Robin van Rijthoven

143 General discussion 6 differences could not influence the impact of the intervention. However, we did find a relationship between phonological awareness (a prime indicator of the phonological deficit, see Shaywitz et al., 2003) and posttest scores. It could be the case that the phonics through spelling intervention helped children with dyslexia to overcome their reading and spelling problems up to the level of their genetically disposed phonological deficit. This could indicate that children with dyslexia have room for improvement despite the severity of their phonological deficit, but after the intervention, children with the weakest phonological abilities (i.e., the most severe phonological deficit) remain the weakest readers and spellers. The only factor that was found to influence the response to intervention of spelling (more specifically the decline in spelling errors) was semantic abilities. Earlier studies showed promising effects of integrating semantic abilities in spelling interventions (Ouellette, 2010; Ouellette & Fraser, 2009) and this study adds to this literature by showing the positive relationship between pre-existing semantic representations and spelling development during a phonics through spelling intervention. From a lexical quality perspective, this can be interpreted as a way of compensation or facilitation of the growth of the phonology-orthography connection, that is necessary for spelling as described in the triangular framework (Seidenberg & McClelland, 1989). A more dynamic approach towards semantic abilities by means of verbal learning and consolidation did not influence the response to intervention of children with dyslexia. A possible relation of verbal learning and spelling was found before the intervention but did not continue to influence the spelling development throughout the intervention. We may speculate that a tailored intervention diminishes the need for compensation for weaker spelling abilities via verbal learning because children are able to integrate visual codes, phonological structures and to retrieve this phonological information which enables them to read and spell more fluently (Price & Friston 1997; Simos et al., 2002). The positive effects of a phonics through spelling intervention that were found, support the hypothesis that combining spelling and reading in one intervention helps to build strong bi-directional relations between phonology and orthography and thereby benefits reading and spelling development. In line with other studies including spelling in phonics interventions (see Kirk & Gillon, 2009; Tijms et al., 2011), we showed that phonics through spelling interventions are relatively successful in helping children with dyslexia in strengthening the connections between phonological and orthographic representations and thereby improved both reading and spelling results. As mentioned before, reading and spelling are reversed processes and combining reading and spelling during instruction and practice could be beneficial for both learning to read and learning to spell (e.g., Conrad, 2008) as better orthographic representations (e.g., spelling) could facilitate phonological growth. Although promising results were found, this study also showed the persistence of spelling but evenmore so of reading problems