Neurocognitive Profiling of Children with Specific or Comorbid Reading Disabilities

This study concerns the question whether different reading-related neurocognitive profiles can be observed for reading proficiency based groups of children, who attend the upper levels of Dutch primary education. Besides distinguishing between normal-to-good reading children and children with Reading Disabilities (RD), subgroups are discerned for two frequently reported comorbidities of RD, i.e., Attention Deficit Hyperactivity Disorder (ADHD) and Specific Language Impairment (SLI).

The research of this PhD thesis is organized into two empirical sections on different branches of reading-related neurocognitive research, which are elaborated in five studies. The first section focuses on the cognitive processes of phonemic awareness and rapid automatized naming, and the first study specifically addresses the question as to how the severity of RD affects the relative importance of these processes. Additionally, it is investigated how this works out for above-average and excellent readers. Involving the same processes, the second and third study focus on the issue of comorbidity with SLI and ADHD. The second section contains the fourth and fifth study which investigate the relatively novel link between word reading and two aspects of visual attention, i.e., selective attention and orienting of attention.

In the general discussion the employed working model of reading is supplied with empirically based estimates of the neurocognitive effect sizes. A main conclusion of the present study is that the addition of visual attention measurements to a phonological reading model provides an enhanced understanding of the cognitive basis of word reading, and offers interesting new perspectives on differential-diagnostic procedures and treatment planning.