Language impairment and executive functioning in children: The 22q11.2 deletion syndrome as an etiologically homogeneous model for Developmental Language Disorder

Abstract

Children with Developmental Language Disorder (DLD) have persistent language difficulties in the absence of a clear cause. Their language difficulties can for example not be explained by hearing loss or a lack of language input. Many children with DLD also have executive functioning (EF) deficits. It is currently unclear how these EF deficits relate to their language difficulties. Children with 22q11.2 deletion syndrome (22q11DS) also frequently have speech-language problems. However, in their case the cause of these problems is known: a genetic disorder stemming from a missing piece of DNA on chromosome 22. This leads to a wide variety of symptoms, most prominently congenital heart defects, palatal abnormalities, and cognitive deficits. The multifactorial nature of DLD hampers our ability to shed light on the relationship between language impairment and EF deficits. The language impairment of children with 22q11DS all stem from the same underlying etiology (i.e., cause of a disease or condition), which might help reduce the complexity of this investigation. This dissertation explores whether 22q11DS can be used as an etiologically homogeneous model for studying the relationship between language and EF in children with DLD. We conclude that, although the groups are phenotypically similar regarding language profile and EF deficits, there are several limitations with using 22q11DS as a model for DLD. Nonetheless, a comparison between these groups is clinically relevant and provides interesting opportunities for fundamental research.