BABYSCREEN

Transient Otoacoustic Emissions (TEOAE)

Otoacoustic emissions (OAE) are low intensity sounds generated by the outer hair cells (OHC) of the inner ear. When we speak about otoacoustics emissions, we primarily think about transient otoacoustic emissions also called TEOAE which are most used in clinical examination. OAE are recorded by a small probe place in the external ear canal. Detection of transient otoacoustic emissions (TEOAE) is a real asset in the series of hearing tests.

User Tips:

• Make sure that ear canal is not obstructed by earwax.
• Choice of eartip is the most important point for the quality of the measurement.
• Eartip should not be pressed against a side of the ear canal.
• Eartip must be sealed to prevent acoustic leaks and isolate to surrounding noise.

Measure specifications:

• Per click
• Sound intensity: 84dB HL

Aimed diseases: deafness screening

Method: The TEOAE are otoacoustic emissions by click, which means that we are going to test patient ear with frequencies between 2000 and 4000 Hz. The result is represented by a curve that simply shows whether otoacoustic emission is present or not. This is an objective test because he does required cooperation of the patient. This test is very important, in especially in the examination of newborns, because if the acoustic otoemissions are present it means that hearing of newborn does not present deafness superior to 30-40 dB. It is a screening test routine, more and more used in examination of newborns.

Distortion Products of otoacoustic emissions (DPOAE)

Auditory brainstem response (ABR)

Auditory brainstem response (ABR), are routinely used in the field of neurological and otological investigation. Non-invasive electrophysiology technique based on the principle of electroencephalography (EEG), ABR provide objective information, reproducible in the hearing function from the cochlea to the brainstem. They help to reveal the electrical activity of peripheral auditory pathways, through the application of acoustic stimulation (usually a click), in the overall activity of the EEG.

User Tips:

• Make sure that ear canal is not obstructed by earwax.
• With an abrasive gel, clean skin surface where electrodes will be attached. It decreases skin impedance.
• The speed and accuracy of the measurement depend mainly on the conditions of the newborn. The ideal being that he sleeps, he should be as relaxed as possible to avoid any excessive muscle tension.

Measure specifications:

• 49 Clicks/sec
• Alternating clicks / Chirps
• 40 dB HL
• Impedance tests
• Automatic stop of the measurement upon detection of the response

Aimed diseases: deafness screening

Method: Typical ABR tracings consist of several waves numbered I to V. In the situation of ABR latency (neurological testing), the waves I, III and V must be clearly identified in a context of normality. These waves should appear in a range of normality. Any lengthening from the latency for waves suspects a conduction disorder and suggests further investigation.
Within the scope of auditory threshold research, analysis of the ABR is centered on the evolution of wave V in the course of decreasing intensity. The intensity at which wave V “disappears” is then associated with the intensity of the auditory threshold for the test ear.
ABR’s are therefore a means of objectively and non-invasive evaluating auditory function and nerve routes on newborn, child, adult whether awake, anesthetized/sedated as in spontaneous sleep (without any alteration).
When it comes to newborn screening, only the detection of the V wave at a low intensity (30 to 40dB) is carried out in order to assess possible hearing disorders.