Perception of speech and non-speech sounds by listeners with real and simulated sensorineural hearing loss

The effects of sensorineural and simulated hearing loss on the perception of speech and cion-speech sounds are evaluated and compared. Two simulations of hearing loss are considered: one introduces additive masking noise to elevate the detection thresholds of listeners with normal hearing, the other applies multiband dynamic expansion to attenuate sound components towards these detection thresholds. Measures of speech perception are derived from intelligibility tests for consonant-vowel syllables presented in a background of speech-spectrum noise. The perception of non-speech sounds was evaluated through measurements of the detection of tones in quiet and in the presence of broadband and narrowband masking noise, psychoacoustic tuning curves measured under forward masking conditions, and intensity discrimination for tone pulses. For mild and moderate hearing losses, both types of simulation alter the perception of speech in noise in a manner similar to sensorineural impairment. These simulations also produce effects similar to sensorineural impairment on the detection of tones in quiet and on simultaneous and forward masking. The expansion simulation tends to improve the ability to discriminate tone intensities, an effect generally not seen in listeners with sensorineural impairments. (C) 2000 Academic Press.