Protection against noise trauma by sound conditioning in the guinea pig appears not to be mediated by the middle ear muscles.
The aim of this study was to test whether the middle ear muscles (MEM) play a significant role in the phenomenon of sound conditioning in guinea pigs. After inducing a temporary threshold shift by noise exposure (2767 Hz tone, 103 dB SPL, 5 min), the magnitude and duration of loss, as well as the rate of recovery of the amplitude of the distortion product emission was determined at 1.75, 2.2, 2.8, and 3.5 kHz followed for 90 min post-exposure for (1) a sound conditioned group with intact MEM, and (2) a sound conditioned group with paralyzed MEM. Significant differences were not found for any of the distortion product parameters tested. The results suggest that the MEM do not significantly contribute to protection against noise trauma by sound conditioning.
D000161:Acoustic Stimulation; D000818:Animals; D003051:Cochlea / Q000502:physiology*; D004432:Ear, Middle / Q000502:physiology*; D006168:Guinea Pigs; D009132:Muscles / Q000502:physiology*; D009622:Noise; D013016:Sound