The application of the equal energy hypothesis (EEH) to interrupted, intermittent and time-varying Gaussian noise exposures.
Qiu-W; Hamernik-RP; Davis-RI
J Acoust Soc Am 2006 Nov; 120(5)(Part 2):3129
Interrupted, intermittent, time-varying (IITV) noise exposures may reduce the susceptibility of the cochlea to hearing loss through toughening or conditioning effects. Six groups of chinchillas were exposed to a broadband Gaussian IITV noise over the course of 19 days at an Leq=101 or 106 dB(A) SPL. All exposures at a given Leq had the same total energy. Each daily exposure consisted of two 4.25-h periods with an hour break in between. Each 4.25-h exposure was interrupted for 15 min and each 5-day sequence was separated by a 2-day break. Daily IITV exposures at 101 dB varied between 90 and 108 dB(A), while those at 106 dB(A) varied between 80 and 115 dB(A). For the IITV exposures three different variations in the SPL temporal profile were used. Five-day continuous, equal energy exposures at 100 or 106 dB(A) SPL served as control conditions. The IITV exposures produced up to 40 dB toughening that did not have any effect on thresholds or sensory cell losses. There were some differences in the permanent threshold shift and cell loss across equal energy exposures but the differences were small. The EEH may be valid for Gaussian IITV exposures.
Noise-exposure; Noise-induced-hearing-loss; Hearing-loss; Hearing-impairment; Hearing-disorders; Animal-studies; Laboratory-animals
Wei Qiu, PhD, Auditory Research Laboratory, State University of New York at Plattsburgh, 101 Broad Street, Plattsburgh, New York, 12901
Abstract; Conference/Symposia Proceedings
Disease and Injury: Hearing Loss
Journal of the Acoustical Society of America