotting the results on a chart known as a tympanogram.

Type C tympanograms are consistent with negative pressure in the middle ear space resulting from compromised eustachian tube function and a retracted tympanic membrane.

Only measures of static acoustic admittance, ear canal volume, and tympanometric width/gradient compared to sex, age, and race specific normative data can be used to somewhat accurately diagnose middle ear pathology along with the use of other audiometric data (e.g. air and bone conduction thresholds, otoscopic examination, normal word recognition at elevated presentation levels, etc.).

[3][4][5] In 2022, University of Washington researchers had demonstrated an end-to-end smartphone-based tympanometer system that consists of a portable phone attachment used to change the air pressure in the ear.

The smartphone-based system operated at 226 Hz and in proof-of-concept testing showed comparable results to commercial tympanometers.

A 2009 study found the Ear Check Middle Ear Monitor consumer model acoustic reflectometer[7] to give few false negative results in detecting middle-ear fluid; specificity and positive predictive values were modest, with many false positives.