Astronauts have developed hearing loss in space, so the goal of this project was to provide a robust, self-administered, accurate noise-tolerance hearing test system for astronauts. The device includes Bekesy-like threshold audiometry, distortion product otoacoustic emission testing, and gap-detection testing.

The system consists of an ear probe containing two speakers and a microphone, electronics to condition the signals sent to the speakers and received from the microphone, and software for collecting, analyzing, and presenting the data. The system provides feedback on probe position in the ear canal, and indicates if the probe needs to be repositioned to match a previous location. Also, the system measures the noise in the ear canal — information that can be used to determine if a valid threshold-based hearing test can be performed. Results to date have shown that all the tests can be completed successfully, a poorly positioned probe can be detected, and ear canal noise measurements can be made. Additionally, some work has been done to explore the use of custom-molded earplugs to provide very repeatable results in those settings where this is particularly important.

This work was done by Odile Clavier and Robert Kline-Schoder of Creare Inc.; and Frank Musiek, Jay Buckey, and Donna Alvarenga of the Dartmouth Medical School for Johnson Space Center. MSC-24757-1