Comparing the oral language abilities of children with autism spectrum disorder and specific language impairment using the Comprehensive Assessment of Spoken Language (CASL)

Abstract

Since the adoption of the DSM-5, there appears to be a shift of focus away from the expressive language difficulties of children with autism spectrum disorder (ASD) to their social communication difficulties only. A significant body of research, on the other hand, has revealed that many children with ASD present with language impairment similar to that found in children with specific language impairment (SLI). It appears that a comprehensive test such as the CASL has not been used to investigate the differences in language impairment in children with ASD and SLI. The aim of the present study was to compare the oral language abilities of children in middle childhood with ASD (n=11) and SLI (n=12) to the corresponding abilities of a matched control group of children with typical development (TD) (n=12). All participants were EAL learners and came from bilingual or multilingual backgrounds. The group with ASD were high functioning. Lexical semantic, syntactic, supralinguistic, and pragmatic abilities were investigated using the CASL. A standard-group comparison design was used and participants were purposively assigned to the three groups (ASD, SLI, and TD). Differences in language scores were determined using analysis of variance and Tukey’s test. Results showed no significant differences between the participants with ASD and SLI for lexical semantic, syntactic, and supralinguistic abilities, but significant differences were evident when their results were compared to those of the TD participants. Great variability was seen in the language abilities of participants with ASD and SLI with the majority scoring one or more standard deviations below the mean of the CASL. Mean scores for pragmatics for the three participant groups differed significantly, with ASD<SLI<TD. Some participants with ASD demonstrated patterns of oral language deficits similar to children with SLI, thereby confirming results of previous findings. The results suggest that pragmatic and supralinguistic abilities should be included in the language assessment of children with ASD and SLI. It appears that the CASL can be applied as a successful tool to identify specific language deficits in children with ASD, but may not fully describe oral language deficits such as echolalia in children with ASD. The results imply that the language impairments of children with ASD and SLI are on a continuum where differences can be seen in severity. This study contributes to a database for multilingual South African children with language impairment.