EFFECTS OF THE CROSSED ACOUSTIC REFLEX ON DISTORTION-PRODUCT OTOACOUSTIC EMISSIONS IN AWAKE RABBITS

Recent studies in anesthetized cats suggest that contralateral-sound stimulation acts to suppress ipsilateral neural responses via the medial olivocochlear-efferent system. Activation of this descending efferent pathway presumably influences ipsilateral outer hair cell motility and, thus, cochlear micromechanics, resulting in reduced input to auditory-nerve fibers. The principal aim of the present study was to determine if contralateral-sound stimuli influence the generation of ipsilateral distortion-product otoacoustic emissions, in the ears of the awake rabbits. The results showed no effects of contralateral stimuli on these emissions that could not be attributed to the crossed acoustic middle-ear reflex. The findings further indicate that distortion-product otoacoustic emission amplitudes over a wide range of frequencies can be dramatically reduced when the middle-ear reflex is activated.