Effect of electronic ANR and conventional hearing protectors on vehicle backup alarm detection in noise.
An experiment was conducted wherein masked thresholds (using ascending method of limits) for a backup alarm were obtained in pink and red noise at 85 and 100 dBA for 12 participants immersed in a probability monitoring task and wearing a conventional passive hearing protection device (HPD, an earmuff or a foam earplug), an active noise reduction (ANR) headset, or no HPD at all (only in 85 dBA noise). Results revealed statistically significant between-HPD differences in red noise (from 2.3 to 3.1 dB) and in the 100-dBA noise level (from 2.6 to 4.3 dB). An additional finding, which corroborates other studies using different protocols, was that masked thresholds in 85-dBA noise were significantly lower (from 3.2 to 4.4 dB) for the occluded conditions (wearing an HPD) than for the open-ear (unoccluded) condition. This result refutes the belief among many normal-hearing workers that the use of HPDs in relatively low levels of noise compromises their ability to hear necessary workplace sounds. Actual or potential applications of this research include (a) the selection of appropriate HPDs for low-frequency-biased noise exposures wherein signal detection is important and (b) gaining insight into the appropriateness of ANR-based HPDs for certain industrial noise environments.
Casali
John G
JG
Grado Department of Industrial and Systems Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA. jcasali@vt.edu
Robinson
Gary S
GS
Dabney
Erika Christian
EC
Gauger
Dan
D
D000293:Adolescent; D000328:Adult; D004430:Ear Protective Devices; D004868:Equipment Failure; D005260:Female; D006317:Hearing Loss, Noise-Induced / Q000517:prevention & control*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018986:Motor Vehicles; D009623:Noise, Occupational / Q000009:adverse effects; D012680:Sensitivity and Specificity; D014481:United States; D014489:United States Occupational Safety and Health Administration