Article
Newborn hearing screening: AEP or OAE?
AEP oder OAE für das Neugeborenenhörscreening?
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Published: | September 7, 2006 |
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General newborn hearing screening (NBHS) using objective audiometric measures is an accepted tool for early recognition of hearing loss. Modern objective methods measure not only a physiological reaction; they provide also an automatic categorization of passing or failing the test.
Two objective tests are generally used in NBHS, the measurement of otoacoustic emissions (OAE) and of auditory evoked potentials (AEP). Both tests can be used with reliable automatic categorization. They may be used alone or in sequence.
The use of a simple ear-canal probe allows measuring OAEs quickly, cheaply, and easily. The efficiency of the test increases in the first view days after birth. It is applied best later than the second day. Moreover, only the functions of the peripheral hearing organ are assessed, no neural functions. In contrast, AEP assess also the neural hearing functions of the brainstem. AEPs seem more reliable than OAEs in the first two days after birth and in babies treated at an intensive care unit. However, the measurement needs more time, more resources, and surface electrodes must be applied.
Many NBHS protocols include a stepwise use of both methods. Normal newborns may be tested once or twice with transiently evoked OAE. If the test fails, a measurement of AEP follows immediately. The exact sequence of measurements depends on the postnatal period available for screening. An immediate sequence of both methods is working best if the measurements are carried out early on the first or second day. A primary use of AEP should be considered in babies with known risks of hearing loss.