Robin van Rijthoven

70 Chapter 3 building strong bi-directional relations between phonology and orthography and thereby benefits reading and spelling development. With respect to the second research question, it was shown that the results of the intervention onword reading, pseudoword reading, and spelling after a phonics through spelling intervention were robust to variation in cognitive profiles (e.g., phonological awareness, rapid automatized naming, and verbal working memory). In other words, the phonics through spelling intervention on average appears to work notwithstanding the variation in cognitive-linguistic profiles within the group of children with dyslexia. These findings are in line with other studies demonstrating the robustness of reading interventions focusing on decoding accuracy training for phonological awareness (Felton, 1993; Tijms, 2011), fluency training for rapid automatized naming (Heikkilä, 2015), and the combination of both decoding accuracy and fluency into one training for phonological awareness, rapid automatized naming (Aravena et al., 2016; Tilanus et al., 2016), and verbal working memory (Tilanus et al., 2016). It is interesting to note that the variation in perceptual cognitive skills and pretest scores did not influence the pseudoword or word reading change scores. Both control variables had small but significant effects on spelling change scores. The positive effect of perceptual cognitive skills found on spelling is in line with findings among typically developing children (Landerl & Wimmer, 2008). The negative effect of spelling pretest scores on the change in spelling scores after a phonics through spelling intervention could indicate a small but significant reverse Matthew effect. This is in line with findings from Aarnoutse and colleagues (2001), who found that low performers in spelling benefit most from instruction. It is possible that the children with lower spelling scores at pretest had more trouble building up a strong and bi-directional network of phonological and orthographic representations by themselves. The phonics through spelling intervention may have helped them to build this network and thereby overcome some of the problems. The unique character of the present study is the relatively large amount of time spent on spelling in order to strengthen the bi-directional relation between phonological and orthographic representations as described by Bosman and Van Orden (1997). Although children in this study significantly improved and many were no longer among the weakest 10% in word reading and spelling, it is important to note that most children remain weak readers and spellers compared to typically developing controls and large variation in reading and spelling levels is present even after the intervention. Interestingly, posttest scores, andnot pretest scores for worddecoding andword spelling were found to be related to phonological awareness that is seen as a prime indicator