Recognition of amplitude modulation patterns in the presence of a simultaneous distractor

Abstract

This experiment tested listener’s ability to compare the amplitude modulation pattern of 200- and 500-Hz signals when distractor signals that were also amplitude modulated were presented simultaneously. The amplitude envelopes of the distractor signals were either uncorrelated, partially correlated, or fully correlated with the amplitude envelopes of the comparison signals. Relative to the case of no distractor, performance tended to decrease when a distractor was present, and the degree of interference increased as the envelope correlations between the comparison and distractor signals decreased. Although the interference was greater when the comparison and distractor signals were separated by 50 Hz, there was also significant interference when the separation was 300 Hz. Whether the distractor was higher or lower in frequency than the comparison had no consistent effect on performance. Implications are discussed for the use of multiple band signals that carry the amplitude envelopes from different spectral regions of a speech signal to convey speech to severely hearing-impaired listeners. [Work supported by NIH.]