Not all reading disabilities are dyslexia: distinct neurobiology of specific comprehension deficits

The relation between reading and externalizing behavior: a correlational meta-analysis

Reading proficiency is important because it has life-long consequences and influences success in other academic areas. Many students with behavior problems are poor readers and many students with learning disabilities have more behavior problems than their typical peers. We conducted a correlational meta-analysis to examine the association between reading and externalizing behavior in students ages 5-12. We identified 33 studies that reported 88 effect sizes. Using a random-effects linear regression model with robust variance estimation, we found a significant, negative correlation (r= -0.1698, SE = 0.01, p < 0.0001) between reading and externalizing behavior. We tested several moderators related to measurement and sample characteristics. We found that rater type, behavior dimension (e.g., aggression), time between longitudinal measurement points, age of the sample, and percentage male of the sample moderated the relation between reading and behavior. Whether the reading assessment measured comprehension or word reading and socioeconomic status of the sample did not moderate the relation. Understanding the association between reading and externalizing behavior has implications for disability identification and intervention practices for children in elementary school. Future research should examine shared cognitive factors and environmental influences that explain the relation between the constructs.

Reading comprehension improvement in autism

Introduction

A subset of autistic children excel at word decoding but have difficulty with reading comprehension (i.e., the discrepant poor comprehender reading profile). Prior research suggests the Visualizing and Verbalizing (V/V) for language comprehension and thinking intervention helps improve reading comprehension in autistic children with this reading profile. Previous studies have demonstrated the role of vocabulary, memory, and social functioning in reading comprehension; however, predictors and moderators of reading comprehension within this specific profile of autistic readers have not been thoroughly explored.

Methods

In this study, we examined the effectiveness of the V/V intervention by comparing reading comprehension scores between groups and across time. Participants included a sample of autistic children (AUT-EXP; n=22) and a waitlist control group of autistic children (AUT-WLC; n=17) with reading comprehension difficulties, as well as a sample of non-autistic children (Non-AUT; n=26) (all age 8-13 years). AUT-EXP and AUT-WLC groups completed a battery of cognitive assessments during pre and post tests. We also analyzed whether cognitive assessment scores predicted reading comprehension, and examined the moderating effects of group (AUT-EXP vs. AUT-WLC) on these relationships.

Results

The AUT-EXP group significantly improved in their pre to post reading comprehension scores (t(21)=4.19, p<.001, d=.89), whereas the AUT-WLC group did not. Verbal memory significantly predicted reading comprehension, though group did not moderate relationships between cognitive test performance and reading comprehension.

Discussion

Results suggest that the V/V intervention may help improve reading comprehension for autistic children with the discrepant poor comprehender reading profile. Additionally, strategies for improving verbal memory may indirectly enhance reading comprehension in autistic children with this reading profile.

Executive functions-based reading training engages the cingulo-opercular and dorsal attention networks

The aim of this study was to determine the effect of a computerized executive functions (EFs)-based reading intervention on neural circuits supporting EFs and visual attention. Seed-to-voxel functional connectivity analysis was conducted focusing on large-scale attention system brain networks, during an fMRI reading fluency task. Participants were 8- to 12-year-old English-speaking children with dyslexia (n = 43) and typical readers (n = 36) trained on an EFs-based reading training (n = 40) versus math training (n = 39). Training duration was 8 weeks. After the EFs-based reading intervention, children with dyslexia improved their scores in reading rate and visual attention (compared to math intervention). Neurobiologically, children with dyslexia displayed an increase in functional connectivity strength after the intervention between the cingulo-opercular network and occipital and precentral regions. Noteworthy, the functional connectivity indices between these brain regions showed a positive correlation with speed of processing and visual attention scores in both pretest and posttest. The results suggest that reading improvement following an EFs-based reading intervention involves neuroplastic connectivity changes in brain areas related to EFs and primary visual processing in children with dyslexia. Our results highlight the need for training underlying cognitive abilities supporting reading, such as EFs and visual attention, in order to enhance reading abilities in dyslexia.

Examination of common and unique brain regions for atypical reading and math: a meta-analysis

The purpose of this study is to identify consistencies across functional neuroimaging studies regarding common and unique brain regions/networks for individuals with reading difficulties (RD) and math difficulties (MD) compared to typically developing (TD) individuals. A systematic search of the literature, utilizing multiple databases, yielded 116 functional magnetic resonance imaging and positron emission tomography studies that met the criteria. Coordinates that directly compared TD with either RD or MD were entered into GingerALE (Brainmap.org). An activation likelihood estimate (ALE) meta-analysis was conducted to examine common and unique brain regions for RD and MD. Overall, more studies examined RD (n = 96) than MD (n = 20). Across studies, overactivation for reading and math occurred in the right insula and inferior frontal gyrus for atypically developing (AD) > TD comparisons, albeit in slightly different areas of these regions; however, inherent threshold variability across imaging studies could diminish overlying regions. For TD > AD comparisons, there were no similar or overlapping brain regions. Results indicate there were domain-specific differences for RD and MD; however, there were some similarities in the ancillary recruitment of executive functioning skills. Theoretical and practical implications for researchers and educators are discussed.

Deep Learning Classification of Reading Disability with Regional Brain Volume Features

Developmental reading disability is a prevalent and often enduring problem with varied mechanisms that contributes to its phenotypic heterogeneity. This mechanistic and phenotypic variation, as well as relatively modest sample sizes, may have limited the development of accurate neuroimaging-based classifiers for reading disability, including because of the large feature space of neuroimaging datasets. An unsupervised learning model was used to reduce deformation-based data to a lower-dimensional manifold and then supervised learning models were used to classify these latent representations in a dataset of 96 reading disability cases and 96 controls (mean age: 9.86 ± 1.56). A combined unsupervised autoencoder and supervised convolutional neural network approach provided an effective classification of cases and controls (accuracy: 77%; precision: 0.75; recall: 0.78). Brain regions that contributed to this classification accuracy were identified by adding noise to the voxel-level image data, which showed that reading disability classification accuracy was most influenced by the superior temporal sulcus, dorsal cingulate, and lateral occipital cortex. Regions that were most important for the accurate classification of controls included the supramarginal gyrus, orbitofrontal, and medial occipital cortex. The contribution of these regions reflected individual differences in reading-related abilities, such as non-word decoding or verbal comprehension. Together, the results demonstrate an optimal deep learning solution for classification using neuroimaging data. In contrast with standard mass-univariate test results, results from the deep learning model also provided evidence for regions that may be specifically affected in reading disability cases.

Distinct neural correlates of poor decoding and poor comprehension in children with reading disability

Reading disability (RD) can manifest itself as a word decoding problem or a reading comprehension problem. In the current study, we identified 3 subtypes of RD: poor decoders (PD), poor comprehenders (PC), and poor-in-both (PB). We found that PD had greater deficits in meta-linguistic skills such as phonological awareness, orthographic skills, and morphological skills than PC, whereas PC had greater deficits in listening comprehension than PD. In the brain, we also found different patterns of deficits during an auditory rhyming judgment task using functional magnetic resonance imaging. PD showed less activation than PC and age controls in the left dorsal inferior frontal gyrus (IFG) and pre-supplementary motor area (SMA), brain activation of which was correlated with phonological awareness and working memory. In contrast, PC showed less activation in the left fusiform gyrus than PD and age controls, which was correlated with reading comprehension fluency and morphological skill. Last, PB showed both PD's and PC's deficits, as well as additional deficits in the bilateral lingual gyri. Our findings contribute to revealing different neural signatures of poor decoding and poor comprehension, which are distinct disorders but co-occur very often. These findings implicate possibility and necessity of precise diagnosis and individualized intervention.

Neural pathways of phonological and semantic processing and its relations to children's reading skills

Behavioral research shows that children's phonological ability is strongly associated with better word reading skills, whereas semantic knowledge is strongly related to better reading comprehension. However, most neuroscience research has investigated how brain activation during phonological and semantic processing is related to word reading skill. This study examines if connectivity during phonological processing in the dorsal inferior frontal gyrus (dIFG) to posterior superior temporal gyrus (pSTG) pathway is related to word reading skill, whereas connectivity during semantic processing in the ventral inferior frontal gyrus (vIFG) to posterior middle temporal gyrus (pMTG) pathway is related to reading comprehension skill. We used behavioral and functional magnetic resonance imaging (fMRI) data from a publicly accessible dataset on OpenNeuro.org. The research hypotheses and analytical plan were pre-registered on the Open Science Framework. Forty-six children ages 8-15 years old were included in the final analyses. Participants completed an in-scanner reading task tapping into phonology (i.e., word rhyming) and semantics (i.e., word meaning) as well as standardized measures of word reading and reading comprehension skill. In a series of registered and exploratory analyses, we correlated connectivity coefficients from generalized psychophysiological interactions (gPPI) with behavioral measures and used z-scores to test the equality of two correlation coefficients. Results from the preregistered and exploratory analyses indicated weak evidence that functional connectivity of dIFG to pSTG during phonological processing is positively correlated with better word reading skill, but no evidence that connectivity in the vIFG-pMTG pathway during semantic processing is related to better reading comprehension skill. Moreover, there was no evidence to support the differentiation between the dorsal pathway's relation to word reading and the ventral pathway's relation to reading comprehension skills. Our finding suggesting the importance of phonological processing to word reading is in line with prior behavioral and neurodevelopmental models.

Researcher-practitioner partnerships and in-school laboratories facilitate translational research in reading

Educational neuroscience approaches have helped to elucidate the brain basis of Reading Disability (RD) and of reading intervention response; however, there is often limited translation of this knowledge to the broader scientific and educational communities. Moreover, this work is traditionally lab-based, and thus the underlying theories and research questions are siloed from classroom practices. With growing awareness of the neurobiological origins of RD and increasing popularity of putative "brain-based" approaches in clinics and classrooms, it is imperative that we create more direct and bidirectional communication between scientists and practitioners. Such direct collaborations can help dispel neuromyths, and lead to increased understanding of the promises and pitfalls of neuroscience approaches. Moreover, direct partnerships between researchers and practitioners can lead to greater ecological validity in study designs to improve upon the translational potential of findings. To this end, we have forged collaborative partnerships, and built cognitive neuroscience laboratories within independent reading disabilities schools. This approach affords frequent and ecologically valid neurobiological assessment as children's reading improves in response to intervention. It also permits the creation of dynamic models of leading and lagging relationships of students' learning, and identification of individual-level predictors of intervention response. The partnerships also provide in-depth knowledge of student characteristics and classroom practices, which, when combined with the data we acquire, may facilitate optimization of instructional approaches. In this commentary, we discuss the creation of our partnerships, the scientific problem we are addressing (variable response to reading intervention), and the epistemological significance of researcher-practitioner bi-directional learning.

A meta-analytic review of comprehension deficits in students with dyslexia

Beyond the established difficulties of individuals with dyslexia in word recognition and spelling, it remains unclear how severe their difficulties in comprehension are. To examine this, we performed a meta-analytic review. A random-effects model analysis of data from 76 studies revealed a large deficit in reading comprehension in individuals with dyslexia compared to their chronological-age (CA) controls (g = 1.43) and a smaller one compared to their reading-level (RL) matched controls (g = 0.64). Individuals with dyslexia also differed significantly from their CA controls in listening comprehension (g = 0.43). Results further showed significant heterogeneity in the effect sizes that was partly explained by orthographic consistency (the deficits were larger in languages with low orthographic consistency) and vocabulary matching (the deficits were larger in studies in which the groups were not matched on vocabulary). These findings suggest, first, that individuals with dyslexia experience significant difficulties in both reading and listening comprehension, but the effect sizes are smaller than those reported in the literature for word reading and spelling. Second, our findings suggest that the deficits in reading comprehension are likely a combination of deficits in both decoding and oral language skills.

Public misconceptions about dyslexia: The role of intuitive psychology

Despite advances in its scientific understanding, dyslexia is still associated with rampant public misconceptions. Here, we trace these misconceptions to the interaction between two intuitive psychological principles: Dualism and Essentialism. We hypothesize that people essentialize dyslexia symptoms that they anchor in the body. Experiment 1 shows that, when dyslexia is associated with visual confusions (b/d reversals)—symptoms that are naturally viewed as embodied (in the eyes), laypeople consider dyslexia as more severe, immutable, biological, and heritable, compared to when dyslexia is linked to difficulties with phonological decoding (a symptom seen as less strongly embodied). Experiments 2–3 show that the embodiment of symptoms plays a causal role in promoting essentialist thinking. Experiment 2 shows that, when participants are provided evidence that the symptoms of dyslexia are embodied (i.e., they “show up” in a brain scan), people are more likely to consider dyslexia as heritable compared to when the same symptoms are diagnosed behaviorally (without any explicit evidence for the body). Finally, Experiment 3 shows that reasoning about the severity of dyslexia symptoms can be modulated by manipulating people’s attitudes about the mind/body links, generally. These results show how public attitudes towards psychological disorders arise from the very principles that make the mind tick.

Faces and words are both associated and dissociated as evidenced by visual problems in dyslexia

Faces and words are traditionally assumed to be independently processed. Dyslexia is also traditionally thought to be a non-visual deficit. Counter to both ideas, face perception deficits in dyslexia have been reported. Others report no such deficits. We sought to resolve this discrepancy. 60 adults participated in the study (24 dyslexic, 36 typical readers). Feature-based processing and configural or global form processing of faces was measured with a face matching task. Opposite laterality effects in these tasks, dependent on left-right orientation of faces, supported that they tapped into separable visual mechanisms. Dyslexic readers tended to be poorer than typical readers at feature-based face matching while no differences were found for global form face matching. We conclude that word and face perception are associated when the latter requires the processing of visual features of a face, while processing the global form of faces apparently shares minimal-if any-resources with visual word processing. The current results indicate that visual word and face processing are both associated and dissociated-but this depends on what visual mechanisms are task-relevant. We suggest that reading deficits could stem from multiple factors, and that one such factor is a problem with feature-based processing of visual objects.

Words as Visual Objects: Neural and Behavioral Evidence for High-Level Visual Impairments in Dyslexia

Developmental dyslexia is defined by reading impairments that are disproportionate to intelligence, motivation, and the educational opportunities considered necessary for reading. Its cause has traditionally been considered to be a phonological deficit, where people have difficulties with differentiating the sounds of spoken language. However, reading is a multidimensional skill and relies on various cognitive abilities. These may include high-level vision—the processes that support visual recognition despite innumerable image variations, such as in viewpoint, position, or size. According to our high-level visual dysfunction hypothesis, reading problems of some people with dyslexia can be a salient manifestation of a more general deficit of high-level vision. This paper provides a perspective on how such non-phonological impairments could, in some cases, cause dyslexia. To argue in favor of this hypothesis, we will discuss work on functional neuroimaging, structural imaging, electrophysiology, and behavior that provides evidence for a link between high-level visual impairment and dyslexia.

Convergent and divergent brain structural and functional abnormalities associated with developmental dyslexia

Brain abnormalities in the reading network have been repeatedly reported in individuals with developmental dyslexia (DD); however, it is still not totally understood where the structural and functional abnormalities are consistent/inconsistent across languages. In the current multimodal meta-analysis, we found convergent structural and functional alterations in the left superior temporal gyrus across languages, suggesting a neural signature of DD. We found greater reduction in grey matter volume and brain activation in the left inferior frontal gyrus in morpho-syllabic languages (e.g. Chinese) than in alphabetic languages, and greater reduction in brain activation in the left middle temporal gyrus and fusiform gyrus in alphabetic languages than in morpho-syllabic languages. These language differences are explained as consequences of being DD while learning a specific language. In addition, we also found brain regions that showed increased grey matter volume and brain activation, presumably suggesting compensations and brain regions that showed inconsistent alterations in brain structure and function. Our study provides important insights about the etiology of DD from a cross-linguistic perspective with considerations of consistency/inconsistency between structural and functional alterations.

Literacy-supporting skills in college students with specific reading comprehension deficit and developmental language disorder

Specific reading comprehension deficit (S-RCD) and developmental language disorder (DLD) are both commonly occurring developmental disorders of language. The ways in which these disorders do and do not overlap during childhood are a matter of debate (Nation & Norbury, 2005). Moreover, in both populations, the challenges faced by individuals in adulthood are understudied. Here, we combined data across cohorts of college students, and classified individuals with only S-RCD (n = 20), only DLD (n = 55), and co-occurring S-RCD and DLD (n = 13). Individuals with good language and reading skills, who matched those with S-RCD on decoding, comprised our typical language and reading group (TD; n = 20). Beyond the measures used for classification, group-level differences were identified in sentence-level reading fluency, phonological processing, verbal working memory, and rapid automatized naming. We found that skill profiles differed across groups; however, we found no evidence of weaknesses beyond the core deficit in reading comprehension observed in those with only S-RCD. In contrast, when S-RCD co-occurs with DLD, weaknesses are observed in phonological processing, as well as reading fluency and verbal working memory. These findings suggest that some adults with S-RCD have co-occurring DLD as a core weakness. These findings, as well as differences between individuals with S-RCD and DLD, are further discussed.

Sleep-dependent consolidation in children with comprehension and vocabulary weaknesses: it'll be alright on the night?

BACKGROUND

Vocabulary is crucial for an array of life outcomes and is frequently impaired in developmental disorders. Notably, 'poor comprehenders' (children with reading comprehension deficits but intact word reading) often have vocabulary deficits, but underlying mechanisms remain unclear. Prior research suggests intact encoding but difficulties consolidating new word knowledge. We test the hypothesis that poor comprehenders' sleep-associated vocabulary consolidation is compromised by their impoverished lexical-semantic knowledge.

METHODS

Memory for new words was tracked across wake and sleep to assess encoding and consolidation in 8-to-12-year-old good and poor comprehenders. Each child participated in two sets of sessions, one beginning in the morning (AM-encoding) and the other in the evening (PM-encoding). In each case, they were taught 12 words and were trained on a spatial memory task. Memory was assessed immediately, 12- and 24-hr later via stem-completion, picture-naming, and definition tasks to probe different aspects of word knowledge. Long-term retention was assessed 1-2 months later.

RESULTS

Recall of word-forms improved over sleep and postsleep wake, as measured in both stem-completion and picture-naming tasks. Counter to hypotheses, deficits for poor comprehenders were not observed in consolidation but instead were seen across measures and throughout testing, suggesting a deficit from encoding. Variability in vocabulary knowledge across the whole sample predicted sleep-associated consolidation, but only when words were learned early in the day and not when sleep followed soon after learning.

CONCLUSIONS

Poor comprehenders showed weaker memory for new words than good comprehenders, but sleep-associated consolidation benefits were comparable between groups. Sleeping soon after learning had long-lasting benefits for memory and may be especially beneficial for children with weaker vocabulary. These results provide new insights into the breadth of poor comprehenders' vocabulary weaknesses, and ways in which learning might be better timed to remediate vocabulary difficulties.

Pinyin Is an Effective Proxy for Early Screening for Mandarin-Speaking Children at Risk of Reading Disorders

Reading disorders (RD) are common and complex neuropsychological conditions associated with decoding printed words and/or reading comprehension. Early identification of children at risk of RD is critical to allow timely interventions before mental suffering and reading impairment take place. Chinese is a unique medium for studying RD because of extra efforts required in reading acquisition of characters based on meaning rather than phonology. Pinyin, an alphabetic coding system mapping Mandarin sounds to characters, is important to develop oral language skills and a promising candidate for early screening for RD. In this pilot study, we used a cohort of 100 students (50 each in Grades 1 and 2) to derive novel profiles of applying Pinyin to identify early schoolers at risk of RD. Each student had comprehensive reading related measures in two consecutive years, including Pinyin reading and reading comprehension tested in the first and second year, respectively. We showed that Pinyin reading was mainly determined by phonological awareness, was well developed in Grade 1 and the top predictor of reading comprehension (explaining ∼30% of variance, p < 1.0e-05). Further, students who performed poorly in Pinyin reading [e.g. 1 standard deviation (SD) below the average, counting 14% in Grade 1 and 10% in Grade 2], tended to perform poorly in future reading comprehension tests, including all four individuals in Grade 1 (two out of three in Grade 2) who scored 1.5 SDs below the average. Pinyin is therefore an effective proxy for early screening for Mandarin-speaking children at risk of RD.

Understanding, educating, and supporting children with specific learning disabilities: 50 years of science and practice

Specific learning disabilities (SLDs) are highly relevant to the science and practice of psychology, both historically and currently, exemplifying the integration of interdisciplinary approaches to human conditions. They can be manifested as primary conditions-as difficulties in acquiring specific academic skills-or as secondary conditions, comorbid to other developmental disorders such as attention-deficit hyperactivity disorder. In this synthesis of historical and contemporary trends in research and practice, we mark the 50th anniversary of the recognition of SLDs as a disability in the United States. Specifically, we address the manifestations, occurrence, identification, comorbidity, etiology, and treatment of SLDs, emphasizing the integration of information from the interdisciplinary fields of psychology, education, psychiatry, genetics, and cognitive neuroscience. SLDs, exemplified here by specific word reading, reading comprehension, mathematics, and written expression disabilities, represent spectrum disorders, each occurring in approximately 5% to 15% of the school-aged population. In addition to risk for academic deficiencies and related functional social, emotional, and behavioral difficulties, those with SLDs often have poorer long-term social and vocational outcomes. Given the high rate of occurrence of SLDs and their lifelong negative impact on functioning if not treated, it is important to establish and maintain effective prevention, surveillance, and treatment systems involving professionals from various disciplines trained to minimize the risk and maximize the protective factors for SLDs. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

The impact of expressive language development and the left inferior longitudinal fasciculus on listening and reading comprehension

BACKGROUND

During the first 3-years of life, as the brain undergoes dramatic growth, children begin to develop speech and language. Hallmarks of this progression are seen when children reach developmental milestones, forming the foundation of language. Expressive language milestones, such as the production of a child's first word, are delayed in 5-8% of children. While for some children delays in reaching these milestones are harbingers of developmental disorders, for others expressive language delays appear to resolve. Regardless of whether or not early language skills appear resolved, difficulty with later comprehension is a likely outcome. Whether this heightened risk for poor comprehension differs based on text features, individual characteristics, or receipt of intervention remains unknown. Moreover, this relationship between expressive language development and comprehension is not yet linked to neurobiology, though the inferior longitudinal fasciculus (ILF) is a potential neurobiological correlate. Therefore, we investigated the impact of, and interactions between, expressive language development, early intervention, and the ILF on comprehension.

METHODS

Longitudinal recurrent survival analyses predicted the risk of answering a comprehension question incorrectly. Predictors of comprehension included expressive language development, passage features, participant characteristics, fractional anisotropy, receipt of early intervention, and later diagnosis of speech or language disorders.

RESULTS

Children with later expressive language milestones had poorer comprehension. When comprehension text features were examined, children with later milestones had poorer listening and reading comprehension, and poorer narrative and expository comprehension. The left ILF acted as a neurodevelopmental correlate, one that moderated the relationship between expressive language milestones and comprehension. Specifically, the left ILF exacerbated the relationship for those who did not receive early intervention and buffered the relationship for those who received intervention services. Early intervention decreased the risk of poor comprehension by 39% for children later diagnosed with a speech or language disorder.

CONCLUSIONS

Early intervention should be provided for children with delayed expressive language milestones, particularly those who are at risk for speech or language disorders. The ILF plays a critical role in the relationship between expressive language development and comprehension, which may be that of a protective factor for children with the most severe early issues with speech and language.

Cognitive, Intervention, and Neuroimaging Perspectives on Executive Function in Children With Reading Disabilities

The role of executive function (EF) in the reading process, and in those with reading difficulties, remains unclear. As members of the Texas Center for Learning Disabilities, we review multiple perspectives regarding EF in reading and then summarize some of our recent studies of struggling and typical readers in grades 3-5. Study 1a found that a bi-factor structure best represented a comprehensive assessment of EF. Study 1b found that cognitive and behavioral measures of EF related independently to math and reading. Study 1c found that EF related to reading, above and beyond other variables, but Study 1d found no evidence that adding an EF training component improved intervention response. Study 1e found that pretest EF abilities did not relate to intervention response. Neuroimaging studies examined EF-related brain activity during both reading and nonlexical EF tasks. In Study 2a, the EF task evoked control activity, but generated no differences between struggling and typical readers. The reading task, however, had group differences in both EF and reading regions. In Study 2b, EF activity during reading at pretest was related to intervention response. Across studies, EF appears involved in the reading process. There is less evidence for general EF predicting or improving intervention outcomes.

A molecular-genetic and imaging-genetic approach to specific comprehension difficulties in children

Children with poor reading comprehension despite typical word reading skills were examined using neuropsychological, genetic, and neuroimaging data collected from the Genes, Reading and Dyslexia Study of 1432 Hispanic American and African American children. This unexpected poor comprehension was associated with profound deficits in vocabulary, when compared to children with comprehension skills consistent with their word reading. Those with specific comprehension difficulties were also more likely to have RU2Short alleles of READ1 regulatory variants of DCDC2, strongly associated with reading and language difficulties. Subjects with RU2Short alleles showed stronger resting state functional connectivity between the right insula/inferior frontal gyrus and the right supramarginal gyrus, even after controlling for potentially confounding variables including genetic ancestry and socioeconomic status. This multi-disciplinary approach advances the current understanding of specific reading comprehension difficulties, and suggests the need for interventions that are more appropriately tailored to the specific comprehension deficits of this group of children.

Cortical regions supporting reading comprehension skill for single words and discourse

A substantial amount of variation in reading comprehension skill is explained by listening comprehension skill, suggesting tight links between printed and spoken discourse processing. In addition, both word level (e.g., vocabulary) and discourse-level sub-skills (e.g., inference-making) support overall comprehension. However, while these contributions to variation in comprehension skill have been well-studied behaviorally, the underlying neurobiological basis of these relationships is less well understood. In order to examine the neural bases of individual differences in reading comprehension as a function of input modality and processing level, we examined functional neural activation to both spoken and printed single words and passages in adolescents with a range of comprehension skill. Data driven Partial Least Squares Correlation (PLSC) analyses revealed that comprehension skill was positively related to activation in a number of regions associated with discourse comprehension and negatively related to activation in regions associated with executive function and memory across processing levels and input modalities.

Control Engagement During Sentence and Inhibition fMRI Tasks in Children With Reading Difficulties

Recent reading research implicates executive control regions as sites of difference in struggling readers. However, as studies often employ only reading or language tasks, the extent of deviation in control engagement in children with reading difficulties is not known. The current study investigated activation in reading and executive control brain regions during both a sentence comprehension task and a nonlexical inhibitory control task in third-fifth grade children with and without reading difficulties. We employed both categorical (group-based) and individual difference approaches to relate reading ability to brain activity. During sentence comprehension, struggling readers had less activation in the left posterior temporal cortex, previously implicated in language, semantic, and reading research. Greater negative activity (relative to fixation) during sentence comprehension in a left inferior parietal region from the executive control literature correlated with poorer reading ability. Greater comprehension scores were associated with less dorsal anterior cingulate activity during the sentence comprehension task. Unlike the sentence task, there were no significant differences between struggling and nonstruggling readers for the nonlexical inhibitory control task. Thus, differences in executive control engagement were largely specific to reading, rather than a general control deficit across tasks in children with reading difficulties, informing future intervention research.

Brain basis of cognitive resilience: Prefrontal cortex predicts better reading comprehension in relation to decoding

OBJECTIVE

The ultimate goal of reading is to understand written text. To accomplish this, children must first master decoding, the ability to translate printed words into sounds. Although decoding and reading comprehension are highly interdependent, some children struggle to decode but comprehend well, whereas others with good decoding skills fail to comprehend. The neural basis underlying individual differences in this discrepancy between decoding and comprehension abilities is virtually unknown.

METHODS

We investigated the neural basis underlying reading discrepancy, defined as the difference between reading comprehension and decoding skills, in a three-part study: 1) The neuroanatomical basis of reading discrepancy in a cross-sectional sample of school-age children with a wide range of reading abilities (Experiment-1; n = 55); 2) Whether a discrepancy-related neural signature is present in beginning readers and predictive of future discrepancy (Experiment-2; n = 43); and 3) Whether discrepancy-related regions are part of a domain-general or a language specialized network, utilizing the 1000 Functional Connectome data and large-scale reverse inference from Neurosynth.org (Experiment-3).

RESULTS

Results converged onto the left dorsolateral prefrontal cortex (DLPFC), as related to having discrepantly higher reading comprehension relative to decoding ability. Increased gray matter volume (GMV) was associated with greater discrepancy (Experiment-1). Region-of-interest (ROI) analyses based on the left DLPFC cluster identified in Experiment-1 revealed that regional GMV within this ROI in beginning readers predicted discrepancy three years later (Experiment-2). This region was associated with the fronto-parietal network that is considered fundamental for working memory and cognitive control (Experiment-3).

INTERPRETATION

Processes related to the prefrontal cortex might be linked to reading discrepancy. The findings may be important for understanding cognitive resilience, which we operationalize as those individuals with greater higher-order reading skills such as reading comprehension compared to lower-order reading skills such as decoding skills. Our study provides insights into reading development, existing theories of reading, and cognitive processes that are potentially significant to a wide range of reading disorders.

Prefrontal mediation of the reading network predicts intervention response in dyslexia

A primary challenge facing the development of interventions for dyslexia is identifying effective predictors of intervention response. While behavioral literature has identified core cognitive characteristics of response, the distinction of reading versus executive cognitive contributions to response profiles remains unclear, due in part to the difficulty of segregating these constructs using behavioral outputs. In the current study we used functional neuroimaging to piece apart the mechanisms of how/whether executive and reading network relationships are predictive of intervention response. We found that readers who are responsive to intervention have more typical pre-intervention functional interactions between executive and reading systems compared to nonresponsive readers. These findings suggest that intervention response in dyslexia is influenced not only by domain-specific reading regions, but also by contributions from intervening domain-general networks. Our results make a significant gain in identifying predictive bio-markers of outcomes in dyslexia, and have important implications for the development of personalized clinical interventions.

The Importance of the Left Occipitotemporal Cortex in Developmental Dyslexia

Purpose of Review

Developmental dyslexia is characterized by an impaired acquisition of fluent and skilled reading ability. Numerous studies have explored the neural correlates of this neurodevelopmental disorder, with most classic accounts strongly focussing on left temporoparietal regions. We will review recent findings from structural and functional MRI studies that suggest a more important role of occipitotemporal cortex abnormalities in dyslexia.

Recent Findings

Recent findings highlight the role of the occipitotemporal cortex which exhibits functional as well as structural abnormalities in dyslexic readers and in children at risk for dyslexia and suggest a more central role for the occipitotemporal cortex in the pathophysiology of dyslexia.

Summary

We demonstrate the importance of the occipitotemporal cortex in for understanding impaired reading acquisition and point out how future research might enhance our understanding of functional and structural impairments in the reading network via large-scale data analysis approaches.

Recognizing Psychiatric Comorbidity With Reading Disorders

Reading disorder (RD), a specific learning disorder (SLD) of reading that includes impairment in word reading, reading fluency, and/or reading comprehension, is common in the general population but often is not comprehensively understood or assessed in mental health settings. In education settings, comorbid mental and associated disorders may be inadequately integrated into intervention plans. Assessment and intervention for RD may be delayed or absent in children with frequently co-occurring mental disorders not fully responding to treatment in both school and mental health settings. To address this oversight, this review summarizes current knowledge regarding RDs and common comorbid or co-occurring disorders that are important for mental health and school settings. We chose to highlight RD because it is the most common SLD, and connections to other often comorbid disorders have been more thoroughly described in the literature. Much of the literature we describe is on decoding-based RD (or developmental dyslexia) as it is the most common form of RD. In addition to risk for academic struggle and social, emotional, and behavioral problems, those with RD often show early evidence of combined or intertwined Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition childhood disorders. These include attention deficit hyperactivity disorder, anxiety and depression, disruptive, impulse-control, and conduct disorders, autism spectrum disorders, and other SLDs. The present review highlights issues and areas of controversy within these comorbidities, as well as directions for future research. An interdisciplinary, integrated approach between mental health professionals and educators can lead to comprehensive and targeted treatments encompassing both academic and mental health interventions. Such targeted treatments may contribute to improved educational and health-related outcomes in vulnerable youth. While there is a growing research literature on this association, more studies are needed of when to intervene and of the early and long-term benefits of comprehensive intervention.

Neuropsychology of Learning Disabilities: The Past and the Future

Over the past 50 years, research on children and adults with learning disabilities has seen significant advances. Neuropsychological research historically focused on the administration of tests sensitive to brain dysfunction to identify putative neural mechanisms underlying learning disabilities that would serve as the basis for treatment. Led by research on classifying and identifying learning disabilities, four pivotal changes in research paradigms have produced a contemporary scientific, interdisciplinary, and international understanding of these disabilities. These changes are (1) the emergence of cognitive science, (2) the development of quantitative and molecular genetics, (3) the advent of noninvasive structural and functional neuroimaging, and (4) experimental trials of interventions focused on improving academic skills and addressing comorbid conditions. Implications for practice indicate a need to move neuropsychological assessment away from a primary focus on systematic, comprehensive assessment of cognitive skills toward more targeted performance-based assessments of academic achievement, comorbid conditions, and intervention response that lead directly to evidence-based treatment plans. Future research will continue to cross disciplinary boundaries to address questions regarding the interaction of neurobiological and contextual variables, the importance of individual differences in treatment response, and an expanded research base on (a) the most severe cases, (b) older people with LDs, and (c) domains of math problem solving, reading comprehension, and written expression. (JINS, 2017, 23, 930-940).

Consolidation of vocabulary during sleep: The rich get richer?

Sleep plays a role in strengthening new words and integrating them with existing vocabulary knowledge, consistent with neural models of learning in which sleep supports hippocampal transfer to neocortical memory. Such models are based on adult research, yet neural maturation may mean that the mechanisms supporting word learning vary across development. Here, we propose a model in which children may capitalise on larger amounts of slow-wave sleep to support a greater demand on learning and neural reorganisation, whereas adults may benefit from a richer knowledge base to support consolidation. Such an argument is reinforced by the well-reported "Matthew effect", whereby rich vocabulary knowledge is associated with better acquisition of new vocabulary. We present a meta-analysis that supports this association between children's existing vocabulary knowledge and their integration of new words overnight. Whilst multiple mechanisms likely contribute to vocabulary consolidation and neural reorganisation across the lifespan, we propose that contributions of existing knowledge should be rigorously examined in developmental studies. Such research has potential to greatly enhance neural models of learning.

Understanding specific reading comprehension deficit: A review

A substantial population of children and adolescents struggle with reading comprehension despite adequate phonemic decoding (word-level reading) and intellectual ability. Individuals with this pattern of performance are considered to have specific reading comprehension deficit(S-RCD).Despite two decades of study on the profiles of behavioral performance associated with S-RCD, there is no current consensus on the causal mechanisms of the disorder. Recent progress in identifying such mechanisms includes studies that have utilized comprehension age match and longitudinal designs which have identified several comprehension subskills that are predictive of S-RCD development. However, disagreement persists over which deficits are core to S-RCD, which are comorbid and which are simply a consequence of poor comprehension. Further, almost no research on this disorder has sought to identify neurobiological endophenotypes that may enhance our understanding of causal mechanisms. Here, we offer a review of the literature on core language and higher-level language deficits associated with S-RCD, including studies that examine the neurobiological basis of this disorder. What emerges is a relatively consistent pattern of subclinical impairments across a range of comprehension subskills that may put pressure on the complex process of reading comprehension. These subskills include semantic and grammatical processing, inference making, and other higher-level language skills such as comprehension monitoring. This disorder also appears to have a neurobiological basis, though further study is needed to establish the precise disruption in neurocircuitry. Suggestions for further research include the continued use of online, temporally-sensitive measures such as eye-tracking and event-related potential, additional studies of the neurobiology of the disorder, as well as longitudinal tracking and identification of early behavioral and brain markers for S-RCD prior to formal schooling.

Anomalous gray matter patterns in specific reading comprehension deficit are independent of dyslexia

Specific reading comprehension deficit (SRCD) affects up to 10 % of all children. SRCD is distinct from dyslexia (DYS) in that individuals with SRCD show poor comprehension despite adequate decoding skills. Despite its prevalence and considerable behavioral research, there is not yet a unified cognitive profile of SRCD. While its neuroanatomical basis is unknown, SRCD could be anomalous in regions subserving their commonly reported cognitive weaknesses in semantic processing or executive function. Here we investigated, for the first time, patterns of gray matter volume difference in SRCD as compared to DYS and typical developing (TD) adolescent readers (N = 41). A linear support vector machine algorithm was applied to whole brain gray matter volumes generated through voxel-based morphometry. As expected, DYS differed significantly from TD in a pattern that included features from left fusiform and supramarginal gyri (DYS vs. TD: 80.0 %, p < 0.01). SRCD was well differentiated not only from TD (92.5 %, p < 0.001) but also from DYS (88.0 %, p < 0.001). Of particular interest were findings of reduced gray matter volume in right frontal areas that were also supported by univariate analysis. These areas are thought to subserve executive processes relevant for reading, such as monitoring and manipulating mental representations. Thus, preliminary analyses suggest that SRCD readers possess a distinct neural profile compared to both TD and DYS readers and that these differences might be linked to domain-general abilities. This work provides a foundation for further investigation into variants of reading disability beyond DYS.

White matter and reading deficits after pediatric traumatic brain injury: A diffusion tensor imaging study

Pediatric traumatic brain injury often results in significant long-term deficits in mastery of reading ability. This study aimed to identify white matter pathways that, when damaged, predicted reading deficits in children. Based on the dual-route model of word reading, we predicted that integrity of the inferior fronto-occipital fasciculus would be related to performance in sight word identification while integrity of the superior longitudinal fasciculus would be related to performance in phonemic decoding. Reading fluency and comprehension were hypothesized to relate to the superior longitudinal fasciculus, inferior fronto-occipital fasciculus, and cingulum bundle. The connectivity of white matter pathways was used to predict reading deficits in children aged 6 to 16 years with traumatic brain injury (n = 29) and those with orthopedic injury (n = 27) using tract-based spatial statistics. Results showed that children with traumatic brain injury and reduced microstructural integrity of the superior longitudinal fasciculus demonstrated reduced word-reading ability on sight word and phonemic decoding tasks. Additionally, children with traumatic brain injury and microstructural changes involving the cingulum bundle demonstrated reduced reading fluency. Results support the association of a dorsal pathway via the superior longitudinal fasciculus with both sight word reading and phonemic decoding. No association was identified between the inferior fronto-occipital fasciculus and sight word reading or phonemic decoding. Reading fluency was associated with the integrity of the cingulum bundle. These findings support dissociable pathways predicting word reading and fluency using Diffusion Tensor Imaging and provide additional information for developing models of acquired reading deficits by specifying areas of brain damage which may predict reading deficits following recovery from the acute phase of TBI.

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We apply models of white matter and reading ability to pediatric brain trauma.

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We report dissociable effects for integrity of specific white matter pathways and specific reading skills following injury.

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We report a relationship between the cingulum bundle and reading ability.

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The implications of these findings are discussed in terms of brain-based reading models as they relate to brain injury.

Involvement of the right hemisphere in reading comprehension: a DTI study

The Simple View of reading emphasizes the critical role of two factors in normal reading skills: word recognition and reading comprehension. The current study aims to identify the anatomical support for aspects of reading performance that fall within these two components. Fractional anisotropy (FA) values were obtained from diffusion tensor images in twenty-one typical adolescents and young adults using the tract based spatial statistics (TBSS) method. We focused on the arcuate fasciculus (AF) and inferior longitudinal fasciculus (ILF) as fiber tracts that connect regions already implicated in the distributed cortical network for reading. Our results demonstrate dissociation between word-level and narrative-level reading skills: the FA values for both left and right ILF were correlated with measures of word reading, while only the left ILF correlated with reading comprehension scores. FA in the AF, however, correlated only with reading comprehension scores, bilaterally. Correlations with the right AF were particularly robust, emphasizing the contribution of the right hemisphere, especially the frontal lobe, to reading comprehension performance on the particular passage comprehension test used in this study. The anatomical dissociation between these reading skills is supported by the Simple View theory and may shed light on why these two skills dissociate in those with reading disorders.

Learning and cognitive disorders: multidiscipline treatment approaches

This article provides a select review of treatments for addressing reading disorder, mathematics disorder, disorder of written expression, auditory processing disorder, and poor working memory. This information will be valuable to practitioners in determining the suitability of certain treatments for these various disorders and problems, which has direct implications for providing comprehensive, multidisciplinary treatment for youth.