[Otoacoustic emissions. A futuristic objective hearing test]

In a third of all persons with normal hearing, the inner ear emits sounds that are caused by movements of the hair cells. By applying an acoustic stimulus, otoacoustic emissions can be provoked in all healthy ears. These transitory evoked otoacoustic emissions (TEOAE) and the distortion products of otoacoustic emissions (DPOAE) can be utilized by two different procedures for testing hearing. The latter parameter reflects possible damage to the inner ear. Such hearing tests are quick, harmless, and can be performed irrespective of patient age. For this reason, they are particularly suitable for use in the screening of the newborn. In addition, they are also suitable for the early diagnosis of hearing impairment and the effects of ototoxic agents, as also for differentiating sensorineural hearing loss.