“Temporal masking” of tone glides in hearing-impaired ears

Abstract

It has been reported previously [M. J. Collins, J. Acoust. Soc. Am. Suppl. 1 69, S22 (1981)] that normal hearers' ability to discriminate the rate of frequency change of a gliding portion of a signal is affected by the duration of an adjacent fixed-frequency segment of the signal. This “temporal masking” is found to be greater when the glide precedes the fixed-frequency segment (backward masking) than when the glide follows the fixed-frequency segment (forward masking). The present paper reports some effects of sensorineural hearing loss on difference limens for glide rate as a function of the duration of an adjacent fixed-frequency segment. Using an adaptive procedure, data were collected on two ears of one, well-trained, hearing-impaired subject. The results show a trend for neither forward nor backward masking to occur when the discrimination is of some glide versus no glide. When the glide segment changes frequency at a rate of 17 Hz/ms, forward and backward masking is observed, with the magnitude of the effect appearing to be independent of degree of loss. The ear with the more severe loss shows the more normal result (greater backward than forward masking), while the ear with the less severe loss shows mixed effects. The results are discussed in relation in implications for speech perception. [Work supported by NINCDS.]