Explanation Of Protocol Parameters - Interacoustics Sera Additional Information

Explanation of protocol parameters

Test frequencies (f ) list the test frequencies in kHz. The two pure tone stimuli used in testing are also
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referred to as primary tones. The f primary is the lower frequency pure tone, while the f primary is the
1 2
higher pure tone. The f primary is the one mentioned when describing the protocol's test frequencies.
2
Stimulus level (L /L ) refers to the stimulus levels of the two pure tones (primaries). L
refers to the
1
1 2
stimulus level for the f primary and L refers to the stimulus level of the f primary.
1 2 2
Stimulus tolerance defines the range in which the presented intensity of the stimuli are still acceptable. The
number indicates the allowed difference in both positive and negative direction from the stimulus level
setting.
The Ratio f / f indicates the ratio relationship between the two primaries f and f .
2 1 1 2
The Noise rejection level is the level in dB SPL above which recordings are considered to be too noisy. No
DPOAE data is collected during rejection.
The Maximum test time is how long the test will continue for if no DPOAE can be detected before it
automatically stops testing and displays a REFER result. The test time on Sera equals the nett time used
TM
for testing. In other words, it does not include time elapsed when measurements are being rejected. For a
test to reach a REFER, 60 seconds of good data must be collected before the test will automatically stop.
Run descending means that testing will begin with the highest frequency and then proceed testing to the
lower frequencies.
Minimum DP level is the minimum level (in dB SPL) that an OAE must be measured at for it to meet the
detection criteria.
SNR is the minimum signal to noise ratio that must be reached to meet the detection criteria. The signal to
noise ratio (in dB) is the difference between the DPOAE level and the noise level.
DP reliability % is the minimum DP reliability % that must be reached to meet the detection criteria.
Basically, the OAE is compared to the noise surrounding it and the calculated reliability % represents the
chance that the OAE is indeed not part of the noise. For this comparison, it is assumed that the noise is
normally distributed.
DP stability defines how stable the OAE level must be over time in order for it to meet the detection criteria.
# frequencies required for a pass indicates the number of frequencies that must be detected before the
test will stop and be labelled with a PASS result.
D-0114042-D – 2020/03
Sera™ - Additional Information Page 28