Auditory filter asymmetry in the hearing impaired.
Thresholds for 2-kHz sinusoidal signals were determined in the presence of a notched-noise masker, for six normal-hearing listeners and 12 listeners with cochlear hearing losses. Following Patterson and Nimmo Smith [J. Acoust. Soc. Am. 67, 229-245 (1980)], conditions were used where the notch was placed both symmetrically and asymmetrically about the signal frequency. The auditory filter shape for both the low- and high-frequency side of the filter was calculated using the rounded-exponential form of the filter. In six hearing-impaired listeners, the auditory filter shape showed a shallow low-frequency skirt indicating pronounced susceptibility to the upward spread of masking. In two hearing-impaired listeners, the filter shape showed a shallow high-frequency skirt, indicating pronounced susceptibility to the downward spread of masking. Two other listeners with mild threshold losses had steeper and more symmetric filters than normal, suggesting either a small conductive loss or an attenuation factor of sensorineural origin not associated with a degradation of frequency resolution. In the remaining two listeners, the auditory filter had too little selectivity for its shape to be reliably determined.
D000328:Adult; D000368:Aged; D001309:Auditory Threshold; D004292:Dominance, Cerebral; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010470:Perceptual Masking; D010898:Pitch Perception