Language development trajectories in young children with developmental disabilities in Taiwan.

BACKGROUND: Language development is critical to various outcomes in young children with developmental disabilities (DD), including autism spectrum disorder (ASD) and non-ASD delays. However, language development trajectories in young children with DD in non-Western populations remain unclear.

AIMS: To investigate the language development trajectories of young children with DD in Taiwan. We investigated the relationship between trajectory class assignment and diagnostic outcomes (ASD or non-ASD delays) at 3 years after enrollment in the study and the differences in early abilities among children in different trajectory classes.

METHODS AND PROCEDURES: The participants were 101 young children with DD (mean age: 21.88 months; follow-up: 1.5 and 3 years after enrollment). Growth mixture modeling analyses were conducted to receptive language developmental quotients (RLDQ) and expressive language developmental quotients (ELDQ) on the basis of the Mullen Scales of Early Learning.

OUTCOMES AND RESULTS: Three RLDQ trajectories were identified, namely age expected, delayed catch-up, and delayed, and two ELDQ trajectories were identified, namely delayed improve and delayed. Trajectory class assignment was related to diagnostic outcomes. Children who demonstrated more proficient skills at the early time point, demonstrated improved language outcomes 3 years later. However, adaptive functioning did not differ between the two ELDQ trajectory classes.

CONCLUSIONS AND IMPLICATIONS: Language development in young children with DD in Taiwan is heterogeneous. Delayed receptive and expressive language development trajectories relate to later ASD diagnoses.