Noise and vibration interactions: effects on hearing.
Hamernik RP; Ahroon WA; Davis RI; Axelsson A
J Acoust Soc Am 1989 Dec; 86(6):2129-2137
The effects of noise and vibration interactions on hearing and the role of various exposure parameters were examined in chinchillas. Animals were made monaural by surgical destruction of the left cochlea. Chronic electrodes were then implanted near the inferior colliculus for single ended near field recording of the evoked potential. Studies were performed using a 30 hertz 3g root mean square (rms) and a 20 hertz 1.3g rms cage vibration separately and in combination with continuous noise (95 decibels, 0.5 kilohertz octave band) and impact noise (113, 119, or 125 decibels peak sound pressure level) exposure paradigms. All exposures lasted for 5 days. The impact noise exposures were designed to have approximately equal total energy. Temporary and permanent threshold shifts were measured using evoked potentials, and sensory cell loss was measured using surface preparation histology. The results obtained from some of the noise and vibration paradigms indicated that such exposures could alter some of the dependent measures of hearing. The effect was statistically significant only for the stronger vibration exposure conditions and was evident primarily in the extent of the outer hair cell losses and in the shape of the permanent threshold shift audiogram. The authors conclude that the increased risk of noise induced hearing loss from vibration in combination with noise in the industrial population is probably relatively small.
Vibration-exposure; Vibration-effects; Noise-exposure; Noise-induced-hearing-loss; Hearing-loss; Auditory-system; Laboratory-animals; Occupational-exposure
Journal of the Acoustical Society of America
State University of New York at Albany