Proportional frequency compression of speech for listeners with sensorineural hearing loss

This study examined proportional frequency compression as a strategy for im proving speech recognition in listeners with high-frequency sensorineural h earing loss. This method of frequency compression preserved the ratios betw een the frequencies of the components of natural speech, as well as the tem poral envelope of the unprocessed speech stimuli. Nonsense syllables spoken by a female and a male talker were used as the speech materials. Both freq uency-compressed speech and the control condition of unprocessed speech wer e presented with high-pass amplification. For the materials spoken by the f emale talker, significant increases in speech recognition were observed in slightly less than one-half of the listeners with hearing impairment. For t he male-talker materials, one-fifth of the hearing-impaired listeners showe d significant recognition improvements. The increases in speech recognition due solely to frequency compression were generally smaller than those sole ly due to high-pass amplification. The results indicate that while high-pas s amplification is still the most effective approach for improving speech r ecognition of listeners with high-frequency hearing loss, proportional freq uency compression can offer significant improvements in addition to those p rovided by amplification for some patients. (C) 1999 Acoustical Society of America. [S0001-4966(99)02308-5].