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PubMed · 10761351

Phonological processing, not inhibitory control, differentiates ADHD and reading disability.

K L Purvis·R Tannock
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Abstract

OBJECTIVE: To test for the distinctiveness of attention-deficit hyperactivity disorder (ADHD) and reading disability (RD) and the independence of the cognitive domains, inhibition and phonological processing, which are proposed as central to ADHD and RD, respectively, using a classic double dissociation design. METHOD: A 2 (ADHD versus no ADHD) x 2 (RD versus no RD) model was used to examine the cognitive profile of 4 groups of children, aged 7 to 11 years. Two measures of inhibitory control and 3 phonological processing measures were used. RESULTS: The 2 RD groups (RD, ADHD + RD) were significantly impaired relative to the 2 non-RD groups (controls, ADHD) on all phonological processing measures. The 2 ADHD groups were significantly impaired on simple go-task responding relative to the non-ADHD groups and in inhibition. Contrary to predictions, an RD effect on inhibitory control was found on one inhibition measure. The comorbid group (ADHD + RD) generally exhibited the deficits of both single groups in an additive fashion. CONCLUSIONS: These findings question the role of inhibitory control as a unique cognitive marker for ADHD and suggest true comorbidity for children with both ADHD and RD.

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Attention Deficit Disorder with HyperactivityCase-Control StudiesChildCognitionComorbidityConfounding Factors, EpidemiologicDyslexiaFemaleHumansInhibition, PsychologicalMaleMultivariate AnalysisNeuropsychological TestsPhoneticsJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.

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K L Purvis, R Tannock. 2000. Phonological processing, not inhibitory control, differentiates ADHD and reading disability.. https://doi.org/10.1097/00004583-200004000-00018

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