Influence of hearing protectors on voice intelligibility
Keywords:
Personal protective equipment, Plugs and shells, Earplugs, Voice intelligibility, Speech discrimination indexAbstract
Although it's not the most appropriate method of combating noise, hearing protectors are the most widely used personal hearing protection equipment to prevent Noise-Induced Hearing Loss (NIHL). However, at the same time as protecting the worker, the protectors interfere with communication, influencing the understanding of the voice.
This study looked at the influence of hearing protectors (plugs and shells) on voice intelligibility in subjects with normal hearing, in quiet situations and with environmental noise. In order to achieve this objective, an experimental study was carried out using independent variables:
- 5 conditions of PPE use: no protector, 2 plugs and 2 shells;
- One type of background noise: pink noise;
- 4 test levels: 60, 70, 80 and 90 dB(A);
- 6 signal-to-noise ratios (S/N): no noise, +5, +10, zero, -5 and -10 dB;
- 5 repetitions for each case, totaling 600 trials, with 10 monosyllables in each. The variable measured was the percentage of correct words (monosyllables) in the test. This percentage was called the speech discrimination index (SDI)". The tests were carried out in the acoustics and vibrations laboratory at Unesp's Bauru campus
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