Receptive Language Abilities in Young Children with Autism Versus Typically Developing Children

Background: Recent research suggests a possible specific receptive language deficiency in children with autism, such that these children may have lower receptive relative to expressive language skills.  However, some limitations of existing studies include the absence of a typically developing comparison control group, as well as use of parent-report measures. 

Objectives: The present study aimed to explore differences in relative receptive versus expressive language skills in children with autism, compared with a typical child sample.  We also explored potential associations between language abilities and autism symptom severity in the children with autism. 

Methods: Participants were 44 children with ASD and 54 typically developing children, aged 2 to 6 years. Both groups underwent verbal and nonverbal cognitive assessment using the Mullen Scales of Early Learning.  The Autism Diagnostic Observation Schedule (ADOS) was also administered to the autism participant group.  The two groups were compared on verbal abilities, including receptive and expressive language age-equivalents, and within-subject difference scores for receptive versus expressive language (RL-EL) whereby a positive value was indicative of higher receptive language than expressive and a negative value was indicative of lower receptive than expressive language.  The ASD group data were also examined for correlations between language abilities and autism symptom severity indexed by ADOS Total scores. 

Results:  Both receptive and expressive language skills were found to be significantly lower in the autism group compared with the typical group (p<0.01).  However, there was no evidence for differences in the relative receptive versus expressive language development trends or trajectories of the autism group compared with the typical group (p=0.23; TD mean RL-EL = 0.5, SE = 0.99; ASD mean RL-EL = -0.6, SE = 1.1).  Furthermore, in the autism group, language scores (receptive and expressive average) were moderately negatively correlated with ADOS Total scores (r=-.48, p<0.01).

Conclusions: These results indicate that the children with autism had clear deficits in both receptive and expressive language when compared with typically developing children. However, although the mean difference between receptive and expressive language (RL-EL) abilities was found to be numerically negative for children with autism and positive for typical controls, this difference did not nearly approach statistical significance. Thus, the current results do not support the hypothesis of a specific receptive language deficiency in young children with autism.  Although some previous studies have uncovered evidence for a specific receptive language deficit in children with autism, some of these studies used developmentally delayed control children who exhibited a tendency for impaired expressive relative to receptive language abilities.  Furthermore, the current findings are consistent with recent findings of Kover et al (2013), who also found no evidence for a relative receptive versus expressive language deficiency in autism compared with typical controls; but did find an impoverished rate of receptive versus expressive language development with age in this population.  Therefore, specific receptive language differences in childhood autism may be a result of early learning differences such that RL-EL performance differences do not become apparent until the children are somewhat older.