Monosyllabic word recognition at higher-than-normal speech and noise levels.
The effects of intensity on monosyllabic word recognition were studied in adults with normal hearing and mild-to-moderate sensorineural hearing loss. The stimuli were bandlimited NU#6 word lists presented in quiet and talker-spectrum-matched noise. Speech levels ranged from 64 to 99 dB SPL and S/N ratios from 28 to -4 dB. In quiet, the performance of normal-hearing subjects remained essentially constant in noise, at a fixed S/N ratio, it decreased as a linear function of speech level. Hearing-impaired subjects performed like normal-hearing subjects tested in noise when the data were corrected for the effects of audibility loss. From these and other results, it was concluded that: (1) speech intelligibility in noise decreases when speech levels exceed 69 dB SPL and the S/N ratio remains constant; (2) the effects of speech and noise level are synergistic; (3) the deterioration in intelligibility can be modeled as a relative increase in the effective masking level; (4) normal-hearing and hearing-impaired subjects are affected similarly by increased signal level when differences in speech audibility are considered; (5) the negative effects of increasing speech and noise levels on speech recognition are similar for all adult subjects, at least up to 80 years; and (6) the effective dynamic range of speech may be larger than the commonly assumed value of 30 dB.
Studebaker
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GA
Memphis Speech & Hearing Center, University of Memphis, Tennessee 38105, USA. gstudbkr@memphis.edu
Sherbecoe
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RL
McDaniel
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DM
Gwaltney
C A
CA
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001301:Audiometry, Pure-Tone / Q000379:methods; D001309:Auditory Threshold / Q000502:physiology; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009622:Noise; D010470:Perceptual Masking; D013063:Speech Discrimination Tests; D013067:Speech Perception / Q000502:physiology*