Poster #16 - The Development of the Cognitive Profile of Preschoolers at risk for Dyslexia and ADHD

• In Event: Poster Session 13

Abstract

Developmental dyslexia (‘dyslexia’) and attention-deficit hyperactivity disorder (‘ADHD’) co-occur frequently, as approximately 15-40% of children with one diagnosis also have symptoms of the other (Pennington, 2006; Willcutt et al., 2010; Willcutt & Pennington, 2000). On a cognitive level, children with a diagnosis of co-occurring dyslexia and ADHD have been found to show deficits related to dyslexia (i.e., phonological deficits), deficits related to ADHD (i.e., executive deficits and delay of gratification difficulties), as well as processing speed deficits (de Jong et al., 2006; Germano et al., 2010; McGrath et al., 2011; Purvis & Tannock, 2000; Shanahan et al., 2006; Willcutt et al., 2001). Compared to children with a single diagnosis, children of the double diagnosis group are also often found to have more severe deficits (Mayes et al., 2000; Tirosh et al., 1998). Because of the severity of their cognitive problems, and an increased risk of poor school performance, internalizing, and externalizing problems, early identification of these disorders is important (Tirosh et al., 1998; Willcutt et al., 2001). It is therefore key to acquire knowledge about predictors of these disorders, to identify young children at risk for developing co-occurring dyslexia and ADHD. In this study, we compared the cognitive profile and development of a group of preschoolers (pre-reading) at risk for both dyslexia and ADHD (n = 47) to the profile of preschoolers at risk for dyslexia (n = 49) or ADHD (n = 39) and follow them up for 3 years. We compared these three preclinical groups to a group of average functioning preschoolers (n = 47). All children were followed up longitudinally and tested at three points in time: in 3rd kindergarten (winter 2019), first (winter 2020) and third grade (winter 2022). They were assessed on several cognitive factors related to dyslexia (i.e., phonological skills), ADHD (i.e., executive functioning and delay of gratification), co-occurring dyslexia and ADHD (i.e., processing speed), and academic achievement. Results revealed that, overall, all children performed better over time on all tasks. Group comparisons showed that children at risk for dyslexia (irrespective of ADHD status) consistently performed lowest on phonological skills, executive functions, processing speed, and academic achievement (i.e., reading and spelling). Children at risk for ADHD showed executive deficits (only on verbal and visuospatial working memory), but only when they were also at risk for dyslexia. They did not show delay of gratification problems. In short, the cognitive profile of children at risk for dyslexia did not differ from the cognitive profile of children at risk for dyslexia and ADHD. Analogously, neither did the cognitive profile of children at risk for ADHD versus those without risk. These results indicate that heterogeneity in these preclinical groups is too large to detect group differences. Retrospective analyses of the cognitive profile in these clinical diagnosis groups will also be discussed. Given the lack of research on preschoolers with a risk for dyslexia and ADHD, this research is not only of clinical value but can also add to the existing body of scientific literature.

Authors

• Silke Kellens, Katholieke Universiteit Leuven (KU Leuven)
  Presenting Author

• Dieter Baeyens

• Pol Ghesquière