Discrimination and identification of frequency-lowered speech in listeners with high-frequency hearing impairment

The effects of frequency lowering on consonant perception were studied in four listeners with high-frequency sensorineural loss. Frequency lowering, accomplished by pitch-invariant nonuniform compression of the short-term spectral envelope, included lowering to bandwidths of 2500 and 1250 Hz. Performance on frequency lowering was compared to that obtained with linear amplification using uniform or high-frequency emphasis. Results of pairwise discrimination tests indicated that performance on lowering to 1250 Hz was inferior to that obtained with linear amplification. After training, performance on consonant identification with lowering to bandwidths of 2500 or 1250 Hz was equivalent or inferior to that obtained with linear amplification, depending on the subject. In most cases, the performance of the impaired subjects on a given lowering condition was inferior to that obtained by normal subjects, except for one impaired subject whose performance on two lowering conditions was similar to normal.