Objectives: The aim of the present prospective study was to assess the development of imitation, joint attention and pretend play in toddlers with ASD compared to toddlers with other developmental difficulties. Objectives:Objectives:
Methods: Data were collected from 9 children with ASD (confirmed by ADOS and ADI; ASD cases) and 9 children with (initial) language or developmental delay (non-ASD cases). The children were between 24 and 45 months old (M= 34) at initial assessment and between 47 and 52 months old (M= 49) at last assessment. Each participant was tested multiple times (2 to 5 times depending on age at first assessment) with approximately 6 months between consecutive assessments. Imitation, joint attention and pretend play were measured using respectively the PIPS, ESCS and TOPP.
Results: Initiating joint attention (IJA): The average number of IJA behaviors seems to remain stable, apart from a slight increase in the ASD cases after 42 months. At all ages non-ASD cases show almost twice as much IJA behaviors than ASD cases. There is great variability in developmental trajectories, especially in ASD cases. More than half of these children show a decrease in IJA behaviors between 30 and 42 months, whereas most non-ASD cases show an increase in IJA behaviors in that period.
Imitation: On average the imitation skills of all children improve between 30 and 48 months. Whereas at 30 months non-ASD cases obtain a higher score on imitation skills than ASD cases, this difference seems to get smaller between 42 and 48 months. Looking at the individual trajectories, there seem to be two subgroups in both groups. Half of the ASD cases show a rapid increase in imitation skills between 36 and 48 months, and have an age appropriate score by 48 months, making up for an initial delay. The other half makes less or no progress and remains to have a substantial delay at 48 months. Non-ASD cases can be divided in similar groups, but the progress in the children that attain an age appropriate score at 48 months seems to begin earlier, at the age of 30 months.
Pretend play: On average the pretend play skills of all children improve between 30 and 48 months. At all ages ASD cases perform worse than non-ASD cases. Individual trajectories show great variability among ASD cases: most children improve as they get older, but not at the same rate.
Conclusions: Early social communicative abilities continue to develop between 30 and 48 months. At all ages ASD cases perform worse than non-ASD cases. Imitation and symbolic play skills improve in most children with ASD, whereas initiating joint attention remains rather stable on average. There is however great variability in individual developmental trajectories, especially in children with ASD.