The effects of high-frequency hearing loss on low-frequency components of the click-evoked otoacoustic emission.

Click-evoked otoacoustic emission (CEOAE) input/output (I/O) functions were measured in ears with normal hearing and in ears with sensorineural hearing loss above 2000 Hz. The low- to midfrequency CEOAEs obtained from the ears with high-frequency hearing loss were significantly reduced in level compared to the CEOAEs obtained from the ears with normal hearing even though there were no significant group differences in the 250-2000 Hz pure-tone thresholds. The findings are discussed within the context of two hypotheses that explain the low- to midfrequency reduction in transient-evoked otoacoustic emission (TEOAE) magnitude: (1) subclinical damage to the more apical regions of the cochlea not detected by behavioral audiometry, or (2) trauma to the basal region of the cochlea that affects the generation of low-frequency emissions. It is proposed that localized damage at basal cochlear sites affects the generation of low- to midfrequency CEOAE energy.