Auditory and Audiovisual Reception of Words in Low-Frequency Noise by Children with Normal Hearing and by Children with Impaired Hearing

Common words (monosyllables, trochees, spondees) were presented in low-frequency noise to children who attempted to detect their acoustic patterns or to recognize them under a range of acoustic speech-to-noise (S/N) ratios. Both profoundly deaf (−10 dB) and severely hearing-impaired children (−17 dB) required higher S/N ratios for auditory detection of words than did children with normal hearing (−23 dB). The normals (92%) were superior to the severely hearing-impaired group (57%) in auditory recognition of words in noise, while the deaf group (3%) were unable to recognize words by ear alone. The deaf group were poor even at classifying the stimulus words by stress pattern. Provision of acoustic cues increased the audio-visual (AV) scores of normal-hearing and severely hearing-impaired subjects 54% and 33% respectively above lipreading alone, but it improved the lipreading performance of profoundly deaf subjects only 9%. Improvement in AV recognition depended for all groups upon their detection of acoustic cues for speech. The profoundly deaf children achieved their maximum AV scores only at a higher S/N ratio (+5 dB) than that for the severely hearing-impaired group (0 dB), who in turn required a higher S/N ratio for maximum AV recognition than did the normals (−10 dB).