Executive function processes: inhibition, working memory, planning and attention in children and youth with Attention Deficit Hyperactivity Disorder

摘要

This study examines the roles of inhibition, attention, working memory, andplanning in youth with and without ADHD. As conceptualized in theories of attention,inhibition, and working memory, difficulties with these executive processes interact tomanifest in the behavioral syndrome(s) of ADHD. Barkley (1997) proposed disinhibitionas the primary deficit of ADHD. Rapport, Chung, Shore, Denney, & Isaacs, (2000)theorized that ADHD results from a primary deficit in working memory. Mirsky (1987)proposed a model of attention which children with ADHD have deficits in abilities tofocus/execute, encode and sustain attention. Posner and Petersen (1990) proposed thatthree attentional networks are responsible for attentional processes and those childrenwith ADHD have deficits in the vigilance network. To investigate the contributions ofinhibition, working memory, attention, and planning in executive dysfunction in childrenwith ADHD, measures were selected from factor analytic studies.Children with ADHD-Combined Type demonstrated poorer inhibition andworking memory than children with no diagnosis after controlling for IQ effects. Nodifferences in planning and attention were indicated after controlling for IQ effects.However, a predictive discriminant analysis indicated that none of the executiveprocesses contributed to the prediction of group membership. Given correlational andpredictive discriminant analysis results, further analyses were conducted to investigatethe contribution of the measures selected for the domains. The theoretical model did notrepresent a good fit of the data. A three-factor model indicated the best representationsuggesting that inhibition and attention were not separable. There were no groupdifferences with the revised measurement model for inhibition/attention, workingmemory and planning. Taken together, results indicated measures originally selected totap executive function may not be clean measures of inhibition, working memory,planning, or attention processes. In addition, recently proposed theories overlap andconceptualize the multiple constructs involved in ADHD with a variety ofmethodologies, further contributing to difficulties in interpreting results andmeasurement issues.