Neurocognitive functioning in children with developmental dyslexia and attention-deficit/hyperactivity disorder: Multiple deficits and diagnostic accuracy

ABSTRACT

Introduction: This study aimed to investigate the neurocognitive functioning of children with developmental dyslexia (DD) and attention-deficit/hyperactivity disorder (ADHD). Method: Four groups of children between the ages of 8 and 10 years participated in the study: typically developing children (TDC; N = 34), children with DD-only (N = 32), children with ADHD-only (N = 32), and children with DD+ADHD (N = 18). Results: Children with DD and ADHD exhibited significant weaknesses on almost all neurocognitive measures compared with TDC. Large effect sizes were observed for naming speed and phonological awareness. The comorbid group showed deficits consistent with both DD and ADHD without additional impairments. Results from binary logistic regression and receiver-operating characteristic (ROC) curve analyses suggested that some neurocognitive measures revealed an adequate sensitivity for the clinical diagnosis of both neurodevelopmental disorders. Specifically, naming speed and phonological awareness were the strongest predictors to correctly discriminate both disorders. Conclusions: Taken together, the results lend support to the multiple cognitive deficit hypothesis showing a considerable overlap of neurocognitive deficits between both disorders.

KEYWORDS:

• Attention-deficit/hyperactivity disorder
• Developmental dyslexia
• Diagnostic accuracy
• Multiple cognitive deficit hypothesis
• Neurocognitive functioning

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

¹ The BANC (Simões et al., 2016) is a comprehensive assessment instrument tapping different functions of a child’s neuropsychological development, which included 16 subtests organized in six main domains: memory, language, attention and executive functions, motor function, laterality, and orientation. The BANC was normed on a representative and stratified sample of 1104 Portuguese children (aged 5–15 years) and revealed adequate psychometric properties (Moura et al., 2016).