General versus executive cognitive ability in pupils with ADHD and with milder attention problems

Ulla Ek,¹ Joakim Westerlund,² Elisabeth Fernell<sup>3

1</sup>Department of Special Education, ²Department of Psychology, Stockholm University, Stockholm, ³Gillberg Neuropsychiatry Centre, Sahlgrenska Academy, University of Gothenburg and the Research and Development Centre, Skaraborg Hospital Skövde, Sweden

Background: The aim of this study was to analyze two main types of cognitive domains in school children with different types and severities of attention-related problems. The cognitive domains examined were general cognitive ability and executive abilities.
Methods: Three different clinical samples of pupils with school problems were analyzed to assess their cognitive Wechsler Intelligence Scale for Children profiles. In particular, the general cognitive ability index and the executive markers (ie, verbal memory index and processing speed index) were of interest. Of the total sample (n = 198), two main groups were contrasted; one met the full criteria for attention deficit hyperactivity disorder (ADHD)/subthreshold ADHD, and one was comprised of those with milder attention problems, insufficient to meet the criteria for ADHD/subthreshold ADHD.
Results: It could be demonstrated that both groups had a significantly higher score on the general cognitive ability index than on measures of working memory and processing speed. This difference was more pronounced for boys.
Conclusion: These types of cognitive differences need to be considered in children with different kinds of learning, behavior, and attention problems; this is also true for children presenting with an average general intelligence quotient and with milder attention problems. Current educational expectations are demanding for children with mild difficulties, and such cognitive information will add to the understanding of the child's learning problems, hopefully leading to a better adapted education than that conventionally available.

Keywords: working memory, processing speed, children, learning and attention problems, attention deficit hyperactivity disorder, subthreshold