Recognition of distorted speech in children with and without learning problems.

The effects of listening to time-compressed speech alone and in a competing babble, with speech in and out of phase between ears, were studied in 10 children with no apparent auditory or learning problems and in 10 children with learning disabilities and a suspected central auditory processing problem. The children ranged in age from 8 to 10 years. Both groups showed significant decreases in speech recognition when speech was compressed at a rate of 60 percent as compared with recognition of normal-rate speech. However, the children in the learning disabilities group showed a greater decrease. Listening to time-compressed speech in a binaural mode resulted in better speech recognition than in a monaural mode for both groups. When speech was shifted 180 degrees out of phase between ears, both groups demonstrated a release from masking for speech presented at a fast rate (60% compression), but the normal group had a greater release from masking than the learning disabilities group. Also, the learning disabilities group did not show a release from masking for normal-rate speech (0% compression). When both groups listened to speech that had been compressed and presented in a babble, their performance supported a multiplicative distortion theory, with children in the learning disabilities group showing a slightly greater multiplicative effect than the children with no apparent problems. The results support the necessity of binaural hearing to maximize auditory performance in difficult listening situations in two populations of subjects.