The application of the equal energy hypothesis (EEH) to interrupted, intermittent, and time-varying non-Gaussian noise exposures.
Hamernik-RP; Qiu-W; Davis-RI
J Acoust Soc Am 2006 Nov; 120(5)(Part 2):3128
Industrial data and animal research show that non-Gaussian (nonG) noise exposures are more hazardous to hearing than energy equivalent Gaussian (G) exposures. A statistical metric, kurtosis [b(t)], was shown to order the severity of noise-induced trauma following a nonG exposure relative to an energy and spectrally equivalent G exposure. Four groups of chinchillas were exposed to one of four different nonG interrupted, intermittent, and time-varying (IITV) noise paradigms over 19 days at an Leq=103 dB(A) SPL, with b(t)=25 or 50. Each daily exposure consisted of two 4.25-h periods with an hour break. Each 4.25-h exposure was interrupted for 15 min and each 5-day sequence was separated by a 2-day break. Each daily IITV exposure followed one of two different SPL temporal patterns that varied between 90 and 108 dB(A). All IITV exposures produced a toughening effect that did not alter the degree of noise-induced trauma. NonG noise produced as much trauma as a G exposure at 110 dB. Despite very different temporal paterrns for the b(t)=50 exposures, trauma was the same. Thus within a common class [i.e., the same Leq and b(t)] of nonG, IITV exposure, the EEH may apply.
Noise-exposure; Noise-induced-hearing-loss; Hearing-loss; Hearing-impairment; Hearing-disorders; Models; Animal-studies; Laboratory-animals
Wei Qiu, PhD, Auditory Research Laboratory, State University of New York at Plattsburgh, 101 Broad Street, Plattsburgh, New York, 12901
Grant-Number-R01-OH-007801; Grant-Number-R03-OH-008175; Grant-Number-R01-OH-002317
Disease and Injury: Hearing Loss
Journal of the Acoustical Society of America