asleep. A pacifier may be used to calm the infant; however, sucking
will add noise to the test and decrease the likelihood of a passing
result. Pull gently down and back on the pinna to straighten out the
ear canal. Gently place the probe tube into the infant’s ear canal.
When testing children and adults, pull gently up and back on the outer
ear during insertion to straighten the ear canal and ensure proper
placement.
Noise Sources
When the noise level exceeds the noise rejection limit of the
instrument, the red NOISE light will appear. It is common for the
NOISE light to appear while testing. The light will appear
infrequently if the noise level in the ear canal is low, and it will appear
more often if the noise level in the ear canal is high. Otoacoustic
emissions are very low-level sounds. Any noise in the ear canal at the
time of testing can mask this emission. This noise can come from a
variety of sources.
For TEOAE protocols, the test will pause when noise levels exceed
the noise rejection limit. Pause is indicated when the Noise, Test and
Ready lights turn on simultaneously. Testing will automatically
resume when noise levels decrease. Total pause time will not exceed
30 seconds.
The largest source of noise can come from the patient. This is
biological noise, such as movement, coughing, sucking, talking, etc.
The patient must be calm and not move or talk. Ambient noise in the
testing environment can also be a large source of noise during the test.
A properly sealed eartip can block a large amount of this noise, but
performing the testing in a relatively quiet environment is
recommended.
Turning Off the Instrument
The Corti instrument has an automatic “shutdown” feature, designed
to prolong battery life. The unit will automatically shut down after 1
minute (default) of inactivity. To turn it back on, simply press the
DOWN key. This feature can be re-programmed for various periods
of inactivity before “shutdown.” (See the Changing Instrument
Settings – Auto Shutdown Time on page 32.)
NOTE:
The up arrow can be used to manually power off the
instrument.
