DISTORTION-PRODUCT OTOACOUSTIC EMISSIONS IN HUMANS WITH HIGH-FREQUENCY SENSORINEURAL HEARING-LOSS

Distortion-product otoacoustic emissions (DPOAEs) and pure-tone behavioral thresholds were compared in 20 ears with normal hearing and in 20 ears with high-frequency sensorineural hearing loss. The purpose was to determine if DPOAE amplitude is associated with pure-tone behavioral threshold. Comparison of results from the two groups of ears indicated that DPOAEs were reduced in amplitude or were absent in ears with high-frequency hearing loss. The differences occurred at frequencies above 1,500 Hz. Comparing results from 750 to 8,000 Hz within the same ear revealed a frequency-related correspondence of elevated behavioral threshold to reduced DPOAE amplitude. When behavioral thresholds were better than 20 dB HL, DPOAE amplitude was within the range (±2 SDs) determined for the ears with normal hearing. When pure-tone threshold was greater than 50 dB HL, DPOAEs were absent or were significantly attenuated in 16/17 subjects (94%). The association of emission level with behavioral threshold level was variable when threshold was between these two extremes. Results imply that the measurement of DPOAEs has clinical potential as a means of detecting hearing loss by frequency.