Dynamic temporal processing of nonspeech acoustic information by children with specific language impairment

The present study investigated whether children with specific language impairment (SLI) differed from children with normal language learning in their ability to process binaural temporal information. The SLI group was matched with peers of the same chronological age, as well as peers with similar language age. All three subject groups were tested with measures of complex sound localization involving the precedence effect phenomenon. Subjects were required to track the apparent motion of a "moving" fused auditory image (FAI). Movement of the FAI was simulated by varying the delay incrementally between pairs of clicks presented, one each, from two matched loudspeakers placed on opposite sides of the child's head. With this task, the SLI subjects' performances were found to be similar to their language age-matched but chronologically younger peers. Both groups exhibited tracking skills that were statistically poorer than that of the chronologically age-matched group. Additional tests indicated this effect was not due to differences in motoric tracking abilities nor to the SLI subjects' abilities to perceive small binaural time cues. Thus, children with SLI appear to be impaired in their ability to use binaural acoustic information in a dynamic ongoing fashion. The requirements for processing such nonlinguistic acoustic information in a "dynamic and ongoing" fashion may be similar to those involved in the ongoing processing of rapid changes in the temporal and spectral components of the speech chain.