Associations Between ADHD Symptom Dimensions and Cognition in Children With ADHD and Learning Difficulties

Background: Attention Deficit Hyperactivity Disorder (ADHD) and Specific Learning Difficulties (SLD) are both associated with attentional and cognitive difficulties. This study examined the extent to which the cognitive impairments could be consequences of elevated levels of inattention and hyperactivity/impulsivity. 

Method: Secondary analysis was conducted on data from four groups selected from the Centre for Attention, Learning, and Memory, a neurodivergent cohort of children aged 5 to 18 years with a mean age of 9 years : children with ADHD only (n = 70), learning difficulties only (n = 406), ADHD with learning difficulties (n = 128), and a comparison group (n = 166). Covariance analyses examined whether any differences in basic cognitive skills and higher executive functions between the neurodivergent and comparison groups could result from variations in inattention and hyperactivity/impulsivity. 

Results: Irrespective of ADHD status, children with learning difficulties had low scores in short-term memory, working memory, sustained attention, processing speed, set sequencing, and set shifting. These cognitive deficits largely persisted when inattention and hyperactivity/impulsivity were covaried. In contrast, the ADHD only group performed at age-appropriate levels on measures of verbal short-term memory, verbal and visuospatial working memory, processing speed, and sustained attention. Their difficulties with set sequencing and visuospatial short-term memory were accounted for by inattention and hyperactivity/impulsivity, whereas their challenges with set shifting were independent of these attentional behaviors. 

Conclusions: The results point to distinct neurodevelopmental pathways to cognitive functioning for children with learning difficulties and those with ADHD. The independence of learning-related cognitive skills from levels of inattention and hyperactivity/impulsivity in children with learning difficulties either with or without ADHD suggests they represent the core deficits that underlie their learning difficulties. The limited cognitive challenges of children with ADHD without learning difficulties may be consequences of their elevated levels of attentional behaviors. Understanding the cognitive and learning profiles of children with ADHD and learning difficulties vital for identifying optimal intervention and support strategies that address their individual needs.