Young Children with Language Difficulties: A Dimensional Approach to Subgrouping

Background: Language difficulties are among the most common developmental problems that clinicians encounter in young children (Buschmann et al., 2008). Nonetheless, the heterogeneity within this group presents challenges, both with respect to diagnostic decision making and intervention. Language difficulties are associated with several developmental disorders such as specific language impairment (SLI), intellectual disability (ID), and autism spectrum disorder (ASD) (Conti-Ramsden & Durkin, 2012). Within diagnostic frameworks as the DSM-IV-TR and ICD-10, these disorders are neatly separated by fixed sets of diagnostic criteria. Especially in young children, however, behavioural overlap between children with a different clinical diagnosis has been reported as well as variability between children categorized into the same diagnostic entity. These findings suggest that the currently demarcated, often top-down constructed, diagnostic categories do not sufficiently capture the complex behavioural profiles of rapidly developing young children (Huziak, Achenbach, Althoff, & Pine, 2007).    

Objectives: This study aims to delineate more homogeneous subgroups of young children with language difficulties. A dimensional, bottom-up approach is used for this purpose, thereby constructing clusters that are based on the abilities of children across developmental domains.   

Methods: 36 children with receptive and/or expressive language difficulties were recruited prospectively and consecutively from two diagnostic centres in Leuven (Flanders, Belgium). The children (between 24 and 46 months of age) were raised in a monolingual Dutch-speaking household and included regardless of their clinical diagnosis. Although most children were involved in an extended diagnostic evaluation trajectory at the time of data analysis, some did receive a clinical diagnosis of ID (n = 5), ASD (n = 5) or ASD with co-occurring ID (n= 3). The cognitive, adaptive and linguistic abilities of all children were assessed in addition to their mastery of two linguistic prerequisites; intentional communication and symbol understanding. The severity of ASD related characteristics present in each of the children was measured as well.  

Results: Four subgroups of young children with language difficulties were delineated. Besides differences in cognitive abilities, clusters were distinguished by differences in symbol understanding, frequency of communication for behaviour regulation and severity of ASD related characteristics. Children with and without a clinical diagnosis were found within a single cluster as were children with a different diagnostic classification.  

Conclusions: The results confirmed previous accounts of behavioural overlap in young children with a different clinical diagnosis and underscore the importance of adopting a dimensional, multidisciplinary approach to the phenotyping of young children with language difficulties. Both in clinical practice and research. The development of the majority of the participants was followed over a twelve-month time interval. Data regarding the association between cluster membership and later language development will also be presented.