Subclinical Auditory Dysfunction: Relationship Between Distortion Product Otoacoustic Emissions and the Audiogram.
Naomi F Bramhall, Garnett P McMillan, Amy N Mashburn
PMID 33465327WHAT IT FOUND
Distortion product otoacoustic emissions did not reliably predict pure tone thresholds in people with clinically normal hearing.
Adding DPOAE data to a statistical model improved prediction accuracy by only 0.4 to 2.1 dB compared to using average thresholds alone.
Key findings
01Inclusion of DPOAE levels in the predictive model improved accuracy over a mean-only model by only 0.4 to 2.1 dB.
02Prediction errors were larger in extended high frequencies (9-16 kHz) than in standard audiometric frequencies (0.25-8 kHz).
03Predicted thresholds were better than observed thresholds for Veterans, individuals with tinnitus, and the oldest age group, suggesting factors other than outer hair cell damage influence the audiogram in these groups.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
DPOAEs were only measured up to 10 kHz, while thresholds were measured up to 16 kHz, limiting the model's ability to predict extended high-frequency thresholds. The groups were not balanced; Veterans were older and more likely to have tinnitus than non-Veterans, making it difficult to separate the effects of age, noise exposure, and tinnitus. The Non-Veteran Firearms group was very small (15 participants), limiting conclusions about that specific exposure history. The study used a specific DPOAE measurement protocol (suprathreshold levels); different protocols might yield different results.
Declared interests
Funding and conflicts of interest are not explicitly detailed in the provided text segments, though the study used data from VA Portland Health Care System and Boys Town National Research Hospital equipment/software.
The easy way to misread this
Do not interpret the small improvement in prediction accuracy (0.4 to 2.1 dB) as evidence that DPOAEs are clinically useful for estimating hearing thresholds. The effect is negligible, and the model fails to account for significant variance in key groups like Veterans and those with tinnitus.