Effect of Titrated Exposure to Non-Traumatic Noise on Unvoiced Speech Recognition in Human Listeners with Normal Audiological Profiles.
Mengchao Zhang, Richard M Stern, Deborah Moncrieff and 2 others
PMID 35929144WHAT IT FOUND
Dental students with normal hearing did not differ from controls on quiet pitch-removed speech or routine hearing tests.
They performed worse only when noise had gaps, including 32-Hz temporal noise and low-pass spectral noise.
Key findings
01Dental students did not differ significantly from controls on unvoiced speech recognition in quiet for either filtering condition.
02In 32-Hz temporally modulated noise, controls had lower speech recognition thresholds than dental students by 1.0 dB for low-pass filtering and 3.1 dB for high-pass filtering; lower thresholds mean less noise was needed for 50% correct.
03In low-pass spectrally modulated noise, controls had a 1.5 dB lower threshold than dental students, and lifetime dental noise exposure was the only significant predictor of that performance, with the final model explaining 19.9% of the variance.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
The study was cross-sectional, so it cannot show that dental noise caused the speech differences. The dental group was selected by being in dental school, not randomly assigned, so other differences between dental students and controls could influence results. Only 52 of 86 recruited participants passed screening and completed tasks, and the analysed sample was young adults with normal hearing. The groups had different sex balance, although the authors reported that female-only analyses and within-group sex comparisons did not change the pattern, with data not shown. Significant differences appeared in some modulated-noise conditions but not all, so the finding is condition-specific. The measure does not identify the site or mechanism of the auditory change.
Declared interests
The authors declared no potential conflicts of interest. Funding came from the National Institute on Deafness and Other Communication Disorders and the University of Pittsburgh School of Health and Rehabilitation Sciences under grant R21DC18408, a PhD Student Research Award.
The easy way to misread this
Do not conclude that dental noise caused the speech differences or that unvoiced speech testing is ready for clinical use. The study compared groups at one time, and the groups did not differ on quiet pitch-removed speech or routine hearing screening; only some modulated-noise conditions differed.