Auditory Processing Performance and Nonsensory Factors in Children with Specific Language Impairment or Auditory Processing Disorder

Abstract

The nature of auditory processing deficits is at the heart of understanding auditory processing disorder (APD) in children. This article reviews evidence that confounding nonsensory factors, including maturation, processing efficiency, and cognition, influence auditory processing in children with APD or language learning impairment. Experimental evidence is presented to show that performance thresholds on nonspeech auditory processing (AP) tests, such as tone detection tasks in noise or in quiet, are poorer in children clinically diagnosed with APD or specific language impairment (SLI), compared to typically developing mainstream school (MS) children. However, with the exception of backward masking, these group differences disappeared for all AP tests after accounting for nonverbal IQ. Intrinsic attention, indexed by variability in AP test performance, was examined alongside AP threshold performance. Generally there was no difference in intrinsic attention across the three participant groups (MS, SLI, APD), but frequency discrimination (FD) was an exception. Thus, although reduced intrinsic attention has been shown to be a factor in the presenting symptoms of APD, including poor listening, speech intelligibility, and communication, there is, surprisingly, no robust evidence that intrinsic attention in children identified with APD or SLI is any poorer than that in typically developing children.