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What are OAEs?

Bilateral OAE testing
Standard bilateral recordings test both ears at the same time. Either TEOAE or DPOAE bilateral measurements are possible with the Echoport ILO292 USB-II two probe system.
The period prior to an OAE test when the probe fit in the ear is assessed. The stimulus response and test noise indicators are checked to ensure conditions are suitable for testing.
Contralateral suppression
Suppression of OAEs is found when a contralateral masker is applied during OAE measurement. Various contralateral maskers can be used, including noise or tones, and it seems irregular sounds are most effective. The Linear TEOAE recording mode is most sensitive to contralateral suppression, although this mode is not suitable for regular screening or diagnostic use.
DP Growth
DP Growth is useful to validate observed DPOAEs. Healthy ears tend to show a shallow linear growth of DP decibel level with stimulus level. Ears with threshold elevation tend to show a more steep rise.
Distortion Product Otoacoustic Emission or dual-tone evoked distortion product OAEs. DPOAEs are produced from an ear during the non-linear amplification of sound energy in the cochlea. The DP technique is more flexible than TEOAE analysis, having a wider useful frequency range. Also, stimulation with pure tones allows a greater intensity of sound to be delivered that can evoke responses from a weaker ear that may not produce TEOAEs.
Linear Click
Provides a uniform click stimulus for accessing the complete OAE response without loss from the standard non-linear processing. The Linear test can record weaker TEOAEs and responses at a lower stimulus level. Not to be used for routine screening and diagnostic applications.
Non-Linear Click
A click stimulus (80 microsecond signal) repeated 50 times per second - resulting in a 20ms response window. This stimulus method is ideal for clinical investigations and capturing low frequency OAEs. The non-linear stimulation and signal processing help eliminate stimulus artefacts from the TEOAE response.
Otoacoustic emissions - sounds made by our inner ear as it works to extract the information from sound to pass on to the brain. These biological sounds are a natural by-product of this energetic biological process and their existence provides us with a valuable ′window′ on the mechanism of hearing, allowing us to detect the first signs of deafness - even in newborn babies.
Probe Cavity Test
Used to perform regular probe and system checks, to help confirm calibration and correct function.
A TEOAE measurement with a short response window. It uses a stimulus with medium frequency emphasis to provide fast and effective data collection. A gold standard method for many large screening programmes.
Sensory transductive loss
Hearing loss resulting from failure of inner hair cells to respond and activate the synapsed auditory nerves.
Sensory transmissive loss
Hearing loss resulting from dysfunction of outer sensory hair cells.
Signal-to-noise ratio. A measure of the OAE signal level above the noise.
Spontaneous Otoacoustic Emissions. Emissions that are produced without stimulation.
Transient Evoked Otoacoustic Emission; click evoked otoacoustic emission. TEOAE measurements, as originally used in universal newborn hearing screening programmes, are useful as a sensitive initial screen prior to full clinical examination. TEOAEs are sensitive to cochlear status changes manifested in subtle changes in the TEOAE waveform.
Tone Pip
Tone pip TEOAEs are used to test specific frequency regions. The stimulus method allows maximum stimulus energy to be concentrated on a selected frequency band.