Comparison of Behavioral and Physiological Measures of the Status of the Cochlear Nonlinearity.
Michal Fereczkowski, Torsten Dau, Ewen N MacDonald
PMID 34041986WHAT IT FOUND
A behavioral test of auditory filter sharpness correlated with cochlear distortion product measurements even after accounting for hearing thresholds.
The temporal masking test was too variable to be useful. This suggests the notch test could become a clinical tool for assessing cochlear health beyond standard audiograms.
Key findings
01The notch test (NN10) and the cochlear distortion product measurement (OAE CE) were significantly correlated at both 1 kHz and 2 kHz, and this relationship persisted when controlling for hearing threshold.
02The temporal masking curve (TMC) measure did not significantly correlate with the notch test or the distortion product measure, likely due to high variability in the TMC estimates.
03The notch test showed less variability than the temporal masking test and returned valid estimates in more participants than the distortion product methods, making it the best candidate for future clinical use.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study had a relatively low number of valid distortion product estimates at 1 kHz due to noise floors. The temporal masking curve (TMC) task showed high variability, limiting its usefulness in this comparison. The notch-in-noise task is time-consuming and currently requires laboratory conditions, making it impractical for immediate clinical use. The sample size was modest (45 listeners with hearing loss), and the participants had mild-to-moderate loss, so results may not generalize to severe hearing loss.
Declared interests
The authors declared no potential conflicts of interest. The study was funded by the Oticon Foundation.
The easy way to misread this
Do not assume these measures are ready for clinical practice. The study found that the temporal masking test was too variable to be reliable, and the notch test, while promising, is currently too time-consuming for standard clinical use. Furthermore, the correlation between the notch test and distortion products was not always independent of hearing threshold, so these measures do not yet offer a clear replacement for or addition to standard audiograms in patient care.