The interaction of impulse and continuous noise: energy and spectral considerations in the production of hearing loss.
Roberto-M; Ahroon-WA; Davis-RI; Hamernik-RP
J Acoust Soc Am 1987 Mar; 81(Suppl 1):S76
Realistic industrial noise environments containing impulsive and continuous noise were modeled using a 5-day exposure paradigm that produces an asymptotic threshold shift (ATS). Pre- and postexposure measures of hearing thresholds were obtained on 96 chinchillas using evoked auditory responses (EAR). Six control groups were exposed to octave bands of noise at 0.5, 2.0, and 4.0 kHz at 95, 90, and 86 dB SPL, respectively, or impacts of 113, 119, or 125 dB peak SPL presented once per 1, 4, or 16 s, respectively. Nine interaction groups were exposed to combinations of an impulse and continuous noise. The greatest spectral overlap of energy occurs between the impulse and the 0.5 kHz octave band of noise. Although each of the different impulse noise exposures were balanced to produce an equal energy exposure, an exacerbation of hearing loss was produced in animals exposed to the 119- and 125-dB impacts in combination with the low-frequency (0.5-kHz) continuous noise. This synergistic effect gradually disappears when the spectral overlap between noises is reduced. [Research supported by NIOSH.]
Industrial-noise; Noise; Noise-exposure; Noise-frequencies; Environmental-exposure; Exposure-levels; Audiofrequency; Sound; Environmental-exposure; Environmental-hazards; Hazards; Sensory-thresholds; Models; Acoustics; Acoustic-signals; Animals; Laboratory-animals; Hearing-loss; Hearing
Journal of the Acoustical Society of America
State University of New York at Buffalo, Buffalo, New York