Hearing Assessments and Tympanometry in NASA Astronauts on the International Space Station.

INTRODUCTION

Exposure to prolonged microgravity is associated with cephalad fluid shifts that potentially could affect tympanomastoid ventilation and auditory mechanisms. We conducted a retrospective review of NASA astronaut on-orbit hearing assessments (OOHAs) and middle-ear pressure measurements obtained during International Space Station missions to search for evidence of spaceflight-related hearing changes and disturbances of middle-ear aeration.

METHODS

Nine NASA astronauts conducted on-orbit hearing assessments and tympanometry at least twice while on space station missions. Kuduwave audiometric instrumentation was used for self-administered air-conduction hearing tests and pressure measurements. Pre- and postflight conventional audiometric data were also reviewed.

RESULTS

OOHAs showed low-frequency mean hearing threshold increases up to 10 dB compared to the preflight Kuduwave baseline. The magnitude of these changes did not correlate with length of time on the space station. Tympanometry was normal in each of 29 measurements that were technically adequate. Postflight audiograms revealed mild residual differences from preflight testing at low frequencies.

DISCUSSION: The results suggest relative resilience of auditory function overall and maintenance of tympanomastoid aeration through prolonged orbital spaceflight, but with evidence of generally small low-frequency hearing threshold increases in some astronauts. Our audiometric findings warrant confirmation and further study of outliers with the larger cohort of NASA astronauts for whom hearing data were obtained with earlier OOHA instrumentation. Wexler DB, Robinette MB, Coble CW, Coste A, Hoffman T, Danielson R. Hearing assessments and tympanometry in NASA astronauts on the International Space Station. Aerosp Med Hum Perform. 2026; 97(1):26-35.