Robin van Rijthoven

Robin van Rijthoven COMPENSATING reading and spelling abilities in childrenwith

Compensating reading and spelling abilities in children with dyslexia Robin Wilhelmus Johannus van Rijthoven

The research presented in this thesis was carried out at the Behavioural Science Institute of the Radboud University, Nijmegen, The Netherlands. ISBN: 978-94-6458-477-6 ELECT ISBN: 987-94-6458-463-9 Cover design & lay-out: Publiss | Print: Ridderprint | © Robin Wilhelmus Johannus van Rijthoven, 2022 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, by photocopying, recording, or otherwise, without the prior written permission of the author.

Compensating reading and spelling abilities in children with dyslexia Proefschrift ter verkrijging van de graad van doctor aan de Radboud Universiteit Nijmegen op gezag van de rector magnificus prof. dr. J.H.J.M. van Krieken, volgens besluit van het college voor promoties in het openbaar te verdedigen op vrijdag 27 januari 2023, om 12.30 uur precies door Wilhelmus Johannus van Rijthoven geboren op 22 februari 1989 te Hooge en Lage Mierde

Promotoren Prof. dr. L.T.W. Verhoeven Prof. dr. P.C.J. Segers Copromotor Dr. M.A.J. Kleemans Manuscriptcommissie Prof. dr. A.M.T. Bosman (voorzitter) Prof. dr. E.H. de Bree (Universiteit Utrecht) Prof. dr. B.A.M. Maassen (Rijksuniversiteit Groningen)

“Tot op de dag van vandaag heeft het verschijnsel dyslexie mij gefascineerd en als de meest op de voorgrond tredende leerstoornis beziggehouden” Joep Dumont

Contents Chapter 1 General introduction 9 Chapter 2 Impact of semantic abilities on word decoding 31 Chapter 3 Response to phonics through spelling intervention 53 Chapter 4 Role of semantic abilities in a phonics through spelling intervention 77 Chapter 5 Compensatory role of verbal learning and consolidation in reading and spelling 103 Chapter 6 General discussion 137 Appendix Nederlandse Samenvatting (Dutch Summary) 157 Dankwoord (Acknowledgements) 164 Curriculum Vitae 172 Publications 174 Data Management and Transparency 175

10 Chapter 1 Reading and spelling abilities are crucial for school success (Savolainen et al., 2008), access to the labour market, and communication in todays (digital) knowledge society (de Greef et al., 2014). Theories regarding learning to read and spell emphasise that in order to become a proficient reader and speller, an efficient recurrent network of phonological, orthographic, and semantic representations needs to be built, which is also known as the triangular framework (e.g., Seidenberg & McClelland, 1989). A strong recurrent network enables children to decode words fluently, which is essential for the future development of reading comprehension (Stanovic, 2000; Verhoeven & Van Leeuwe, 2009). Children with developmental dyslexia (henceforward dyslexia) stay behind in their reading and spelling development and there seems to be consensus that multiple factors combine and/or interact to cause difficulties in learning to read and spell (Catts et al., 2017; McGrath et al, 2020; O’Brien & Yeatman, 2021; Pennington, 2006; Protopapas, 2019; Van Bergen et al., 2014b). This Multifactorial model of dyslexia includes causes from genetic, neural, cognitive, and environmental level (see Zuk et al., 2020). Among the factors on a cognitive level a large amount of research supports the notion that reading and spelling problems of children with dyslexia are associated with deficiencies in phonological processing (Melby-Lervåg et al., 2012; Pennington et al., 2012). As a consequence, childrenwithdyslexia oftenhave inaccurate andunderspecified phonological representations (Conrad, 2008; Nation & Snowling, 2004), which results in difficulties in accurate and fluent reading and correct spelling (Lyon et al., 2003). Besides the weaknesses associated with dyslexia, there are also several resources/strengths that foster the reading and spelling proces (Catts & Petscher, 2020) and these are important to build on when addressing weaknesses (Protopapas, 2019). It is possible that children with dyslexia to a greater extent draw upon on relative strengths in the semantic and orthographic representations, the two other parts of the triangular framework, as a way to compensate for their weak phonological pathways. When the quality of the semantic representations increases, the lexical restructuring hypothesis assumes that this may cause pressure on phonological representations be strengthened as well (Metsala & Walley, 1998). A reciprocal connection between semantic abilities and phonology in the mental lexicon (Li et al., 2004) could indicate that the development of semantic abilities may give a boost to the development of phonological abilities (Van Goch et al., 2014) and thus indirectly facilitate the process of learning to read (e.g., Van Bergen et al. 2014a) and spell (Ouellette, 2010; Tainturier & Rapp, 2001). It has also been suggested that children use their semantic knowledge to circumvent phonological decoding deficits (Haft et al., 2016) and that children at risk for developing reading problems may use their early vocabulary knowledge to compensate for deficient phonological and reading abilities (Duff et al., 2015; Hulme et al. 2010; Torppa et al., 2010). So far, the possible compensatory role of semantic abilities and the ability to expand semantic abilities among children with dyslexia received scant attention in behavioural research.

11 General introduction 1 To overcome reading and spelling problems, children with dyslexia need interventions to build strong and bi-directional phonology-orthography connections. However, most interventions thus far focused primarily on reading (see Galuschka, 2014) and thus only stimulate the orthography-phonology connections instead of stimulating the bidirectional relationship via combining both reading and spelling. As a case in point, prior research showed that spelling development benefits reading development as well (see Ehri & Wilce, 1987) and so more focus on orthographic learning could compensate for phonological shortcomings. The response to a so-called phonics through spelling intervention, aiming to enhance the bi-directional relationships between phonology and orthography, has not yet been studied and could give more insight in the benefits of adding a solid amount of spelling to an intervention for children with dyslexia. Furthermore, it is important to gain insight in relative strengths and weakness, profiles and its relation to intervention outcomes in order to optimize the (choice of) interventions and to build upon strengths to overcome difficulties (see Protopapas, 2019). In line with the reasoning above, the focus of this dissertation was to examine two sources of compensation for the phonological shortcomings underlying the reading and spelling problems of children with dyslexia: (i) enhancing semantic representations and (ii) enhancing orthographic representations bymeans of a phonics through spelling intervention. Dyslexia Learning to read and spell According to the lexical quality hypothesis (Perfetti, 2007), becoming a proficient reader or speller requires high-quality lexical representations. According to the triangular framework, phonological, orthographic, and semantic representations are built throughout literacy development, which together form an efficient and recurrent network that is necessary to read and spell efficiently (Seidenberg & McClelland, 1989). Wordswithmorehigh-qualityphonological, orthographic and semantic representations are easier to read and spell than words with lower lexical quality (Perfetti, 2007; Perfetti et al., 2005). According to the lexical quality hypothesis word representations can be characterized by two dimensions: specificity and redundancy. Lexical specificity refers to the degree to which words are specified phonologically, semantically, and orthographically. Redundancy refers to the extent that lexical representations can be retrieved from memory; lexically and/or sublexically (Perfetti, 2007). Already at young age, the foundation of literacy is laid, as children start to develop their spoken language. Children learn large numbers of words (phonological representations) and their meanings (semantic representations). By learning these words phonological and semantic representations are connected (Levelt, 1989; Levelt et al., 1999). Reading

12 Chapter 1 and spelling development builds upon this basis of representations (Shaywitz et al., 2003) as children become aware that the known words consist of speech sounds (phonological representation) that can be represented by graphemes (orthographic representation) and vice versa. This awareness of ‘phonemes’ is associated with a growing understanding of the alphabetical principle (Galuschka et al., 2014). In this phase of literacy development, children learn to recode graphemes into sounds in order to read (orthography-phonology connection) and to code phonemes into graphemes in order to spell (phonology-orthography connection). During this process, children recognize the meaning of words, which connects both phonology and orthography to the semantic representations. The more children practice the grapheme-sound correspondences, the faster the correct graphemes or sounds are retrieved from long-term memory, and decoding and coding words gets faster and more fluent. In addition, as a result of encountering printed or written words several times, children learn to read or write the whole word (or sometimes parts of words) accurately and instantly without decoding or recoding each grapheme. This process is also known as sight reading or spelling frommemory (Ehri, 2005a) and enables readers and spellers to become even more fluent. The graphemes or sounds are then immediately connected to semantic representations (see Pugh et al., 2013). Both decoding and coding as well as the sight word reading and spelling frommemory, stimulate high-quality bi-directional relationships between phonological and orthographic representations, which makes children proficient in both reading and spelling (see Ehri, 2005b; Perfetti & Hart, 2002). As can be seen throughout literacy development, reading and spelling are reversed processes, which could clarify why it has been shown in previous research among typically developing children that combining an emphasis on both reading and spelling can be beneficial for both learning to read and learning to spell (e.g., Conrad, 2008; De Graaff et al., 2009; Ehri, 2000; Ehri & Wilce, 1987; Ellis & Cataldo, 1990; Fitzgerald & Shanahan, 2000; Ise & Schulte-Körne, 2010; Ouellette & Sénéchal, 2008). Reading and spelling problems Despite the effort schools puts into learning children to read and spell, large individual differences occur in the extent to which children benefit from reading and spelling lessons. According to the lexical quality hypothesis, these differences in reading and spelling levels are mainly due to differences in the strength of the bi-directional relationship and the specificity of both phonological and orthographic representations (Perfetti & Hart, 2002). When the bi-directional relations are weaker, children may develop reading and spelling problems (Melby-Lervåg et al., 2012; Wimmer & Mayringer, 2002). This is especially the case for children with dyslexia, who read and spell at much lower levels than can be expected based on their age and educational level. Dyslexia is a specific learning disability that is characterized by difficulties in reading and spelling

13 General introduction 1 with a base in neurobiological development (American Psychiatric Association, 2013). There seems to be consensus that dyslexia can best be understood from a Multifactorial model (seeCatts&Petscher, 2020; Cattset al., 2017;McGrathet al, 2020;O’Brien&Yeatman, 2021; Pennington, 2006; Van Bergen et al., 2014b). According to the Multifactorial model multiple factors combine and/or interact and cause difficulties in learning to read and spell (see Catts & Petscher, 2020). These factors occur at genetic, neural, cognitive, and environmental level (see Zuk et al., 2020). A large amount of research supports the notion that reading and spelling problems of children with dyslexia are associated with deficiencies in phonological processing on the cognitive level (see Pugh & Verhoeven, 2018). These deficiencies are reflected in problems in manipulating speech sounds that may hamper the grasping of the alphabetic principle (Bradley & Bryant, 1983). This socalled phonological deficit seems to underlie most reading and spelling problems of children with dyslexia (Melby-Lervåg et al., 2012, Pennington et al., 2012) and causes inaccurate or underspecified phonological and orthographic representations (Conrad, 2008). This, as a result, leads to problems in accurate and fluent reading and spelling among children with dyslexia (Lyon et al., 2003). The phonological deficit is domainspecific and independent of other linguistic abilities (Shaywitz et al., 2003). Already at a preliterate age, the phonological deficit influences the development of reading and spelling. Children at risk for dyslexia have been found to lag behind in phonological awareness, rapid naming, and verbal working memory (Melby-Lervåg et al., 2012; Puolakanaho et al., 2007). Phonological awareness is the awareness of spoken sounds in a language and has been found to be related to the process of mastering the systematic grapheme-sound correspondences and contribute to accurate and fluent word decoding (Melby-Lervåg et al., 2012) and spelling (Landerl &Wimmer, 2008). Rapid automatized naming involves accurate and efficient storing of detailed phonological or orthographic information, and has been found to be closely related to word decoding as well (Georgiou et al., 2012; Norton & Wolf, 2012). Verbal working memory is the ability to store verbal information temporarily and can be a constraint when excessive demands are being made, such as is the case in reading and spelling (Swanson et al., 1996). Despite the fact that the phonological deficit is often associated with reading and spelling problems in children with dyslexia, not all children with reading and spelling problems have the same underlying deficit (Catts et al, 2017; O’Brien & Yeatman, 2021; Pennington et al., 2012; Snowling, 2008) and there is considerable variation in the causal base of reading and spelling difficulties (O’Brien & Yeatman, 2021; Pennington et al., 2012; Snowling, 2008). According to Multifactorial causal models of dyslexia, reading and spelling problems and variation in these problems could be caused by a complex interplay of weaknesses, but also strengths (Astle & Fletcher-Martin, 2020). Following a Multifactorial account of dyslexia, an important question is to what extent children with dyslexia may compensate for weaknesses with relative strengths.

14 Chapter 1 Compensatory semantic abilities in children with dyslexia Results from neuroimaging studies have indicated that children with dyslexia, in contrast to typically developing children, show differences in brain activation during reading and spelling with underactivation in the posterior regions of the brain and relative overactivation in the anterior regions of the brain (Georgiewa et al, 2002; Hoeft et al., 2007; Shaywitz et al., 2005; Turkeltaub et al., 2003). The posterior regions are associated with the phonological deficit (Brunswick et al., 1999; Georgiewa et al., 1999). The anterior regions are known for various aspects of language processing (Bookheimer, 2002), making efficient processing of language possible (Bookheimer, 2002), such as encoding new memories, retrieval and selection of declarative and procedural knowledge (Buckner et al., 2001; Ullman, 2004), and memorization of verbal information (Smith & Jonides, 1999). Based on these findings, Kearns and colleagues (2019) and Hoeft et al. (2011) suggested that children with dyslexia may use different pathways to read compared to typically developing peers in an attempt to compensate for the dysfunctions in the posterior regions of the brain. This line of reasoning fits with the idea of Multifactorial causal models of dyslexia, in which both weaknesses and strengths together determine reading and spelling levels. It is also in line with the triangular framework, in which semantic representations are reciprocally connected to both phonological and orthographic representations (Seidenberg & McClelland, 1989). When the quality of semantic representations increases, phonological representations are pressured to improve as well according to the lexical restructuring hypothesis (Metsala & Walley, 1998). Indeed, prior behavioural research found a reciprocal connection between semantic and phonological representationsin the mental lexicon (Li et al., 2004). The development of these semantic representations may therefore give a boost to the development of phonological abilities (Duff et al., 2015; Haft et al., 2016; Hulme et al. 2010; Torppa et al.; 2010; Van Goch et al., 2014) and facilitate the process of learning to read (e.g., Van Bergen et al., 2014a) and spell (Ouellette, 2010; Tainturier & Rapp, 2001). Phonological and semantic skills may influence reading development from its earliest stages and influence each other as well (e.g., Laing & Hulme, 1999). In addition, Nation and Snowling (2004) and Ouellette and Beers (2010) showed that within the typically developing readers, semantic abilities beyond phonology make important contributions to word recognition development. Furthermore, Gijsel (2007) concluded that semantic orientated reading programs worked just as well as programs that focus on phonological training only. Prior research regarding reading indeed showed the benefits of well-developed semantic representations (e.g., Gijsel, 2007; Nation & Snowling, 2004; Torppa et al., 2010) and suggested semantic representations to play a role in spelling development as well (Ouellette, 2010; Ouellette & Fraser, 2009; Tainturier & Rapp, 2001).

15 General introduction 1 In line with the lexical restructuring hypothesis, converging evidence from neuroimaging studies (e.g., Shaywitz et al., 2005) as well as the triangular framework (Seidenberg & McClelland, 1989) suggest that high-quality semantic representations could be a source of compensation for the weak orthographic and phonological representations in children with dyslexia. However, most studies regarding the role of semantic abilities in reading and spelling were performed among typically developing children, children with reading problems, or children at risk for dyslexia. Research among children with the actual diagnoses of dyslexia is currently missing. Furthermore, the existing research mostly included the broadness of vocabulary (i.e., quantity). However, in contrast to the broadness of the available semantic network, the depth of the semantic representations seems to be a better indicator of the semantic representations that are necessary in order to compensate for weaknesses in the phonological representations. To be more specific, according to the lexical quality hypothesis, semantic abilities can be defined as a fuller range of meaning dimensions to discriminate amongwords in the same semantic field (Perfetti, 2007), which is reflected in the quality of themeaning network surrounding a word (i.e., Nagy & Herman, 1987). In order to find out the compensatory role that semantic abilities can play, the depth of the semantic representations should therefore be included as well. As children with dyslexia could benefit from a well-developed semantic network, the ability to expand the specificity and redundancy of the (phonological) lexicon could be important too. In order to develop such a lexicon, one needs to be able to learn and consolidate verbally presented information in memory, processes that are also known as verbal learning and verbal consolidation (Kibby, 2009). As differences between children with dyslexia and typiccaly developing children were found in verbal learning (e.g., Elbro et al., 2005; Kibby, 2009) and in a single case also in consolidation (e.g. Kibby, 2009; Kramer et al., 2002) this could possibly be a facilitating or constraining factor causing differences in reading and spelling outcomes. Only two studies related verbal learning and consolidation (measured by verbal list learning) to reading and spelling outcomes (Kibby, 2009; Tijms, 2004) and only one study did so for verbal consolidation (Tijms, 2004). However, the debate on the compensatory role of verbal learning and consolidation can best be called inconclusive for several reasons. First, research so far, did not include a typically developing control group, nor did it control for all other important cognitive factors (phonological awareness, rapid automatized naming, verbal working memory and already acquired semantic abilities). Second, differences in conceptualization of verbal learning could have influenced the results because the operationalization of a learning measure should not reflect the result at the end of the learning process (see Tijms, 2004; Kibby, 2009) but should rather focus on the learning process itself. No prior study related this dynamic aspect of verbal learning and consolidation to reading and spelling outcomes, which is important because this shows the learning potential of semantic information that could facilitate phonological representations.

16 Chapter 1 To sum up, the Multifactorial causal model of dyslexia implies that reading and spelling difficulties are a consequence of a complex interplay of strengths and weaknesses (Astle & Fletcher-Martin, 2020) and in such a model semantic abilities could be a strength to rely on. However, despite the clear role of semantic abilities in brain studies that found overcompensation among children with dyslexia in verbal areas (e.g., Shaywitz et al., 2005) and the triangular framework (see Seidenberg & McClelland, 1989), most research regarding children with dyslexia focused on the weak bi-directional relationship between phonological and orthographic representations, instead of focusing on the possible compensatory role of broad and deep semantic abilities. Research on the role of semantic abilities is limited and mostly includes measures of broad semantic knowledge rather than the deeper knowledge that is important in order to compensate for weak phonological representations (Li et al., 2004). Moreover, the available researchmostly does not include children with the actual diagnosis of dyslexia, while specific explanations, such as a general learning disability, inadequate teaching, or sensory impairments are ruled out in the assessment and therefore a group of children with a specific reading and/ or spelling problem remains. Furthermore, besides the role of verbal abilities present in children, the possibility to learn and maintain new verbal information could be important as well. These processes take place in the overactivated areas of the brain of children with dyslexia. Research regarding learning and maintaining verbal information (verbal learning and consolidation), however, is limited and still inconclusive. Compensatory phonics through spelling intervention As reading and spelling are both very important skills (seeDeGreef et al., 2014; Savolainen et al., 2008;), children with dyslexia need help to overcome their difficulties and become better at reading and spelling by building strong and bi-directional phonologyorthography connections. Previous research showed that phonics interventions were relatively successful at helping children with reading disabilities in strengthening the connections between phonological and orthographic representations and thereby improved both reading and spelling results (see review by Galuschka et al., 2014 and meta-analysis by Ehri et al., 2001). Galuschka and colleagues (2014) showed that a phonics intervention was, compared to reading fluency training, phoneme awareness instructions, reading comprehension trainings, auditory trainings, medical treatment, and coloured overlays or lenses, the only intervention with statistical confirmed efficacy on reading and spelling. A phonics intervention (i.e., a combination of reading fluency training and phonemic awareness training) includes systematic instruction of lettersound-correspondences, decoding strategies, and the application of these skills in reading and writing activities (Galuschka et al., 2014). However, considerable individual variation in response to intervention exists (Galuschka et al., 2014) and research including both strengths and weakness profiles is limited (see Burns et al., 2016). In a subgroup

17 General introduction 1 analysis of Galuschka and colleagues (2014) it was mentioned that some studies did incorporate some writing activities, whereas other studies did not include writing activities at all. As mentioned earlier, reading and spelling are reversed processes and combining reading and spelling during instruction and practice can 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. Thus, according to Galuschka and colleagues (2014) most interventions focus on the orthography to phonology relationship instead of the bi-directional relationship that is stimulated when reading and spelling are combined. A phonics intervention that incorporates spelling is a so-called phonics through spelling intervention (as described in Ehri et al., 2001) in which the recoding process of spelling is learned in addition to the decoding process. The few studies regarding phonics through spelling intervention (i.e., phonics interventions with the inclusion of writing activities) found effects for word decoding (e.g., Tijms, 2011), pseudoword decoding (e.g., Kirk & Gillon, 2009), and spelling (e.g., Kirk & Gillon, 2009). These findings highlight the importance of a high-quality bi-directional relationship between both phonological and orthographic representations in learning to read and spell and show the benefits of a phonics through spelling intervention. As spelling is more difficult to learn than reading (Bosman & Van Orden, 1997; Ehri, 1997; O’Connor & Jenkins, 1995) one would expect that phonics through spelling interventions would include both reading and spelling instructions and divide time at least evenly. However, in the aforementioned studies very limited amounts of time were spent on spelling activities (at most onethird in Tilanus et al., 2016). Therefore, more research is needed to determine whether a phonics through spelling intervention with more time for spelling can be effective in increasing both reading and spelling levels of children with dyslexia. When including spelling it is important to start with a strong base of phonological processes in spelling based on grapheme-phoneme translation and add specific and complex orthographic processes in spelling by learning children morphological and orthographic patterns later on (Caravolas et al., 2001). For spelling, it was found that phonics, morphological, and orthographic interventions are all effective in treating spelling problems of children with dyslexia (Galuschka et al., 2020). One way of addressing phonological and orthographic errors separately is to analyze and categorize spelling errors. Spelling errors can be subdivided into three broad categories in order to define the source of the errors: phonological, morphological, and orthographic errors (Tops et al., 2014; Vanderswalmen et al., 2010). Previous studies showed that children with dyslexia (before an intervention) do not make qualitatively different, but more phonological, morphological, and orthographic spelling errors compared to typically developing children (Bourassa & Treiman, 2003; Bourassa et al., 2006). However, studies

18 Chapter 1 so far did not incorporate all three errors types (phonological, morphological, and orthographic errors) in one study in order to compare phonological and orthographic processes in spelling with one another. As known fromprevious studies, not all childrenwith dyslexia benefit from 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). In order to gain insight in which children benefit from certain interventions it is necessary to match profiles of relative strengths and weaknesses with specific intervention approaches (see also Burns et al., 2016). These profiles could include phonological awareness, rapid automatized naming, verbal working memory, semantic abilities, verbal learning, and verbal consolidation. Currently, research including effects all of the aforementioned predictors on response to phonics through spelling intervention (with time evenly spent on reading and spelling) in children with dyslexia is missing. Strengths in semantic representations or the ability to expand these could, as mentioned earlier, be sources of compensation for both reading and spelling. Furthermore, regarding individual spelling profiles of children with dyslexia, results of phonics interventions on spelling have only been expressed in the number of words written correctly, whereas comparing spelling error profiles before and after the intervention could give new insights in the phonological and orthographic processes in spelling development among children with dyslexia due to the intervention. It can thus be concluded that weak phonological abilities in children with dyslexia can be compensated by enhancing the orthographic representations and its connections with the phonological part of the recurrent network. However, more in-depth knowledge is needed regarding the spelling profiles of children with dyslexia to determine what effects phonics through spelling interventions have on spelling development of children with dyslexia. Moreover, most intervention studies regarding children with dyslexia have focused on reading or spelling whereas both processes can enhance the quality of the bidirectional relations betweenphonological and orthographic representations andbenefit each other as well. Phonics through spelling interventions (i.e., interventions in which at least 50% of the time is spent on spelling activities) could have many beneficial effects but research regarding this specific type of intervention is scarce and have not yet been related to relevant cognitive precursors (i.e., phonological awareness, rapid automatized naming, working memory, semantic abilities, and verbal learning and consolidation). Present research The present research focused on compensating reading and spelling in children with dyslexia in the Netherlands. The first goal was to examine the compensatory role of

19 General introduction 1 semantic abilities of children with dyslexia on word reading, pseudoword reading, and spelling. The second goal is to study whether strengthening the orthographic representations bymeans of a phonics through spelling intervention has positive effects on word reading, pseudoword reading, and spelling and if cognitive profiles (including phonological awareness, rapid automatized naming, working memory, semantic abilities, and verbal learning and consolidation) influence response to intervention. Diagnosis of dyslexia in the Netherlands In the Netherlands, all children learn to read and spell by means of highly structured phonics reading and spelling instructions starting from grade 1. Since Dutch is a rather transparent language (see Landerl & Wimmer, 2008) most children benefit from these instructions and learn to read and spell at appropriate levels. However, some children do not reach appropriate levels. The Netherlands has a nation-wide protocol for diagnosis of and intervention for dyslexia (Blomert, 2006). The nation-wide protocol is recently revised based on developments in research and clinical practice and this renewed protocol (Tijms et al., 2021) was implemented in January 2022. Throughout the current study, the preceding protocol was used but the results of the present study will be related to the changes in the renewed protocol in the discussion section of this thesis. The protocol used in this thesis (Blomert, 2006) states that children with severe and persistent reading problems or combined reading and spelling problems can be referred to a specialized clinic for assessment (private institutes). Teachers have to prove that the persistent and severe reading problems or combined reading and spelling problems were at place during one and a half school year (word reading scores below 10th percentile or below 15th percentile combined with spelling scores below 10th percentile). Children visit the clinic at different moments in their school carriers (varying fromgrade 2 to grade 6). In the subsequent diagnosis, a phonological deficit needs to be evidenced and other explanations of reading or spelling problems need to be excluded by a certified clinical psychologist. This is in line with the definition of dyslexia in the International Dyslexia Association (2002). After formally being diagnosed with dyslexia, children in the Netherlands receive a free, in-service intervention in a specialized clinic that aims to help these children to learn to read and spell at age-appropriate levels. During and after the intervention word reading, pseudoword reading and word spelling levels are monitored to see whether the intervention is beneficial. Design and research questions For the purpose of this study, 99 files of Dutch childrenwith dyslexiaweremade available by a clinic for assessment and intervention of children with learning difficulties in the east of the Netherlands. Parents had given active consent to use the data collected

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

21 General introduction 1 were addressed by BSc andMSc students andwhen schools agreed to participate parents were informed about the research and asked for permission. Parents of all children within the control groups gave active consent to participate in the presented studies. Outline of this thesis This thesis studied clinical data in order to find out more about two possible ways of compensating for a phonological deficit in reading and spelling development of children with dyslexia. Each chapter in the present thesis represents an empirical article. Each of these articles have been accepted for publication. The goal of Chapter 2 was to explore the direct and indirect contribution of semantic abilities to the levels of phonological and orthographical abilities in 55 children with dyslexia. Semantic abilities, phonological awareness, rapid automatized naming and, verbal working memory were included as precursor measures. In Chapter 3, an attempt was made to test the response to intervention in a phonics through spelling intervention for 54 children with dyslexia in word and pseudoword reading efficiency, and word spelling. Furthermore, we investigated to what extent the response to intervention is robust across different cognitive profiles (phonological awareness, rapid automatized naming, andworkingmemory). Response to intervention was studied using change-scores. Chapter 4 examined the differences in phonological, morphological, and orthographic spelling errors between 52 children with dyslexia and 105 typically developing spellers. Cognitive profiles (phonological awareness, rapid automatized naming, working memory, and semantic abilities) of children with dyslexia were related to these errors with a special interest for the effect of semantic abilities. Furthermore, the response to a phonics through spelling intervention was measured by studying the change in spelling errors and profiles. The change in each spelling error category was related to cognitive profiles as well, again with a special interest for the effects of semantic abilities. Chapter 5 reports about the extent to which reading and spelling performances of 54 children with dyslexia both before and after a phonics through spelling intervention were predicted by their verbal learning and consolidation. The ability to learn and maintain verbal information and its influence on reading and spelling measured before the intervention were compared to 36 typically developing children. Response to intervention was studied using change-scores.

22 Chapter 1 In Chapter 6, the key findings of this dissertation are discussed along with limitations and direction for future research and implications for practice. Finally, in the Appendix a Dutch summary of the findings from the preceding chapters was provided along with Acknowledgments, CurriculumVitae of the author, List of publications, and information about datamanagement and transparency.

23 General introduction 1 References American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Author. doi:10.1176/appi.books.9780890425596 Aravena, S., Tijms, J., Snellings, P., & Van der Molen, M. W. (2016). Predicting responsiveness to intervention in dyslexia using dynamic assessment. Learning and Individual Differences, 49, 209-215. doi:10.1016/j.lindif.2016.06.024. Astle, D., & Fletcher-Martin, S. (2020). Beyond core deficit models in developmental disorders. Current Directions in Psychological Sciences, 29, 431–437. doi:10.1177/0963721420925518 Blomert, L. (2006). Protocol dyslexie diagnostiek en behandeling. College voor Zorgverzekeringen. Blomert, L., & Vaessen, A. A. A. (2009). 3DMDifferential Diagnostiek van Dyslexie: Cognitieve Analyse van lezen en Spellen. Boom test Uitgevers. Bookheimer, S. (2002). Functional MRI of language: new approaches to understanding the cortical organization of semantic processing. Annual Review of Neuroscience, 25(1), 151-188. doi:10.1146/ annurev.neuro.25.112701.142946 Bosman, A. M., & Van Orden, G. C. (1997). Why spelling is more difficult than reading. Learning to Spell: Research, Theory, and Practice across Languages, 10, 173-194. Bourassa, D., & Treiman, R. (2003). Spelling in children with dyslexia: Analyses from the Treiman-Bourassa early spelling test. Scientific Studies of Reading, 7(4), 309-333. doi:10.1207/ S1532799XSSR0704_1 Bourassa, D. C., Treiman, R., & Kessler, B. (2006). Use of morphology in spelling by children with dyslexia and typically developing children. Memory & Cognition, 34(3), 703-714. doi:10.3758/ BF03193589 Bradley, L., & Bryant, P. E. (1983). Categorizing sounds and learning to read - a causal connection. Nature, 301, 419–421. doi:10.1038/301419a0 Brunswick, N., McCrory, E., Price, C. J., Frith, C. D., & Frith, U. (1999). Explicit and implicit processing of words and pseudowords by adult developmental dyslexics: A search for Wernicke’s Wortschatz?. Brain, 122(10), 1901-1917. doi:10.1093/brain/122.10.1901 Brus, B. T., & Voeten, M. J. M. (2010). Eén-minuut-test: vorm A en B. Berkhout. Buckner, R. L., Wheeler, M. E., & Sheridan, M. A. (2001). Encoding processes during retrieval tasks. Journal of Cognitive Neuroscience, 13(3), 406-415. doi:10.1162/08989290151137430 Burns, M.K., Petersen-Brown, S., Haegele, K., Rodriguez, M., Schmitt, B., Cooper, M., … VanDerHeyden, A. M. (2016). Meta-analysis of academic interventions derived from neuropsychological data. School Psychology Quarterly, 31(1), 28–42. doi:10.1037/spq0000117 Caravolas, M., Hulme, C., & Snowling, M. J. (2001). The foundations of spelling ability: Evidence from a 3-year longitudinal study. Journal of Memory and Language, 45(4), 751-774. doi:10.1006/ jmla.2000.2785 Catts, H. W., McIlraith, A., Bridges, M., & Nielsen, D. (2017). Viewing a phonological deficit within a multifactorial model of dyslexia. Reading &Writing, 30(3), 613–629. doi:10.1007/s11145-016-9692-2 Catts, H. W., & Petscher, Y. (2020). A Cumulative Risk and Resilience Model of Dyslexia. Journal of Learning Disabilities, 00(0), 1-14. doi:10.1177/00222194211037062 Conrad, N. J. (2008). From reading to spelling and spelling to reading: Transfer goes both ways. Journal of Educational Psychology, 100(4), 869–878. doi:10.1037/a0012544. De Graaf, S., Bosman, A. M. T., Hasselman, F., & Verhoeven, L. (2009). Benefits of systematic phonics instruction. Scientific Studies of Reading, 13(4), 318-333. doi:10.1080/ 10888430903001308 De Greef, M., Segers, M., &Nijhuis, J. (2014). Feiten en cijfers geletterdheid. Stichting Lezen & Schrijven. Duff, F. J., Reen, G., Plunkett, K., & Nation, K. (2015). Do infant vocabulary skills predict school-age language and literacy outcomes? Journal of Child Psychology and Psychiatry, 56, 848–856. doi:10.1111/jcpp.12378

24 Chapter 1 Ehri, L. C. (1997). Learning to read and learning to spell are one and the same, almost. Learning to spell: Research, Theory, and Practice across Languages, 13, 237-268. Ehri, L. C. (2000). Learning to read and learning to spell: Two sides of a coin. Topics in Language Disorders, 20(3), 19-49. doi:10.1097/00011363-200020030-0005 Ehri, L. (2005a). Development of sight word reading: Phases and findings. In M. Snowling & C. Hulme (Eds.), The science of reading: A handbook (pp. 135–1 54). Blackwell. Ehri, L. C. (2005b). Learning to read words: Theory, findings, and issues. Scientific Studies of Reading, 9(2), 167-188. doi:10.1207/s1532799xssr0902_4 Ehri, L. C., Nunes, S. R., Stahl, S. A., & Willows, D. M. (2001). Systematic phonics instruction helps students learn to read: Evidence from the National Reading Panel’s meta-analysis. Review of Educational Research, 71(3), 393-447. doi:10.3102/00346543071003393 Ehri, L. C., & Wilce, L. S. (1987). Does learning to spell help beginners learn to read words? Reading Research Quarterly, 47-65. doi:10.2307/747720. Ellis, N., & Cataldo, S. (1990). The role of spelling in learning to read. Language and Education, 4(1), 1-28. doi:10.1080/09500789009541270 Fitzgerald, J.,&Shanahan, T. (2000).Readingandwritingrelationsandtheirdevelopment. Educational Psychologist, 35(1), 39-50. doi:10.1207/S15326985EP3501_5 Galuschka, K., Görgen, R., Kalmar, J., Haberstroh, S., Schmalz, X., & Schulte-Körne, G. (2020). Effectiveness of spelling interventions for learnerswithdyslexia: Ameta-analysis and systematic review. Educational Psychologist, 55(1), 1-20. doi:10.1080/00461520.2019.1659794 Galuschka, K., Ise, E., Krick, K., & Schulte-Körne, G. (2014). Effectiveness of treatment approaches for children and adolescents with reading disabilities: A meta-analysis of randomized controlled trials. PloS one, 9(2), e89900. doi:10.1371/journal.pone.0089900 Geelhoed, J., & Reitsma, P. (1999). PI-dictee. Harcourt Test Publishers. Georgiou, G. K., Papadopoulos, T. C., Fella, A., & Parrila, R. (2012). Rapid naming speed components and reading development in a consistent orthography. Journal of Experimental Child Psychology, 112(1), 1–17. doi:10.1016/j.jecp.2011.11.006 Georgiewa, P., Rzanny, R., Gaser, C., Gerhard, U. J., Vieweg, U., Freesmeyer, D., ... & Blanz, B. (2002). Phonological processing in dyslexic children: a study combining functional imaging and event related potentials. Neuroscience Letters, 318(1), 5-8. doi:10.1016/S0304-3940(01)02236-4 Georgiewa, P., Rzanny, R., Hopf, J. M., Knab, R., Glauche, V., Kaiser, W. A., & Blanz, B. (1999). fMRI during word processing in dyslexic and normal reading children. Neuroreport, 10(16), 34593465. doi:10.1097/00001756-199911080-00036 Gijsel, M.A.R. (2007). The role of semantic abilities in early reading. PrintPartners Ipskamp. Haft, S. L., Myers, C. A., & Hoeft, F. (2016). Socio-emotional and cognitive resilience in children with reading disabilities. Current Opinion in Behavioral Sciences, 10, 133-141. doi:10.1016/j. cobeha.2016.06.005 Hoeft, F., McCandliss, B. D., Black, J. M., Gantman, A., Zakerani, N., Hulme, C., ... & Gabrieli, J. D. (2011). Neural systems predicting long-term outcome in dyslexia. Proceedings of the National Academy of Sciences, 108(1), 361-366. doi:10.1073/pnas.1008950108 Hoeft, F., Meyler, A., Hernandez, A., Juel, C., Taylor-Hill, H., Martindale, J. L., ... & Gabrieli, J. D. (2007). Functional and morphometric brain dissociation between dyslexia and reading ability. Proceedings of the National Academy of Sciences, 104(10), 4234-4239. doi:10.1073/ pnas.0609399104 Hulme, C., Nash, H. M., Gooch, D., Lervåg, A., & Snowling, M. J. (2015). The foundations of literacy development in children at familial risk of dyslexia. Psychological Science, 26, 1877–1886. doi:10.1177/0956797615603702 Ise, E., & Schulte-Körne, G. (2010). Spelling deficits in dyslexia: Evaluation of an orthographic spelling training. Annals of Dyslexia, 60(1), 18–39. doi:10.1007/s11881-010-0035-8

25 General introduction 1 Kearns, D. M., Hancock, R., Hoeft, F., Pugh, K. R., & Frost, S. J. (2019). The neurobiology of dyslexia. Teaching Exceptional Children, 51(3), 175-188. doi:10.1177/0040059918820051 Kibby, M. Y. (2009). Memory functioning in developmental dyslexia: an analysis using two clinical memory measures. Archives of Clinical Neuropsychology, 24(3), 245-254. doi:10.1093/arclin/ acp028 Kingma, A., & Van den Burg, W. (2005). Drie parallelversies van de 15-woordentest voor kinderen: handleiding & normering. Stichting Kinderneuropsychologie Noord Nederland. Kirk, C., & Gillon, G. T. (2009). Integratedmorphological awareness intervention as a tool for improving literacy. Language, Speech, and Hearing Services in Schools, 40(3), 341-351. doi:10.1044/01611461(2008/08-0009) Kort, W., Schittekatte, M., Van den Bos, K.P., Vermeir, G., Lutje Spelberg, H.C., & Verhaeghe, P., et al. (2005a). Dyslexie screening test NL. Harcourt Test Publishers. Kort, W., Schittekatte, M., Dekker, P. H., Verhaeghe, P., Compaan, E. L., Bosmans, M., & Vermeir, G. (2005b). WISC-III NL Wechsler Intelligence Scale for Children. Derde Editie NL. Handleiding en Verantwoording. Harcourt Test Publishers/Nederlands Instituut voor Psychologen. Laing, E., & Hulme, C. (1999). Phonological and semantic processes influence beginning readers’ ability to learn to read words. Journal of Experimental Child Psychology, 73(3), 183-207. doi:10.1006/jecp.1999.2500 Landerl, K., & Wimmer, H. (2008). Development of word reading fluency and spelling in a consistent orthography: an 8-year follow-up. Journal of Educational Psychology, 100(1), 150. doi:10.1037/0022-0663.100.1.150 Levelt, W. J. M. (1989) Speaking: From Intention to Articulation. MIT Press. doi:10.7551/ mitpress/6393.001.0001 Levelt, W. J. M., Roelofs, A., & Meyer, A. S. (1999). A theory of lexical access in speech production. Behavioral and Brain Sciences, 22(1), 1-38. doi:10.1017/S0140525X99001776 Li, P., Farkas, I., & MacWhinney, B. (2004). Early lexical development in a self-organizing neural network. Neural Networks, 17(8-9), 1345-1362. doi:10.1016/j.neunet.2004.07.004. Lyon, G. R., Shaywitz, S. E., & Shaywitz, B. A. (2003). A definition of dyslexia. Annals of Dyslexia, 53(1), 1–14. doi:10.1007/s11881-003-0001-9 McGrath,L.M.,Peterson,R.L.,&Pennington,B.F. (2020).Themultipledeficitmodel:Progress,problems and prospects. Scientific Studies in Reading, 24, 7–13. doi:10.108 0/10888438.2019.1706180 Metsala, J. L., & Walley, A. C. (1998). Spoken vocabulary growth and the segmental restructuring of lexical representations: Precursors to phonemic awareness and early reading ability. In J. L. Metsala & L. C. Ehri (Eds.), Word recognition in beginning literacy (pp. 89–120). Erlbaum doi:10.4324/9781410602718-9. Melby-Lervåg, M., Lyster, S. A. H., & Hulme, C. (2012). Phonological skills and their role in learning to read: a meta-analytic review. Psychological Bulletin, 138(2), 322. doi:10.1037/a0026744. Nagy, W. E., & Herman, P. A. (1987). Breadth and depth of vocabulary knowledge: Implications for acquisition and instruction. The Nature of Vocabulary Acquisition, 19, 35. Nation, K., & Snowling, M. J. (2004). Beyond phonological skills: Broader language skills contribute to the development of reading. Journal of Research in Reading, 27(4), 342-356. doi:10.1111/j.14679817.2004.00238.x Norton, E. S., & Wolf, M. (2012). Rapid automatized naming (RAN) and reading fluency: Implications for understanding and treatment of reading disabilities. Annual Review of Psychology, 63, 427452. doi:10.1146/annurev-psych-120710-100431 O’Brien, G., & Yeatman, J. (2021). Bridging the sensory and language theories of dyslexia: Toward a multifactorial model. Developmental Science, 24, e13039. doi:10.1111/ desc.13039 O’Connor, R. E., & Jenkins, J. R. (1995). Improving the generalization of sound/symbol knowledge: Teaching spelling to kindergarten children with disabilities. The Journal of Special Education, 29(3), 255-275. doi:10.1177/002246699502900301