Abstract
Introduction Distortion product otoacoustic emissions (DPOAE) and their suppression may be considered
useful in monitoring cochlear function and the efferent auditory pathway inhibitory
effect. Nonetheless, the establishment of reliable parameters of response variations
is of great importance.
Objectives To verify the replicability of test and retest in the research of the inhibitory
effect of the efferent pathway using contralateral suppressing stimulus during DPOAE
recording for clinical applicability.
Methods Cross-sectional study with 48 volunteers, aged 18 to 30 years, with normal audiometric
thresholds. The procedures included were audiometric and immittance measures to overrule
any conductive or sensorineural conditions and DPOAE recordings without and with contralateral
suppression with a 60 dBHL white noise. Distortion product otoacoustic emissions amplitudes
were analyzed and compared in both conditions with Wilcoxon test, and the Spearman
correlation test was used to assess test-retest reliability.
Results The comparative analysis showed differences between amplitudes in test and retest
conditions only in 1,500 Hz for DPOAE measures with all other tested frequencies showing
no differences, and no difference was observed in all recorded frequencies in the
test and retest comparison for DPOAE suppression. The degree of correlation between
test and retest of DPOAE amplitude was good at 6,000 Hz and strong (r > 0.880) at
the other frequencies. For DPOAE with suppression, all frequencies presented strong
correlation between test and retest: 1,500 Hz (r = 0.880), 2,000 Hz (r = 0.882), 3,000 Hz
(r = 0.940), and 6,000 Hz (r = 0.957).
Conclusions The study found good replicability in contralateral suppression of DPOAE with potential
clinical applicability, and we recommend conducting the test from 2000Hz to higher
frequencies for more reliable results.
Keywords
cochlear hair cells - auditory efferent pathway - reproducibility of results - hearing
loss - young adult - noise effects
