Robin van Rijthoven

20 Chapter 1 during the intervention for research purposes. All assessments and interventions were performed between 2009 and 2012 by a certified clinic at various locations in the east of the Netherlands. The files of the selected children included data from assessment and intervention based on the previously described protocol and included an extensive history of the child’s development and school results, information about school-based interventions, Brus One Minute test (Brus & Voeten, 1973) for word reading, Klepel (Van den Bos et al., 1994) for pseudoword reading, the PI-dictation (Kingsma & Van den Burg, 2005) for word spelling, the complete Wechsler Intelligence Scale for Children-III (WISC-IIINL; Kort et al., 2005b) for verbal reasoning skills, verbal working memory, and perceptual organization, Continuous Naming and Reading Words (Van den Bos & Lutje Spelberg, 2007) for rapid automatized naming, and in most cases the 15 Words test for children (Kingsma & Van den Burg, 2005) for verbal learning tasks. For Phonological Awareness, three measures were administered; subtests of the Screening Test for Dyslexia (Kort et al., 2005b), the phonemic analysis Test (Van den Bos et al., 2010), and subtests from 3DM (Blomert & Vaessen, 2009). Most files were present containing the Screening Test for Dyslexia and considering the required power for our analyses these files were selected. Because of the variety in instruments for phonological awareness, a group of 63 children (43 boys and 20 girls) with Dutch as their first language remained for the present research. All children with dyslexia scored, weak on word reading (n = 61, M = 4.42, SD = 1.816), and pseudoword reading (n = 62, M = 5.25, SD = 1.795) when compared to norms (n = 62, M = 10, SD = 3). For spelling, these children scored weak (n = 62, M = 7.27, SD= 14.228) compared to norms (M = 50, SD = 34). Some additional variables were missing that were important for some papers only and thus group size can differ per study. In Chapter two, eight children were excluded since data was missing on reading tests, semantic abilities, and/or workingmemory. In Chapter three, nine children were excluded since data was missing on semantic abilities and/or working memory and some did not have an intervention. In Chapter four, the same nine children as in chapter three were excluded, supplemented with two children of whom the dictation tasks were not in the files. For Chapter five, eight children were excluded, since data was missing on verbal learning and consolidation and/or reading tests. Two research questions were formulated: 1. To what extent can semantic abilities compensate for reading and spelling development in children with dyslexia? 2. To what extent can the reading and spelling development of children with dyslexia with varying cognitive profiles benefit from a phonics to spelling intervention? During the project two control groups of typically developing children were collected for studies on spelling errors (Chapter 4, n = 104) and verbal learning (Chapter 5, n = 36). The first control groupwas gathered at six different schools in the east of the Netherlands. The second control group was gathered at one school in the east of the Netherlands. Schools