Article,
Speech perception in noise when wearing hearing protectors with little low-frequency attenuation
International Journal of Industrial Ergonomics, (1996)
Abstract
In industrial workplaces, it is widely believed that the use of hearing
protectors interferes with communication and with the perception
of warming signals. The objective of this study was to estimate effects
of attenuation of the protectors on speech perception in noise. In
the experiment, the intelligibility of monosyllables was assessed
for ten normal-hearing adults, using three types of protectors with
different attenuation characteristics. The speech materials were
presented at two speech levels (65 and 85 dBA) in noise. The noise
level was altered at signal-to-noise ratios (SNR) of 0, +5, and +10
dB. The results showed that speech intelligibility was significantly
influenced by type of protector, speech level, and SNR. The interaction
between these factors was statistically significant. The wearing
of the earplug with decreased low-frequency attenuation resulted
in less deterioration when the speech was presented at 65 dBA. On
the other hand, such an earplug did not improve speech intelligibly
as compared with other protectors when the speech was presented at
85 dBA. Therefore, the use of the protectors with decreased attenuation
to improve speech communication for workers wearing protectors needs
to be re-examined.
