Click- and tone-burst-evoked otoacoustic emissions in normal-hearing and hearing-impaired ears.

Click-evoked otoacoustic emission (COAE) and tone-burst-evoked otoacoustic emission (TBOAE) input/output (I/O) functions and group latencies were measured in normal-hearing and hearing-impaired ears to determine the extent to which these two types of transient-evoked otoacoustic emissions (TEOAEs) were similar. When stimulus levels measured in 1/3 octave bands centered at 500, 1000, 2000, and 4000 Hz were similar, TBOAE and COAE I/O functions were essentially identical in regions of normal hearing. This held true in subjects who had normal hearing from 250 to 8000 Hz as well as for subjects who had normal hearing across some frequency ranges but hearing impairment across others. The high degree of correlation offers support to the view that both types of transient emissions share common generators. There were no significant differences in group delay between TBOAEs measured from normal-hearing and hearing-impaired subjects.