The contribution of early hot versus cold executive functions in differentiating ADHD symptomatology

Abstract

Background: Accumulating evidence supports executive functioning (EF) deficits as the core manifestations of Attention-Deficit/Hyperactivity Disorder (ADHD). As EF is measurable and modifiable, dimensions of EF with predictive validity for a heterogeneous set of ADHD symptomatology may help to detect at-risk children early and give clues on potential EF interventions during preschool years.

Objective: To examine the contributions of hot (“motivation and affective regulation in emotionally-laden contexts") and cold (“more neutral cognitive control”) EFs prior to age 5 on ADHD symptomology at age 8.5.

Design/Methods: We used a prospective birth cohort consisting of 862 children who underwent multiple hot and cold EF laboratory tasks prior to age 5 and continued to be active in the cohort at age 9. At age 8.5, we used the parent and teacher Vanderbilt ADHD Rating Scale (i.e., DSM symptoms), Child Behavior Checklist (CBCL), and Child Global Assessment Scale (CGAS) to determine the likelihood of ADHD. Structural Equation Models (SEM) were performed to examine how early hot EF and cold EF differentially predicted ADHD symptom profiles (see Table).

Results: Compared to typically developing children, those meeting research criteria for ADHD at age 8.5 (7.8% in the cohort) showed pronounced cold and hot EF impairments prior to age 5. Our SEM confirmed that both cold (β = -0.20, SE=0.06, p=0.002) and hot EF (β = -0.80, SE=0.11, p<0.001) impairments were strong indicators of a later ADHD profile. This model reproduced the covariance matrix of our sample data with reasonable fit indices (χ =224.12, p<0.001; RMSEA=0.04; CFI=0.96; AIC=38945.10). The hot EF category of motivation regulation during preschool (e.g., sustained engagement in an impossible task, delayed gratification) was the most salient (β = -0.54, SE=0.13, p< 0.001) in predicting later inattention symptoms, while none of the EF measures differentially predicted children with predominantly hyperactive-impulsive symptoms of ADHD.

Conclusion(s): Hot and cold EF impairments are evident and stable prior to age 5 in children who have the highest likelihood of ADHD at age 8.5. As inattention, hyperactive, and impulsive symptoms are difficult to distinguish and often normative in preschool, different aspects of EF, particularly hot EF, may be better determinants of risks of later ADHD. More research on how preschool children engage in decision making during motivationally significant contexts may be warranted to ascertain its prediction of inattention in school age.