Relation Between Socioeconomic Status and Symptom Severity, Cognitive, and Language Ability in ASD

Background: The factors associated with low socioeconomic status (SES) are known to have negative impacts on language and cognitive development (Hart & Risley, 1995). While the negative effects of poverty on typical development have been widely documented, little is known about how socioeconomic factors may influence developmental outcomes in children with ASD. There is some evidence that low SES is associated with later age of diagnosis and reduced access to intervention services in ASD (Dickerson et al., 2016). Examining the relationship between SES and developmental outcomes in ASD is critical for understanding the impact of socio-contextual factors on symptom presentation in ASD. Knowledge thereof also has the potential to inform intervention efforts in vulnerable populations.

Objectives:  To investigate the relationship between SES, cognitive ability, and ASD symptomatology in a cohort of children and adolescents with ASD taking part in brain imaging studies.

Methods:  96 participants (80 males) ages 7 – 18 (mean ±SD = 13.6 ± 2.7) with confirmed ASD diagnoses completed neuropsychological and diagnostic assessment as part of an ongoing study of brain development and ASD. Participants completed the CELF-4, WASI-II, ADOS-2 and the ADI-R. Additionally, primary caregivers of 37 participants (30 males) provided information on both maternal and paternal income and education level. SES variables were submitted to Principal Component Analysis (PCA), which yielded two principal components (PCs) accounting for 49% and 28% of the variance, respectively. PC1 and PC2 were then used as predictors in multiple linear regression models to test for associations between SES, ASD symptomatology, and cognitive ability.

Results: Maternal income and education both loaded positively onto PC1 (rs = 0.88 and 0.44, respectively), whereas paternal education loaded positively onto PC2 (r = 0.80). Thus, PC1 and PC2 were interpreted to represent maternal SES and paternal education, respectively. Consistent with previous findings on the effects of maternal SES factors on language ability, maternal SES (PC1) was significantly associated with language skills (r = 0.47, ß = 4.41, t₂₂ = 2.52, p = 0.02), and cognitive ability (r = 0.43, ß = 4.04, t₂₉ = 2.56, p = 0.01) (see Figure 1). Notably, PC1 scores were negatively associated with ASD symptom severity on the ADI-R (r = -0.41, ß = -1.64, t₂₈ = -2.38, p = 0.02) (see Figure 1). Paternal SES factors were not associated with any outcome measures.

Conclusions:  Consistent with findings in the general population, we found that lower maternal income and education were associated with lower cognitive ability and weaker language skills in children and adolescents with ASD. Lower maternal SES was associated with increased symptom severity on the ADI-R, a parent report of the child’s symptoms at age 4-5 years. Intriguingly, this association was not significant on the ADOS-2, a clinician-rated measure. This discrepancy merits further research on the use of parent-report and clinician-rated diagnostic tools in low-SES populations. Paternal SES factors were not associated with any clinical or cognitive outcomes, corroborating previous findings that maternal SES factors have a greater effect on developmental outcomes than paternal factors.