1.5
Advanced DPOAE test measurements
1.5.1
Setting stimulus parameters
DPOAE tests are defined by the frequencies presented (referred to as F1
and F2) and the amplitude level at which they are presented (L1, the level
of F1 and L2 the level of F2).
The DPOAE response on the Otoport is recorded at third frequency 2F1-
F2. It is possible to record DPOAEs at other frequencies but the responses
are smaller and are not recorded by the Otoport.
Standard DP tests (DPgrams) present tones at constant levels (L1 and L2)
with F1 and F2 varying.
DP Growth tests present tones at constant F1 and F2 frequencies with the
levels L1 and L2 varying.
Setting frequencies
On the Otoport the ratio between the frequencies F1 and F2 is fixed so that
F2/F1 = 1.22. This is the ratio that gives the greatest DPOAE response at
the frequency 2F1-F2.
The 2F1-F2 response is believed to originate largely in the region of the
cochlea which is most sensitive to the frequency F2, so the response can
be taken as a measure of the health of that region. Because of this the
2F1-F2 response is displayed at the frequency F2 and tests are described
by the F2 frequencies presented.
On standard DP tests (DPgrams) DPOAE responses are recorded in
response to F2 (and F1) tones at a number of different frequency pairs.
The test frequencies are described on the Otoport by the lowest frequency,
the highest frequency and the spacing of the frequencies tested expressed
as points per octave (pts/oct). For example, a test 2-4kHz at 4 pts/oct
would be presenting tones and recording DPOAEs at the frequencies:
OTOPORT
ADVANCE
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Introduction
Otoport OAE+ABR
User Manual for Advance and Screener
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