Relative strengths in daily living skills among autistic individuals and individuals with related developmental conditions who have co-occurring intellectual disability.
Academic Article
Overview
abstract
BACKGROUND: Strong daily living skills (DLS) are associated with positive outcomes. Prior studies have documented intellectual quotient (IQ)-DLS discrepancies in autistic individuals with average or higher cognitive abilities. Little work in this area includes individuals with co-occurring intellectual disability (ID) or examines IQ-DLS discrepancies at the level of DLS subdomains (i.e., Personal, Domestic, and Community skills). This study examined trajectories of IQ-DLS discrepancies from ages 2-25 in autistic individuals with ID. METHODS: A total of 127 individuals from a well-characterized longitudinal cohort with verbal IQ < 70 at age 9 were included. IQ-DLS discrepancy scores were calculated by subtracting DLS AEs from nonverbal mental age (NVMA) estimates. Group-based trajectory modeling identified IQ-DLS discrepancy trajectory groups for the DLS domain and Personal, Domestic, and Community subdomains. One-way ANOVA and chi-square analyses were used to compare trajectory groups on demographic and phenotypic characteristics. RESULTS: Two DLS domain discrepancy trajectory groups emerged: IQ > DLS (cognitive abilities exceeded DLS) and IQ < DLS (DLS exceeded cognitive abilities); most participants (78%) were in the IQ > DLS group. An additional group, IQ = DLS (cognitive abilities and DLS were commensurate), emerged in each of the DLS subdomains, for a total of three trajectory groups. Within DLS subdomains, approximately 80% of participants were in either the IQ = DLS or the IQ < DLS trajectory group. In other words, examining scores at the DLS domain-level indicated most participants had cognitive abilities that exceeded DLS, but subdomain scores indicated most participants had DLS that equaled or exceeded cognitive abilities. CONCLUSIONS: These results challenge the notion that autism is usually associated with weaknesses in DLS compared to IQ. At the subdomain level, 80% of participants had DLS commensurate with or stronger than their cognitive abilities, indicating domain-level scores may obscure important variability in daily functioning. This work highlights the importance of including autistic individuals with ID in research; patterns observed in samples without ID may not be generalizable.
