Smith Magenis

Concrete and relational vocabulary: Comparison between Williams and Smith-Magenis Syndromes

A new study has compared the concrete and relational vocabulary performance of individuals with two neurodevelopmental disorders, Williams syndrome (WS) and Smith-Magenis syndrome (SMS). Concrete vocabulary refers to tangible qualities or characteristics, things we know through our senses whereas relational vocabulary refers to language that links at least two elements and therefore provides context to what has been said or heard.

These two disorders are both rare and caused by microdeletions – Williams syndrome on chromosome 7 and Smith-Magenis syndrome on chromosome 17.  Not only do these two conditions share similar genetic mechanisms, they also share some cognitive, behavioural and linguistic phenotypes. They are characterised by intellectual disability, attention deficits, strong adherence to routines and extroverted social behaviours. Both syndromes are also characterised by deficient pragmatic skills, however individuals with both disorders are able to reach adequate levels of expressive language, particularly in childhood and adolescence.

In this study, participants were assessed using two different tests. The Peabody Picture Vocabulary Test-lll (PPVT-lll) was conducted which measured performance on concrete vocabulary. During the Peabody test, the children were presented with a series of pictures, these pictures are then described and the children were asked to identify the number of the picture that the word described.  The second assessment was the Boehm Test of Basic Concepts which was used to assess the understanding of abstract vocabulary comprehension relating to quantity, time and space. In the Boehm test, concepts are represented in very simple line drawings, the researcher then verbally expresses the target concept and the child has to identify the concept that is being referred to.

Despite both groups showing similar levels of receptive concrete and relational vocabulary, performance on relational space concepts was lower in Williams syndrome when compared with Smith-Magenis syndrome. Importantly in this study, different vocabulary profiles emerged for each syndrome – there was an association between concrete and relational vocabulary ability in the SMS group, but not in the Williams syndrome group. Not only this, but in Williams syndrome, performance on relational space concepts was marginally poorer than performance on the Peabody Picture Vocabulary Test, however in Smith-Magenis syndrome, performance on relational space concepts was superior to performance on the Peabody test.

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