Does the Development of Syntax Comprehension Show a Premature Asymptote Among Persons With Down Syndrome? A...

Area of Science:

• Linguistics
• Developmental Psychology
• Genetics

Background:

• The developmental trajectory of syntactic acquisition in individuals with Down syndrome (DS) after childhood remains unclear.
• Previous research presents conflicting findings on whether syntactic development plateaus in adolescence or continues into early adulthood.

Purpose of the Study:

• To investigate the post-childhood trajectory of syntactic and vocabulary comprehension in individuals with Down syndrome (DS).
• To compare the language development of individuals with DS to those with other forms of intellectual disability (ID).

Main Methods:

• A cross-sectional study was conducted involving 62 participants with DS and 62 participants with non-DS intellectual disability (ID).
• Participants were matched on chronological age and cognitive level.
• Receptive syntax and vocabulary were assessed for all participants.

Main Results:

• Both chronological age and diagnosis had significant effects on receptive syntax and vocabulary comprehension.
• No significant interaction was found between chronological age and diagnosis.
• Comprehension of vocabulary and syntax did not asymptote prematurely in individuals with DS compared to controls with other forms of ID.

Conclusions:

• Language development, specifically syntactic comprehension, continues beyond adolescence for individuals with Down syndrome.
• Individuals with Down syndrome show comparable language development trajectories to those with other intellectual disabilities when matched for age and cognitive level.