testing has been shown to produce reliable results in high frequencies up to 8.
The PCB-associated decrease in DPOAE
amplitude was not large.
One proposed DPOAE
screening protocol is analogous to the behavioral SRO technique in that it includes an initial broad frequency sweep done in 1/6-octave steps to identify the highest frequency at which a valid response of +6 signal-to-noise ratio can be measured followed by additional monitoring of several frequencies near this limit at each chemotherapy treatment.
The order of conventional and high-frequency pure-tone audiometry and DPOAE
tests were counter-balanced and the same clinician tested each participant in the pre- and post-match assessments.
was absent in the left ear and intense at 1 to 2 kHz in the right.
Reasons that the DPOAE
could not be conducted or the reading was not valid included the child not staying still or the child having upper respiratory/ear conditions such as acute sinusitis or inflammation of the middle ear/acute tubotympanic catarrh at the time of testing at 45 months.
Likewise, there was no significant difference in mean DPOAE
amplitudes at 0.
In particular, DPOAE
and acoustic reflex threshold examinations both produced abnormal findings in several patients considered normal after initial hearing testing.
All subjects had acoustic reflex thresholds, acoustic reflex decay test results, tympanograms, and DPOAEs
within normal limits (at least 6 dB above the noise floor).
Numerous studies indicate that DPOAE
testing can reveal ototoxic changes before cochlear damage is detectable by conventional audiometry.
Corresponding noise floors were computed by averaging the levels of the ear-canal sound pressure for five frequency bins above and below the DPOAE
frequency bin ([+ or -]54.
15) They found SNHL of unknown etiology in 5 of these patients (56%) on pure-tone audiometry and DPOAE