Variation in morpho-lexical development within and between diagnoses in children with neurodevelopmental disorders

Area of Science:

• Child Development
• Linguistics
• Pediatric Neurology

Background:

• Understanding early expressive language is crucial for differentiating neurodevelopmental disorders.
• Clinicians must recognize similarities and differences across diagnostic groups to avoid misinterpretation.

Purpose of the Study:

• To investigate how early morphological and lexical development varies within and between diagnostic groups of children with neurodevelopmental delays.
• To determine if diagnosis can predict individual language growth trajectories.

Main Methods:

• Utilized data from the New Zealand MacArthur-Bates Communicative Development Inventory (NZCDI) for 88 children (2.5-5.5 years).
• Employed data visualization and mixed-effects modeling to compare morpho-lexical development across six diagnostic groups.
• Analyzed longitudinal data from 62 children to assess vocabulary growth patterns.

Main Results:

• Morpho-lexical development showed significant variation within and between groups, with prematurity interacting with age as a key predictor.
• Diagnosis did not reliably predict individual vocabulary growth trajectories in longitudinal analyses.
• Word type distribution differentiated only premature children with language delay from those with Down syndrome and disorders of relating and communicating.

Conclusions:

• There are broad similarities in early morpho-lexical development across diverse clinical populations.
• Individual variation within diagnoses and similarities across diagnostic groups should be accommodated in clinical and research approaches.