Developmental trajectories of adaptive behavior in Autism Spectrum Disorder and Down syndrome
Date
2017
Authors
Gerlach-McDonald, Brianne, author
Hepburn, Susan, advisor
Fidler, Deborah, advisor
Daunhauer, Lisa, committee member
Riggs, Nathaniel, committee member
Sample, Pat, committee member
Journal Title
Journal ISSN
Volume Title
Abstract
The increasing prevalence of developmental disabilities indicates a need for research and interventions for these populations. One growing area of interest is adaptive behavior or the functional skills individuals perform in their everyday lives, such as communication and daily living skills. Individuals with developmental disabilities with greater adaptive behavior skills experience a better quality of life in childhood and achieve better functional outcomes in adulthood (e.g., living independently). However, more research is needed to understand how adaptive behavior develops in childhood to identify critical time points for targeted interventions. The current study examined developmental trajectories of adaptive behavior across childhood in two developmental disabilities: Autism Spectrum Disorder(ASD) and Down syndrome (DS). This study examined secondary data obtained from a longitudinal study conducted at the University of Colorado Health Sciences Center between 1997 and 2007. The aim of this dissertation was to examine the extent to which individual differences in diagnostic status, maternal education, intellectual functioning, executive function, and autism symptoms predicted developmental trajectories of adaptive behavior. Examination of the predictors of developmental trajectories of adaptive behavior provided information regarding potential intervention targets to promote optimal adaptive behavior. This study used growth modeling techniques to compare two developmental disabilities. Participants included 77 children with ASD and 24 children with DS who were assessed in toddlerhood (ages 1-3 years), preschool (ages 4-6), and during the school years (ages 7-10). Parents completed a demographic questionnaire and interviews of adaptive behavior (Vineland Adaptive Behavior Scales; Sparrow, Balla, & Cicchetti, 1984), and autism symptoms (Autism Diagnostic Interview-Revised; Lord, Rutter, & LeCouteur, 1994). Child participants completed standardized developmental testing (Mullens Scales of Early Learning; Mullen, 1995), an executive function task measuring cognitive flexibility and working memory (Spatial Reversal; Kaufmann, Leckman, & Ort, 1989), and a semi-structured play-based assessment of autism symptoms (Autism Diagnostic Observation Schedule; Lord, Rutter, DiLavore, & Risi, 1999). Growth models were specified for developmental trajectories of communication, daily living skills, and socialization as measured by the Vineland Adaptive Behavior Scales. Diagnostic status, maternal education, intellectual functioning, executive function, and autism symptoms were added as predictors. Children with ASD and DS made gains in their adaptive behavior skills from toddlerhood to middle childhood but had significantly delayed scores compared to children in the standardization sample. The best fitting models of communication and socialization indicated significant linear and quadratic growth, and the best fitting model of daily living skills indicated significant linear growth. Diagnostic status was a significant predictor of initial starting states of communication and socialization in toddlerhood, but not daily living skills. Diagnostic status was a significant predictor of linear and quadratic slopes of communication. Maternal education was a significant predictor of initial starting states of socialization in toddlerhood in both groups. Mental age in toddlerhood was a significant predictor of initial starting states in toddlerhood for communication, daily living skills, and socialization in both groups. Mental age was a significant predictor of linear slopes of communication, daily living skills, and socialization, and quadratic slopes for communication and socialization in both groups. These findings provide implications for intervention; many existing manualized early intervention treatments do not explicitly target adaptive behavior. Implications for available programs are discussed, followed by recommendations for targeting adaptive behavior and expanding research efforts to promote these skills in children with ASD and DS.