Daily Living Skills of Adolescents and Adults with Autism Spectrum Disorders: Growth Curve Trajectories Over a 10-Year Period

Background: In recent years, increasing attention has been given to understanding the behavioral phenotype of autism spectrum disorders (ASDs) during adolescence and adulthood. However, virtually no studies have explored changes in daily living skills of individuals with ASD later in the lifespan, even though such functional abilities are often cited as important factors for successful adult outcomes.

 

Objectives: The present study aimed (1) to investigate the longitudinal course of daily living skills in a large, community-based sample of adolescents and adults with ASD over a 10-year period and (2) to provide a benchmark for the level and change in daily living skills among the individuals with ASD by exploring change in daily living skills among similarly-aged individuals with DS.

 

Methods: Adolescents and adults with ASD (n=397) were drawn from an ongoing, longitudinal study of individuals with ASD and their families. The individuals with ASD ranged in age from 10 to 52 years at Time 1 (M = 22.06, SD = 9.82).  The majority of the sample was male (74.7%) and had a comorbid diagnosis of intellectual disability (68%) Additionally, 167 adolescents and adults with Down syndrome (DS) were drawn from a longitudinal study of aging families of individuals with intellectual and developmental disabilities. Individuals with DS ranged in age from 13 to 56 years at Time 1 (M = 31.6, SD = 7.2).

Procedures were identical for both the ASD and DS samples. Parents reported on their son or daughter’s daily living skills using the Waisman Activities of Daily Living (W-ADL) Scale at 4 time points over a 10-year period.

 

Results: We utilized latent growth curve modeling to examine change in daily living skills over time. For the ASD sample, child age and intellectual disability status were included as predictors of initial level of daily living skills as well as linear and quadratic change over time. Daily living skills were improving for the individuals with ASD during adolescence and their early 20s, but plateaued during their late 20s, and started to decline during their early 30s. Older individuals had higher scores at the beginning of the study and also began to plateau at a faster rate than younger individuals. Having an intellectual disability was associated with lower initial levels of daily living skills and a slower rate of growth over time.  For the DS sample, a different pattern of change was observed. There was a significant positive linear slope, but the quadratic latent factor was non-significant, indicating that individuals with DS were gaining daily living skills over time and that there was no significant curvature in the change.  

 

Conclusions: Findings indicated that individuals with ASD gained daily living skills through their 20s but began to loose skills by their early 30s. This pattern is markedly different from what was observed with individuals with DS who did not show declines in skills. It will be critical for future research to explore what environmental factors and interventions may be associated with continued gains of living daily skills for adults with ASD.