Early Adaptive Functioning Trajectories in Preschoolers with Autism Spectrum Disorders

Background:  In preschoolers with Autism Spectrum Disorders (ASD), symptom severity has a negative impact on the development of adaptive functioning (Szatmari et al., 2015). Adaptive functioning impairments (e.g. dependency in activity as personal hygiene) critically impact the quality of life of those children and their family. Developmental features such as reduced social interest or the presence of behavioral problems can further impede daily life learning experiences (e.g. Chevallier et al., 2012, Fulton et al., 2014). However, so far, the development of adaptive functioning in young children with ASD remains speculative and has to be tested in a longitudinal multiple visits design.

Objectives: The first aim of the current study is to confirm the impact of high symptom severity on adaptive functioning trajectories in a sample of preschoolers with autism spectrum disorder. The second objective intends to explore whether reduced social interest and severe behavioral problems negatively affect developmental trajectories of adaptive functioning in young children with ASD.

Methods: Fifty-eight children with ASD (141 visits in total) and 29 age and gender matched typical developing (TD) children (64 visits in total) were longitudinally followed between 1.8 and 5.0 years old. At the baseline, diagnosis of ASD was confirmed with the Autism Diagnostic Observation Schedule (ADOS, Lord et al., 2000), which also allows defining symptom severity. Behavioral problems and social interest were also measured, using respectively, the Child Behavior Checklist for Ages 1.5-5 (CBCL/1.5-5, Achenbach & Rescorla, 2001) and a validated eye-tracking paradigm of visual preference for biological and non-biological motion (Pierce et al., 2012; Franchini et al., 2016). Besides baseline assessment, data on adaptive functioning were collected with the Vineland Adaptive Behavior Scales, 2^nd edition (standard scores; Sparrow et al., 2005) every 6 months (for a maximum of two years).

Results:  Using mixed models regression analyses we first demonstrated that children with ASD showed parallel developmental trajectories but significantly lower performance of adaptive functioning as compared to TD children (p<0.0001). Second, within ASD children, our results demonstrated that those with: 1) higher symptom severity (p<0.0001); 2) reduced social interest (p=0.03) and; 3) higher scores of behavioral problems (p=0.01) exhibited especially lower trajectories of adaptive functioning. However, the group by diagnosis interaction (i.e. slope of the trajectories) did not differ between these groups.

Conclusions: Our results support that, beyond high symptom severity, both reduced social interest and higher behavioral problems are also associated with lower adaptive functioning in young children with ASD. These findings further bolster the idea that social interest and behavioral problems are crucial for the early adaptive functioning development of children with autism. The current study has clinical implication in pointing out relevant targets for early intervention in ASD children.