Behaviors related to autism spectrum disorder in children with developmental language disorder and children with 22q11.2 deletion syndrome

Abstract

Background and aim: Children with Developmental Language Disorder (DLD) are at an increased risk to develop behaviors associated with Autism Spectrum Disorder (ASD). The relationship between early language difficulties and the occurrence of ASD-related behaviors in DLD is poorly understood. One factor that may hinder progress in understanding this relationship is the etiological heterogeneity of DLD. We therefore study this relationship in an etiologically homogeneous group of children, who share phenotypic characteristics with children with DLD: children with the 22q11.2 Deletion Syndrome (22q11DS). We compare children with 22q11DS, to children with DLD and age-matched typically developing children (TD).

Method: 44 children with 22q11DS, 65 children with DLD and 81 TD children, between 3.0-6.5 years old, participated in a longitudinal cohort study that included a baseline measure and a follow-up measure with a 1-year interval. A parental questionnaire (SRS-2) was used to measure the incidence of behaviors in two key behavioral domains associated with ASD: Social Communication and Interaction and Restricted Repetitive Behaviors and Interests. At baseline, we assessed children's expressive and receptive language abilities as well as their intellectual functioning with standardized tests. We compared the distribution of ASD-related behaviors between the three groups. We used regression analyses to investigate whether language abilities at baseline predict ASD-related behavior at follow-up, accounting for ASD-related behavior at baseline, demographic variables and intellectual functioning.

Results: Both the children with 22q11DS and the children with DLD displayed significantly more ASD-related behaviors than the TD children. Over 30% of children in both clinical groups had scores exceeding the subclinical threshold for ASD in both behavioral domains. Both in 22q11DS and DLD, baseline receptive language scores were negatively correlated with ASD-related behaviors 1 year later, when controlling for baseline SRS-scores. However, this association was statistically significant only in children with 22q11DS, even when controlled for IQ-scores, and it was significantly stronger as than in the TD group. The strength of the association did not differ significantly between 22q11DS and DLD.

Conclusion: Both children with 22q11DS and children with DLD present with elevated rates of ASD-related behaviors at a preschool-age. Only in children with 22q11DS we observed that weaker receptive language skills were related to increased behavioral problems in the domain of social communication and interaction one year later.

Implications: Our findings indicate that relations between early language impairment and other behavioral phenotypes may be more feasible to detect in a subgroup of children with a homogeneous etiology, than in a group of children with a heterogeneous etiology (such as children with DLD). Our results in 22q11DS reveal that receptive language is especially important in predicting the occurrence of ASD-related behaviors. Future research is needed to determine to what extent receptive language predicts the occurrence of ASD-related behaviors in children with DLD, especially among those children with DLD with the weakest receptive language. Clinically, screening for ASD-related behaviors in children with developmental language difficulties is recommended from a young age, especially among children with receptive language difficulties.

Keywords: 22q11.2 deletion syndrome; autism spectrum disorder; developmental language disorder.

Figure 1.

Distribution of T-scores on the two subscales of the SRS (SRS SCI and SRS RRB) for children with 22q11DS (n  =  42), children with DLD (n  =  57), and TD children (n  =  75). Each dot indicates the score of an individual participant. Abbreviations. SCI  =  Social communication and Interaction. RRBI  =  Restricted Repetitive Behaviors and Interests. Note. A higher T-score on the SRS indicates more ASD-related behaviors. The horizontal dotted line reflects the cut-off score for the subclinical range (T  =  60). Each box represents the middle 50% of T-scores ranging from the 25^th percentile to the 75^th percentile. Black bar in each box represents the median. Whiskers represent the 2,5^th percentile and 97,5^th percentile.

Figure 2.

Plot presenting the relationship between receptive language and ASD-related behaviors in the domain of social communication and interaction in children with 22q11DS (n  =  28), children with DLD (n  =  52) and TD-children (N  =  72), using the predicted values resulting from the regression model. Abbreviations. SRS SCI  =  Social Communication and Interaction (SRS-scale SCI). CELF RLC  =  Receptive Language Composite score (measured with the CELF). Note. Individual dots represent data points of individual participants. Solid line is predicted mean per group.