Feedback-based noise management matrix in action.
Nomfundo F Moroe, Katijah Khoza-Shangase, Milka Madahana and 1 others
PMID 32242446WHAT IT FOUND
The model predicts hearing loss, but actual damage is worse than predicted.
Earmuffs failed because noise exceeded their rating. Workers still developed hearing loss even with protection, so rely on custom devices and reduce exposure time.
Key findings
01Predicted hearing loss was less severe than actual loss, suggesting the model missed key risk factors.
02Standard earmuffs provided no better protection than custom devices because noise levels exceeded the earmuffs' safety rating.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The model did not include non-noise risk factors like tuberculosis, HIV, dust, or smoking, which likely explains why it underestimated actual hearing loss. Only five workers were simulated in detail, though data came from 210. The study assumes perfect use of hearing protection, which is rarely achieved in practice. It is a validation of a predictive tool, not a clinical trial of an intervention.
Declared interests
Ethical approval from University of the Witwatersrand. Data from a larger funded study. No specific commercial conflicts declared in the text.
The easy way to misread this
Do not trust the model's predictions as a guarantee of safety. The model consistently under-predicted actual hearing loss because it ignored non-noise risk factors like age and ototoxic exposures. A predicted 'slight loss' did not prevent 'mild-to-severe' loss in real workers.