Adaptation of distortion product otoacoustic emissions predicts susceptibility to acoustic over-exposure in alert rabbits

作者：Luebke Anne E^*; Stagner Barden B; Martin Glen K; Lon**ury Martin Brenda L

来源：Journal of the Acoustical Society of America, 2014, 135(4): 1941-1949.

DOI：10.1121/1.4868389

A noninvasive test was developed in rabbits based on fast adaptation measures for 2f(1)-f(2) distortion-product otoacoustic emissions (DPOAEs). The goal was to evaluate the effective reflex activation, i.e., %26quot;functional strength,%26quot; of both the descending medial olivocochlear efferent reflex (MOC-R) and the middle-ear muscle reflex (MEM-R) through sound activation. Classically, it is assumed that both reflexes contribute toward protecting the inner ear from cochlear damage caused by noise exposure. The DP-gram method described here evaluated the MOC-R effect on DPOAE levels over a two-octave (oct) frequency range. To estimate the related activation of the middle-ear muscles (MEMs), the MEM-R was measured by monitoring the level of the f(1)-primary tone throughout its duration. Following baseline measures, rabbits were subjected to noise over-exposure. A main finding was that the measured adaptive activity was highly variable between rabbits but less so between the ears of the same animal. Also, together, the MOC-R and MEM-R tests showed that, on average, DPOAE adaptation consisted of a combined contribution from both systems. Despite this shared involvement, the amount of DPOAE adaptation measured for a particular animal%26apos;s ear predicted that ear%26apos;s subsequent susceptibility to the noise over-exposure for alert but not for deeply anesthetized rabbits.

• 出版日期2014-4