Robin van Rijthoven

57 Response to phonics through spelling intervention 3 and word spelling. Pseudoword reading was not included in this study. The training with the whole-word approach showed more transfer to untrained content. Finally, Kirk and Gillon (2009) tested the effectiveness of a training by sorting tasks and spelling with prompts with a control condition among 16 children with spelling problems. The experimental group significantly gained in pseudoword reading and spelling accuracy and was able to generalize their trained skills to new words. No effects were found on word reading. Two studies examined the benefits of adding spelling activities to a phonics intervention for children with dyslexia in the Netherlands. Tilanus and colleagues (2016) examined a group of 54 children with dyslexia, who had received a 12-week intervention. Approximately one-third of the instruction time was spent on writing activities. Compared to typically developing peers, positive effects were found of this intervention on pseudoword reading accuracy and efficiency and spelling, but not on word reading accuracy or efficiency. Furthermore, Tijms (2011) tested the effectiveness of a computer-based phonics intervention including both reading and spelling activities among 99 children diagnosed with dyslexia. Significant gains were found, and after the intervention word reading accuracy and spelling levels were comparable to the lower bound of normal range. Robustness of the intervention Not all children with dyslexia benefit from phonics interventions to the same extent, and individual differences in responsiveness have been reported repeatedly (see, e.g., Galuschka et al., 2014; Singleton, 2009; Snowling & Hayiou-Thomas, 2006; Torgesen, 2006). Attempts have been made to relate the responsiveness to intervention to the cognitive profile of the child. Given the fact that dyslexia can be characterized by an underlying phonological deficit, phonological awareness, rapid automatized naming, and verbal working memory are generally considered cognitive precursor measures that may also predict children’s responsiveness to intervention (Shaywitz et al., 2003; Snowling, 1998). In line with the double deficit hypothesis (as described by Wolf & Bowers, 1999), it is argued that phonological awareness and rapid automatized naming can be seen as critical sources of reading impairment (Landerl & Wimmer, 2008). Prior research on the robustness of response-to-intervention effects showed that decoding accuracy training effects were sustained across individual differences in phonological awareness (Felton, 1993; Tijms, 2011) and that reading fluency training was robust across individual differences in rapid automatized naming training (Heikkilä, 2015). Combiningaccuracy andfluency trainingalso showed robustness across individual differences in both phonological awareness and rapid automatized naming (Aravena et