Reaching the Other Half: Executive Function Deficits in a Community Based Sample

Background: Most ASD research recruits individuals with prior diagnoses, limiting generalizability to families who have sought care, which is particularly problematic for low resource families (Durkin et al., 2015). Our group has previously reported on children recruited based on symptomology, rather than prior diagnosis (Kraper et al., poster at 2016 IMFAR conference), finding that while clinician observation of ASD symptoms was similar between children previously diagnosed with ASD and those who were not, parents of children without any prior diagnosis reported fewer symptoms. The current study follows up on that same group of children to report the degree that parents recognized problems with executive functioning (EF).

Objectives: To compare EF skills in children meeting criteria for ASD on the ADOS-2 with a prior ASD or comorbid ASD and ADHD diagnosis to those with a prior ADHD diagnosis or no prior diagnosis.

Methods: Families at high-poverty schools in the broader Washington, DC area were referred to participate in a comparative effectiveness trial of two school-based EF interventions. The current study uses a subsample of this population meeting criteria for ASD on the ADOS-2 for whom parents reported on prior diagnostic status. Specifically, this included 39 children (mean age=9.8 years, SD=0.79) of whom 12 had a prior ASD diagnosis, 7 had prior comorbid diagnoses of ASD and ADHD, 10 had a prior ADHD diagnosis, and 10 had no prior diagnosis. EF was measured by parent report on the BRIEF, clinician observations of skills in the classroom, and teacher report of classroom performance.

Results: Clinician Comparison Score rating of social communication and restricted interests/repetitive behaviors on the ADOS-2 did not differ between the four groups (F_3,35=1.67, p>.05). The groups also did not differ on age, Full Scale IQ, family income, or child’s ethno-racial category. Parent-reported level of EF problems on the BRIEF differed significantly between groups (F_3,35=8.443, p<.01). Post-hoc comparisons showed children with prior comorbid diagnoses had significantly higher levels of parent-reported EF problems than children with a prior ASD diagnosis (Sheffe’s p=.004) or no prior diagnosis (Sheffe’s p=.002). The children with a prior ADHD diagnosis had significantly higher levels of parent-reported EF problems than children with no prior diagnosis (Sheffe’s p=.047). Despite differences in parent report of EF problems, there were no differences in clinician observations of classroom behaviors (F_3,35=.365, p>.05) nor in teacher report of classroom performance (F_3,24 =.665, p>.05).

Conclusions: Greater levels of EF problems were reported by parents of children with prior comorbid diagnoses of ASD and ADHD or a prior ADHD diagnosis, suggesting that parent-report of EF problems resulted in a diagnosis of ADHD, either alone or in combination with ASD. In contrast, blind observations of classroom behaviors and teacher report of concerns were similar, indicating comparable functional impairment from EF problems at school across groups. This suggests the importance of multiple methods of gathering information for accurate diagnosis (e.g., parent-report, teacher-report, observations). Further research should continue exploring factors related to difficulty accessing specialized ASD assessment and methods to identify children most likely to require those assessments.