Neurocognitive functioning in children with developmental dyslexia and attention-deficit/hyperactivity disorder: Multiple deficits and diagnostic accuracy.
BACKGROUND
This study aimed to investigate the neurocognitive functioning of children with developmental dyslexia (DD) and attention-deficit/hyperactivity disorder (ADHD).


METHODS
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.
a Psychological Assessment and Psychometrics Laboratory, Faculty of Psychology and Educational Sciences , University of Coimbra , Coimbra , Portugal.|b Neurosciences, Neuropsychology and Cognitive Assessment group from the Cognitive and Behavioral Center for Research and Intervention (CINEICC) , University of Coimbra , Coimbra , Portugal.
Octávio
O
Moura
a Psychological Assessment and Psychometrics Laboratory, Faculty of Psychology and Educational Sciences , University of Coimbra , Coimbra , Portugal.|b Neurosciences, Neuropsychology and Cognitive Assessment group from the Cognitive and Behavioral Center for Research and Intervention (CINEICC) , University of Coimbra , Coimbra , Portugal.|c Faculty of Psychology and Educational Sciences , University of Coimbra , Coimbra , Portugal.
Marcelino
M
Pereira
d Pediatric Hospital , Coimbra University Hospitals , Coimbra , Portugal.
Cláudia
C
Alfaiate
d Pediatric Hospital , Coimbra University Hospitals , Coimbra , Portugal.
Eva
E
Fernandes
d Pediatric Hospital , Coimbra University Hospitals , Coimbra , Portugal.
Boavida
B
Fernandes
d Pediatric Hospital , Coimbra University Hospitals , Coimbra , Portugal.
Susana
S
Nogueira
c Faculty of Psychology and Educational Sciences , University of Coimbra , Coimbra , Portugal.
Joana
J
Moreno
a Psychological Assessment and Psychometrics Laboratory, Faculty of Psychology and Educational Sciences , University of Coimbra , Coimbra , Portugal.|b Neurosciences, Neuropsychology and Cognitive Assessment group from the Cognitive and Behavioral Center for Research and Intervention (CINEICC) , University of Coimbra , Coimbra , Portugal.|c Faculty of Psychology and Educational Sciences , University of Coimbra , Coimbra , Portugal.
Mário R
MR
Simões
D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications / Q000175:diagnosis / Q000523:psychology*; D002648:Child; D003071:Cognition / Q000502:physiology*; D003072:Cognition Disorders / Q000150:complications / Q000175:diagnosis* / Q000523:psychology; D004410:Dyslexia / Q000150:complications / Q000175:diagnosis / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests
Attention-deficit/hyperactivity disorder; Developmental dyslexia; Diagnostic accuracy; Multiple cognitive deficit hypothesis; Neurocognitive functioning