Robin van Rijthoven

58 Chapter 3 al., 2016; Tilanus et al., 2016). Responsiveness to intervention may also be dependent on children’s verbal working memory. A limited verbal working memory reduces the amount of phonological and orthographic information that can be co-activated during the reading process, especially during the decoding process (Gathercole & Baddeley, 1993; Perez et al., 2012). Hulme (1987), and De Jong (1998) argued that constraints in verbal working memory negatively influence phonological decoding skills since during decodingmany segmentsmust beheld inmemory. However, theeffect of verbalworking memory on the progress during reading and spelling interventions has received scant attention. Tijms (2011) found verbal working memory to be a significant moderator for reading abilities and not for spelling abilities, whereas Tilanus and colleagues (2016) did not find direct effects of verbal working memory on reading and spelling outcomes. The present study From the research conducted so far, it can be concluded that the reading and spelling abilities of children with reading and spelling problems could benefit from the addition of spelling to a phonics intervention. However, the effectiveness of a phonics through spelling intervention in which an equal amount of time is devoted to spelling and reading is still unknown. Given the fact that children with dyslexia have problems in forming strong bi-directional relations between phonology and orthography, a phonics through spelling intervention could indeed enhance the reading and spelling abilities of children with dyslexia. Furthermore, little is known about the robustness of a phonics through spelling intervention in respect of the cognitive profile of the child. The purpose of the present study was, therefore, to measure the responsiveness of a phonics through spelling intervention among Dutch children with dyslexia. It can be hypothesized that an effect of the quality of the bi-directional relationships between phonological and orthographic representations is highly prominent in the case of a transparent orthography like Dutch. In order to find out more about the robustness of this Dutch phonics through spelling intervention, the role of individual differences among children with dyslexia will also be taken into account. Specifically, we addressed the following research questions: 1. What is the effect of a phonics through spelling intervention on pseudoword reading, word reading, and word spelling scores in Dutch children with dyslexia? 2. To what extent are the outcomes of a phonics through spelling intervention robust across different cognitive profiles? Given the fact that spelling contributes to the deeper knowledge of our sound system and prior research found transfer effects of spelling to reading, we expected that children with dyslexia would show a substantial change in their reading and spelling skills after the phonics through spelling intervention. Second, based on prior research, we expected