Deaf signers and hearing non-signers have previously been shown to recruit partially different brain regions during simple arithmetic. In light of the triple code model, the differences were interpreted as relating to stronger recruitment of the verbal system of numerical processing, that is, left angular and inferior frontal gyrus, in hearing non-signers, and of the quantity system of numerical processing, that is, right horizontal intraparietal sulcus, for deaf signers. The main aim of the present study was to better understand similarities and differences in the neural correlates supporting arithmetic in deaf compared to hearing individuals. Twenty-nine adult deaf signers and 29 hearing non-signers were enrolled in an functional magnetic resonance imaging study of simple and difficult subtraction and multiplication. Brain imaging data were analyzed using whole-brain analysis, region of interest analysis, and functional connectivity analysis. Although the groups were matched on age, gender, and nonverbal intelligence, the deaf group performed generally poorer than the hearing group in arithmetic. Nevertheless, we found generally similar networks to be involved for both groups, the only exception being the involvement of the left inferior frontal gyrus. This region was activated significantly stronger for the hearing compared to the deaf group but showed stronger functional connectivity with the left superior temporal gyrus in the deaf, compared to the hearing, group. These results lend no support to increased recruitment of the quantity system in deaf signers. Perhaps the reason for performance differences is to be found in other brain regions not included in the original triple code model.

Teaching phoneme awareness to children at risk for early reading difficulties has been recognized as successful in several studies. In this randomized controlled trial (RCT)-study, we add to this research by optimizing core procedural as well as teaching components in a phonics-directed intervention and extend the RCT reading intervention research into a semi-transparent language context. The aim of the present study was to evaluate the effects of a novel Swedish intensive phonics program. This randomized controlled pre-test and post-test intervention study targeted second-grade students with early reading difficulties. Students were identified by a repeated screening procedure and allocated to intervention (n = 34) and control (n = 34) conditions. A 9-week intensive phonics-based program was administrated one-to-one, by special education teachers in Swedish mainstream elementary schools. Results show an improvement in the intervention group, compared with the controls on all outcome measures. Findings indicate that the supplementary phonics program, delivered with high intensity, can significantly increase word reading skills and reading comprehension in second-grade students with early reading difficulties.

PurposeUsing data from 1,868 children from the US, Australia, and Sweden who took a 10-word spelling test in kindergarten and a standardized spelling test in Grades 1, 2, and (except for the Australian children) Grade 4, we examined two questions. First, does the quality of a childs errors on the kindergarten test help predict later spelling performance even after controlling for the number of correct responses on the kindergarten test? Second, does spelling develop at a faster pace in Swedish than in English?MethodWe measured kindergarten error quality based on the number of letter additions, deletions, and substitutions by which each error differed from the correct spelling. Using mixed-model analyses, we examined the relationship of this and other variables to later spelling performance.ResultsKindergarten error quality contributed significantly to the prediction of later spelling performance even after consideration of the number of correct spellings in kindergarten and other relevant variables. The Swedish children showed more rapid growth in spelling than the U.S. and Australian children, a difference that may reflect the greater transparency of sound-to-spelling links in Swedish.ConclusionInformation from a spelling test that is typically discarded - information about the nature of the errors -has value.

We investigated the stability and developmental interplay of word reading and spelling in samples of Swedish (N = 191) and U.S. children (N = 489) followed across four time points: end of kindergarten, grades 1, 2, and 4. Cross-lagged path models revealed that reading and spelling showed moderate to strong autoregressive effects, with reading being more predictable over time than spelling. Regarding the developmental interplay, we found a bidirectional relationship between reading and spelling from kindergarten to Grade 1. However, starting in Grade 1, reading predicted subsequent spelling beyond the autoregressor but not the other way around. In all analyses, the findings were similar across the two orthographies. The theoretical and practical implications of these findings are discussed.

Decoding abilities in individuals with intellectual disabilities (ID) are substantially lower than for typical readers. The underlying mechanisms of their poor reading remain uncertain. The aim of this study was to investigate the concurrent predictors of decoding ability in 136 adolescents with non-specific ID, and to evaluate the results in relation to previous findings on typical readers. The study included a broad range of cognitive and language measures as predictors of decoding ability. A LASSO regression analysis identified phonological awareness and rapid automatized naming (RAN) as the most important predictors. The predictors explained 57.73% of the variance in decoding abilities. These variables are similar to the ones found in earlier research on typically developing children, hence supporting our hypothesis of a delayed rather than a different reading profile. These results lend some support to the use of interventions and reading instructions, originally developed for typically developing children, for children and adolescents with non-specific ID.

Reading comprehension difficulties are common in individuals with intellectual disabilities (ID), but the influences of underlying abilities related to reading comprehension in this group have rarely been investigated. One aim of this study was to investigate the Simple View of Reading as a theoretical framework to describe cognitive and linguistic abilities predicting individual differences in reading comprehension in adolescents with non-specific ID. A second aim was to investigate whether predictors of listening comprehension and reading comprehension suggest that individuals with ID have a delayed pattern of development (copying early grade variance in reading comprehension) or a different pattern of development involving a new or an unusual pattern of cognitive and linguistic predictors. A sample of 136 adolescents with non-specific ID was assessed on reading comprehension, decoding, linguistic, and cognitive measures. The hypotheses were evaluated using structural equation models. The results showed that the Simple View of Reading was not applicable in explaining reading comprehension in this group, however, the concurrent predictors of comprehension (vocabulary and phonological executive-loaded working memory) followed a delayed profile.

We have previously shown that deaf signers recruit partially different brain regions during simple arithmetic compared to a group of hearing non-signers, despite similar performance. Specifically, hearing individuals show more widespread activation in brain areas that have been related to the verbal system of numerical processing, i.e., the left angular and inferior frontal gyrus, whereas deaf individuals engaged brain areas that have been related to the quantity system of numerical processing, i.e., the right horizontal intraparietal sulcus. This indicates that compared to hearing non-signers, deaf signers can successfully make use of processes located in partially different brain areas during simple arithmetic. In this study, which is a conceptual replication and extension of the above-presented study, the main aim is to understand similarities and differences in neural correlates supporting arithmetic in deaf compared to hearing individuals. The primary objective is to investigate the role of the right horizontal intraparietal gyrus, the left inferior frontal gyrus, the hippocampus, and the left angular gyrus during simple and difficult arithmetic and how these regions are connected to each other. A second objective is to explore what other brain regions support arithmetic in deaf signers. Up to 34 adult deaf signers and the same amount of hearing non-signers will be enrolled in an functional magnetic resonance imaging study that will include simple and difficult subtraction and multiplication. Brain imaging data will be analyzed using whole-brain analysis, region of interest analysis and connectivity analysis. This is the first study to investigate neural underpinnings of arithmetic of different difficulties in deaf individuals.

We investigated the double-deficit hypothesis (DDH) in samples of U.S. (N = 489), Australian (N = 264), and Scandinavian (N = 293) children followed from preschool to grade 2. Children were assigned to double deficit, single deficit and no deficit subtypes in preschool, kindergarten, and grade 1 and compared on reading and spelling in grades 1 and 2. In most analyses, the double deficit subtype scored significantly lower in reading and spelling than the single deficits, a pattern of findings that was identical across samples. Moreover, across countries, RAN deficits showed a stronger effect on reading whereas PA deficits showed stronger effects on spelling. Overall, the results supported the basic premises of the DDH suggesting that the double deficit subtype represents the most impaired readers, and that RAN and PA are separable deficits with different effects on reading and spelling. The results also supported a universal view of literacy development, with similar predictive patterns of DDH subtypes across orthographies.

Fifty-six specific poor reading comprehenders (SPRC) were selected in Grade 4 and retrospectively compared to good comprehenders at preschool (age 5) and at the end of kindergarten, Grade 1, and Grade 2. The results revealed deficits in vocabulary, grammar, verbal memory and early deficits in phonological awareness in most of the SPRC sample, beginning in preschool. The reading comprehension deficits in children with SPRC were not as marked in earlier assessments in Grade 1 and 2, probably because of the greater dependence on word decoding in reading comprehension in the early grades.

Fifty-six specific poor reading comprehenders (SPRC) were selected in grade 4 and retrospectively compared to good comprehenders at preschool age 5 and at the end of kindergarten, grade 1 and 2. The results showed a widespread language-deficit profile in children with SPRC, including deficits in vocabulary, grammar, verbal memory and early phonological awareness in a large part of the sample beginning in preschool. The reading comprehension deficits in children with SPRC were not as apparent in earlier assessments at grade 1 and 2, likely because of the greater dependence on word decoding in reading comprehension in the early grades.

The aim of the present thesis was to examine the cognitive and language profile in children with poor reading comprehension using a longitudinal perspective. Even though comprehension skills are closely connected to educational success, comprehension deficits in children have been neglected in reading research. Understanding factors underlying reading is important as it improves possibilities of early identification of children at risk of developing reading problems. In addition, targeted interventions may prevent or reduce future problems. Descriptions of the cognitive and language profile in children with different types of reading problems from an early age and over time is an important first step.

The three studies included in this thesis have been conducted using data from the International Longitudinal Twin Study (ILTS). In the ILTS, parallel data have been collected in the US, Australia, Sweden and Norway. Altogether, more than 1000 twin pairs have been examined between the ages 5 and 15 years using well known predictors of reading, along with decoding, spelling, reading comprehension and oral language measures.

In the three studies, the Simple View of Reading has been used as a theoretical framework and children who exhibited different kinds of comprehension related difficulties have been identified at different ages. The studies include both retrospective and prospective analyses. The results across studies indicated a robust oral language deficit in all subtypes displaying comprehension problems. The oral language deficit was widespread and included vocabulary, grammar and verbal memory. In addition, the oral language deficit was manifested as compromised phonological awareness and print knowledge prior to reading instruction. Reading comprehension deficits were late emerging across studies in children with comprehension difficulties.

Compromised reading comprehension will invariably influence future academic achievements. In reading research there has been an emphasis on early identification of poor decoders to reduce future difficulties. Only a few studies have examined preschool prediction of reading comprehension impairments beyond the first grades of school, and these studies have presented different patterns of results. As studies have mostly been conducted in English; it is unclear how the results generalize to languages with transparent orthographies. In this study, a Swedish and a Norwegian twin sample were used to predict reading comprehension and decoding impairments in grade 2, 4 and 8/9 from preschool. The results suggested an important role for RAN and verbal memory. Compromised RAN was consistently associated with the poor decoders, as well as in identifying poor reading comprehenders in grade 8/9. Verbal memory tasks at preschool contributed to the identification of children with reading comprehension impairment across grades.

Two groups of fourth-grade children were selected from a population sample (N = 926) to be either poor oral comprehenders (poor oral comprehension but normal word decoding) or poor decoders (poor decoding but normal oral comprehension). By examining both groups in the same study with varied cognitive and literacy predictors, and examining them both retrospectively and prospectively, we could assess how distinctive and stable the predictors of each deficit are. Predictors were assessed retrospectively at preschool and at the end of kindergarten, Grade 1, and Grade 2. Group effects were significant at all test occasions, including those for preschool vocabulary (worse in poor oral comprehenders) and rapid automatized naming (RAN) (worse in poor decoders). Preschool RAN and vocabulary prospectively predicted Grade 4 group membership (77–79% correct classification) within the selected samples. Reselection in preschool of “at-risk” poor decoder and poor oral comprehender subgroups based on these variables led to significant but relatively weak prediction of subtype membership at Grade 4. Implications of the predictive stability of our results for identification and intervention of these important subgroups are discussed.

Human implicit learning can be investigated with implicit artificial grammar learning, a paradigm that has been proposed as a simple model for aspects of natural language acquisition. In the present study we compared the typical yes–no grammaticality classification, with yes–no preference classification. In the case of preference instruction no reference to the underlying generative mechanism (i.e., grammar) is needed and the subjects are therefore completely uninformed about an underlying structure in the acquisition material. In experiment 1, subjects engaged in a short-term memory task using only grammatical strings without performance feedback for 5 days. As a result of the 5 acquisition days, classification performance was independent of instruction type and both the preference and the grammaticality group acquired relevant knowledge of the underlying generative mechanism to a similar degree. Changing the grammatical stings to random strings in the acquisition material (experiment 2) resulted in classification being driven by local substring familiarity. Contrasting repeated vs. non-repeated preference classification (experiment 3) showed that the effect of local substring familiarity decreases with repeated classification. This was not the case for repeated grammaticality classifications. We conclude that classification performance is largely independent of instruction type and that forced-choice preference classification is equivalent to the typical grammaticality classification.