CHAPTER SEVENTEEN
Test set-up
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Max NLo
This is a test timeout function, which stops the test when the
specified number of low noise data samples (when the noise
present is below the reject level) has been collected.
Range:
10-990
Max time
The maximum time the test will run before automatic stop.
Range:
10-900 secs
TE
response
window
The TE response window sets how long after the presentation of
the stimulus the recording of the measured response starts and
ends. So, setting ‘response window’ to 3-13 ms means that the
response is measurement begins 3ms and ends 13ms after the
stimulus was presented. The structure of the cochlea means
that low frequency OAEs occur longer after the stimulus than
higher frequency OAEs. The 3-13ms response window
captures TEOAE responses across a wide frequency range.
The 3-9ms response window captures a narrower frequency
range of emissions but includes the period in which the largest
emissions are generally recorded. Because it includes only the
period when emissions are strongest this setting can improve
the Signal to Noise Ratio (SNR) of the recording.
Used in combination with the narrow 1600-3200Hz noise filter the
3-9ms sometimes enables TEOAE testing to take place in noisy
environments which prohibit testing with other settings.
6K Band
Sets whether waveform energy in the half-octave frequency
region centred 6kHz is displayed. The 6kHz OAE response
is often absent in waveforms recorded in normal ears as the
emission occurs very early following the stimulus and is
often lost within the stimulus waveform. However, 6kHz
emissions can be recorded especially in neonate ears and
their presence may be clinically significant.
Range:
On or Off
Note:
If the maximum test time specified is not long enough for the
device to complete the max NLo requirement, then the test time
is automatically reset to longer than the Max NLo.
Test set-up
