Acquired spatial dyslexia is a reading disorder frequently occurring after left or right posterior brain lesions. This article describes several types of spatial dyslexia with an attentional approach. After right posterior lesions, patients show left neglect dyslexia with errors on the left side of text, words, and non-words. The deficit is frequently associated with left unilateral spatial neglect. Severe left neglect dyslexia can be detected with unlimited exposure duration of words or non-words. Minor neglect dyslexia is detected with brief presentation of bilateral words, one in the left and one in the right visual field (phenomenon of contralesional extinction). Neglect dyslexia can be explained as a difficulty in orienting attention to the left side of verbal stimuli. With left posterior lesions, spatial dyslexia is also frequent but multiform. Right neglect dyslexia is frequent, but right unilateral spatial neglect is rare. Attentional dyslexia represents difficulty in selecting a stimulus, letter or word among other similar stimuli; it is a deficit of attentional selection, and the left hemisphere plays a crucial role in selection. Two other types of spatial dyslexia can be found after left posterior lesions: paradoxical ipsilesional extinction and stimulus-centred neglect dyslexia. Disconnections between left or right parietal attentional areas and the left temporal visual word form area could explain these deficits. Overall, a model of attention dissociating modulation, selection control, and selection positioning can help in understanding these reading disorders.
Schattka, Kerstin I.; Radach, Ralph; Huber, Walter
Based on recent progress in theory and measurement techniques, the analysis of eye movements has become one of the major methodological tools in experimental reading research. Our work uses this approach to advance the understanding of impaired information processing in acquired central dyslexia of stroke patients with aphasia. Up to now there has…
Woollams, Anna M.
Acquired dyslexia offers a unique window on to the nature of the cognitive and neural architecture supporting skilled reading. This paper provides an integrative overview of recent empirical and computational work on acquired dyslexia within the context of the primary systems framework as implemented in connectionist neuropsychological models. This view proposes that damage to general visual, phonological or semantic processing abilities are the root causes of different forms of acquired dyslexia. Recent case-series behavioural evidence concerning pure alexia, phonological dyslexia and surface dyslexia that supports this perspective is presented. Lesion simulations of these findings within connectionist models of reading demonstrate the viability of this approach. The commitment of such models to learnt representations allows them to capture key aspects of performance in each type of acquired dyslexia, particularly the associated non-reading deficits, the role of relearning and the influence of individual differences in the premorbid state of the reading system. Identification of these factors not only advances our understanding of acquired dyslexia and the mechanisms of normal reading but they are also relevant to the complex interactions underpinning developmental reading disorders. PMID:24324241
Woollams, Anna M
Acquired dyslexia offers a unique window on to the nature of the cognitive and neural architecture supporting skilled reading. This paper provides an integrative overview of recent empirical and computational work on acquired dyslexia within the context of the primary systems framework as implemented in connectionist neuropsychological models. This view proposes that damage to general visual, phonological or semantic processing abilities are the root causes of different forms of acquired dyslexia. Recent case-series behavioural evidence concerning pure alexia, phonological dyslexia and surface dyslexia that supports this perspective is presented. Lesion simulations of these findings within connectionist models of reading demonstrate the viability of this approach. The commitment of such models to learnt representations allows them to capture key aspects of performance in each type of acquired dyslexia, particularly the associated non-reading deficits, the role of relearning and the influence of individual differences in the premorbid state of the reading system. Identification of these factors not only advances our understanding of acquired dyslexia and the mechanisms of normal reading but they are also relevant to the complex interactions underpinning developmental reading disorders.
Raman, Ilhan; Weekes, Brendan S.
The Turkish script is characterised by completely transparent bidirectional mappings between orthography and phonology. To date, there has been no reported evidence of acquired dyslexia in Turkish speakers leading to the naive view that reading and writing problems in Turkish are probably rare. We examined the extent to which phonological…
... de los dientes Video: Getting an X-ray Dyslexia KidsHealth > For Kids > Dyslexia Print A A A ... look like this: What's It Like to Have Dyslexia? Even before kindergarten, a kid who has dyslexia ...
... What's It Like to Have Dyslexia? Even before kindergarten, a kid who has dyslexia usually has trouble ... The Nemours Foundation, iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and Clipart. ...
It is stated that dyslexia is a disorder of auditory origin. The meaning of dyslexia is divided into the medical and educational aspects of the disease in an attempt to lead the teacher to emphasize hearing in education rather than merely sight. The role of the teacher, doctor, and psychologist in the history of dyslexia is discussed. In dealing…
Riley, Ellyn Anne
Individuals with acquired phonological dyslexia experience difficulty associating written letters with their corresponding sounds, especially in pseudowords. Several studies have attempted to improve reading in this population by training letter-to-sound correspondence, general phonological skills, or a combination of these approaches; however,…
Senaha, Mirna Lie Hosogi; de Mattos Pimenta Parente, Maria Alice
The Japanese language is represented by two different codes: syllabic and logographic while Portuguese employs an alphabetic writing system. Studies on bilingual Portuguese-Japanese individuals with acquired dyslexia therefore allow an investigation of the interaction between reading strategies and characteristics of three different writing codes. The aim of this study was to examine the differential impact of an acquired brain lesion on the reading of the logographic, syllabic and alphabetic writing systems of a bilingual Portuguese-Japanese aphasic patient (PF). Results showed impaired reading in the logographic system and when reading irregularly spelled Portuguese words but no effects on reading regular words and nonwords in syllabic and alphabetic writing systems. These dissociations are interpreted according to a multi-route cognitive model of reading assuming selective damage in the lexical route can result in acquired dyslexia across at least three different writing codes. PMID:22713387
... as "piece of cake" meaning "easy" Difficulty with time management Difficulty summarizing a story Trouble learning a foreign ... with severe dyslexia may never have an easy time reading, but he or she can learn skills that improve reading. Academic problems don't necessarily mean a person with ...
Ablinger, Irene; von Heyden, Kerstin; Vorstius, Christian; Halm, Katja; Huber, Walter; Radach, Ralph
Due to their brain damage, aphasic patients with acquired dyslexia often rely to a greater extent on lexical or segmental reading procedures. Thus, therapy intervention is mostly targeted on the more impaired reading strategy. In the present work we introduce a novel therapy approach based on real-time measurement of patients' eye movements as they attempt to read words. More specifically, an eye movement contingent technique of stepwise letter de-masking was used to support sequential reading, whereas fixation-dependent initial masking of non-central letters stimulated a lexical (parallel) reading strategy. Four lexical and four segmental readers with acquired central dyslexia received our intensive reading intervention. All participants showed remarkable improvements as evident in reduced total reading time, a reduced number of fixations per word and improved reading accuracy. Both types of intervention led to item-specific training effects in all subjects. A generalisation to untrained items was only found in segmental readers after the lexical training. Eye movement analyses were also used to compare word processing before and after therapy, indicating that all patients, with one exclusion, maintained their preferred reading strategy. However, in several cases the balance between sequential and lexical processing became less extreme, indicating a more effective individual interplay of both word processing routes.
Hricová, Marianna; Weekes, Brendan Stuart
The first reports of phonological, surface and deep dyslexia come from orthographies containing quasi-regular mappings between orthography and phonology including English and French. Slovakian is a language with a relatively transparent orthography and hence a mostly regular script. The aim of this study was to investigate impaired oral reading in Slovakian. A novel diagnostic procedure was devised to determine whether disorders of Slovakian reading resemble characteristics in other languages. Slovakian speaking aphasics showed symptoms similar to phonological dyslexia and deep dyslexia in English and French, but there was no evidence of surface dyslexia. The findings are discussed in terms of the orthographic depth hypothesis.
Hricová, Marianna; Weekes, Brendan Stuart
The first reports of phonological, surface and deep dyslexia come from orthographies containing quasi-regular mappings between orthography and phonology including English and French. Slovakian is a language with a relatively transparent orthography and hence a mostly regular script. The aim of this study was to investigate impaired oral reading in Slovakian. A novel diagnostic procedure was devised to determine whether disorders of Slovakian reading resemble characteristics in other languages. Slovakian speaking aphasics showed symptoms similar to phonological dyslexia and deep dyslexia in English and French, but there was no evidence of surface dyslexia. The findings are discussed in terms of the orthographic depth hypothesis. PMID:22713384
Hamilton, A Cris; Coslett, H Branch
We report two patients with acquired phonological dyslexia who have great difficulty reading affixed words. Experiment 1 demonstrates that both patients' reading performance is influenced by the apparent morphological status of words by comparing the patients' reading of suffixed and pseudo-suffixed words. Experiment 2 was designed to examine reading performance of both regularly and irregularly inflected words. Experiment 3 examines the patients' reading of derivational forms with particular emphasis of the role of 'semantic transparency'. Experiment 4 tested both patients' reading of prefixed words. Finally, Experiment 5 examined performance on a lexical decision task using affixed words. These data support models in which regularly formed inflections and semantically transparent derived forms are subjected to decomposition during processing, whereas irregularly inflected forms and semantically opaque forms may be represented independently. Data are discussed with regard to current 'dual mechanism' models of morphological processing as well as connectionist perspectives, with particular emphasis of the types of data that will ultimately be necessary to arbitrate between the rival theories.
Richlan, Fabio; Sturm, Denise; Schurz, Matthias; Kronbichler, Martin; Ladurner, Gunther; Wimmer, Heinz
Background We used fMRI to examine functional brain abnormalities of German-speaking dyslexics who suffer from slow effortful reading but not from a reading accuracy problem. Similar to acquired cases of letter-by-letter reading, the developmental cases exhibited an abnormal strong effect of length (i.e., number of letters) on response time for words and pseudowords. Results Corresponding to lesions of left occipito-temporal (OT) regions in acquired cases, we found a dysfunction of this region in our developmental cases who failed to exhibit responsiveness of left OT regions to the length of words and pseudowords. This abnormality in the left OT cortex was accompanied by absent responsiveness to increased sublexical reading demands in phonological inferior frontal gyrus (IFG) regions. Interestingly, there was no abnormality in the left superior temporal cortex which—corresponding to the onological deficit explanation—is considered to be the prime locus of the reading difficulties of developmental dyslexia cases. Conclusions The present functional imaging results suggest that developmental dyslexia similar to acquired letter-by-letter reading is due to a primary dysfunction of left OT regions. PMID:20711448
Gvion, Aviah; Friedmann, Naama
Lexical retrieval and reading aloud are often viewed as two separate processes. However, they are not completely separate-they share components. This study assessed the effect of an impairment in a shared component, the phonological output lexicon, on lexical retrieval and on reading aloud. Because the phonological output lexicon is part of the lexical route for reading, individuals with an impairment in this lexicon may be forced to read aloud via the sublexical route and therefore show a reading pattern that is typical of surface dyslexia. To examine the effect of phonological output lexicon deficit on reading, we tested the reading of 16 Hebrew-speaking individuals with phonological output lexicon anomia, eight with acquired anomia following brain damage and eight with developmental anomia. We established that they had a phonological output lexicon deficit according to the types of errors and the effects on their naming in a picture naming task, and excluded other deficit loci in the lexical retrieval process according to a line of tests assessing their picture and word comprehension, word and non-word repetition, and phonological working memory. After we have established that the participants have a phonological output lexicon deficit, we tested their reading. To assess their reading and type of reading impairment, we tested their reading aloud, lexical decision, and written word comprehension. We found that all of the participants with phonological output lexicon impairment showed, in addition to anomia, also the typical surface dyslexia errors in reading aloud of irregular words, words with ambiguous conversion to phonemes, and potentiophones (words like "now" that, when read via the sublexical route, can be sounded out as another word, "know"). Importantly, the participants performed normally on pseudohomophone lexical decision and on homophone/potentiophone reading comprehension, indicating spared orthographic input lexicon and spared access to it and from
Gvion, Aviah; Friedmann, Naama
Lexical retrieval and reading aloud are often viewed as two separate processes. However, they are not completely separate—they share components. This study assessed the effect of an impairment in a shared component, the phonological output lexicon, on lexical retrieval and on reading aloud. Because the phonological output lexicon is part of the lexical route for reading, individuals with an impairment in this lexicon may be forced to read aloud via the sublexical route and therefore show a reading pattern that is typical of surface dyslexia. To examine the effect of phonological output lexicon deficit on reading, we tested the reading of 16 Hebrew-speaking individuals with phonological output lexicon anomia, eight with acquired anomia following brain damage and eight with developmental anomia. We established that they had a phonological output lexicon deficit according to the types of errors and the effects on their naming in a picture naming task, and excluded other deficit loci in the lexical retrieval process according to a line of tests assessing their picture and word comprehension, word and non-word repetition, and phonological working memory. After we have established that the participants have a phonological output lexicon deficit, we tested their reading. To assess their reading and type of reading impairment, we tested their reading aloud, lexical decision, and written word comprehension. We found that all of the participants with phonological output lexicon impairment showed, in addition to anomia, also the typical surface dyslexia errors in reading aloud of irregular words, words with ambiguous conversion to phonemes, and potentiophones (words like “now” that, when read via the sublexical route, can be sounded out as another word, “know”). Importantly, the participants performed normally on pseudohomophone lexical decision and on homophone/potentiophone reading comprehension, indicating spared orthographic input lexicon and spared access to it
More and more, one encounters people who describe themselves as dyslectic. What is dyslexia? A detailed article in the July issue of Science, explains the phenomenon, and related aspects (1). The following are some of its points. Dyslexia is characterized by a difficulty is understanding and using alphabetic or logographic principles to acquire accurate and fluent reading skills. Dyslexia is persistent: a child who fails to read adequately in 1st grade has a high probability of reading poorly in 4th grade and in high school. Thus, difficulty in early reading limits reading comprehension in the later years of education, as students shift from learning to read to reading to learn. Dyslexia is often defined by a discrepancy between an average or above-average score on a test of general intelligence (intelligence quotient [IQ] test) and a low score on a standardized reading test. There is an observation that dyslexia is independent of other talents that allow some children with dyslexia to grow into re markably successful adults. Dyslexia is strongly heritable, occurring in up to 70% of identical twins and 50% of individuals who have a parent or sibling with dyslexia. Environmental factors are also important in reading development, even in children at genetic risk for dyslexia. Dyslexia can be treated. Once children are diagnosed with dyslexia because of reading failure, treatments are instructional. Instruction yields substantial improvement in reading accuracy for many, but not all, children if instruction is more intensive (for instance, 100 minutes per day for 8 weeks), occurs in small groups (1 or 2 students per teacher), and includes explicit and systematic instruction in phonological awareness and decoding strategies.
Dickerson, J; Johnson, H
A case study is reported of a female patient (JAH), who following a left middle cerebral artery infarct, presented with the cardinal symptoms of deep dyslexia and deep dysphasia (semantic errors when reading and repeating words aloud, respectively). Detailed assessment revealed impaired performance across modalities for many tasks, but particularly those tasks that depend on an intact store of semantic knowledge. Her acquired dyslexia is best characterised as deep dyslexia of a central sub-type.
Friedmann, Naama; Rahamim, Einav
Letter position dyslexia (LPD) is a peripheral dyslexia that causes errors of letter order within words. So far, only cases of acquired LPD have been reported. This study presents selective LPD in its developmental form, via the testing of II Hebrew-speaking individuals with developmental dyslexia. The study explores the types of errors and effects on reading in this dyslexia, using a variety of tests: reading aloud, lexical decision, same-different decision, definition and letter naming. The findings indicate that individuals with developmental LPD have a deficit in the letter position encoding function of the orthographic visual analyser, which leads to underspecification of letter position within words. Letter position errors occur mainly in adjacent middle letters, when the error creates another existing word. The participants did not show an output deficit or phonemic awareness deficit. The selectivity of the deficit, causing letter position errors but no letter identity errors and no migrations between words, supports the existence of letter position encoding function as separate from letter identification and letter-to-word binding.
... provide any book on tape, even textbooks. Computer software is also available that "reads" printed material aloud. ... dyslexia, offering them trained tutors, learning aids, computer software, reading assignments on tape, and special arrangements for ...
Virasoro, M. A.
We show that certain specific correlations in the probability of errors observed in dyslexic patients that are normally explained by introducing additional complexity in the model for the reading process are typical of any Neural Network system that has learned to deal with a quasiregular environment. On the other hand we show that in Neural Networks the more regular behavior does not become naturally the default behavior.
Jordan, Dale R.
Dyslexia is defined in this book as the inability to process language symbols. Dyslexia is seen as a continuum ranging from mild forms of symbol confusion to complex syndromes of disabilities. Three specific kinds of dyslexia are identified: visual dyslexia, auditory dyslexia, and dysgraphia. Two chapters, one describing and one suggesting…
Galaburda, A M; Cestnick, L
Developmental dyslexia makes up an important proportion of the known learning disorders. Until the late 1970s most research on dyslexia was carried out by educators and educational psychologists, but soon after the publication of some dyslexic cases with focal disorders of neuronal migration to the cerebral cortex, interest in the neurobiological and neurocognitive underpinnings of dyslexia grew, especially in Europe and North America. There are at least two types of developmental dyslexia--phonological and surface. Surface dyslexia refers to a disorder in which the difficulty lies in reading irregular words, whereas phonological dyslexia is characterized by difficulty with pseudowords. Phonological dyslexia is the more common of the two types. Surface dyslexia does not present a major problem in a language such as Spanish, where the number of irregular words is indeed very small. Still, in languages such as English, where irregular words are common, the phonological type of developmental dyslexia is much more common. Phonologic dyslexics have problems with phonological awareness, that is, the conscious knowledge and manipulation of speech sounds, which is the most proximate explanation for their difficulty in reading pseudowords. Many, but not all, phonologic dyslexics also have problems processing rapidly changing sounds, even if not linguistic, and some slow sounds, too. The same group tends to have visual problems, especially involving the so-called magnocellular pathway of the visual system, which, among others, has the role of analyzing movement. Accompanying these perceptual and cognitive deficits, phonologic dyslexics also show abnormal brain activation to phonological tasks, as shown in functional magnetic resonance studies (figure). In addition, dyslexic brains show focal malformations, ectopias and microgyria, of the cerebral cortex, involving mainly the left perisylvian region and the word form area in the temporo-occipital junction. There are also
Auclair-Ouellet, Noémie; Fossard, Marion; St-Pierre, Marie-Catherine; Macoir, Joël
Phonological dyslexia is a written language disorder characterized by poor reading of nonwords when compared with relatively preserved ability in reading real words. In this study, we report the case of FG, a 74-year-old man with phonological dyslexia. The nature and origin of his reading impairment were assessed using tasks involving activation and explicit manipulation of phonological representations as well as reading of words and nonwords in which the nature and complexity of grapheme-to-phoneme conversion rules (GPC rules) were manipulated. FG also underwent an extensive neuropsychological assessment battery in which he showed impaired performance in tests exploring verbal working memory and executive functions. FG showed no phonological impairment, and his performance was also largely unimpaired for reading words, with no effect of concreteness, grammatical class, morphological complexity, length or nature and complexity of the GPC rules. However, he showed substantial difficulties when asked to read nonwords with contextual GPC rules. The contribution of FG’s executive deficits to his performance in reading is discussed. PMID:22713417
Ansara, Alice, Ed.
This bulletin is published annually in the interest of children with learning disabilities, language disabilities, or dyslexia. The 22 articles discuss the following topics: current issues in dyslexia, language disorders, subgroups in dyslexia, specificity and parameters in defining dyslexia, strategies for recognition and management of reading…
Magowan, S. A.
This brief overview on dyslexia notes the problems of defining this syndrome, presents a profile of a "typical" dyslexic child, and describes the three sub-types of dyslexia which have been identified. (SJL)
Moll, Kristina; Loff, Ariana; Snowling, Margaret J.
The study investigated cognitive deficits associated with dyslexia and familial risk of dyslexia (endophenotypes) by comparing children from families with and without a history of dyslexia. Eighty-eight school-aged children were assessed on measures of phonology, language and rapid automatized naming. A series of regression analyses with family…
Ozernov-Palchik, Ola; Gaab, Nadine
Developmental dyslexia is an unexplained inability to acquire accurate or fluent reading that affects approximately 5–17% of children. Dyslexia is associated with structural and functional alterations in various brain regions that support reading. Neuroimaging studies in infants and pre-reading children suggest that these alterations predate reading instruction and reading failure, supporting the hypothesis that variant function in dyslexia susceptibility genes lead to atypical neural migration and/or axonal growth during early, most likely in utero, brain development. Yet, dyslexia is typically not diagnosed until a child has failed to learn to read as expected (usually in second grade or later). There is emerging evidence that neuroimaging measures, when combined with key behavioral measures, can enhance the accuracy of identification of dyslexia risk in prereading children but its sensitivity, specificity, and cost-efficiency is still unclear. Early identification of dyslexia risk carries important implications for dyslexia remediation and the amelioration of the psychosocial consequences commonly associated with reading failure. PMID:26836227
Schneps, Matthew H.; Greenhill, L. J.; Rose, L. T.
Dyslexia is a hereditary neurological disability that impairs reading. It is believed that anywhere from 5% to 20% of all people in the US may have dyslexia to a greater or lesser degree. Though dyslexia is common, it is a "silent disability" in the sense that it is not easy to tell which individuals suffer from dyslexia and which do not. There is a substantial body of evidence to suggest that people with dyslexia tend to do well in science. For example, Baruj Benacerraf, a Nobel laureate in medicine, is among those whose impairments have been documented and studied. Given that dyslexia was not diagnosed in schools prior to the late 1970's, many established science researchers may have dyslexia and be unaware of their impairment. Therefore, it would not be surprising to find that substantial numbers of scientists working in the fields of astronomy and astrophysics have dyslexia, and yet be unaware of the effects this disability has had on their research. A recently proposed theory by the authors suggests that there may be specific neurological reasons why those with dyslexia may be predisposed to science, and predicts that dyslexia may be associated with enhanced abilities for certain types of visual processing, with special implications for image processing. Our study, funded by the NSF, investigates this hypothesis in the context of astronomy and astrophysics. We expect this work will uncover and document challenges faced by scientists with dyslexia, but perhaps more importantly, lead to an understanding of the strengths these scientists bring to research. The program will serve as a clearing-house of information for scientists and students with dyslexia, and begin to provide mentoring for young people with dyslexia interested in astronomy. Scientists who have reason to believe they may have dyslexia are encouraged to contact the authors.
Helland, Turid; Asbjørnsen, Arve E; Hushovd, Aud Ellen; Hugdahl, Kenneth
This study focused on the relationship between school performance and performance on a dichotic listening (DL) task in dyslexic children. Dyslexia is associated with impaired phonological processing, related to functions in the left temporal lobe. DL is a frequently used task to assess functions of the left temporal lobe. Due to the predominance of the contralateral neuronal pathways, a right ear advantage in the DL task reflects the superior processing capacity for the right ear stimulus in the left hemisphere (Kimura, 1963). Previous studies using DL in dyslexia are, however, inconclusive, and may reflect degree of severity of dyslexia. The aim of the present study was therefore to investigate lateralized processing in two sub-groups of dyslexia, differing in symptom severity. Two groups of dyslexic 12-year-old children and an age-matched control group were tested with a consonant-vowel DL task. The two dyslexia groups differed in severity through how they responded to training efforts being made in their schools, while otherwise being matched for age, IQ and diagnosis. The D1 (respondent group) group showed a DL performance pattern similar to the control group, i.e. a right ear advantage, while the D2 (non-respondent) group failed to show a right ear advantage on the DL task. The performance on the DL task by the two dyslexia groups may provide better insight as to the degree of reading and writing impairment in dyslexia. 'Cracking the code' and acquiring automatized literacy skills may seem harder for the D2 group children compared to the D1 children. Also, the present study points to the use of DL as a valid assessment tool in clinical work to improve differential diagnoses, particularly in relation to measures of school performance.
Norton, Elizabeth S; Beach, Sara D; Gabrieli, John D E
Dyslexia is one of the most common learning disabilities, yet its brain basis and core causes are not yet fully understood. Neuroimaging methods, including structural and functional magnetic resonance imaging, diffusion tensor imaging, and electrophysiology, have significantly contributed to knowledge about the neurobiology of dyslexia. Recent studies have discovered brain differences before formal instruction that likely encourage or discourage learning to read effectively, distinguished between brain differences that likely reflect the etiology of dyslexia versus brain differences that are the consequences of variation in reading experience, and identified distinct neural networks associated with specific psychological factors that are associated with dyslexia.
Bartlett, Diana; Moody, Sylvia
This book is designed for both adults with dyslexia and for professionals concerned with helping them, such as psychologists, tutors, therapists, researchers, disability advisors, and welfare officers. It also offers advice to employers on how to help staff with dyslexia. The text covers the nature of dyslexic difficulties and their effects, both…
Elbeheri, Gad; Everatt, John; Reid, Gavin; Mannai, Haya al
Despite advancements in empirical studies of developmental dyslexia, progress on methods of dyslexia assessment have been hampered by ongoing debate concerning diverse issues such as the role and validity of IQ in the assessment process, labelling and definitions (Miles, 1994; Stanovich, 1991, 1992). With the emergence of cross-linguistic studies…
Manzo, Anthony V.; Duffelmeyer, Fred
A formulated definition of the term dyslexia is proposed in this paper in order to clarify the semantical confusion which exists among both specialists and the general public. Dyslexia is explained as a generic term for severe and puzzling reading disability, found to be both acute (where reading-age lags 25 percent or more below mental age) and…
Hoyles, Asher; Hoyles, Martin
This article begins with a definition of dyslexia as genetic, involving language processing and phonological awareness. It goes beyond reading and writing difficulties to include, for example, sequencing, orientation, short-term memory, speed, circumlocution, organisational skills, visual thinking, self-esteem and anger. Dyslexia, though…
Fostick, Leah; Bar-El, Sharona; Ram-Tsur, Ronit
Dyslexia is a neuro-cognitive disorder with a strong genetic basis, characterized by a difficulty in acquiring reading skills. Several hypotheses have been suggested in an attempt to explain the origin of dyslexia, among which some have suggested that dyslexic readers might have a deficit in auditory temporal processing, while others hypothesized…
Peterson, Robin L.; Pennington, Bruce F.
Summary Dyslexia is a neurodevelopmental disorder that is characterized by slow and inaccurate word recognition. Dyslexia has been found in every culture studied, and mounting evidence underscores cross-linguistic similarity in its neurobiological and neurocognitive bases. There has been considerable progress across levels of analysis in the last five years. At a neuropsychological level, the phonological theory remains the most compelling, though it is increasingly clear that phonological problems interact with other cognitive risk factors. At a neurobiological level, recent research confirms that dyslexia is characterized by dysfunction of the normal left hemisphere language network and also implicates abnormal white matter development. Studies accounting for reading experience demonstrate that many observed neural differences reflect causes rather than effects of dyslexia. At an etiologic risk level, six candidate genes have been identified, and there is evidence for gene by environment interaction. This review includes a focus on these and other recent developments. PMID:22513218
... a bigger reading problem and a drop in self-esteem. So it's important to recognize symptoms early in ... and falling further behind their classmates. And their self-esteem may take a beating. Treating Dyslexia Fortunately, with ...
Pacheco, Andreia; Reis, Alexandra; Araújo, Susana; Inácio, Filomena; Petersson, Karl Magnus; Faísca, Luís
Recent studies have emphasized that developmental dyslexia is a multiple-deficit disorder, in contrast to the traditional single-deficit view. In this context, cognitive profiling of children with dyslexia may be a relevant contribution to this unresolved discussion. The aim of this study was to profile 36 Portuguese children with dyslexia from…
Tamboer, Peter; Vorst, Harrie C. M.; Oort, Frans J.
Two subtypes of dyslexia (phonological, visual) have been under debate in various studies. However, the number of symptoms of dyslexia described in the literature exceeds the number of subtypes, and underlying relations remain unclear. We investigated underlying cognitive features of dyslexia with exploratory and confirmatory factor analyses. A…
Thompson, Paul A.; Hulme, Charles; Nash, Hannah M.; Gooch, Debbie; Hayiou-Thomas, Emma; Snowling, Margaret J.
Background: Causal theories of dyslexia suggest that it is a heritable disorder, which is the outcome of multiple risk factors. However, whether early screening for dyslexia is viable is not yet known. Methods: The study followed children at high risk of dyslexia from preschool through the early primary years assessing them from age 3 years and 6…
Sawyer, Diane J.
This article provides a brief overview of the various areas of research that have served to clarify the condition of dyslexia. Using topics and content appearing in A. L. Benton and D. Pearl's (1978) text, Dyslexia: An Appraisal of Current Knowledge, as the point of departure, evolution of the definitions of dyslexia is traced to the current and…
Hulme, Charles; Snowling, Margaret J.
Purpose of review We review current knowledge about the nature of reading development and disorders, distinguishing between the processes involved in learning to decode print, and the processes involved in reading comprehension. Recent findings Children with decoding difficulties/dyslexia experience deficits in phoneme awareness, letter-sound knowledge and rapid automatized naming in the preschool years and beyond. These phonological/language difficulties appear to be proximal causes of the problems in learning to decode print in dyslexia. We review data from a prospective study of children at high risk of dyslexia to show that being at family risk of dyslexia is a primary risk factor for poor reading and children with persistent language difficulties at school entry are more likely to develop reading problems. Early oral language difficulties are strong predictors of later difficulties in reading comprehension. Summary There are two distinct forms of reading disorder in children: dyslexia (a difficulty in learning to translate print into speech) and reading comprehension impairment. Both forms of reading problem appear to be predominantly caused by deficits in underlying oral language skills. Implications for screening and for the delivery of robust interventions for language and reading are discussed. PMID:27496059
Lukov, Limor; Friedmann, Naama; Shalev, Lilach; Khentov-Kraus, Lilach; Shalev, Nir; Lorber, Rakefet; Guggenheim, Revital
We examine whether attention deficits underlie developmental dyslexia, or certain types of dyslexia, by presenting double dissociations between the two. We took into account the existence of distinct types of dyslexia and of attention deficits, and focused on dyslexias that may be thought to have an attentional basis: letter position dyslexia (LPD), in which letters migrate within words, attentional dyslexia (AD), in which letters migrate between words, neglect dyslexia, in which letters on one side of the word are omitted or substituted, and surface dyslexia, in which words are read via the sublexical route. We tested 110 children and adults with developmental dyslexia and/or attention deficits, using extensive batteries of reading and attention. For each participant, the existence of dyslexia and the dyslexia type were tested using reading tests that included stimuli sensitive to the various dyslexia types. Attention deficit and its type was established through attention tasks assessing sustained, selective, orienting, and executive attention functioning. Using this procedure, we identified 55 participants who showed a double dissociation between reading and attention: 28 had dyslexia with normal attention and 27 had attention deficits with normal reading. Importantly, each dyslexia with suspected attentional basis dissociated from attention: we found 21 individuals with LPD, 13 AD, 2 neglect dyslexia, and 12 surface dyslexia without attention deficits. Other dyslexia types (vowel dyslexia, phonological dyslexia, visual dyslexia) also dissociated from attention deficits. Examination of 55 additional individuals with both a specific dyslexia and a certain attention deficit found no attention function that was consistently linked with any dyslexia type. Specifically, LPD and AD dissociated from selective attention, neglect dyslexia dissociated from orienting, and surface dyslexia dissociated from sustained and executive attention. These results indicate that
Lukov, Limor; Friedmann, Naama; Shalev, Lilach; Khentov-Kraus, Lilach; Shalev, Nir; Lorber, Rakefet; Guggenheim, Revital
We examine whether attention deficits underlie developmental dyslexia, or certain types of dyslexia, by presenting double dissociations between the two. We took into account the existence of distinct types of dyslexia and of attention deficits, and focused on dyslexias that may be thought to have an attentional basis: letter position dyslexia (LPD), in which letters migrate within words, attentional dyslexia (AD), in which letters migrate between words, neglect dyslexia, in which letters on one side of the word are omitted or substituted, and surface dyslexia, in which words are read via the sublexical route. We tested 110 children and adults with developmental dyslexia and/or attention deficits, using extensive batteries of reading and attention. For each participant, the existence of dyslexia and the dyslexia type were tested using reading tests that included stimuli sensitive to the various dyslexia types. Attention deficit and its type was established through attention tasks assessing sustained, selective, orienting, and executive attention functioning. Using this procedure, we identified 55 participants who showed a double dissociation between reading and attention: 28 had dyslexia with normal attention and 27 had attention deficits with normal reading. Importantly, each dyslexia with suspected attentional basis dissociated from attention: we found 21 individuals with LPD, 13 AD, 2 neglect dyslexia, and 12 surface dyslexia without attention deficits. Other dyslexia types (vowel dyslexia, phonological dyslexia, visual dyslexia) also dissociated from attention deficits. Examination of 55 additional individuals with both a specific dyslexia and a certain attention deficit found no attention function that was consistently linked with any dyslexia type. Specifically, LPD and AD dissociated from selective attention, neglect dyslexia dissociated from orienting, and surface dyslexia dissociated from sustained and executive attention. These results indicate that
Colangelo, Annette; Buchanan, Lori; Westbury, Chris
Deep dyslexia is an acquired reading disorder that involves the production of semantic errors and the inability to read aloud nonwords successfully. Several explanations for this reading impairment posit multiple loci of damage to account for the various error types produced in deep dyslexia. In contrast, the failure of inhibition hypothesis…
The main objective of this book is to explain the thinking that is involved in working out a systematic scheme of the variables related to dyslexia. The contents of the book include "Origins of the Approach,""Some Principles of Instruction"; "Verbal Behavior"; "Our Ideas about Language"; "Left and Right"; "The Biology of the Book"; "Exploring…
Nicolson, R. I.; Fawcett, A. J.; Brookes, R. L.; Needle, J.
Three major "neural systems", specialized for different types of information processing, are the sensory, declarative, and procedural systems. It has been proposed ("Trends Neurosci.",30(4), 135-141) that dyslexia may be attributable to impaired function in the procedural system together with intact declarative function. We provide a brief…
Gabel, Lisa A.; Manglani, Monica; Escalona, Nicholas; Cysner, Jessica; Hamilton, Rachel; Pfaffmann, Jeffrey; Johnson, Evelyn
Direct relationships between induced mutation in the "DCDC2" candidate dyslexia susceptibility gene in mice and changes in behavioral measures of visual spatial learning have been reported. We were interested in determining whether performance on a visual-spatial learning and memory task could be translated across species (study 1) and…
Williams, Joan A.; Lynch, Sharon A.
Though the term dyslexia is familiar to the American public and is frequently seen in the media, it often is misunderstood, even in the educational setting. The International Dyslexia Association established the following definition of dyslexia: Dyslexia is a specific learning disability that is neurological in origin. It is characterized by…
Friedmann, Naama; Tzailer-Gross, Lital; Gvion, Aviah
Individuals with text-based neglect dyslexia omit words on the neglected side of the sentence or text, usually on the left side. This study tested whether the syntactic structure of the target sentence affects reading in this type of neglect dyslexia. Because Hebrew is read from right to left, it enables testing whether the beginning of the sentence and its syntactic properties determine if the final, leftmost, constituent is omitted or not. The participants were 7 Hebrew-speaking individuals with acquired left text-based neglect dyslexia, without syntactic impairments. Each participant read 310 sentences, in which we compared 5 types of minimal pairs of sentences that differed in the obligatoriness of the final (left) constituent. Complements were compared with adjuncts, obligatory pronouns were compared with optional resumptive pronouns, and the object of a past tense verb was compared with the object of a present tense verb, which can also be taken to be an adjective, which does not require an object. Questions that require a verb were compared with questions that can appear without a verb, and clauses that serve as sentential complements of a verb were compared with coordinated clauses, which are not required by the verb. In addition, we compared the reading of noun sequences to the reading of meaningful sentences, and assessed the neglect point in reading 2 texts. The results clearly indicated that the syntactic knowledge of the readers with neglect dyslexia modulated their sentence reading. They tended to keep on reading as long as the syntactic and lexical-syntactic requirements of the sentence had not been met. In 4 of the conditions twice as many omissions occurred when the final constituent was optional than when it was obligatory. Text reading was also guided by a search for a "happy end" that does not violate syntactic or semantic requirements. Thus, the syntactic structure of the target sentence modulates reading and neglect errors in text
This article discusses dyslexia (one of the many complex issues that affects students) and the ways to tackle it appropriately. Dyslexia is described as a syndrome in which a person's reading and/or writing ability is significantly lower than that which would be predicted by his or her general level of intelligence. People are diagnosed as…
Hynd, George W.; Hynd, Cynthia R.
Reviews attempts to adequately define dyslexia with a focus on recent efforts at developing a nosology of dyslexia and discusses the neurological basis of reading and severe reading failure with an emphasis on validating evidence provided through brain-mapping procedures and postmortem studies. (HOD)
Shaywitz, Sally E; Shaywitz, Bennett A
Converging evidence from a number of lines of investigation indicates that dyslexia represents a disorder within the language system and more specifically within a particular subcomponent of that system, phonological processing. Recent advances in imaging technology, particularly the development of functional magnetic resonance imaging, provide evidence of a neurobiological signature for dyslexia, specifically a disruption of two left hemisphere posterior brain systems, one parieto-temporal, the other occipito-temporal, with compensatory engagement of anterior systems around the inferior frontal gyrus and a posterior (right occipito-temporal) system. Furthermore, good evidence indicates a computational role for the left occipito-temporal system: the development of fluent (automatic) reading. The brain systems for reading are malleable and their disruption in dyslexic children may be remediated by provision of an evidence-based, effective reading intervention. In addition, functional magnetic resonance imaging studies of young adults with reading difficulties followed prospectively and longitudinally from age 5 through their mid twenties suggests that there may be two types of reading difficulties, one primarily on a genetic basis, the other, and far more common, reflecting environmental influences. These studies offer the promise for more precise identification and effective management of dyslexia in children, adolescents and adults.
Ozernov-Palchik, Ola; Gaab, Nadine
Developmental dyslexia is an unexplained inability to acquire accurate or fluent reading that affects approximately 5-17% of children. Dyslexia is associated with structural and functional alterations in various brain regions that support reading. Neuroimaging studies in infants and pre-reading children suggest that these alterations predate reading instruction and reading failure, supporting the hypothesis that variant function in dyslexia susceptibility genes lead to atypical neural migration and/or axonal growth during early, most likely in utero, brain development. Yet, dyslexia is typically not diagnosed until a child has failed to learn to read as expected (usually in second grade or later). There is emerging evidence that neuroimaging measures, when combined with key behavioral measures, can enhance the accuracy of identification of dyslexia risk in pre-reading children but its sensitivity, specificity, and cost-efficiency is still unclear. Early identification of dyslexia risk carries important implications for dyslexia remediation and the amelioration of the psychosocial consequences commonly associated with reading failure.
This article addresses the issue of whether difficulties with reading and writing in a second language learner stem from developmental dyslexia or from issues associated with second language acquisition. In line with a phonological explanatory model of dyslexia, phonological processing and reading (decoding at both word and text levels) were tested, using data from 10 Spanish-Swedish speaking adolescents whose teachers had identified them as possibly having dyslectic difficulties, and a matched comparison group of 10 Spanish-Swedish speaking adolescents with no reading difficulties. Unlike previous studies, this analysis takes into account results from both languages and uses a matched bilingual comparison group as the norm. Based on these results, a bilingual dyslexia continuum is proposed as an analytical tool to be used for the assessment of developmental dyslexia from a bilingual perspective. The systematized continuum offers various degrees of difficulty -from high indications of dyslexia to no indications of dyslexia-and the positioning along this continuum by the target group participants of this study provides examples of both over- and under-identification of dyslexia. Overall, a greater number of participants in the target group were under-identified rather than over-identified by the schools. An important insight of this study is that the positioning of bilingual participants on the continuum would have been different if the analysis had taken only one of the two languages into account. Furthermore, possible effects from differences between Spanish and Swedish orthographies and syllable structure were observed, as, in general, the participants read more accurately in Spanish. The present data also suggest that decoding processing might vary more in second-language learners with dyslexia compared to monolingual individuals with dyslexia.
Barnes, James; Hinkley, Lisa; Masters, Stuart; Boubert, Laura
Representational Momentum refers to observers' distortion of recognition memory for pictures that imply motion because of an automatic mental process which extrapolates along the implied trajectory of the picture. Neuroimaging evidence suggests that activity in the magnocellular visual pathway is necessary for representational momentum to occur. It has been proposed that individuals with dyslexia have a magnocellular deficit, so it was hypothesised that these individuals would show reduced or absent representational momentum. In this study, 30 adults with dyslexia and 30 age-matched controls were compared on two tasks, one linear and one rotation, which had previously elicited the representational momentum effect. Analysis indicated significant differences in the performance of the two groups, with the dyslexia group having a reduced susceptibility to representational momentum in both linear and rotational directions. The findings highlight that deficits in temporal spatial processing may contribute to the perceptual profile of dyslexia.
Nicolson, R I; Fawcett, A J; Brookes, R L; Needle, J
Three major 'neural systems', specialized for different types of information processing, are the sensory, declarative, and procedural systems. It has been proposed (Trends Neurosci., 30(4), 135-141) that dyslexia may be attributable to impaired function in the procedural system together with intact declarative function. We provide a brief overview of the increasing evidence relating to the hypothesis, noting that the framework involves two main claims: first that 'neural systems' provides a productive level of description avoiding the underspecificity of cognitive descriptions and the overspecificity of brain structural accounts; and second that a distinctive feature of procedural learning is its extended time course, covering from minutes to months. In this article, we focus on the second claim. Three studies-speeded single word reading, long-term response learning, and overnight skill consolidation-are reviewed which together provide clear evidence of difficulties in procedural learning for individuals with dyslexia, even when the tasks are outside the literacy domain. The educational implications of the results are then discussed, and in particular the potential difficulties that impaired overnight procedural consolidation would entail. It is proposed that response to intervention could be better predicted if diagnostic tests on the different forms of learning were first undertaken.
Suárez-Coalla, Paz; Cuetos, Fernando
Recent studies show that dyslexia persists into adulthood, even in highly educated and well-read people. The main characteristic that adults with dyslexia present is a low speed when reading. In Spanish, a shallow orthographic system, no studies about adults with dyslexia are available; and it is possible that the consistency of the orthographic…
Worthy, Jo; DeJulio, Samuel; Svrcek, Natalie; Villarreal, Doris Ann; Derbyshire, Christine; LeeKeenan, Kira; Wiebe, Molly Trinh; Lammert, Catherine; Rubin, Jessica Cira; Salmerón, Cori
Dyslexia policy and practice have been rapidly outpacing research. Due to legislation and media attention, schools are under pressure to attend to dyslexia, but research provides few clear answers about characteristics, identification, or instruction. Most dyslexia research takes place outside literacy education, and teachers' perspectives are…
Dahle, Anne Elisabeth; Knivsberg, Ann-Mari; Andreassen, Anne Brit
A small group of children and young adolescent with dyslexia has severely impaired reading skills despite prolonged special education. These are the students in focus. In dyslexia, problem behaviour, internalised as well as externalised, has previously been reported, so also for the participants with dyslexia in this study. The aim of the present…
Willburger, Edith; Fussenegger, Barbara; Moll, Kristina; Wood, Guilherme; Landerl, Karin
In four carefully selected samples of 8- to 10-year old children with dyslexia (but age adequate arithmetic skills), dyscalculia (but age adequate reading skills), dyslexia/dyscalculia and controls a domain-general deficit in rapid automatized naming (RAN) was found for both dyslexia groups. Dyscalculic children exhibited a domain-specific deficit…
Of all human maladies which account for learning disabilities among young and old alike, few remain as poorly understood and inconclusively defined as dyslexia. The general public perceives dyslexia to be a reading problem; some psychologists believe that dyslexia can stem from a low socio-economic status; educators see the term as involving…
Wadlington, Elizabeth M.; Wadlington, Patrick L.
The purposes of this study were (a) to create and validate a scale measuring beliefs regarding dyslexia, (b) to use the scale to investigate the beliefs of educators regarding dyslexia, and (c) to recommend ways that educators can be better prepared to help students with dyslexia. Participants included university faculty as well as undergraduate…
While there is a wealth of literature about childhood dyslexia, adult dyslexia remains relatively undocumented, particularly from a lived perspective. This paper focuses on the "deficit perspective of failure", as highlighted in current literature, which addresses issues confronting adults with dyslexia. Within this theme of failure a…
LDA of Minnesota, 2004
Learning Disabilities Association (LDA) of Minnesota has gotten many questions over the years about dyslexia. Examples of questions answered in this issue include: (1) When a learner reverses letters, is this dyslexia? (2) How does one teach an adult with dyslexia? (3) Can dyslexia be cured? and (4) Can GED accommodations be received for dyslexia?…
Friedmann, Naama; Kerbel, Noa; Shvimer, Lilach
Attentional dyslexia is a reading deficit in which letters migrate between neighboring words, but are correctly identified and keep their correct relative position within the word. Thus, for example, fig tree can be read as fig free or even tie free. This study reports on 10 Hebrew-speaking individuals with developmental attentional dyslexia and explores in detail the characteristics of their between-word errors. Each participant read 2290 words, presented in word pairs: 845 horizontally presented word pairs, 240 vertically presented word pairs, and 60 nonword pairs. The main results are that almost all migrations preserve the relative position of the migrating letter within the word, indicating that the between-word position can be impaired while the within-word position encoding remains intact. This result is also supported by the finding that the participants did not make many letter position errors within words. Further analyses indicated that more errors occur in longer words, that most migrations occur in final letters (which are the leftmost letters in Hebrew), and that letters migrate both horizontally and vertically, and more frequently from the first to the second word in horizontal presentation. More migrations occurred when the result of migration was an existing word. Similarity between words in a pair did not increase error rates, and more migrations occurred when the words shared fewer letters. The between-word errors included the classic errors of migration of a letter between words, but also omission of one instance of a letter that appeared in the same position in the two words, an error that constituted a considerable percentage of the between-word errors, and intrusion of a letter from one word to the corresponding position in the neighboring word without erasing the original letter in the same position.
Proulx, Michael J; Elmasry, Hannah-May
Prior research on developmental dyslexia using Stroop tasks with young participants has found increased interference in participants with dyslexia relative to controls. Here we extend these findings to adult participants, and introduce a novel test of Stroop incongruity, whereby the color names appeared on an object colored in the incongruent color. The results imply that impaired inhibitory and executive attentional mechanisms are still deficient in adults with dyslexia and that other forms of attentional mechanisms, such as object-based attention, might also be impaired in dyslexia. Dyslexia arises not only from deficits in phonological processing, but from attentional mechanisms as well.
Nittrouer, Susan; Lowenstein, Joanna H.
Developmental dyslexia is a condition in which children encounter difficulty learning to read in spite of adequate instruction. Although considerable effort has been expended trying to identify the source of the problem, no single solution has been agreed upon. The current study explored a new hypothesis, that developmental dyslexia may be due to faulty perceptual organization of linguistically relevant sensory input. To test that idea, sentence-length speech signals were processed to create either sine-wave or noise-vocoded analogs. Seventy children between 8 and 11 years of age, with and without dyslexia participated. Children with dyslexia were selected to have phonological awareness deficits, although those without such deficits were retained in the study. The processed sentences were presented for recognition, and measures of reading, phonological awareness, and expressive vocabulary were collected. Results showed that children with dyslexia, regardless of phonological subtype, had poorer recognition scores than children without dyslexia for both kinds of degraded sentences. Older children with dyslexia recognized the sine-wave sentences better than younger children with dyslexia, but no such effect of age was found for the vocoded materials. Recognition scores were used as predictor variables in regression analyses with reading, phonological awareness, and vocabulary measures used as dependent variables. Scores for both sorts of sentence materials were strong predictors of performance on all three dependent measures when all children were included, but only performance for the sine-wave materials explained significant proportions of variance when only children with dyslexia were included. Finally, matching young, typical readers with older children with dyslexia on reading abilities did not mitigate the group difference in recognition of vocoded sentences. Conclusions were that children with dyslexia have difficulty organizing linguistically relevant sensory
Youman, Martha; Mather, Nancy
Throughout the various states of the USA, the appropriate identification of dyslexia and the timely provision of interventions are characterized by variability and inconsistency. Several states have recognized the existence of this disorder and the well-established need for services. These states have taken proactive steps to implement laws and regulations for both identification and treatment, and the provision of equal access to students who are diagnosed with dyslexia. The majority of states, however, have not developed such laws and guidelines. The purposes of this article are to review the present status and content of these dyslexia laws, highlight some differences among the laws and regulations across states, and suggest strategies for initiating such laws.
The acquisition of literacy in an alphabetic script such as English makes heavy demands on linguistic skills. The relation between spoken and written language however, is far from straightforward. This article reviews the research that suggests that phonological processing skills are crucial in the translation of symbols to sounds, and the development of rapid and automatic decoding skills. It examines research that indicates that children whose phonological processing skills are compromised in some way, are at-risk of experiencing difficulties in the acquisition of literacy; it supports the suggestion that dyslexia can be viewed as lying on the continuum of developmental language disorders. It goes on to relate theory to practice and discusses the responsibilities of health care professionals in relation to the early identification of dyslexia, and makes suggestions regarding intervention. In particular, it looks at the responsibilities of speech and language therapy services in the care and management of children with dyslexia.
Hayek, Maisam; Dorfberger, Shoshi; Karni, Avi
Children with developmental dyslexia (DD) may differ from typical readers in aspects other than reading. The notion of a general deficit in the ability to acquire and retain procedural ("how to") knowledge as long-term procedural memory has been proposed. Here, we compared the ability of elementary school children, with and without…
Quercia, Patrick; Feiss, Léonard; Michel, Carine
Developmental dyslexia affects almost 10% of school-aged children and represents a significant public health problem. Its etiology is unknown. The consistent presence of phonological difficulties combined with an inability to manipulate language sounds and the grapheme–phoneme conversion is widely acknowledged. Numerous scientific studies have also documented the presence of eye movement anomalies and deficits of perception of low contrast, low spatial frequency, and high frequency temporal visual information in dyslexics. Anomalies of visual attention with short visual attention spans have also been demonstrated in a large number of cases. Spatial orientation is also affected in dyslexics who manifest a preference for spatial attention to the right. This asymmetry may be so pronounced that it leads to a veritable neglect of space on the left side. The evaluation of treatments proposed to dyslexics whether speech or oriented towards the visual anomalies remains fragmentary. The advent of new explanatory theories, notably cerebellar, magnocellular, or proprioceptive, is an incentive for ophthalmologists to enter the world of multimodal cognition given the importance of the eye’s visual input. PMID:23690677
Leonard, Christiana M; Eckert, Mark A
Developmental language disorders are characterized by a maturational trajectory that deviates or lags that of normal children. Given the wide variation in the rate of normal language development, diagnosis and classification of these disorders poses severe problems for the clinician. Our laboratory has been searching for anatomical signatures that could aid the development of a neurobiologically based classification. Quantitative analysis of the magnetic resonance imaging (MRI) brain scans of a series of samples of children and adults with reading and language disorders has identified two clusters with contrasting anatomical and reading profiles. Individuals with small symmetrical brain structures tend to have deficits in multiple domains of written and oral language whereas those with larger asymmetrical structures are more likely to have the isolated phonological deficits seen in adults with compensated dyslexia. Surprisingly, the anatomical risk factors that define these clusters do not form a continuum of increasing severity but deviate in opposite directions from normal. Individuals with moderate brain size and asymmetry typically demonstrate the best overall performance. Further research should determine if phonological impairments in the two clusters are associated with differing genetic and environmental risk factors requiring different types of intervention.
McBride-Chang, Catherine; Lam, Fanny; Lam, Catherine; Chan, Becky; Fong, Cathy Y. C.; Wong, Terry T. Y.; Wong, Simpson W. L.
Background: This work tested the rates at which Chinese children with either language delay or familial history of dyslexia at age 5 manifested dyslexia at age 7, identified which cognitive skills at age 5 best distinguished children with and without dyslexia at age 7, and examined how these early abilities predicted subsequent literacy skills.…
Ade-Ojo, Gordon O.
Learners with dyslexia are likely to be over-represented in adult literacy classes because of the convergence in perceptions, causes and understanding of literacy problems and dyslexia. Given the great amount of apprehension about practitioners' and policy makers' understanding of dyslexia itself, it is important to carry out an exploration of the…
Hornstra, Lisette; Denessen, Eddie; Bakker, Joep; van den Bergh, Linda; Voeten, Marinus
The present study examined teacher attitudes toward dyslexia and the effects of these attitudes on teacher expectations and the academic achievement of students with dyslexia compared to students without learning disabilities. The attitudes of 30 regular education teachers toward dyslexia were determined using both an implicit measure and an…
Dyslexia is a specific learning disability, which affects reading in as many as one in five people. Many children go without proper interventions because of ineffective teaching strategies, and common myths associated with this disability. The purpose of this study was to test how deeply ingrained some myths might be, and decipher where educators…
Malatesha Joshi, R.; Padakannaya, Prakash; Nishanimath, S.
This study explores the nature of reading difficulties of two bilinguals in Kannada and English, which vary in their orthographic depth and script layout. VN and MS manifest two different types of reading disabilities, dyslexia and hyperlexia, respectively. The performance of VN was below average on Kannada and English tests of phonemic awareness,…
Background: Neuroimaging offers unique opportunities for understanding the acquisition of reading by children and for unravelling the mystery of developmental dyslexia. Here, I provide a selective overview of recent neuroimaging studies, drawing out implications for education and the teaching of reading. Purpose: The different neuroimaging…
Vlachos, Filippos; Andreou, Eleni; Delliou, Afroditi
The present study examined the link between brain hemisphericity and dyslexia in secondary school students, using the Preference Test (PT), a widely used self-report index of preferred hemisphere thinking styles. The hypothesis was that differences would be revealed between the dyslexic group and their peers in hemispheric preference. A total of…
Osisanya, Ayo; Lazarus, Kelechi; Adewunmi, Abiodun
This study examined the prevalence of dyslexia and dyscalculia among persons with academic deficits in English Language and Mathematics in public primary schools in Ibadan metropolis. A correlational survey study, sampling 477 pupils who were between the ages of eight and 12 years, and in 4th and 5th grades with the use of four research…
Youman, Martha; Mather, Nancy
Throughout the various states of the USA, the appropriate identification of dyslexia and the timely provision of interventions are characterized by variability and inconsistency. Several states have recognized the existence of this disorder and the well-established need for services. These states have taken proactive steps to implement laws and…
Casalis, Severine; Cole, Pascale; Sopo, Delphine
This study examines morphological awareness in developmental dyslexia. While the poor phonological awareness of dyslexic children has been related to their difficulty in handling the alphabetical principle, less is known about their morphological awareness, which also plays an important part in reading development. The aim of this study was to…
Gabay, Yafit; Holt, Lori L
Developmental dyslexia is commonly thought to arise from specific phonological impairments. However, recent evidence is consistent with the possibility that phonological impairments arise as symptoms of an underlying dysfunction of procedural learning. The nature of the link between impaired procedural learning and phonological dysfunction is unresolved. Motivated by the observation that speech processing involves the acquisition of procedural category knowledge, the present study investigates the possibility that procedural learning impairment may affect phonological processing by interfering with the typical course of phonetic category learning. The present study tests this hypothesis while controlling for linguistic experience and possible speech-specific deficits by comparing auditory category learning across artificial, nonlinguistic sounds among dyslexic adults and matched controls in a specialized first-person shooter videogame that has been shown to engage procedural learning. Nonspeech auditory category learning was assessed online via within-game measures and also with a post-training task involving overt categorization of familiar and novel sound exemplars. Each measure reveals that dyslexic participants do not acquire procedural category knowledge as effectively as age- and cognitive-ability matched controls. This difference cannot be explained by differences in perceptual acuity for the sounds. Moreover, poor nonspeech category learning is associated with slower phonological processing. Whereas phonological processing impairments have been emphasized as the cause of dyslexia, the current results suggest that impaired auditory category learning, general in nature and not specific to speech signals, could contribute to phonological deficits in dyslexia with subsequent negative effects on language acquisition and reading. Implications for the neuro-cognitive mechanisms of developmental dyslexia are discussed.
Gabay, Yafit; Holt, Lori L.
Developmental dyslexia is commonly thought to arise from specific phonological impairments. However, recent evidence is consistent with the possibility that phonological impairments arise as symptoms of an underlying dysfunction of procedural learning. The nature of the link between impaired procedural learning and phonological dysfunction is unresolved. Motivated by the observation that speech processing involves the acquisition of procedural category knowledge, the present study investigates the possibility that procedural learning impairment may affect phonological processing by interfering with the typical course of phonetic category learning. The present study tests this hypothesis while controlling for linguistic experience and possible speech-specific deficits by comparing auditory category learning across artificial, nonlinguistic sounds among dyslexic adults and matched controls in a specialized first-person shooter videogame that has been shown to engage procedural learning. Nonspeech auditory category learning was assessed online via within-game measures and also with a post-training task involving overt categorization of familiar and novel sound exemplars. Each measure reveals that dyslexic participants do not acquire procedural category knowledge as effectively as age- and cognitive-ability matched controls. This difference cannot be explained by differences in perceptual acuity for the sounds. Moreover, poor nonspeech category learning is associated with slower phonological processing. Whereas phonological processing impairments have been emphasized as the cause of dyslexia, the current results suggest that impaired auditory category learning, general in nature and not specific to speech signals, could contribute to phonological deficits in dyslexia with subsequent negative effects on language acquisition and reading. Implications for the neuro-cognitive mechanisms of developmental dyslexia are discussed. PMID:26409017
Pitchford, Nicola J; Funnell, Elaine; De Haan, Bianca; Morgan, Paul S
The right-hemisphere hypothesis of deep dyslexia has received support from functional imaging studies of acquired deep dyslexia following damage to the left cerebral hemisphere, but no imaging studies of cases of developmental deep dyslexia, in which brain damage is not suspected, have been reported. In this paper, we report the first evidence of right hyperactivation in an adult case of developmental deep dyslexia. Hyperactivation was observed in the right inferior frontal cortex during functional magnetic resonance imaging (fMRI) of the oral reading of imageable content words and nonwords to which imageable lexical responses were frequently made. No evidence of right hyperactivation was observed in the oral reading of function words, nor during the naming of imageable words in response to pictured objects. The results reveal strategic and selective use of right-hemisphere functions for particular types of written stimuli. We propose that children with developmental deep dyslexia compensate for their lack of phonological skills by accessing right-hemisphere imageable associations that provide a mnemonic for linking written forms to spoken names.
Kast, Monika; Baschera, Gian-Marco; Gross, Markus; Jäncke, Lutz; Meyer, Martin
Our spelling training software recodes words into multisensory representations comprising visual and auditory codes. These codes represent information about letters and syllables of a word. An enhanced version, developed for this study, contains an additional phonological code and an improved word selection controller relying on a phoneme-based student model. We investigated the spelling behavior of children by means of learning curves based on log-file data of the previous and the enhanced software version. First, we compared the learning progress of children with dyslexia working either with the previous software (n = 28) or the adapted version (n = 37). Second, we investigated the spelling behavior of children with dyslexia (n = 37) and matched children without dyslexia (n = 25). To gain deeper insight into which factors are relevant for acquiring spelling skills, we analyzed the influence of cognitive abilities, such as attention functions and verbal memory skills, on the learning behavior. All investigations of the learning process are based on learning curve analyses of the collected log-file data. The results evidenced that those children with dyslexia benefit significantly from the additional phonological cue and the corresponding phoneme-based student model. Actually, children with dyslexia improve their spelling skills to the same extent as children without dyslexia and were able to memorize phoneme to grapheme correspondence when given the correct support and adequate training. In addition, children with low attention functions benefit from the structured learning environment. Generally, our data showed that memory sources are supportive cognitive functions for acquiring spelling skills and for using the information cues of a multi-modal learning environment.
Hornstra, Lisette; Denessen, Eddie; Bakker, Joep; van den Bergh, Linda; Voeten, Marinus
The present study examined teacher attitudes toward dyslexia and the effects of these attitudes on teacher expectations and the academic achievement of students with dyslexia compared to students without learning disabilities. The attitudes of 30 regular education teachers toward dyslexia were determined using both an implicit measure and an explicit, self-report measure. Achievement scores for 307 students were also obtained. Implicit teacher attitudes toward dyslexia related to teacher ratings of student achievement on a writing task and also to student achievement on standardized tests of spelling but not math for those students with dyslexia. Self-reported attitudes of the teachers toward dyslexia did not relate to any of the outcome measures. Neither the implicit nor the explicit measures of teacher attitudes related to teacher expectations. The results show implicit attitude measures to be a more valuable predictor of the achievement of students with dyslexia than explicit, self-report attitude measures.
Jordan, Dale R.
This book aims to interpret recent research on dyslexia into practical information for those who work with individuals with dyslexia. Chapter 1 summarizes new information about how genetic codes determine brian development and how differences in brain structure cause dyslexia. Chapter 2 explains the perceptual and emotional nature of dyslexia.…
Goldstein, Bram H.; Obrzut, John E.
A study provided hemisphere specific simulation and hemispheric alluding stimuli to 15 middle school students with L-type dyslexia and 15 with P-type dyslexia. Traditional decoding and comprehension exercises were provided to 15 students with M-type dyslexia. Readers with all types of dyslexia exhibited significant improvement in reading accuracy…
This article explains dyslexia and characteristics of students with dyslexia and discusses types of instruction that are most appropriate for students with dyslexia, including multisensory instruction, explicit instruction, and phonemic awareness. It provides techniques for enabling students with dyslexia to succeed in reading, writing, listening,…
Altieri, Jennifer L.
This article specifically looks at children's literature that portrays school-age characters with dyslexia so that the educational field can better understand how the books depict dyslexia and the school experience. Although the use of the term "dyslexia" is controversial, experts agree that dyslexia is a learning disability that affects language…
Romberg, Frederick; Shaywitz, Bennett A; Shaywitz, Sally E
We examine the dilemmas faced by a medical student with dyslexia who wonders whether he should "out" himself to faculty to receive the accommodations entitled by federal law. We first discuss scientific evidence on dyslexia's prevalence, unexpected nature, and neurobiology. We then examine the experiences of medical students who have revealed their dyslexia to illustrate the point that, far too often, attending physicians who know little about dyslexia can misperceive the motives or behavior of students with dyslexia. Because ignorance and misperception of dyslexia can result in bias against students with dyslexia, we strongly recommend a mandatory course for faculty that provides a basic scientific and clinical overview of dyslexia to facilitate greater understanding of dyslexia and support for students with dyslexia.
Gan, Zhuo; Li, Chengjun; Gong, Hui; Luo, Qingming; Yao, Bin; Song, Ranran; Wu, Hanrong
Developmental dyslexia is a kind of prevalent psychologic disease. Some functional imaging technologies, such as FMRI and PET, have been used to study the brain activities of dyslexics. NIRS is a kind of novel technology which is more and more widely being used for study of the cognitive psychology. However, there aren"t reports about the dyslexic research using NIRS to be found until now. This paper introduces a NIRS system of four measuring channels. Brain activities of dyslexic subjects and normal subjects during reading task were studied with the NIRS system. Two groups of subjects, the group of dyslexia and the group of normal, were appointed to perform two reading tasks. At the same time, their cortical activities were measured with the NIRS system. This experimental result indicates that the brain activities of the dyslexic group were significantly higher than the control group in BA 48 and that NIRS can be used for the study of human brain activity.
Joshi, R Malatesha; Padakannaya, Prakash; Nishanimath, S
This study explores the nature of reading difficulties of two bilinguals in Kannada and English, which vary in their orthographic depth and script layout. VN and MS manifest two different types of reading disabilities, dyslexia and hyperlexia, respectively. The performance of VN was below average on Kannada and English tests of phonemic awareness, spelling, and pseudoword naming. Despite his poor decoding skills, the listening comprehension skill both at the word level and at the sentence level of VN was within the normal range. VN, therefore, can be described to have developmental dyslexia. MS, in contrast, showed good decoding ability in both Kannada and English, but his listening and reading comprehension were poor in both languages. MS, therefore, displays a pattern of reading disability akin to that of hyperlexia. The deficits of both VN and MS, although dissimilar from each other, cut across the linguistic boundaries and affect their performance in both Kannada and English.
Feifer, Steven G.
This literature review provides support for the idea that subtle anatomical and functional deviations in the brain correlate with specific types of reading disorders. It finds evidence that symmetry or reversed asymmetry in the plana temporale may be associated with difficulty in acquiring sound/symbol relationships. Studies are reported to show…
Desroches, Amy S.; Newman, Randy Lynn; Robertson, Erin K.; Joanisse, Marc F.
Purpose: A range of studies have shown difficulties in perceiving acoustic and phonetic information in dyslexia; however, much less is known about how such difficulties relate to the perception of individual words. The authors present data from event-related potentials (ERPs) examining the hypothesis that children with dyslexia have difficulties…
O'Brien, Beth A.; Wolf, Maryanne; Lovett, Maureen W.
Long-standing issues with the conceptualization, identification and subtyping of developmental dyslexia persist. This study takes an alternative approach to examine the heterogeneity of developmental dyslexia using taxometric classification techniques. These methods were used with a large sample of 671 children ages 6-8 who were diagnosed with…
Lockiewicz, Marta; Bogdanowicz, Katarzyna M.; Bogdanowicz, Marta
The aim of our study was to describe specific psychological resources of adults with developmental dyslexia and compare them with psychological resources of adults without developmental dyslexia. Potential differences were analyzed in visual-spatial, creative, and motivational abilities. No evidence was found for either creative, or visuospatial…
Altmann, Lori J. P.; Lombardino, Linda J.; Puranik, Cynthia
Background: While spoken language deficits have been identified in children with developmental dyslexia, microanalysis of sentence production proficiency in these children is a largely unexplored area. Aims: The current study examines proficiency of syntactic production in children and young adults with dyslexia and typically developing…
Macnamara, Gael R.
This easy-to-use book of case studies helps you recognize the signs of dyslexia and prescribe effective teaching strategies for students with dyslexia. It includes a Case Study Analysis Sheet so you can work through important aspects of a student's personal, academic, and social life. You can then compare what you've compiled to the author's…
Chung, Kevin K. H.; Ho, Connie Suk-Han; Chan, David W.; Tsang, Suk-Man; Lee, Suk-Han
The present study sought to identify cognitive abilities that might distinguish Hong Kong Chinese adolescents with and without dyslexia and examined the cognitive profile of dyslexic adolescents in order to better understand this important problem. The performance of 27 Chinese adolescents with childhood diagnoses of dyslexia was compared with 27…
Liddle, Elizabeth B.; Jackson, Georgina M.; Rorden, Chris; Jackson, Stephen R.
Temporal and spatial attentional deficits in dyslexia were investigated using a lateralized visual temporal order judgment (TOJ) paradigm that allowed both sensitivity to temporal order and spatial attentional bias to be measured. Findings indicate that adult participants with a positive screen for dyslexia were significantly less sensitive to the…
Satz, Paul; Van Nostrand, Gary K.
The paper reviews a theory advanced by Satz and Sparrow (1970) which purports to explain the nature and cause of specific developmental dyslexia, and evaluates several developmental hypotheses which are generated bythe theory. The theory postulates that developmental dyslexia is not a unitary syndrome but rather reflects a lag in the maturation of…
Le Jan, Guylaine; Le Bouquin-Jeannes, Regine; Costet, Nathalie; Troles, Nolwenn; Scalart, Pascal; Pichancourt, Dominique; Faucon, Gerard; Gombert, Jean-Emile
Dyslexia is a specific disorder of language development that mainly affects reading. Etiological researches have led to multiple hypotheses which induced various diagnosis methods and rehabilitation treatments so that many different tests are used by practitioners to identify dyslexia symptoms. Our purpose is to determine a subset of the most…
Developmental dyslexia is believed to involve a phonological deficit of which the exact properties have not been clearly established. This article presents the findings of a longitudinal case study that suggest that, at least for some people with dyslexia, the fundamental problem involves a disturbance of temporal-spatial ordering abilities. A…
The research question here was whether whole-word shape cues might facilitate reading in dyslexia following reports of how normal-reading children benefit from using this cue when learning to read. We predicted that adults with dyslexia would tend to rely more on orthographic rather than other cues when reading, and therefore would be more…
Brunswick, Nicola, Ed.; McDougall, Sine, Ed.; de Mornay Davies, Paul, Ed.
This book provides a unique and accessible account of current research on reading and dyslexia in different orthographies. While most research has been conducted in English, this text presents cross-language comparisons to provide insights into universal aspects of reading development and developmental dyslexia in alphabetic and non-alphabetic…
Morken, Froydis; Helland, Turid
Research on dyslexia has largely centred on reading. The aim of this study was to assess the writing of 13 children with and 28 without dyslexia at age 11?years. A programme for keystroke logging was used to allow recording of typing activity as the children performed a sentence dictation task. Five sentences were read aloud twice each. The task…
Bogaerts, Louisa; Szmalec, Arnaud; Hachmann, Wibke M; Page, Mike P A; Duyck, Wouter
The present study investigated long-term serial-order learning impairments, operationalized as reduced Hebb repetition learning (HRL), in people with dyslexia. In a first multi-session experiment, we investigated both the persistence of a serial-order learning impairment as well as the long-term retention of serial-order representations, both in a group of Dutch-speaking adults with developmental dyslexia and in a matched control group. In a second experiment, we relied on the assumption that HRL mimics naturalistic word-form acquisition and we investigated the lexicalization of novel word-forms acquired through HRL. First, our results demonstrate that adults with dyslexia are fundamentally impaired in the long-term acquisition of serial-order information. Second, dyslexic and control participants show comparable retention of the long-term serial-order representations in memory over a period of 1 month. Third, the data suggest weaker lexicalization of newly acquired word-forms in the dyslexic group. We discuss the integration of these findings into current theoretical views of dyslexia.
O'Brien, Beth A; Wolf, Maryanne; Lovett, Maureen W
Long-standing issues with the conceptualization, identification and subtyping of developmental dyslexia persist. This study takes an alternative approach to examine the heterogeneity of developmental dyslexia using taxometric classification techniques. These methods were used with a large sample of 671 children ages 6-8 who were diagnosed with severe reading disorders. Latent characteristics of the sample are assessed in regard to posited subtypes with phonological deficits and naming speed deficits, thus extending prior work by addressing whether these deficits embody separate classes of individuals. Findings support separate taxa of dyslexia with and without phonological deficits. Different latent structure for naming speed deficits was found depending on the definitional criterion used to define dyslexia. Non-phonologically based forms of dyslexia showed particular difficulty with naming speed and reading fluency.
Helland, Turid; Kaasa, Randi
This study focused on English as L2 in a group of Norwegian dyslexic 12 year olds, compared to an age and gender matched control group. Norwegian school children learn English from the first grades on. The subjects were assessed with a test battery of verbal and written tasks. First, they were given a comprehension task; second, a model sentence task; third, two pragmatic tasks, and fourth, three tasks of literacy. The verbal tasks were scored according to comprehension, morphology, syntax and semantics, while the literacy tasks were scored by spelling, translation and reading skills. It was hypothesized that the results of the control group and the dyslexia group would differ on all tasks, but that subgrouping the dyslexia group by comprehension skills would show heterogeneity within the dyslexia group. The data analyses confirmed these hypotheses. Significant differences were seen between the dyslexia group and the control group. However, the subgrouping revealed minor differences between the control group and the subgroup with good comprehension skills, and major differences between the control group and the subgroup with poor comprehension skills. Especially morphology and spelling were difficult for the dyslexia group. The results were tentatively discussed within the framework of biological and cognitive models of how to interpret L2 performance in dyslexia, underlining the importance of further research in L2 acquisition in dyslexia.
Kibby, Michelle Y.; Kroese, Judith M.; Krebbs, Hillery; Hill, Crystal E.; Hynd, George W.
Limited research has been conducted on the structure of the pars triangularis (PT) in dyslexia despite functional neuroimaging research finding it may play a role in phonological processing. Furthermore, research to date has not examined PT size in ADHD even though the right inferior frontal region has been implicated in the disorder. Hence, one of the purposes of this study was to examine the structure of the PT in dyslexia and ADHD. The other purposes included examining the PT in relation to overall expressive language ability and in relation to several specific linguistic functions given language functioning often is affected in both dyslexia and ADHD. Participants included 50 children: 10 with dyslexia, 15 with comorbid dyslexia/ADHD, 15 with ADHD, and 10 controls. Using a 2 (dyslexia or not) X 2 (ADHD or not) MANCOVA, findings revealed PT length and shape were comparable between those with and without dyslexia. However, children with ADHD had smaller right PT lengths than those without ADHD, and right anterior ascending ramus length was related to attention problems in the total sample. In terms of linguistic functioning, presence of an extra sulcus in the left PT was related to poor expressive language ability. In those with adequate expressive language functioning, left PT length was related to phonological awareness, phonological short-term memory and rapid automatic naming (RAN). Right PT length was related to RAN and semantic processing. Further work on PT morphology in relation to ADHD and linguistic functioning is warranted. PMID:19356794
Bakker, Dirk J
Remarkably few research articles on the treatment of developmental dyslexia were published during the last 25 years. Some treatment research arose from the temporal processing theory, some from the phonological deficit hypothesis and some more from the balance model of learning to read and dyslexia. Within the framework of that model, this article reviews the aetiology of dyslexia sub-types, the neuropsychological rationale for treatment, the treatment techniques and the outcomes of treatment research. The possible mechanisms underlying the effects of treatment are discussed.
Handler, Sheryl M; Fierson, Walter M; Section on Ophthalmology
Learning disabilities constitute a diverse group of disorders in which children who generally possess at least average intelligence have problems processing information or generating output. Their etiologies are multifactorial and reflect genetic influences and dysfunction of brain systems. Reading disability, or dyslexia, is the most common learning disability. It is a receptive language-based learning disability that is characterized by difficulties with decoding, fluent word recognition, rapid automatic naming, and/or reading-comprehension skills. These difficulties typically result from a deficit in the phonologic component of language that makes it difficult to use the alphabetic code to decode the written word. Early recognition and referral to qualified professionals for evidence-based evaluations and treatments are necessary to achieve the best possible outcome. Because dyslexia is a language-based disorder, treatment should be directed at this etiology. Remedial programs should include specific instruction in decoding, fluency training, vocabulary, and comprehension. Most programs include daily intensive individualized instruction that explicitly teaches phonemic awareness and the application of phonics. Vision problems can interfere with the process of reading, but children with dyslexia or related learning disabilities have the same visual function and ocular health as children without such conditions. Currently, there is inadequate scientific evidence to support the view that subtle eye or visual problems cause or increase the severity of learning disabilities. Because they are difficult for the public to understand and for educators to treat, learning disabilities have spawned a wide variety of scientifically unsupported vision-based diagnostic and treatment procedures. Scientific evidence does not support the claims that visual training, muscle exercises, ocular pursuit-and-tracking exercises, behavioral/perceptual vision therapy, "training" glasses
Friedmann, Naama; Haddad-Hanna, Manar
This study reports the reading of 11 Arabic-speaking individuals with letter position dyslexia (LPD), and the effect of letter form on their reading errors. LPD is a peripheral dyslexia caused by a selective deficit to letter position encoding in the orthographic-visual analyzer, which results in migration of letters within words, primarily of middle letters. The Arabic orthography is especially interesting for the study of LPD because Arabic letters have different forms in different positions in the word. As a result, some letter position errors require letter form change. We compared the rate of letter migrations that change letter form with migrations that do not change letter form in 10 Arabic-speaking individuals with developmental LPD, and one bilingual Arabic and Hebrew-speaking individual with acquired LPD. The results indicated that the participants made 40% letter position errors in migratable words when the resulting word included the letters in the same form, whereas migrations that changed letter form almost never occurred. The error rate of the Arabic-Hebrew bilingual reader was smaller in Arabic than in Hebrew. However, when only words in which migrations do not change letter form were counted, the rate was similar in Arabic and Hebrew. Hence, whereas orthographies with multiple letter forms for each letter might seem more difficult in some respects, these orthographies are in fact easier to read in some forms of dyslexia. Thus, the diagnosis of LPD in Arabic should consider the effect of letter forms on migration errors, and use only migratable words that do not require letter-form change. The theoretical implications for the reading model are that letter form (of the position-dependent type found in Arabic) is part of the information encoded in the abstract letter identity, and thus affects further word recognition processes, and that there might be a pre-lexical graphemic buffer in which the checking of orthographic well-formedness takes place
Booker, Anne B.; Chen, Fuyi; Sloan, Andrew M.; Carraway, Ryan S.; Rennaker, Robert L.; LoTurco, Joseph J.; Kilgard, Michael P.
Dyslexia is the most common developmental language disorder and is marked by deficits in reading and phonological awareness. One theory of dyslexia suggests that the phonological awareness deficit is due to abnormal auditory processing of speech sounds. Variants in DCDC2 and several other neural migration genes are associated with dyslexia and may contribute to auditory processing deficits. In the current study, we tested the hypothesis that RNAi suppression of Dcdc2 in rats causes abnormal cortical responses to sound and impaired speech sound discrimination. In the current study, rats were subjected in utero to RNA interference targeting of the gene Dcdc2 or a scrambled sequence. Primary auditory cortex (A1) responses were acquired from 11 rats (5 with Dcdc2 RNAi; DC−) before any behavioral training. A separate group of 8 rats (3 DC−) were trained on a variety of speech sound discrimination tasks, and auditory cortex responses were acquired following training. Dcdc2 RNAi nearly eliminated the ability of rats to identify specific speech sounds from a continuous train of speech sounds but did not impair performance during discrimination of isolated speech sounds. The neural responses to speech sounds in A1 were not degraded as a function of presentation rate before training. These results suggest that A1 is not directly involved in the impaired speech discrimination caused by Dcdc2 RNAi. This result contrasts earlier results using Kiaa0319 RNAi and suggests that different dyslexia genes may cause different deficits in the speech processing circuitry, which may explain differential responses to therapy. SIGNIFICANCE STATEMENT Although dyslexia is diagnosed through reading difficulty, there is a great deal of variation in the phenotypes of these individuals. The underlying neural and genetic mechanisms causing these differences are still widely debated. In the current study, we demonstrate that suppression of a candidate-dyslexia gene causes deficits on tasks of
This article reviews 95 publications (based on 21 independent samples) that have examined children at family risk of reading disorders. We report that children at family risk of dyslexia experience delayed language development as infants and toddlers. In the preschool period, they have significant difficulties in phonological processes as well as with broader language skills and in acquiring the foundations of decoding skill (letter knowledge, phonological awareness and rapid automatized naming [RAN]). Findings are mixed with regard to auditory and visual perception: they do not appear subject to slow motor development, but lack of control for comorbidities confounds interpretation. Longitudinal studies of outcomes show that children at family risk who go on to fulfil criteria for dyslexia have more severe impairments in preschool language than those who are defined as normal readers, but the latter group do less well than controls. Similarly at school age, family risk of dyslexia is associated with significantly poor phonological awareness and literacy skills. Although there is no strong evidence that children at family risk are brought up in an environment that differs significantly from that of controls, their parents tend to have lower educational levels and read less frequently to themselves. Together, the findings suggest that a phonological processing deficit can be conceptualized as an endophenotype of dyslexia that increases the continuous risk of reading difficulties; in turn its impact may be moderated by protective factors. PMID:26727308
Snowling, Margaret J; Melby-Lervåg, Monica
This article reviews 95 publications (based on 21 independent samples) that have examined children at family risk of reading disorders. We report that children at family risk of dyslexia experience delayed language development as infants and toddlers. In the preschool period, they have significant difficulties in phonological processes as well as with broader language skills and in acquiring the foundations of decoding skill (letter knowledge, phonological awareness and rapid automatized naming [RAN]). Findings are mixed with regard to auditory and visual perception: they do not appear subject to slow motor development, but lack of control for comorbidities confounds interpretation. Longitudinal studies of outcomes show that children at family risk who go on to fulfil criteria for dyslexia have more severe impairments in preschool language than those who are defined as normal readers, but the latter group do less well than controls. Similarly at school age, family risk of dyslexia is associated with significantly poor phonological awareness and literacy skills. Although there is no strong evidence that children at family risk are brought up in an environment that differs significantly from that of controls, their parents tend to have lower educational levels and read less frequently to themselves. Together, the findings suggest that a phonological processing deficit can be conceptualized as an endophenotype of dyslexia that increases the continuous risk of reading difficulties; in turn its impact may be moderated by protective factors. (PsycINFO Database Record
Łockiewicz, Marta; Bogdanowicz, Katarzyna M; Bogdanowicz, Marta
The aim of our study was to describe specific psychological resources of adults with developmental dyslexia and compare them with psychological resources of adults without developmental dyslexia. Potential differences were analyzed in visual-spatial, creative, and motivational abilities. No evidence was found for either creative, or visuospatial superiority in adults with developmental dyslexia. The results suggest, however, that visual-spatial processing of nonverbal material by adults with developmental dyslexia allows them to efficiently execute tasks that are based on sequential material. Moreover, the participants with specific difficulties in reading and writing exhibited a significantly higher level of aspirations than their peers without such difficulties with a comparable level of educational achievement. These results suggest that succeeding in different fields by highly functioning adult dyslexics may depend on personality and motivational factors, rather than cognitive factors.
Describes two cases of developmental dyslexia in whom learning to read English as compared to Kannada and Hindi (two Indian scripts) were differentially affected. Discusses implications for the understanding of reading acquisition and models of reading. (RS)
Punt, Marja; de Jong, Marianne; de Groot, Erik; Hadders-Algra, Mijna
Aim: To improve understanding of brain function in children with severe dyslexia in terms of minor neurological dysfunctions (MNDs). Method: One hundred and four children (81 males, 23 females; age range 7-12y; mean age 9y 7mo, SD 1y 2mo;) with severe dyslexia (the presence of a Full-scale IQ score of greater than or equal to 85, retardation in…
Hiscox, Lucy; Leonavičiūtė, Erika; Humby, Trevor
Dyslexia is associated with difficulties in language-specific skills such as spelling, writing and reading; the difficulty in acquiring literacy skills is not a result of low intelligence or the absence of learning opportunity, but these issues will persist throughout life and could affect long-term education. Writing is a complex process involving many different functions, integrated by the working memory system; people with dyslexia have a working memory deficit, which means that concentration on writing quality may be detrimental to understanding. We confirm impaired working memory in a sample of university students with (compensated) dyslexia, and using a within-subject design with three test conditions, we show that these participants demonstrated better understanding of a piece of text if they had used automatic spelling correction software during a dictation/transcription task. We hypothesize that the use of the autocorrecting software reduced demand on working memory, by allowing word writing to be more automatic, thus enabling better processing and understanding of the content of the transcriptions and improved recall. Long-term and regular use of autocorrecting assistive software should be beneficial for people with and without dyslexia and may improve confidence, written work, academic achievement and self-esteem, which are all affected in dyslexia.
Olofsson, Åke; Taube, Karin; Ahl, Astrid
Broadened recruitment to higher education is on the agenda in many countries, and it is also widely recognized that the number of dyslexic students entering higher education is increasing. In Sweden, as in many other European countries, higher education institutions are required to accommodate students with dyslexia. The present study focuses on the study outcome for 50 students with diagnosed dyslexia, mainly in teacher education and nurses' training, at three universities in Northern Sweden. The students trusted their own ability to find information on the Internet but mistrusted their own abilities in reading course books and articles in English and in taking notes. The mean rate of study was 23.5 European Credit Transfer and Accumulation System credits per semester, which is slightly below the national baseline of 26.7. The results show that more than half of the students are examined at a normal rate of study but that about one fifth have a very low rate of study. Messages Most students with dyslexia can compensate for their reading problems. Taking notes during lessons and reading in foreign language may be especially difficult for students with dyslexia. Diagnoses should distinguish between reading comprehension and word decoding. More than half of the students with dyslexia can achieve at a normal rate of study. One-fifth of the students with dyslexia may need a longer period of study than other students.
Vicari, S; Finzi, A; Menghini, D; Marotta, L; Baldi, S; Petrosini, L
Objective: The purpose of this study was to investigate the effects of specific types of tasks on the efficiency of implicit procedural learning in the presence of developmental dyslexia (DD). Methods: Sixteen children with DD (mean (SD) age 11.6 (1.4) years) and 16 matched normal reader controls (mean age 11.4 (1.9) years) were administered two tests (the Serial Reaction Time test and the Mirror Drawing test) in which implicit knowledge was gradually acquired across multiple trials. Although both tests analyse implicit learning abilities, they tap different competencies. The Serial Reaction Time test requires the development of sequential learning and little (if any) procedural learning, whereas the Mirror Drawing test involves fast and repetitive processing of visuospatial stimuli but no acquisition of sequences. Results: The children with DD were impaired on both implicit learning tasks, suggesting that the learning deficit observed in dyslexia does not depend on the material to be learned (with or without motor sequence of response action) but on the implicit nature of the learning that characterises the tasks. Conclusion: Individuals with DD have impaired implicit procedural learning. PMID:16170083
Ripamonti, E; Aggujaro, S; Molteni, F; Zonca, G; Frustaci, M; Luzzatti, C
In this study we investigated the neural correlates of acquired reading disorders through an anatomo-correlative procedure of the lesions of 59 focal brain damaged patients suffering from acquired surface, phonological, deep, undifferentiated dyslexia and pure alexia. Two reading tasks, one of words and nonwords and one of words with unpredictable stress position, were used for this study. We found that surface dyslexia was predominantly associated with left temporal lesions, while in phonological dyslexia the lesions overlapped in the left insula and the left inferior frontal gyrus (pars opercularis) and that pure alexia was associated with lesions in the left fusiform gyrus. A number of areas and white matter tracts, which seemed to involve processing along both the lexical and the sublexical routes, were identified for undifferentiated dyslexia. Two cases of deep dyslexia with relatively dissimilar anatomical correlates were studied, one compatible with Coltheart's right-hemisphere hypothesis (1980) whereas the other could be interpreted in the context of Morton and Patterson's (1980), multiply-damaged left-hemisphere hypothesis. In brief, the results of this study are only partially consistent with the current state of the art, and propose new and stimulating challenges; indeed, based on these results we suggest that different types of acquired dyslexia may ensue after different cortical damage, but white matter disconnection may play a crucial role in some cases.
Hudson, Roxanne F.; High, Leslie; Al Otaiba, Stephanie
Dyslexia is a disorder of the language-processing systems in the brain. It is a specific learning disability in reading that often affects spelling as well. This article describes: (1) Common characteristics experienced by people with dyslexia or reading disabilities; (2) Common misconceptions about dyslexia; (3) What brain research tell us about…
Lindgren, Signe-Anita; Laine, Matti
High-performing adults with compensated dyslexia pose particular challenges to dyslexia diagnostics. We compared the performance of 20 multilingual Finnish university students with suspected dyslexia with 20 age-matched and education-matched controls on an extensive test battery. The battery tapped various aspects of reading, writing, word…
Bacon, Alison M.; Bennett, Samantha
Increasing numbers of students in Higher Education (HE) have dyslexia and are particularly over represented in the visual and creative arts. While dyslexia has been associated with artistic talent, some applicants may perceive their academic opportunities as limited because of negative learning experiences associated with their dyslexia. This…
LDA Minnesota, 2010
This issue of "Learning Times" includes a feature on understanding dyslexia. Dyslexia is a brain-based, often inherited, disorder that impairs a person's ability to read. It is not the result of low intelligence, lack of motivation, sensory impairment, or inadequate instruction. Early diagnosis of dyslexia is critical, and a child can be…
Two studies investigated whether an appropriate versus an inappropriate hemisphere alluding stimulation treatment of children with L-type dyslexia produces differential reading effects, and effects of hemisphere specific stimulation on children with L-, P-, and M-type dyslexia. Results support the validity of dyslexia subtyping and the…
Leong, Che Kan
This commentary reviews forthcoming articles on the scientific study of dyslexia, genetic and neurophysiological aspects of dyslexia, cross-linguistic aspects of literacy development and dyslexia, and theory-based practice. It concludes that educators should continue to strive to promote theory-based research and evidence-based practice to achieve…
Manis, Franklin R.; And Others
Studied 51 dyslexic children, 51 age-matched normal readers, and 27 younger normal readers to explore whether there are different subtypes of developmental dyslexia, and whether developmental dyslexia represents delay or deviance. Found evidence to support two subtypes: surface and phonological dyslexia. (DR)
Nelson, Jason M.; Gregg, Noel
Objective: To investigate depressive and anxious symptomatology among transitioning adolescents and college students with ADHD, dyslexia, or comorbid ADHD/dyslexia. Method: Transitioning adolescents and college students with these disorders along with a non-ADHD/dyslexia college sample completed self-report measures of depression and anxiety.…
Houpt, Joseph W; Sussman, Bethany L; Townsend, James T; Newman, Sharlene D
Developmental dyslexia is a complex and heterogeneous disorder characterized by unexpected difficulty in learning to read. Although it is considered to be biologically based, the degree of variation has made the nature and locus of dyslexia difficult to ascertain. Hypotheses regarding the cause have ranged from low-level perceptual deficits to higher order cognitive deficits, such as phonological processing and visual-spatial attention. We applied the capacity coefficient, a measure obtained from a mathematical cognitive model of response times to measure how efficiently participants processed different classes of stimuli. The capacity coefficient was used to test the extent to which individuals with dyslexia can be distinguished from normal reading individuals based on their ability to take advantage of word, pronounceable non-word, consonant sequence or unfamiliar context when categorizing character strings. Within subject variability of the capacity coefficient across character string types was fairly regular across normal reading adults and consistent with a previous study of word perception with the capacity coefficient-words and pseudowords were processed at super-capacity and unfamiliar characters strings at limited-capacity. Two distinct patterns were observed in individuals with dyslexia. One group had a profile similar to the normal reading adults while the other group showed very little variation in capacity across string-type. It is possible that these individuals used a similar strategy for all four string-types and were able to generalize this strategy when processing unfamiliar characters. This difference across dyslexia groups may be used to identify sub-types of the disorder and suggest significant differences in word level processing among these subtypes. Therefore, this approach may be useful in further delineating among types of dyslexia, which in turn may lead to better understanding of the etiologies of dyslexia.
Doron, Adi; Manassi, Mauro; Herzog, Michael H; Ahissar, Merav
Phonological deficits in dyslexia are well documented. However, there is an ongoing discussion about whether visual deficits limit the reading skills of people with dyslexia. Here, we investigated visual crowding and backward masking. We presented a Vernier (i.e., two vertical bars slightly offset to the left or right) and asked observers to indicate the offset direction. Vernier stimuli are visually similar to letters and are strongly affected by crowding, even in the fovea. To increase task difficulty, Verniers are often followed by a mask (i.e., backward masking). We measured Vernier offset discrimination thresholds for the basic Vernier task, under crowding, and under backward masking, in students with dyslexia (n = 19) and age and intelligence matched students (n = 27). We found no group differences in any of these conditions. Controls with fast visual processing (good backward masking performance), were faster readers. By contrast, no such correlation was found among the students with dyslexia, suggesting that backward masking does not limit their reading efficiency. These findings indicate that neither elevated crowding nor elevated backward masking pose a bottleneck to reading skills of people with dyslexia.
Bishop-Liebler, Paula; Welch, Graham; Huss, Martina; Thomson, Jennifer M; Goswami, Usha
The core cognitive difficulty in developmental dyslexia involves phonological processing, but adults and children with dyslexia also have sensory impairments. Impairments in basic auditory processing show particular links with phonological impairments, and recent studies with dyslexic children across languages reveal a relationship between auditory temporal processing and sensitivity to rhythmic timing and speech rhythm. As rhythm is explicit in music, musical training might have a beneficial effect on the auditory perception of acoustic cues to rhythm in dyslexia. Here we took advantage of the presence of musicians with and without dyslexia in musical conservatoires, comparing their auditory temporal processing abilities with those of dyslexic non-musicians matched for cognitive ability. Musicians with dyslexia showed equivalent auditory sensitivity to musicians without dyslexia and also showed equivalent rhythm perception. The data support the view that extensive rhythmic experience initiated during childhood (here in the form of music training) can affect basic auditory processing skills which are found to be deficient in individuals with dyslexia.
Carrion-Castillo, Amaia; Franke, Barbara; Fisher, Simon E
Dyslexia is a highly heritable learning disorder with a complex underlying genetic architecture. Over the past decade, researchers have pinpointed a number of candidate genes that may contribute to dyslexia susceptibility. Here, we provide an overview of the state of the art, describing how studies have moved from mapping potential risk loci, through identification of associated gene variants, to characterization of gene function in cellular and animal model systems. Work thus far has highlighted some intriguing mechanistic pathways, such as neuronal migration, axon guidance, and ciliary biology, but it is clear that we still have much to learn about the molecular networks that are involved. We end the review by highlighting the past, present, and future contributions of the Dutch Dyslexia Programme to studies of genetic factors. In particular, we emphasize the importance of relating genetic information to intermediate neurobiological measures, as well as the value of incorporating longitudinal and developmental data into molecular designs.
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Wilcke, Arndt; Ligges, Carolin; Burkhardt, Jana; Alexander, Michael; Wolf, Christiane; Quente, Elfi; Ahnert, Peter; Hoffmann, Per; Becker, Albert; Müller-Myhsok, Bertram; Cichon, Sven; Boltze, Johannes; Kirsten, Holger
Dyslexia is a developmental disorder characterised by extensive difficulties in the acquisition of reading or spelling. Genetic influence is estimated at 50-70%. However, the link between genetic variants and phenotypic deficits is largely unknown. Our aim was to investigate a role of genetic variants of FOXP2, a prominent speech and language gene, in dyslexia using imaging genetics. This technique combines functional magnetic resonance imaging (fMRI) and genetics to investigate relevance of genetic variants on brain activation. To our knowledge, this represents the first usage of fMRI-based imaging genetics in dyslexia. In an initial case/control study (n = 245) for prioritisation of FOXP2 polymorphisms for later use in imaging genetics, nine SNPs were selected. A non-synonymously coding mutation involved in verbal dyspraxia was also investigated. SNP rs12533005 showed nominally significant association with dyslexia (genotype GG odds ratio recessive model = 2.1 (95% confidence interval 1.1-3.9), P = 0.016). A correlated SNP was associated with altered expression of FOXP2 in vivo in human hippocampal tissue. Therefore, influence of the rs12533005-G risk variant on brain activity was studied. fMRI revealed a significant main effect for the factor 'genetic risk' in a temporo-parietal area involved in phonological processing as well as a significant interaction effect between the factors 'disorder' and 'genetic risk' in activation of inferior frontal brain areas. Hence, our data may hint at a role of FOXP2 genetic variants in dyslexia-specific brain activation and demonstrate use of imaging genetics in dyslexia research.
Cestari, Tania Ferreira; Dantas, Lia Pinheiro; Boza, Juliana Catucci
Cutaneous hyperpigmentations are frequent complaints, motivating around 8.5% of all dermatological consultations in our country. They can be congenital, with different patterns of inheritance, or acquired in consequence of skin problems, systemic diseases or secondary to environmental factors. The vast majority of them are linked to alterations on the pigment melanin, induced by different mechanisms. This review will focus on the major acquired hyperpigmentations associated with increased melanin, reviewing their mechanisms of action and possible preventive measures. Particularly prominent aspects of diagnosis and therapy will be emphasized, with focus on melasma, post-inflammatory hyperpigmentation, periorbital pigmentation, dermatosis papulosa nigra, phytophotodermatoses, flagellate dermatosis, erythema dyschromicum perstans, cervical poikiloderma (Poikiloderma of Civatte), acanthosis nigricans, cutaneous amyloidosis and reticulated confluent dermatitis PMID:24626644
Männel, Claudia; Meyer, Lars; Wilcke, Arndt; Boltze, Johannes; Kirsten, Holger; Friederici, Angela D
Developmental dyslexia, a severe impairment of literacy acquisition, is known to have a neurological basis and a strong genetic background. However, effects of individual genetic variations on dyslexia-associated deficits are only moderate and call for the assessment of the genotype's impact on mediating neuro-endophenotypes by the imaging genetics approach. Using voxel-based morphometry (VBM) in German participants with and without dyslexia, we investigated gray matter changes and their association with impaired phonological processing, such as reduced verbal working memory. These endophenotypical alterations were, together with dyslexia-associated genetic variations, examined on their suitability as potential predictors of dyslexia. We identified two gray matter clusters in the left posterior temporal cortex related to verbal working memory capacity. Regional cluster differences correlated with genetic risk variants in TNFRSF1B. High-genetic-risk participants exhibit a structural predominance of auditory-association areas relative to auditory-sensory areas, which may partly compensate for deficient early auditory-sensory processing stages of verbal working memory. The reverse regional predominance observed in low-genetic-risk participants may in turn reflect reliance on these early auditory-sensory processing stages. Logistic regression analysis further supported that regional gray matter differences and genetic risk interact in the prediction of individuals' diagnostic status: With increasing genetic risk, the working-memory related structural predominance of auditory-association areas relative to auditory-sensory areas classifies participants with dyslexia versus control participants. Focusing on phonological deficits in dyslexia, our findings suggest endophenotypical changes in the left posterior temporal cortex could comprise novel pathomechanisms for verbal working memory-related processes translating TNFRSF1B genotype into the dyslexia phenotype.
Fitzpatrick, Velvet R.
In the United States, institutions have established multiple programs and initiatives aimed at increasing the diversity of both faculty and students in engineering as means to produce a workforce that will better serve society. However, there are two major problems in addressing engineering student diversity. First, the engineering education research community has paid little attention to date as to how engineering education research characterizes diversity in its broadest sense. Second, research on persons with disabilities in undergraduates engineering, a population of interests within diversity, is minimal. Available disability studies tend to be skewed toward physical disabilities, leading to a neglect of cognitive differences such as learning disabilities (LD). In addition, disability research questions and study designs are inherently steeped in ability bias. The purpose of this dissertation is to explore the meaning of ability for students with dyslexia while in undergraduate engineering and establish the significance of cognitive diversity, focusing on LD and more specifically dyslexia, in undergraduate engineering education and answer the following research question: How do undergraduate engineering students with dyslexia experience ability while pursuing and persisting in engineering? The motivation was to lay the groundwork for future engineering education studies on undergraduate students with LD in general but dyslexia in specific. The first goal was to conduct a critical literature review pertaining to the academic strengths of undergraduate students with LD, specifically, dyslexia and the second goal was to describe how undergraduate engineering students with dyslexia experience ability. The intent was not to redefine dyslexia or disability. The intent is to provide an inclusive account of dyslexia, weakness and strengths, within the field of engineering education. This study was conducted from a qualitative inquiry approach, within the social
Kezilas, Yvette; Kohnen, Saskia; McKague, Meredith; Castles, Anne
Many children with reading difficulties display phonological deficits and struggle to acquire non-lexical reading skills. However, not all children with reading difficulties have these problems, such as children with selective letter position dyslexia (LPD), who make excessive migration errors (such as reading slime as "smile"). Previous research has explored three possible loci for the deficit - the phonological output buffer, the orthographic input lexicon, and the orthographic-visual analysis stage of reading. While there is compelling evidence against a phonological output buffer and orthographic input lexicon deficit account of English LPD, the evidence in support of an orthographic-visual analysis deficit is currently limited. In this multiple single-case study with three English-speaking children with developmental LPD, we aimed to both replicate and extend previous findings regarding the locus of impairment in English LPD. First, we ruled out a phonological output buffer and an orthographic input lexicon deficit by administering tasks that directly assess phonological processing and lexical guessing. We then went on to directly assess whether or not children with LPD have an orthographic-visual analysis deficit by modifying two tasks that have previously been used to localize processing at this level: a same-different decision task and a non-word reading task. The results from these tasks indicate that LPD is most likely caused by a deficit specific to the coding of letter positions at the orthographic-visual analysis stage of reading. These findings provide further evidence for the heterogeneity of dyslexia and its underlying causes.
Kezilas, Yvette; Kohnen, Saskia; McKague, Meredith; Castles, Anne
Many children with reading difficulties display phonological deficits and struggle to acquire non-lexical reading skills. However, not all children with reading difficulties have these problems, such as children with selective letter position dyslexia (LPD), who make excessive migration errors (such as reading slime as “smile”). Previous research has explored three possible loci for the deficit – the phonological output buffer, the orthographic input lexicon, and the orthographic-visual analysis stage of reading. While there is compelling evidence against a phonological output buffer and orthographic input lexicon deficit account of English LPD, the evidence in support of an orthographic-visual analysis deficit is currently limited. In this multiple single-case study with three English-speaking children with developmental LPD, we aimed to both replicate and extend previous findings regarding the locus of impairment in English LPD. First, we ruled out a phonological output buffer and an orthographic input lexicon deficit by administering tasks that directly assess phonological processing and lexical guessing. We then went on to directly assess whether or not children with LPD have an orthographic-visual analysis deficit by modifying two tasks that have previously been used to localize processing at this level: a same-different decision task and a non-word reading task. The results from these tasks indicate that LPD is most likely caused by a deficit specific to the coding of letter positions at the orthographic-visual analysis stage of reading. These findings provide further evidence for the heterogeneity of dyslexia and its underlying causes. PMID:24917802
Duranovic, Mirela; Tinjak, Sanela; Turbic-Hadzagic, Amira
The phonological skills are not the only linguistic abilities which are observed to have some influence on reading achievement in dyslexics. In addition to phonological skills, morphological skills should be also taken in consideration. The aim of this study is to extend investigation the linguistic abilities of children with dyslexia to the…
Morken, Frøydis; Helland, Turid
Research on dyslexia has largely centred on reading. The aim of this study was to assess the writing of 13 children with and 28 without dyslexia at age 11 years. A programme for keystroke logging was used to allow recording of typing activity as the children performed a sentence dictation task. Five sentences were read aloud twice each. The task was to type the sentence as correctly as possible, with no time constraints. The data were analysed from a product (spelling, grammar and semantics) and process (transcription fluency and revisions) perspective, using repeated measures ANOVA and t-tests to investigate group differences. Furthermore, the data were correlated with measures of rapid automatic naming and working memory. Results showed that the group with dyslexia revised their texts as much as the typical group, but they used more time, and the result was poorer. Moreover, rapid automatic naming correlated with transcription fluency, and working memory correlated with the number of semantic errors. This shows that dyslexia is generally not an issue of effort and that cognitive skills that are known to be important for reading also affect writing.
Galaburda, Albert M.
In response to M. Rawson's paper, the author uses an analogy with coronary artery disease to show that current brain research is not entirely at odds with the position that dyslexia may be a developmental variation, rather than a defect. (Author/DB)
Singleton, Chris; Horne, Joanna; Simmons, Fiona
Identifying dyslexia in adulthood presents particular challenges because of complicating factors such as acquisition of compensatory strategies, differing degrees of intervention and the problem of distinguishing dyslexic adults from those whose literacy difficulties have non-cognitive causes. One of the implications is that conventional literacy…
Taylor, Mark J.; Duffy, Sandi; England, David
Purpose: The purpose of this paper is to examine the type of adjustments to delivery appropriate for students with dyslexia in a UK higher education setting. Design/methodology/approach: A case study in a UK university department was conducted over a four-year period. Findings: It was found that a variety of adjustments may be required for…
Tops, Wim; Callens, Maaike; Lammertyn, Jan; Van Hees, Valérie; Brysbaert, Marc
An increasing number of students with dyslexia enter higher education. As a result, there is a growing need for standardized diagnosis. Previous research has suggested that a small number of tests may suffice to reliably assess students with dyslexia, but these studies were based on post hoc discriminant analysis, which tends to overestimate the percentage of systematic variance, and were limited to the English language (and the Anglo-Saxon education system). Therefore, we repeated the research in a non-English language (Dutch) and we selected variables on the basis of a prediction analysis. The results of our study confirm that it is not necessary to administer a wide range of tests to diagnose dyslexia in (young) adults. Three tests sufficed: word reading, word spelling and phonological awareness, in line with the proposal that higher education students with dyslexia continue to have specific problems with reading and writing. We also show that a traditional postdiction analysis selects more variables of importance than the prediction analysis. However, these extra variables explain study-specific variance and do not result in more predictive power of the model.
Howard Gardner's multiple intelligences theory has exciting implications for planning new curricula, especially for children with dyslexia. These children have been "educated" in a system that has failed them. Gardner's theory allows an open-ended approach to assessing dyslexic children's intelligence. Understanding the eight…
Haddad, Herskel M.; And Others
In 73 children (6-13 years old) with reading difficulty, ophthalmological evaluation showed that 18 had overt refractive errors, 18 dyslexia and no ocular anomalies, and 37 impaired fusional amplitudes, 24 of whom were dyslexic. In all Ss with poor fusional amplitudes the reading mechanism could be improved with orthoptic exercises. (Author/CL)
Buchholz, Judy; Davies, Anne Aimola
Alerting, orienting and executive control of attention are investigated in five adult cases of dyslexia. In comparison with a control group, alerting and executive control were found to be generally intact for each case. Two spatial cueing tasks were employed. For the task requiring target detection, orienting difficulties were evident only in…
In a continuation study, 12 students with dyslexia participated in muscle testing and exercises. Six areas were evaluated via pre- and post-tests: academics (using measures of spelling, reading, and math); parental observations of changes in their children (behavioral, academic or affective); perceptual drawing; oral reading; written language; and…
Galaburda, Albert M.
The author considers cerebral dominance and brain asymmetry, the development of the cerebral cortex and examples of aberrancy, and diseases of the immune system, all of which relate to recent anatomical and epidemiological findings in developmental dyslexia. These discoveries have led to testable hypotheses which may enhance current understandings…
Gabay, Yafit; Thiessen, Erik D.; Holt, Lori L.
Purpose: Developmental dyslexia (DD) is commonly thought to arise from phonological impairments. However, an emerging perspective is that a more general procedural learning deficit, not specific to phonological processing, may underlie DD. The current study examined if individuals with DD are capable of extracting statistical regularities across…
Salmelin, Riitta; Helenius, Paivi
In reading tasks, an underactivation of the left inferior occipitotemporal cortex in dyslexia seems to be the most consistent finding both in neurophysiological and hemodynamic studies. This marked difference appears at about 150 msec after word presentation when the brain enters the letter-string-specific (or, more generally, object-specific)…
Serniclaes, Willy; Van Heghe, Sandra; Mousty, Philippe; Carre, Rene; Sprenger-Charolles, Liliane
Perceptual discrimination between speech sounds belonging to different phoneme categories is better than that between sounds falling within the same category. This property, known as ''categorical perception,'' is weaker in children affected by dyslexia. Categorical perception develops from the predispositions of newborns for discriminating all…
Moncrieff, Deborah W.; Black, Jeffrey R.
Several auditory processing deficits have been reported in children with dyslexia. In order to assess for the presence of a binaural integration type of auditory processing deficit, dichotic listening tests with digits, words and consonant-vowel (CV) pairs were administered to two groups of right-handed 11-year-old children, one group diagnosed…
Festinger, Leon; And Others
Eye movements of 18 male and seven female dyslexic children and 10 normal children were evaluated to determine if eye movement disorders may be the cause of some of the symptoms associated with dyslexia. Data on eye movements were collected while Ss moved their eyes from one fixation point to another in a nonreading situation. Errors in vertical…
Primativo, Silvia; Arduino, Lisa S; De Luca, Maria; Daini, Roberta; Martelli, Marialuisa
Brain-damaged patients with right-sided unilateral spatial neglect (USN) often make left-sided errors in reading single words or pseudowords (neglect dyslexia, ND). We propose that both left neglect and low fixation accuracy account for reading errors in neglect dyslexia. Eye movements were recorded in USN patients with (ND+) and without (ND-) neglect dyslexia and in a matched control group of right brain-damaged patients without neglect (USN-). Unlike ND- and controls, ND+ patients showed left lateralized omission errors and a distorted eye movement pattern in both a reading aloud task and a non-verbal saccadic task. During reading, the total number of fixations was larger in these patients independent of visual hemispace, and most fixations were inaccurate. Similarly, in the saccadic task only ND+ patients were unable to reach the moving dot. A third experiment addressed the nature of the left lateralization in reading error distribution by simulating neglect dyslexia in ND- patients. ND- and USN- patients had to perform a speeded reading-at-threshold task that did not allow for eye movements. When stimulus exploration was prevented, ND- patients, but not controls, produced a pattern of errors similar to that of ND+ with unlimited exposure time (e.g., left-sided errors). We conclude that neglect dyslexia reading errors may arise in USN patients as a consequence of an additional and independent deficit unrelated to the orthographic material. In particular, the presence of an altered oculo-motor pattern, preventing the automatic execution of the fine saccadic eye movements involved in reading, uncovers, in USN patients, the attentional bias also in reading single centrally presented words.
Cui, Zaixu; Xia, Zhichao; Su, Mengmeng; Shu, Hua; Gong, Gaolang
Developmental dyslexia has been hypothesized to result from multiple causes and exhibit multiple manifestations, implying a distributed multidimensional effect on human brain. The disruption of specific white-matter (WM) tracts/regions has been observed in dyslexic children. However, it remains unknown if developmental dyslexia affects the human brain WM in a multidimensional manner. Being a natural tool for evaluating this hypothesis, the multivariate machine learning approach was applied in this study to compare 28 school-aged dyslexic children with 33 age-matched controls. Structural magnetic resonance imaging (MRI) and diffusion tensor imaging were acquired to extract five multitype WM features at a regional level: white matter volume, fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity. A linear support vector machine (LSVM) classifier achieved an accuracy of 83.61% using these MRI features to distinguish dyslexic children from controls. Notably, the most discriminative features that contributed to the classification were primarily associated with WM regions within the putative reading network/system (e.g., the superior longitudinal fasciculus, inferior fronto-occipital fasciculus, thalamocortical projections, and corpus callosum), the limbic system (e.g., the cingulum and fornix), and the motor system (e.g., the cerebellar peduncle, corona radiata, and corticospinal tract). These results were well replicated using a logistic regression classifier. These findings provided direct evidence supporting a multidimensional effect of developmental dyslexia on WM connectivity of human brain, and highlighted the involvement of WM tracts/regions beyond the well-recognized reading system in dyslexia. Finally, the discriminating results demonstrated a potential of WM neuroimaging features as imaging markers for identifying dyslexic individuals.
Angelelli, Paola; Marinelli, Chiara Valeria; De Salvatore, Marinella; Burani, Cristina
Italian sixth graders, with and without dyslexia, read pseudowords and low-frequency words that include high-frequency morphemes better than stimuli not including any morpheme. The present study assessed whether morphemes affect (1) younger children, with and without dyslexia; (2) spelling as well as reading; and (3) words with low-frequency morphemes. Two groups of third graders (16 children with dyslexia and dysorthography and 16 age-matched typically developing children) read aloud and spelt to dictation pseudowords and words. Pseudowords included (1) root + suffix in not existing combinations (e.g. lampadista, formed by lampad-, 'lamp', and -ista, '-ist') and (2) orthographic sequences not corresponding to any Italian root or suffix (e.g. livonosto). Words had low frequency and included: (1) root + suffix, both of high frequency (e.g. bestiale, 'beastly'); (2) root + suffix, both of low frequency (e.g. asprigno, 'rather sour'); and (3) simple words (e.g. insulso, 'vapid'). Children with dyslexia and dysorthography were less accurate than typically developing children. Root + suffix pseudowords were read and spelt more accurately than non-morphological pseudowords by both groups. Morphologically complex (root + suffix) words were read and spelt better than simple words. However, task interacted with morphology: reading was not facilitated by low-frequency morphemes. We conclude that children acquiring a transparent orthography exploit morpheme-based reading and spelling to face difficulties in processing long unfamiliar stimuli. Copyright © 2017 John Wiley & Sons, Ltd.
van Viersen, Sietske; Kroesbergen, Evelyn H; Slot, Esther M; de Bree, Elise H
This study investigated how gifted children with dyslexia might be able to mask literacy problems and the role of possible compensatory mechanisms. The sample consisted of 121 Dutch primary school children that were divided over four groups (typically developing [TD] children, children with dyslexia, gifted children, gifted children with dyslexia). The test battery included measures of literacy (reading/spelling) and cognitive abilities related to literacy and language (phonological awareness [PA], rapid automatized naming [RAN], verbal short-term memory [VSTM], working memory [WM], grammar, and vocabulary). It was hypothesized that gifted children with dyslexia would outperform children with dyslexia on literacy tests. In addition, a core-deficit model including dyslexia-related weaknesses and a compensational model involving giftedness-related strengths were tested using Bayesian statistics to explain their reading/spelling performance. Gifted children with dyslexia performed on all literacy tests in between children with dyslexia and TD children. Their cognitive profile showed signs of weaknesses in PA and RAN and strengths in VSTM, WM, and language skills. Findings indicate that phonology is a risk factor for gifted children with dyslexia, but this is moderated by other skills such as WM, grammar, and vocabulary, providing opportunities for compensation of a cognitive deficit and masking of literacy difficulties.
Over the last two decades there has been an expansion of activity and substantial progress in research on dyslexia and research on bilingualism and multilingualism. But the study of dyslexia has generally focused on monolingual learners and the study of bilingualism has tended to focus on speakers who do not have special educational needs. This paper will review the strands of research to date that have a bearing on multilingualism and dyslexia and attempt to identify the major challenges that face researchers and teachers. A satisfactory response cannot be developed without a full understanding of the impact that dyslexia has on language learning and the impact that multilingualism has on literacy learning.
Wybrow, Dean P; Hanley, J Richard
Previous investigations of the incidence of developmental surface and phonological dyslexia using reading-age-matched control groups have identified many more phonological dyslexics (poor nonword reading relative to irregular-word reading) than surface dyslexics (poor irregular-word reading relative to nonword reading). However, because the measures that have been used to estimate reading age include irregular-word reading ability, they appear inappropriate for assessing the incidence of surface dyslexia. The current study used a novel method for generating control groups whose reading ability was matched to that of the dyslexic sample. The incidence of surface dyslexia was assessed by comparing dyslexic performance with that of a control group who were matched with the dyslexics on a test of nonword reading. The incidence of phonological dyslexia was assessed with reference to a control group who were matched with the dyslexics at irregular-word reading. These control groups led to the identification of an approximately equal number of children with surface and phonological dyslexia. It appeared that selecting control participants who were matched with dyslexics for reading age led to the recruitment of individuals with relatively high nonword reading scores relative to their irregular-word reading scores compared with other types of control group. The theoretical implications of these findings are discussed.
van der Leij, Aryan
Part of the Dutch Dyslexia Programme has been dedicated to early intervention. The question of whether the genetically affected learning mechanism of children who are at familial risk (FR) of developing dyslexia could be influenced by training phoneme awareness and letter-sound associations in the prereading phase was investigated. The rationale was that intervention studies reveal insights about the weaknesses of the learning mechanisms of FR children. In addition, the studies aimed to gather practical insights to be used in the development of a system of early diagnosis and prevention. Focused on the last period of kindergarten before formal reading instruction starts in Grade 1, intervention methods with comparable samples and designs but differences in delivery mode (use of computer or manual), tutor (semi-professional or parent), location (at school or at home), and additional practices (serial rapid naming or simple word reading) have been executed to test the hypothesis that the incidence and degree of dyslexia can be reduced. The present position paper summarizes the Dutch Dyslexia Programme findings and relates them to findings of other studies. It is discussed that the Dutch studies provide evidence on why prevention of dyslexia is hard to accomplish. It is argued that effective intervention should not only start early but also be adapted to the individual and often long-lasting educational needs of children at risk of reading failure.
Helland, Turid; Plante, Elena; Hugdahl, Kenneth
This study focused on predicting dyslexia in children ahead of formal literacy training. Because dyslexia is a constitutional impairment, risk factors should be seen in preschool. It was hypothesized that data gathered at age 5 using questions targeting the dyslexia endophenotype should be reliable and valid predictors of dyslexia at age 11. A…
Carroll, Julia M.; Myers, Joanne M.
Comorbidity between SLI and dyslexia is well documented. Researchers have variously argued that dyslexia is a separate disorder from SLI, or that children with dyslexia show a subset of the difficulties shown in SLI. This study examines these hypotheses by assessing whether family history of dyslexia and speech and language difficulties are…
Firth, Nola; Frydenberg, Erica; Steeg, Charlotte; Bond, Lyndal
A dyslexia coping programme entitled "Success and Dyslexia" was implemented in two primary schools within a whole-class coping programme and whole-school dyslexia professional development context. One hundred and two year 6 students, 23 of whom had dyslexia, undertook surveys pretest, post-test and at 1-year follow-up. Effectiveness of…
Tops, W.; Callens, C.; Van Cauwenberghe, E.; Adriaens, J.; Brysbaert, M.
To have a clearer idea of the problems students with dyslexia may face during their studies, we compared writings of 100 students with dyslexia and 100 age matched control students in higher education. The aim of this study was to compare the writing of young adults with dyslexia and young adults without dyslexia. The study was carried out in…
Hoeft, Fumiko; McCandliss, Bruce D; Black, Jessica M; Gantman, Alexander; Zakerani, Nahal; Hulme, Charles; Lyytinen, Heikki; Whitfield-Gabrieli, Susan; Glover, Gary H; Reiss, Allan L; Gabrieli, John D E
Individuals with developmental dyslexia vary in their ability to improve reading skills, but the brain basis for improvement remains largely unknown. We performed a prospective, longitudinal study over 2.5 y in children with dyslexia (n = 25) or without dyslexia (n = 20) to discover whether initial behavioral or brain measures, including functional MRI (fMRI) and diffusion tensor imaging (DTI), can predict future long-term reading gains in dyslexia. No behavioral measure, including widely used and standardized reading and language tests, reliably predicted future reading gains in dyslexia. Greater right prefrontal activation during a reading task that demanded phonological awareness and right superior longitudinal fasciculus (including arcuate fasciculus) white-matter organization significantly predicted future reading gains in dyslexia. Multivariate pattern analysis (MVPA) of these two brain measures, using linear support vector machine (SVM) and cross-validation, predicted significantly above chance (72% accuracy) which particular child would or would not improve reading skills (behavioral measures were at chance). MVPA of whole-brain activation pattern during phonological processing predicted which children with dyslexia would improve reading skills 2.5 y later with >90% accuracy. These findings identify right prefrontal brain mechanisms that may be critical for reading improvement in dyslexia and that may differ from typical reading development. Brain measures that predict future behavioral outcomes (neuroprognosis) may be more accurate, in some cases, than available behavioral measures.
Gooch, Debbie; Hulme, Charles; Nash, Hannah M.; Snowling, Margaret J.
Background: Comorbidity among developmental disorders such as dyslexia, language impairment, attention deficit/hyperactivity disorder and developmental coordination disorder is common. This study explores comorbid weaknesses in preschool children at family risk of dyslexia with and without language impairment and considers the role that…
Patel, M.; Magnusson, M.; Lush, D.; Gomez, S.; Fransson, P. A.
Dyslexia has been shown to affect postural control. The aim of the present study was to investigate the difference in postural stability measured as torque variance in an adult dyslexic group (n=14, determined using the Adult Dyslexia Checklist (ADCL) and nonsense word repetition test) and an adult non-dyslexic group (n=39) on a firm surface and…
Williams, Victoria J; Juranek, Jenifer; Cirino, Paul; Fletcher, Jack M
Developmental dyslexia is frequently associated with atypical brain structure and function within regions of the left hemisphere reading network. To date, few studies have employed surface-based techniques to evaluate cortical thickness and local gyrification in dyslexia. Of the existing cortical thickness studies in children, many are limited by small sample size, variability in dyslexia identification, and the recruitment of prereaders who may or may not develop reading impairment. Further, no known study has assessed local gyrification index (LGI) in dyslexia, which may serve as a sensitive indicator of atypical neurodevelopment. In this study, children with dyslexia (n = 31) and typically decoding peers (n = 45) underwent structural magnetic resonance imaging to assess whole-brain vertex-wise cortical thickness and LGI. Children with dyslexia demonstrated reduced cortical thickness compared with controls within previously identified reading areas including bilateral occipitotemporal and occipitoparietal regions. Compared with controls, children with dyslexia also showed increased gyrification in left occipitotemporal and right superior frontal cortices. The convergence of thinner and more gyrified cortex within the left occipitotemporal region among children with dyslexia may reflect its early temporal role in processing word forms, and highlights the importance of the ventral stream for successful word reading.
It has recently been suggested that dyslexia may manifest as a deficit in the neural synchrony underlying language-based codes (Goswami, 2011), such that the phonological deficits apparent in dyslexia occur as a consequence of poor synchronisation of oscillatory brain signals to the sounds of language. There is compelling evidence to support this suggestion, and it provides an intriguing new development in understanding the aetiology of dyslexia. It is undeniable that dyslexia is associated with poor phonological coding, however, reading is also a visual task, and dyslexia has also been associated with poor visual coding, particularly visuo-spatial sensitivity. It has been hypothesized for some time that specific frequency oscillations underlie visual perception. Although little research has been done looking specifically at dyslexia and cortical frequency oscillations, it is possible to draw on converging evidence from visual tasks to speculate that similar deficits could occur in temporal frequency oscillations in the visual domain in dyslexia. Thus, here the plausibility of a visual correlate of the Temporal Sampling Framework is considered, leading to specific hypotheses and predictions for future research. A common underlying neural mechanism in dyslexia, may subsume qualitatively different manifestations of reading difficulty, which is consistent with the heterogeneity of the disorder, and may open the door for a new generation of exciting research. PMID:24596549
Friedmann, Naama; Tzailer-Gross, Lital; Gvion, Aviah
Individuals with text-based neglect dyslexia omit words on the neglected side of the sentence or text, usually on the left side. This study tested whether the syntactic structure of the target sentence affects reading in this type of neglect dyslexia. Because Hebrew is read from right to left, it enables testing whether the beginning of the…
Wright, Craig M.; Conlon, Elizabeth G.; Dyck, Murray
The aim of this study was to investigate the theory that visual magnocellular deficits seen in groups with dyslexia are linked to reading via the mechanisms of visual attention. Visual attention was measured with a serial search task and magnocellular function with a coherent motion task. A large group of children with dyslexia (n = 70) had slower…
Baillieux, Hanne; Vandervliet, Everhard J. M.; Manto, Mario; Parizel, Paul M.; De Deyn, Peter P.; Marien, Peter
Developmental dyslexia is the most common learning disability in school-aged children with an estimated incidence of five to ten percent. The cause and pathophysiological substrate of this developmental disorder is unclear. Recently, a possible involvement of the cerebellum in the pathogenesis of dyslexia has been postulated. In this study, 15…
The aim of this study was to see whether patterns of neuro-cognitive assets and deficits seen in dyslexia also would lead to different patterns of reading and writing. A group of dyslexic children was subgrouped by language comprehension and mathematics skills in accordance with the definition of the British Dyslexia Association of 1998. This…
The prevalence of phonological and surface dyslexia subtypes among Swedish university students with dyslexia (n = 40) was examined using both the regression method, developed by Castles and Coltheart, and latent profile analysis. When an academic-level control group was used as a reference group in a regression, eight students with phonological…
van Viersen, Sietske; Kroesbergen, Evelyn H.; Slot, Esther M.; de Bree, Elise H.
This study investigated how gifted children with dyslexia might be able to mask literacy problems and the role of possible compensatory mechanisms. The sample consisted of 121 Dutch primary school children that were divided over four groups (typically developing [TD] children, children with dyslexia, gifted children, gifted children with…
This article shares the author's research focusing on the facilitation of acting students with dyslexia in actor-training. For some individuals with dyslexia the translation of the written text into image-based symbols using technological modalities can play a crucial role to access and make concrete the meaning of the words; in this case…
Chung, Kevin K. H.; Ho, Connie S. H.
Dyslexia appears to be the most prevalent disability of students with special educational needs in many mainstream classes, affecting around 9.7% of the school population in Hong Kong. The education of these students is therefore of great concern to the community. In the present paper research into dyslexia in the Chinese language is briefly…
Tops, Wim; Callens, Maaike; Bijn, Evi; Brysbaert, Marc
In this study we focused on the spelling of high-functioning students with dyslexia. We made a detailed classification of the errors in a word and sentence dictation task made by 100 students with dyslexia and 100 matched control students. All participants were in the first year of their bachelor's studies and had Dutch as mother tongue. Three…
Friedmann, Naama; Rahamim, Einav
Letter position dyslexia (LPD) is a peripheral dyslexia that causes errors of letter position within words, such as reading "cloud" as "could." In this study, we assessed the effect of various display manipulations and reading methods on the reading of 10 Hebrew readers with developmental LPD. These manipulations included…
Ho, Connie Suk-Han; Chan, David Wai-Ock; Lee, Suk-Han; Tsang, Suk-Man; Luan, Vivian Hui
The present study examined the cognitive profile and subtypes of developmental dyslexia in a nonalphabetic script, Chinese. One hundred and forty-seven Chinese primary school children with developmental dyslexia were tested on a number of literacy and cognitive tasks. The results showed that rapid naming deficit and orthographic deficit were the…
McArthur, Genevieve; Castles, Anne; Kohnen, Saskia; Larsen, Linda; Jones, Kristy; Anandakumar, Thushara; Banales, Erin
The aims of this study were to (a) compare sight word training and phonics training in children with dyslexia, and (b) determine if different orders of sight word and phonics training have different effects on the reading skills of children with dyslexia. One group of children (n = 36) did 8 weeks of phonics training (reading via grapheme-phoneme…
Simmons, Fiona Rachel; Singleton, Chris
The abilities of 19 adult students with dyslexia and 19 students without dyslexia to recall number facts were compared. Despite being matched for estimated IQ, the dyslexic students were less accurate than the non-dyslexic students when answering subtraction and multiplication questions. When the dyslexic students answered addition and subtraction…
Landerl, Karin; Fussenegger, Barbara; Moll, Kristina; Willburger, Edith
This study tests the hypothesis that dyslexia and dyscalculia are associated with two largely independent cognitive deficits, namely a phonological deficit in the case of dyslexia and a deficit in the number module in the case of dyscalculia. In four groups of 8- to 10-year-olds (42 control, 21 dyslexic, 20 dyscalculic, and 26…
Serrano, Francisca; Defior, Sylvia
Dyslexia is a persistent problem in written language, consisting of a severe difficulty in word recognition. It is characterized by low reading performance, while other skills are not impaired, being normal or even superior in some cases. This paper reviews different proposals for defining and clarifying causes of dyslexia. Additionally, we…
Vagge, Aldo; Cavanna, Margherita; Traverso, Carlo Enrico; Iester, Michele
The aims of this study were to analyze the relationship between dyslexia and eye movements and to assess whether this method can be added to the workup of dyslexic patients. The sample was comprised of 11 children with a diagnosis of dyslexia and 11 normal between 8 and 13 years of age. All subjects underwent orthoptic evaluation, ophthalmological…
Raveh, Michal; Schiff, Rachel
The quality of implicit morphological knowledge in adult Hebrew readers with developmental dyslexia was investigated. The priming paradigm was used to examine whether these adults extract and represent morphemic units similarly to normal readers during online word recognition. The group with dyslexia as a whole did not exhibit priming with visual…
Long, Gayle Beam; Jacewicz, Ewa
Purpose The purpose of this study was to determine whether the underlying phonological impairment in dyslexia is associated with a deficit in categorizing regional dialects. Method Twenty adults with dyslexia, 20 school-age children with dyslexia, and 40 corresponding control listeners with average reading ability listened to sentences produced by multiple talkers (both sexes) representing two dialects: Midland dialect in Ohio (same as listeners' dialect) and Southern dialect in Western North Carolina. Participants' responses were analyzed using signal detection theory. Results Listeners with dyslexia were less sensitive to talker dialect than listeners with average reading ability. Children were less sensitive to dialect than adults. Under stimulus uncertainty, listeners with average reading ability were biased toward Ohio dialect, whereas listeners with dyslexia were unbiased in their responses. Talker sex interacted with sensitivity and bias differently for listeners with dyslexia than for listeners with average reading ability. The correlations between dialect sensitivity and phonological memory scores were strongest for adults with dyslexia. Conclusions The results imply that the phonological deficit in dyslexia arises from impaired access to intact phonological representations rather than from poorly specified representations. It can be presumed that the impeded access to implicit long-term memory representations for indexical (dialect) information is due to less efficient operations in working memory, including deficiencies in utilizing talker normalization processes. PMID:27575597
Rubinsten, Orly; Henik, Avishai
This work examines the association between symbols and their representation in adult developmental dyscalculia and dyslexia. Experiment 1 used comparative judgment of numerals, and it was found that in physical comparisons (e.g., 3-5 vs. 3-5) the dyscalculia group showed a significantly smaller congruity effect than did the dyslexia and the…
Chait, Maria; Eden, Guinevere; Poeppel, David; Simon, Jonathan Z.; Hill, Deborah F.; Flowers, D. Lynn
Individuals with developmental dyslexia are often impaired in their ability to process certain linguistic and even basic non-linguistic auditory signals. Recent investigations report conflicting findings regarding impaired low-level binaural detection mechanisms associated with dyslexia. Binaural impairment has been hypothesized to stem from a…
Bell, Sheena; McPhillips, Therese; Doveston, Mary
This paper presents the findings of a comparative study using data from questionnaire surveys carried out in England (n = 57) and Ireland (n = 72). The researchers examine how teachers and teaching assistants who are currently teaching pupils with dyslexia in primary schools describe dyslexia and what may have influenced their conceptualisation.…
Brunswick, Nicola; Martin, G. Neil; Marzano, Lisa
Anecdotal evidence indicates that dyslexia is positively associated with superior visuospatial ability but empirical evidence is inconsistent. We explicitly tested the hypothesis that dyslexia is associated with visuospatial advantage in 20 dyslexic and 21 unimpaired adult readers using paper-and-pencil measures and tests of "everyday"…
Benasich, April A., Ed.; Fitch, R. Holly, Ed.
Understanding the precursors and early indicators of dyslexia is key to early identification and effective intervention. Now there's a single research volume that brings together the very latest knowledge on the earliest stages of dyslexia and the diverse genetic, neurobiological, and cognitive factors that may contribute to it. Based on findings…
Pickering, Joyce S.
This article uses a question-answer format to present information for parents on dyslexia and attention deficit disorders (ADD). Information includes typical behaviors and skills of children with dyslexia or ADD, how parents can help their children, and the use of medication to control hyperactivity. (KB)
Ziegler, Johannes C.
It has been commonly agreed that developmental dyslexia in different languages has a common biological origin: a dysfunction of left posterior temporal brain regions dealing with phonological processes. Siok, Perfetti, Jin, and Tan (2004, "Nature," 431, 71-76) challenge this biological unity theory of dyslexia: Chinese dyslexics show no deficits…
Galaburda, Albert M.
For 25 years now, there has been a serious attempt to get at the fundamental cause(s) of dyslexia in our laboratory. A great deal of research has been carried out on the psychological and brain underpinnings of the linguistic dysfunctions seen in dyslexia, but attempts to get at its cause have been limited. Initially, observations were made on the…
Partanen, Marita; Fitzpatrick, Kevin; Madler, Burkhard; Edgell, Dorothy; Bjornson, Bruce; Giaschi, Deborah E.
The current study examined auditory processing deficits in dyslexia using a dichotic pitch stimulus and functional MRI. Cortical activation by the dichotic pitch task occurred in bilateral Heschl's gyri, right planum temporale, and right superior temporal sulcus. Adolescents with dyslexia, relative to age-matched controls, illustrated greater…
Schulte-Korne, Gerd; Ludwig, Kerstin U.; el Sharkawy, Jennifer; Nothen, Markus M.; Muller-Myhsok, Bertram; Hoffmann, Per
Our understanding of the causes of a developmental disorder like dyslexia has received recent input from both neuroscience and genetics. The discovery of 4 candidate genes for dyslexia and the identification of neuronal networks engaged when children read and spell are the basis for introducing this knowledge into education. However, the input…
Tilanus, Elisabeth A T; Segers, Eliane; Verhoeven, Ludo
We examined the responsiveness to a 12-week phonics intervention in 54 s-grade Dutch children with dyslexia, and compared their reading and spelling gains to a control group of 61 typical readers. The intervention aimed to train grapheme-phoneme correspondences (GPCs), and word reading and spelling by using phonics instruction. We examined the accuracy and efficiency of grapheme-phoneme correspondences, decoding words and pseudowords, as well as the accuracy of spelling words before and after the intervention. Moreover, responsiveness to intervention was examined by studying to what extent scores at posttest could directly or indirectly be predicted from precursor measures. Results showed that the children with dyslexia were significantly behind in all reading and spelling measures at pretest. During the intervention, the children with dyslexia made more progress on GPC, (pseudo)word decoding accuracy and efficiency, and spelling accuracy than the typical reading group. Furthermore, we found a direct effect of the precursor measures rapid automatized naming, verbal working memory and phoneme deletion on the dyslexic children's progress in GPC speed, and indirect effects of rapid automatized naming and phoneme deletion on word and pseudoword efficiency and word decoding accuracy via the scores at pretest. Copyright © 2016 John Wiley & Sons, Ltd.
van Daal, V H; Reitsma, P
The effects of a Dutch intervention program for dyslexia are reported. The program was individually tailored, depending on the style of reading, the phase of the learning process, and the intermediate results of the treatment. Two groups of participants were involved: (a) a group of children with pure dyslexia (n = 109) and (b) a group that had reading problems but also suffered from cognitive deficits or psychiatric symptoms (n = 29). Scores of reading single words and text at intake and after the intervention were analyzed to assess the efficacy of the intervention program. Furthermore, the effects of pre-intervention variables such as intelligence, reported speech, and language problems and of intervention variables such as the initial level of performance and the duration of the treatment were examined. Both groups benefitted from the intervention, but the children with pure dyslexia profited most. Neither of the groups could catch up the reading deficit. Intelligence and reported speech and language problems did not affect the treatment outcomes. Individual differences in treatment outcome were related to the absolute level of word reading and age at intake. In the group with comorbidity, the intervention program was more successful in relatively younger children. Within this group, the cognitive deficits and types of psychiatric problems were not related to the treatment.
Jones, Manon W; Branigan, Holly P; Parra, Mario A; Logie, Robert H
The ability to learn visual-phonological associations is a unique predictor of word reading, and individuals with developmental dyslexia show impaired ability in learning these associations. In this study, we compared developmentally dyslexic and nondyslexic adults on their ability to form cross-modal associations (or "bindings") based on a single exposure to pairs of visual and phonological features. Reading groups were therefore compared on the very early stages of associative learning. We used a working memory framework-including experimental designs used to investigate cross-modal binding. Two change-detection experiments showed a group discrepancy in binding that was dependent on spatial location encoding: Whereas group performance was similar when location was an inconsistent cue (Experiment 1), nondyslexic readers showed higher accuracy in binding than dyslexics when location was a consistent cue (Experiment 2). A cued-recall task confirmed that location information discriminates binding ability between reading groups in a more explicit memory recall task (Experiment 3). Our results show that recall for ephemeral cross-modal bindings is supported by location information in nondyslexics, but this information cannot be used to similar effect in dyslexic readers. Our findings support previous demonstrations of cross-modal association difficulty in dyslexia and show that a group discrepancy exists even in a single, initial presentation of visual-phonological pairs. Effective use of location information as a retrieval cue is one mechanism that discriminates reading groups, which may contribute to the longer term cross-modal association problems characteristic of dyslexia.
Harrar, Vanessa; Tammam, Jonathan; Pérez-Bellido, Alexis; Pitt, Anna; Stein, John; Spence, Charles
Developmental dyslexia affects 5%-10% of the population, resulting in poor spelling and reading skills. While there are well-documented differences in the way dyslexics process low-level visual and auditory stimuli, it is mostly unknown whether there are similar differences in audiovisual multisensory processes. Here, we investigated audiovisual integration using the redundant target effect (RTE) paradigm. Some conditions demonstrating audiovisual integration appear to depend upon magnocellular pathways, and dyslexia has been associated with deficits in this pathway; so, we postulated that developmental dyslexics ("dyslexics" hereafter) would show differences in audiovisual integration compared with controls. Reaction times (RTs) to multisensory stimuli were compared with predictions from Miller's race model. Dyslexics showed difficulty shifting their attention between modalities; but such "sluggish attention shifting" (SAS) appeared only when dyslexics shifted their attention from the visual to the auditory modality. These results suggest that dyslexics distribute their crossmodal attention resources differently from controls, causing different patterns in multisensory responses compared to controls. From this, we propose that dyslexia training programs should take into account the asymmetric shifts of crossmodal attention.
Moncrieff, Deborah W; Black, Jeffrey R
Several auditory processing deficits have been reported in children with dyslexia. In order to assess for the presence of a binaural integration type of auditory processing deficit, dichotic listening tests with digits, words and consonant-vowel (CV) pairs were administered to two groups of right-handed 11-year-old children, one group diagnosed with developmental dyslexia and an age-matched control group. Dyslexic children performed more poorly than controls from their left ears when listening to digits and words and from their right ears when listening to CVs. Direction of ear advantage varied across individuals in both groups when tested with digits and CVs, but ear advantage was stable with words. Several factors that may have contributed to inconsistencies in direction of ear advantage are discussed. When the children were tested in a directed response mode, degree of ear advantage differed significantly between groups with both words and digits. More dyslexic than control children demonstrated clinically significant reductions in dichotic listening performance, but no uniform pattern of deficit emerged. Only the double correct score and the left ear score with CV pairs were predictive of word recognition performance in dyslexic children. Binaural integration deficits are present in some children with dyslexia. Auditory processing disorder assessment may help delineate factors that underlie or are associated with reading impairment in this population.
Fabbro, F; Pesenti, S; Facoetti, A; Bonanomi, M; Libera, L; Lorusso, M L
Sixteen controls (age 6-13) and 20 native Italian children with developmental dyslexia (age 7-15) received a test of callosal transfer of tactile information. Among the dyslexic children, 7 had a diagnosis of L-type, 7 of P-type and 6 of M-type dyslexia according to Bakker's classification. Both control children and children with dyslexia made a significantly larger number of errors in the crossed localization condition (implying callosal transfer of tactile information) vs. the uncrossed condition. In the same condition, children with dyslexia made a significantly larger number of errors than controls. In the crossed localization condition L-types and M-types made a significantly larger number of errors than P-types and controls, while there was no significant difference in performance between P-types and controls. These findings are discussed in terms of defective callosal transfer or deficient somatosensory representation in children with L- and M-dyslexia.
Bloom, Juliana Sanchez; Garcia-Barrera, Mauricio A.; Miller, Carlin J.; Miller, Scott R.; Hynd, George W.
The planum temporale is a highly lateralized cortical region, located within Wernicke’s area, which is thought to be involved in auditory processing, phonological processing, and language. Research has linked abnormal morphology of the planum temporale to developmental dyslexia, although results have varied in large part due to methodological inconsistencies in the literature. This study examined the asymmetry of the planum temporale in 29 children who met criteria for dyslexia and 26 children whose reading was unimpaired. Leftward asymmetry of the planum temporale was found in the total sample and this leftward asymmetry was significantly reduced in children with dyslexia. This reduced leftward asymmetry in children with dyslexia was due to a planum temporale that is larger in the right hemisphere. This study lends support to the idea that planum temporale asymmetry is altered in children with developmental dyslexia. PMID:23707683
Tops, Wim; Callens, Maaike; Bijn, Evi; Brysbaert, Marc
In this study we focused on the spelling of high-functioning students with dyslexia. We made a detailed classification of the errors in a word and sentence dictation task made by 100 students with dyslexia and 100 matched control students. All participants were in the first year of their bachelor's studies and had Dutch as mother tongue. Three main error categories were distinguished: phonological, orthographic, and grammatical errors (on the basis of morphology and language-specific spelling rules). The results indicated that higher-education students with dyslexia made on average twice as many spelling errors as the controls, with effect sizes of d ≥ 2. When the errors were classified as phonological, orthographic, or grammatical, we found a slight dominance of phonological errors in students with dyslexia. Sentence dictation did not provide more information than word dictation in the correct classification of students with and without dyslexia.
Yang, Yang; Chen, Bao-Guo; Zhang, Yi-Wei; Bi, Hong-Yan
The cerebellar deficit hypothesis for developmental dyslexia claims that cerebellar dysfunction causes the failures in the acquisition of visuomotor skills and automatic reading and writing skills. In people with dyslexia in the alphabetic languages, the abnormal activation and structure of the right or bilateral cerebellar lobes have been identified. Using a typical implicit motor learning task, however, one neuroimaging study demonstrated the left cerebellar dysfunction in Chinese children with dyslexia. In the present study, using voxel-based morphometry, we found decreased gray matter volume in the left cerebellum in Chinese children with dyslexia relative to age-matched controls. The positive correlation between reading performance and regional gray matter volume suggests that the abnormal structure in the left cerebellum is responsible for reading disability in Chinese children with dyslexia. PMID:27047403
Geiser, Eveline; Kjelgaard, Margaret; Christodoulou, Joanna A.; Cyr, Abigail; Gabrieli, John D. E.
Reading disability in children with dyslexia has been proposed to reflect impairment in auditory timing perception. We investigated one aspect of timing perception--"temporal grouping"--as present in prosodic phrase boundaries of natural speech, in age-matched groups of children, ages 6-8 years, with and without dyslexia. Prosodic phrase…
Tamboer, Peter; Scholte, H. Steven; Vorst, Harrie C. M.
In voxel-based morphometry studies of dyslexia, the relation between causal theories of dyslexia and gray matter (GM) and white matter (WM) volume alterations is still under debate. Some alterations are consistently reported, but others failed to reach significance. We investigated GM alterations in a large sample of Dutch students (37 dyslexics…
Smith-Spark, James H; Zięcik, Adam P; Sterling, Christopher
Prospective memory (PM) is memory for delayed intentions. Despite its importance to everyday life, the few studies on PM function in adults with dyslexia which exist have relied on self-report measures. To determine whether self-reported PM deficits can be measured objectively, laboratory-based PM tasks were administered to 24 adults with dyslexia and 25 age- and IQ-matched adults without dyslexia. Self-report data indicated that people with dyslexia felt that time-based PM (TBPM; requiring responses at certain times in the future) was most problematic for them and so this form of PM was the focus of investigation. Whilst performing the ongoing task from which they were required to break out every 3 min to make a PM-related response, the participants were allowed to make clock checks whenever they wished. The cognitive demands made on ongoing behaviour were manipulated to determine whether loading executive resources had a mediating role in dyslexia-related deficits in PM, resulting in three tasks with varying working memory load. A semi-naturalistic TBPM task was also administered, in which the participants were asked to remind the experimenter to save a data file 40 min after being given this instruction. Dyslexia-related differences were found across all three computerized tasks, regardless of cognitive load. The adults with dyslexia made fewer correct PM responses and also fewer clock checks. On the semi-naturalistic task, the participants with dyslexia were less likely to remember to remind the experimenter to save the file. This is the first study to document PM deficits in dyslexia using objective measures of performance. Since TBPM impairments were found under more naturalistic conditions as well as on computerized tasks, the results have implications for workplace support for adults with dyslexia.
Lorusso, Maria Luisa; Cantiani, Chiara; Molteni, Massimo
The nature of Rapid Auditory Processing (RAP) deficits in dyslexia remains debated, together with the specificity of the problem to certain types of stimuli and/or restricted subgroups of individuals. Following the hypothesis that the heterogeneity of the dyslexic population may have led to contrasting results, the aim of the study was to define the effect of age, dyslexia subtype and comorbidity on the discrimination and reproduction of non-verbal tone sequences. Participants were 46 children aged 8–14 (26 with dyslexia, subdivided according to age, presence of a previous language delay, and type of dyslexia). Experimental tasks were a Temporal Order Judgment (TOJ) (manipulating tone length, ISI and sequence length), and a Pattern Discrimination Task. Dyslexic children showed general RAP deficits. Tone length and ISI influenced dyslexic and control children's performance in a similar way, but dyslexic children were more affected by an increase from 2 to 5 sounds. As to age, older dyslexic children's difficulty in reproducing sequences of 4 and 5 tones was similar to that of normally reading younger (but not older) children. In the analysis of subgroup profiles, the crucial variable appears to be the advantage, or lack thereof, in processing long vs. short sounds. Dyslexic children with a previous language delay obtained the lowest scores in RAP measures, but they performed worse with shorter stimuli, similar to control children, while dyslexic-only children showed no advantage for longer stimuli. As to dyslexia subtype, only surface dyslexics improved their performance with longer stimuli, while phonological dyslexics did not. Differential scores for short vs. long tones and for long vs. short ISIs predict non-word and word reading, respectively, and the former correlate with phonemic awareness. In conclusion, the relationship between non-verbal RAP, phonemic skills and reading abilities appears to be characterized by complex interactions with subgroup
van der Leij, Aryan; van Bergen, Elsje; van Zuijen, Titia; de Jong, Peter; Maurits, Natasha; Maassen, Ben
Converging evidence suggests that developmental dyslexia is a neurobiological disorder, characterized by deficits in the auditory, visual, and linguistic domains. In the longitudinal project of the Dutch Dyslexia Programme, 180 children with a familial risk of dyslexia (FR) and a comparison group of 120 children without FR (noFR) were followed from the age of 2 months up to 9 years. Children were assessed on (1) auditory, speech, and visual event-related potentials every half year between 2 and 41 months; (2) expressive and receptive language, motor development, behaviour problems, and home-literacy environment by questionnaires at the age of 2 and 3; (3) speech-language and cognitive development from 47 months onwards; and (4) preliteracy and subskills of reading, and reading development during kindergarten and Grades 2 and 3. With regard to precursors of reading disability, first analyses showed specific differences between FR and noFR children in neurophysiological, cognitive, and early language measures. Once reading tests administered from age 7 to 9 years were available, the children were divided into three groups: FR children with and without dyslexia, and controls. Analyses of the differences between reading groups yielded distinct profiles and developmental trajectories. On early speech and visual processing, and several cognitive measures, performance of the non-dyslexic FR group differed from the dyslexic FR group and controls, indicating continuity of the influence of familial risk. Parental reading and rapid naming skills appeared to indicate their offspring's degree of familial risk. Furthermore, on rapid naming and nonverbal IQ, the non-dyslexic FR group performed similarly to the controls, suggesting protective factors. There are indications of differences between the FR and control groups, irrespective of reading outcome. These results contribute to the distinction between the deficits correlated to dyslexia as a manifest reading disorder
Lorusso, Maria Luisa; Cantiani, Chiara; Molteni, Massimo
The nature of Rapid Auditory Processing (RAP) deficits in dyslexia remains debated, together with the specificity of the problem to certain types of stimuli and/or restricted subgroups of individuals. Following the hypothesis that the heterogeneity of the dyslexic population may have led to contrasting results, the aim of the study was to define the effect of age, dyslexia subtype and comorbidity on the discrimination and reproduction of non-verbal tone sequences. Participants were 46 children aged 8-14 (26 with dyslexia, subdivided according to age, presence of a previous language delay, and type of dyslexia). Experimental tasks were a Temporal Order Judgment (TOJ) (manipulating tone length, ISI and sequence length), and a Pattern Discrimination Task. Dyslexic children showed general RAP deficits. Tone length and ISI influenced dyslexic and control children's performance in a similar way, but dyslexic children were more affected by an increase from 2 to 5 sounds. As to age, older dyslexic children's difficulty in reproducing sequences of 4 and 5 tones was similar to that of normally reading younger (but not older) children. In the analysis of subgroup profiles, the crucial variable appears to be the advantage, or lack thereof, in processing long vs. short sounds. Dyslexic children with a previous language delay obtained the lowest scores in RAP measures, but they performed worse with shorter stimuli, similar to control children, while dyslexic-only children showed no advantage for longer stimuli. As to dyslexia subtype, only surface dyslexics improved their performance with longer stimuli, while phonological dyslexics did not. Differential scores for short vs. long tones and for long vs. short ISIs predict non-word and word reading, respectively, and the former correlate with phonemic awareness. In conclusion, the relationship between non-verbal RAP, phonemic skills and reading abilities appears to be characterized by complex interactions with subgroup
Elbeheri, Gad; Everatt, John; Al Malki, Mohammad
This paper investigates the incidence of dyslexia among young offenders in Kuwait. A total of 91 children/young adults from 8 juvenile delinquent welfare centres across Kuwait were interviewed and tested. A measure of non-verbal reasoning ability was used to exclude those with low general ability. The remaining 53 participants were tested on their ability to identify alliteration and rhyme, retain and manipulate sequences of digit and letter names, decode novel letter strings and identify words within letter chains. Participants' reading accuracy, rate of reading, reading comprehension and ability to spell correctly dictated text were also assessed. These measures were used to determine those with indicators of dyslexia. The results indicated that the percentage of individuals presenting evidence of dyslexia was much larger (greater than 20%) in this population of young offenders than would be expected based on the national average (around 6%) of dyslexics in Kuwait derived from a nationwide study (A survey study of dyslexia in Kuwait, Kuwait Dyslexia Association: Kuwait City; 2002). These findings replicate previous evidence for an increased frequency of dyslexia among young offenders. The implications of such findings are discussed in terms of dyslexia awareness, socio-cultural factors, education and intervention, particularly in Kuwait juvenile delinquent welfare centres.
Kalashnikova, Marina; Goswami, Usha; Burnham, Denis
Dyslexia is a neurodevelopmental disorder manifested in deficits in reading and spelling skills that is consistently associated with difficulties in phonological processing. Dyslexia is genetically transmitted, but its manifestation in a particular individual is thought to depend on the interaction of epigenetic and environmental factors. We adopt a novel interactional perspective on early linguistic environment and dyslexia by simultaneously studying two pre-existing factors, one maternal and one infant, that may contribute to these interactions; and two behaviours, one maternal and one infant, to index the effect of these factors. The maternal factor is whether mothers are themselves dyslexic or not (with/without dyslexia) and the infant factor is whether infants are at-/not-at family risk for dyslexia (due to their mother or father being dyslexic). The maternal behaviour is mothers' infant-directed speech (IDS), which typically involves vowel hyperarticulation, thought to benefit speech perception and language acquisition. The infant behaviour is auditory perception measured by infant sensitivity to amplitude envelope rise time, which has been found to be reduced in dyslexic children. Here, at-risk infants showed significantly poorer acoustic sensitivity than not-at-risk infants and mothers only hyperarticulated vowels to infants who were not at-risk for dyslexia. Mothers' own dyslexia status had no effect on IDS quality. Parental speech input is thus affected by infant risk status, with likely consequences for later linguistic development.
Ma, Yizhou; Koyama, Maki S.; Milham, Michael P.; Castellanos, F. Xavier; Quinn, Brian T.; Pardoe, Heath; Wang, Xiuyuan; Kuzniecky, Ruben; Devinsky, Orrin; Thesen, Thomas; Blackmon, Karen
Abnormalities in cortical structure are commonly observed in children with dyslexia in key regions of the “reading network.” Whether alteration in cortical features reflects pathology inherent to dyslexia or environmental influence (e.g., impoverished reading experience) remains unclear. To address this question, we compared MRI-derived metrics of cortical thickness (CT), surface area (SA), gray matter volume (GMV), and their lateralization across three different groups of children with a historical diagnosis of dyslexia, who varied in current reading level. We compared three dyslexia subgroups with: (1) persistent reading and spelling impairment; (2) remediated reading impairment (normal reading scores), and (3) remediated reading and spelling impairments (normal reading and spelling scores); and a control group of (4) typically developing children. All groups were matched for age, gender, handedness, and IQ. We hypothesized that the dyslexia group would show cortical abnormalities in regions of the reading network relative to controls, irrespective of remediation status. Such a finding would support that cortical abnormalities are inherent to dyslexia and are not a consequence of abnormal reading experience. Results revealed increased CT of the left fusiform gyrus in the dyslexia group relative to controls. Similarly, the dyslexia group showed CT increase of the right superior temporal gyrus, extending into the planum temporale, which resulted in a rightward CT asymmetry on lateralization indices. There were no group differences in SA, GMV, or their lateralization. These findings held true regardless of remediation status. Each reading level group showed the same “double hit” of atypically increased left fusiform CT and rightward superior temporal CT asymmetry. Thus, findings provide evidence that a developmental history of dyslexia is associated with CT abnormalities, independent of remediation status. PMID:25610779
Schneps, Matthew H.; Brockmole, J. R.; Rose, L. T.; Pomplun, M.; Sonnert, G.; Greenhill, L. J.
Dyslexia is a hereditary neurological condition characterized by difficulties in reading, writing, and spelling. The fact that those with dyslexia include many accomplished scientists, including some recognized with a Nobel Prize, has prompted researchers to suggest that the neurology of dyslexia may predispose these individuals to advantages in visually-intensive domains such as science. Here, we report evidence of a link between dyslexia and abilities for visual processing useful in astronomy. First, we show that when images of natural scenes are Gaussian-blurred, so as to remove high-frequency detail (and resemble many astronomical images), college students with dyslexia significantly outperform those who are typical readers in learning the spatial contexts presented. Second, we show that when the threshold ability to detect radio signatures characteristic of black holes is measured in a laboratory simulation, astrophysicists with dyslexia significantly outperform those who are typical readers in this task when the visual periphery is important. In a third experiment, using eye-tracking technologies, we demonstrate that visual strategies significantly correlate with success in the black hole task, but that college students with dyslexia tend not to employ the strategies most likely to lead to success. Collectively, these studies suggest that dyslexia is linked to neurological advantages useful in astronomical careers, but that left to their own devices students with dyslexia may not benefit from these advantages without practice or training. These studies imply that many students who are struggling to read may find successful careers in astronomy or other fields that build on visual advantages linked to their reading disability, but that education and training may be vital in helping these students realize their strengths. This material is based upon work supported by the George E. Burch Fellowship (Smithsonian Institution) and the National Science Foundation
Ma, Yizhou; Koyama, Maki S; Milham, Michael P; Castellanos, F Xavier; Quinn, Brian T; Pardoe, Heath; Wang, Xiuyuan; Kuzniecky, Ruben; Devinsky, Orrin; Thesen, Thomas; Blackmon, Karen
Abnormalities in cortical structure are commonly observed in children with dyslexia in key regions of the "reading network." Whether alteration in cortical features reflects pathology inherent to dyslexia or environmental influence (e.g., impoverished reading experience) remains unclear. To address this question, we compared MRI-derived metrics of cortical thickness (CT), surface area (SA), gray matter volume (GMV), and their lateralization across three different groups of children with a historical diagnosis of dyslexia, who varied in current reading level. We compared three dyslexia subgroups with: (1) persistent reading and spelling impairment; (2) remediated reading impairment (normal reading scores), and (3) remediated reading and spelling impairments (normal reading and spelling scores); and a control group of (4) typically developing children. All groups were matched for age, gender, handedness, and IQ. We hypothesized that the dyslexia group would show cortical abnormalities in regions of the reading network relative to controls, irrespective of remediation status. Such a finding would support that cortical abnormalities are inherent to dyslexia and are not a consequence of abnormal reading experience. Results revealed increased CT of the left fusiform gyrus in the dyslexia group relative to controls. Similarly, the dyslexia group showed CT increase of the right superior temporal gyrus, extending into the planum temporale, which resulted in a rightward CT asymmetry on lateralization indices. There were no group differences in SA, GMV, or their lateralization. These findings held true regardless of remediation status. Each reading level group showed the same "double hit" of atypically increased left fusiform CT and rightward superior temporal CT asymmetry. Thus, findings provide evidence that a developmental history of dyslexia is associated with CT abnormalities, independent of remediation status.
Harm, M W; Seidenberg, M S
The development of reading skill and bases of developmental dyslexia were explored using connectionist models. Four issues were examined: the acquisition of phonological knowledge prior to reading, how this knowledge facilitates learning to read, phonological and nonphonological bases of dyslexia, and effects of literacy on phonological representation. Compared with simple feedforward networks, representing phonological knowledge in an attractor network yielded improved learning and generalization. Phonological and surface forms of developmental dyslexia, which are usually attributed to impairments in distinct lexical and nonlexical processing "routes," were derived from different types of damage to the network. The results provide a computationally explicit account of many aspects of reading acquisition using connectionist principles.
Wright, Craig M; Conlon, Elizabeth G
This study investigated the temporal stability and longitudinal replicability of visual and auditory sensory processes found to be poor in children with dyslexia. Seventy children with dyslexia and 52 normal readers were tested twice, 9 months apart, on measures of visual and auditory sensory processing and on phonological and orthographic skills. About 30% of children with dyslexia were found to have sensory deficits. Associations were found between sensory and cognitive skills. Based on analyses of agreement, the temporal stability of the sensory tasks was poor. Future research should develop sensory measures with high temporal stability that can control for maturation.
Fahle, M; Luberichs, J
Recently, peculiarities of visual perception were found in dyslexic patients. Therefore, we investigated visual acuity, reading and spelling capabilities, as well as peripheral letter recognition in 54 children with reading and/or spelling problems. Subsequently, the children and their parents trained at home for approximately 0.5 h daily during 2-3 months. Training consisted of reading through a small aperture and of visuomotor coordination tasks. The mean results obtained in a reading test for all patients improved significantly after the training, but less so than those recorded in previous studies on children suffering from dyslexia. Although the therapy clearly improved performance, it was less specific than previously claimed.
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Orthographic depth (OD) (i.e., the complexity, consistency, or transparency of grapheme-phoneme correspondences in written alphabetic language) plays an important role in the acquisition of reading skills. Correspondingly, developmental dyslexia is characterized by different behavioral manifestations across languages varying in OD. This review focuses on the question of whether these different behavioral manifestations are associated with different functional neuroanatomical manifestations. It provides a review and critique of cross-linguistic brain imaging studies of developmental dyslexia. In addition, it includes an analysis of state-of-the-art functional neuroanatomical models of developmental dyslexia together with orthography-specific predictions derived from these models. These predictions should be tested in future brain imaging studies of typical and atypical reading in order to refine the current neurobiological understanding of developmental dyslexia, especially with respect to orthography-specific and universal aspects. PMID:24904383
Georgiou, George K; Papadopoulos, Timothy C; Zarouna, Elena; Parrila, Rauno
The purpose of this study was to examine if children with dyslexia learning to read a consistent orthography (Greek) experience auditory and visual processing deficits and if these deficits are associated with phonological awareness, rapid naming speed and orthographic processing. We administered measures of general cognitive ability, phonological awareness, orthographic processing, short-term memory, rapid automatized naming, auditory and visual processing, and reading fluency to 21 Grade 6 children with dyslexia, 21 chronological age-matched controls and 20 Grade 3 reading age-matched controls. The results indicated that the children with dyslexia did not experience auditory processing deficits, but about half of them showed visual processing deficits. Both orthographic processing and rapid automatized naming deficits were associated with dyslexia in our sample, but it is less clear that they were associated with visual processing deficits.
Richardson, John T E
This investigation studied attainment in students with dyslexia or other specific learning difficulties who were taking modules by distance learning with the Open University in 2012. Students with dyslexia or other specific learning difficulties who had no additional disabilities were just as likely as nondisabled students to complete their modules, but they were less likely to pass the modules that they had completed and less likely to obtain good grades on the modules that they had passed. Students with dyslexia or other specific learning difficulties who had additional disabilities were less likely to complete their modules, less likely to pass the modules that they had completed and less likely to obtain good grades on the modules that they had passed than were nondisabled students. Nevertheless, around 40% of students with dyslexia or other specific learning difficulties obtained good grades (i.e. those that would lead to a bachelor's degree with first-class or upper second-class honours).
Jimenez, Juan E.; Hernandez-Valle, Isabel; Rodriguez, Cristina; Guzman, Remedios; Diaz, Alicia; Ortiz, Rosario
The double-deficit hypothesis (DDH) of developmental dyslexia was investigated in seven to twelve year old Spanish children. It was observed that the double deficit (DD) group had the greatest difficulty with reading.
... a cause of dyslexia -- partly because the reduced adaptation was seen in young kids, and not only ... The new study aimed to see whether "neural adaptation" might play a role. Adaptation is how the ...
Simon, C S
Individuals with dyslexia can expect to have difficulties learning a second language since second language learning builds on native language learning. The factors that have a negative impact on learning one's native language have a similar impact on learning a foreign language (e.g., difficulties with phonemic awareness, retrieving and processing linguistic information, working memory, metalinguistic explanations, stabilizing sound-symbol relationships). This participant observer report provides (1) a brief review of research on how dyslexia complicates learning a second language; (2) a description of how dyslexia has affected my educational experiences; (3) a description of personal experiences learning a foreign language between 1992-1998; and (4) recommendations for individuals with dyslexia who are faced with fulfilling a foreign language requirement and for their foreign language instructors.
Bavelier, D; Green, C S; Seidenberg, M S
A recent study found that dyslexic children trained on action video games show significant improvements on basic measures of both attention and reading ability, suggesting future directions for the study of dyslexia intervention paradigms.
Tressoldi, Patrizio E; Rosati, Mario; Lucangeli, Daniela
This study has been conducted in order to investigate the extent to which some characteristics of dyscalculia may be common to dyslexia. Seven multiple single-cases were studied: two children with dyslexia only, two with dyscalculia only, and three more children with comorbidity of dyslexia and dyscalculia. Each participant was assessed with a standardized comprehensive battery of arithmetical, reading, and cognitive tests. We observed that a clinical impairment in mental and written calculations, arithmetical facts retrieval, number comparison, number alignment, and identification of arithmetical signs may appear with a normal reading capacity and independently of a short-term verbal memory deficit. These findings add convergent support to the evidence mainly obtained from group comparisons that the more distinctive characteristics of dyscalculia are functionally independent of dyslexia.
Conlon, Elizabeth G; Lilleskaret, Gry; Wright, Craig M; Power, Garry F
The aim of the experiments was to investigate how manipulating the contrast of the signal and noise dots in a random dot kinematogram (RDK), influenced on motion coherence thresholds in adults with dyslexia. In the first of two experiments, coherent motion thresholds were measured when the contrasts of the signal and noise dots in an RDK were manipulated. A significantly greater processing benefit was found for the group with dyslexia than a control group when the signal dots were of higher contrast than the noise dots. However, a significant processing disadvantage was found for the group with dyslexia relative to the control group when the signal dots were of lower contrast than the noise dots. These findings were interpreted as supporting evidence for the noise exclusion hypothesis of dyslexia. In Experiment 2, the effect on coherent motion thresholds of presenting a cue that alerted observers to which stimuli, high or low contrast contained the signals dots was investigated. When the cue directed attention to low contrast signal dots presented in high contrast noise, coherent motion thresholds were only enhanced for the group with dyslexia. This manipulation produced equivalent coherent motion thresholds in the reader groups. In other conditions, the group with dyslexia had significantly higher coherent motion thresholds than the control group. It was concluded that adults with dyslexia who show evidence of a coherent motion deficit (37% of the dyslexia group in each experiment), have a specific difficulty in noise exclusion. This appears to occur as consequence of a sensory processing deficit in the magnocellular or dorsal stream.
Landerl, Karin; Fussenegger, Barbara; Moll, Kristina; Willburger, Edith
This study tests the hypothesis that dyslexia and dyscalculia are associated with two largely independent cognitive deficits, namely a phonological deficit in the case of dyslexia and a deficit in the number module in the case of dyscalculia. In four groups of 8- to 10-year-olds (42 control, 21 dyslexic, 20 dyscalculic, and 26 dyslexic/dyscalculic), phonological awareness, phonological and visual-spatial short-term and working memory, naming speed, and basic number processing skills were assessed. A phonological deficit was found for both dyslexic groups, irrespective of additional arithmetic deficits, but not for the dyscalculia-only group. In contrast, deficits in processing of symbolic and nonsymbolic magnitudes were observed in both groups of dyscalculic children, irrespective of additional reading difficulties, but not in the dyslexia-only group. Cognitive deficits in the comorbid dyslexia/dyscalculia group were additive; that is, they resulted from the combination of two learning disorders. These findings suggest that dyslexia and dyscalculia have separable cognitive profiles, namely a phonological deficit in the case of dyslexia and a deficient number module in the case of dyscalculia.
Boets, Bart; De Smedt, Bert
It has been suggested that individuals with dyslexia show poorer performance on those aspects of arithmetic that involve the manipulation of verbal representations, such as the use of fact retrieval strategies. The present study examined this in 13 children with dyslexia who showed normal general mathematics achievement and 16 matched controls. All children completed a multiplication and a subtraction task, which were specifically designed to elicit the use of retrieval and procedural strategies, respectively. Our findings revealed that despite normal mathematics achievement, children with dyslexia were less accurate and slower in single-digit arithmetic, particularly in multiplication. The reaction time data revealed an interesting group by operation interaction. Control children were significantly faster in multiplication than in subtraction, whereas no such operation effect was found in children with dyslexia. This suggests that in multiplication children with dyslexia used less retrieval or less efficient retrieval (or both). This is in line with the hypothesis that children with dyslexia may have difficulties with the verbal aspects of number and arithmetic, as retrieval strategies depend upon phonological representations in long-term memory.
Li, Hong; Shu, Hua; McBride-Chang, Catherine; Liu, Hong Yun; Xue, Jin
A total of 82 Chinese 11- and 12-year-olds with and without dyslexia were tested on four paired associate learning (PAL) tasks, phonological awareness, morphological awareness, rapid naming, and verbal short-term memory in three different experiments. Experiment 1 demonstrated that children with dyslexia were significantly poorer in visual-verbal PAL than nondyslexic children but that these groups did not differ in visual-visual PAL performance. In Experiment 2, children with dyslexia had more difficulties in transferring rules to new stimuli in a rule-based visual-verbal PAL task as compared with children without dyslexia. Long-term retention of PAL was not impaired in dyslexic children across either experiment. In Experiment 3, rates of visual-verbal PAL deficits among children with dyslexia were all at or above 39%, the highest among all cognitive deficits tested. Moreover, rule-based visual-verbal PAL, in addition to morphological awareness and rapid naming ability, uniquely distinguished children with and without dyslexia even with other metalinguistic skills statistically controlled. Results underscore the importance of visual-verbal PAL for understanding reading impairment in Chinese children.
Messaoud-Galusi, Souhila; Hazan, Valerie; Rosen, Stuart
Purpose: The claim that speech perception abilities are impaired in dyslexia was investigated in a group of 62 children with dyslexia and 51 average readers matched in age. Method: To test whether there was robust evidence of speech perception deficits in children with dyslexia, speech perception in noise and quiet was measured using 8 different…
Sumner, Emma; Connelly, Vincent; Barnett, Anna L.
Spelling is a prerequisite to expressing vocabulary in writing. Research has shown that children with dyslexia are hesitant spellers when composing. This study aimed to determine whether the hesitant spelling of children with dyslexia, evidenced by frequent pausing, affects vocabulary choices when writing. A total of 31 children with dyslexia,…
Wijnen, Frank; Kappers, Astrid M. L.; Vlutters, Leoni D.; Winkel, Sven
Purpose: A recent hypothesis ascribes dyslexia to a perceptual anchoring deficit. Supporting results have so far been obtained only in children with dyslexia and additional learning difficulties, but the hypothesis has been argued to apply to all individuals with dyslexia. Method: The authors measured auditory frequency discrimination thresholds…
Berninger, Virginia W.; Nielsen, Kathleen H.; Abbott, Robert D.; Wijsman, Ellen; Raskind, Wendy
The International Dyslexia Association defines dyslexia as unexpected problems of neurobiological origin in accuracy and rate of oral reading of single real words, single pseudowords, or text or of written spelling. However, prior research has focused more on the reading than the spelling problems of students with dyslexia. A test battery was…
Burden, Robert; Burdett, Julia
In 2002, Neil Humphrey and Patricia Mullins published their research into personal constructs and attribution for academic success and failure in dyslexia in BJSE's "Research Section". Their work suggested that pupils with dyslexia, in a range of settings, experience real challenges to their self-esteem and that dyslexia leads to "negative…
Strien, Jan W.; And Others
Forty children with dyslexia were treated with visual hemisphere-specific stimulation based on their subtype of dyslexia. Children with L-type dyslexia (hurried, inaccurate reading) who received treatment with anxiety-laden words made fewer substantive errors and more fragmentations on a text-reading task, compared to children who received…
Schmid, Johanna M.; Labuhn, Andju S.; Hasselhorn, Marcus
This study investigates response inhibition and its relationship to phonological processing in third-graders with and without dyslexia. Children with dyslexia (n = 20) and children without dyslexia (n = 16) were administered a stop signal task and a digit span forwards task. Initial analyses revealed phonological processing deficits in terms of a…
Duranovic, Mirela; Sehic, Sabina
A group of children with dyslexia (mean ages 9 and 14 years) was studied, together with group of children without dyslexia matched for age. Participants were monolingual native speakers of the Bosnian language with transparent orthography. In total, the diagnostic tests were performed with 41 children with dyslexia and 41 nondyslexic children. The…
Burns, Eila; Bell, Sheena
This paper sheds light onto a poorly presented group of professionals--teachers with dyslexia in Finnish and English further and higher educational settings. The purpose of this qualitative study was, firstly, to discover what teachers with dyslexia could tell us about the manifestation of dyslexia and the challenges they face in the practice of…
Selenius, Heidi; Hellstrom, Ake; Belfrage, Henrik
Dyslexia does not cause criminal behaviour, but it may worsen aggressive behaviour tendencies. In this study, aggressive behaviour and risk of future violence were compared between forensic psychiatric patients with and without dyslexia. Dyslexia was assessed using the Swedish phonological processing battery "The Pigeon". The patients…
Simmons, Fiona R.; Singleton, Chris
We review significant empirical studies of the arithmetic abilities of children with dyslexia. These studies suggest that the academic impairments of children with dyslexia are not limited to reading and spelling, but also include aspects of mathematics. A consistent finding across a number of studies is that children with dyslexia have difficulty…
Hoeft, Fumiko; Meyler, Ann; Hernandez, Arvel; Juel, Connie; Taylor-Hill, Heather; Martindale, Jennifer L; McMillon, Glenn; Kolchugina, Galena; Black, Jessica M; Faizi, Afrooz; Deutsch, Gayle K; Siok, Wai Ting; Reiss, Allan L; Whitfield-Gabrieli, Susan; Gabrieli, John D E
In functional neuroimaging studies, individuals with dyslexia frequently exhibit both hypoactivation, often in the left parietotemporal cortex, and hyperactivation, often in the left inferior frontal cortex, but there has been no evidence to suggest how to interpret the differential relations of hypoactivation and hyperactivation to dyslexia. To address this question, we measured brain activation by functional MRI during visual word rhyme judgment compared with visual cross-hair fixation rest, and we measured gray matter morphology by voxel-based morphometry in dyslexic adolescents in comparison with (i) an age-matched group, and (ii) a reading-matched group younger than the dyslexic group but equal to the dyslexic group in reading performance. Relative to the age-matched group (n = 19; mean 14.4 years), the dyslexic group (n = 19; mean 14.4 years) exhibited hypoactivation in left parietal and bilateral fusiform cortices and hyperactivation in left inferior and middle frontal gyri, caudate, and thalamus. Relative to the reading-matched group (n = 12; mean 9.8 years), the dyslexic group (n = 12; mean 14.5 years) also exhibited hypoactivation in left parietal and fusiform regions but equal activation in all four areas that had exhibited hyperactivation relative to age-matched controls as well. In regions that exhibited atypical activation in the dyslexic group, only the left parietal region exhibited reduced gray matter volume relative to both control groups. Thus, areas of hyperactivation in dyslexia reflected processes related to the level of current reading ability independent of dyslexia. In contrast, areas of hypoactivation in dyslexia reflected functional atypicalities related to dyslexia itself, independent of current reading ability, and related to atypical brain morphology in dyslexia.
Egan, Joanne; Tainturier, Marie-Josèphe
The goal of this study was to examine past-tense spelling deficits in developmental dyslexia and their relationship to phonological abilities, spoken morphological awareness and word specific orthographic memory. Three groups of children (28 9-year-old dyslexic, 28 chronological age-matched and 28 reading/spelling age-matched children) completed a battery of tests including spelling regularly inflected words (e.g., kissed) and matched one-morpheme words (e.g., wrist). They were also assessed on a range of tests of reading and spelling abilities and associated linguistic measures. Dyslexic children were impaired in relation to chronological age-matched controls on all measures. Furthermore, they were significantly poorer than younger reading and spelling age-matched controls at spelling inflected verbs, supporting the existence of a specific deficit in past-tense spelling in dyslexia. In addition to under-using the -ed spelling on inflected verbs, the dyslexic children were less likely to erroneously apply this spelling to one-morpheme words than younger controls. Dyslexics were also poorer than younger controls at using a consistent spelling for stems presented in isolation versus as part of an inflected word, indicating that they make less use of the morphological relations between words to support their spelling. In line with this interpretation, regression analyses revealed another qualitative difference between the spelling and reading age-matched group and the dyslexic group: while both spoken morphological awareness and orthographic word specific memory were significant predictors of the accuracy of past-tense spelling in the former group, only orthographic memory (irregular word reading and spelling) was a significant factor in the dyslexic group. Finally, we identified a subgroup of seven dyslexic children who were severely deficient in past-tense spelling. This subgroup was also significantly worse than other dyslexics and than younger controls on scores
Moskal, Barbara M.; Wright, Lyndsey; Taylor, P. C.
Researchers have found that children with dyslexia reason differently with respect to language from those who do not have dyslexia. Dyslexic students' brains work differently than do students without dyslexia. Some researchers speculate that these differences provide dyslexic students with an advantage in science. The presentation will describe an outreach activity which developed and delivered instructional modules in physics to students in grades kindergarten through sixth. These modules were tested on thirty students who attended a summer camp designed for students who have been diagnosed with dyslexia. Eighty percent of students who have learning disabilities have dyslexia. Many of the students who attended this camp have experienced repeated failure in the traditional school system, which emphasizes literacy with little attention to science. A number of science and engineering professors collaborated with this camp to build instructional modules that were delivered one hour per day, during two weeks of this five week summer camp (ten hours of hands-on physics instruction). Both quantitative and qualitative data were collected with respect to the impact that this camp had on students' understanding and interests in science. The results of these efforts will be presented.
van Viersen, Sietske; de Bree, Elise H; Kroesbergen, Evelyn H; Slot, Esther M; de Jong, Peter F
This study investigated risk and protective factors associated with dyslexia and literacy development, both at the group and individual level, to gain more insight in underlying cognitive profiles and possibilities for compensation in high-IQ children. A sample of 73 Dutch primary school children included a dyslexic group, a gifted-dyslexic group, and a borderline-dyslexic group (i.e., gifted children with relative literacy problems). Children were assessed on literacy, phonology, language, and working memory. Competing hypotheses were formulated, comparing the core-deficit view to the twice-exceptionality view on compensation with giftedness-related strengths. The results showed no indication of compensation of dyslexia-related deficits by giftedness-related strengths in gifted children with dyslexia. The higher literacy levels of borderline children compared to gifted children with dyslexia seemed the result of both fewer combinations of risk factors and less severe phonological deficits in this group. There was no evidence for compensation by specific strengths more relevant to literacy development in the borderline group. Accordingly, the findings largely supported the core-deficit view, whereas no evidence for the twice-exceptionality view was found. Besides practical implications, the findings also add to knowledge about the different manifestations of dyslexia and associated underlying cognitive factors at the higher end of the intelligence spectrum.
Yang, Xiujie; Meng, Xiangzhi
Previous research has suggested that number sense and language are involved in number representation and calculation, in which number sense supports approximate arithmetic, and language permits exact enumeration and calculation. Meanwhile, individuals with dyslexia have a core deficit in phonological processing. Based on these findings, we thus hypothesized that children with dyslexia may exhibit exact calculation impairment while doing mental arithmetic. The reaction time and accuracy while doing exact and approximate addition with symbolic Arabic digits and non-symbolic visual arrays of dots were compared between typically developing children and children with dyslexia. Reaction time analyses did not reveal any differences across two groups of children, the accuracies, interestingly, revealed a distinction of approximation and exact addition across two groups of children. Specifically, two groups of children had no differences in approximation. Children with dyslexia, however, had significantly lower accuracy in exact addition in both symbolic and non-symbolic tasks than that of typically developing children. Moreover, linguistic performances were selectively associated with exact calculation across individuals. These results suggested that children with dyslexia have a mental arithmetic deficit specifically in the realm of exact calculation, while their approximation ability is relatively intact.
Washburn, Erin K; Joshi, R Malatesha; Binks-Cantrell, Emily S
Roughly one-fifth of the US population displays one or more symptoms of dyslexia: a specific learning disability that affects an individual's ability to process written language. Consequently, elementary school teachers are teaching students who struggle with inaccurate or slow reading, poor spelling, poor writing, and other language processing difficulties. Findings from studies have indicated that teachers lack essential knowledge needed to teach struggling readers, particularly children with dyslexia. However, few studies have sought to assess teachers' knowledge and perceptions about dyslexia in conjunction with knowledge of basic language concepts related to reading instruction. Thus, the purpose of the present study was to examine elementary school teachers' knowledge of basic language concepts and their knowledge and perceptions about dyslexia. Findings from the present study indicated that teachers, on average, were able to display implicit skills related to certain basic language concepts (i.e. syllable counting), but failed to demonstrate explicit knowledge of others (i.e. phonics principles). Also, teachers seemed to hold the common misconception that dyslexia is a visual processing deficit rather than phonological processing deficit.
Wolff, P.H.; Melngailis, I.; Bedrosian, M.
The motor control of bimanual coordination and motor speech was compared between first degree relatives from families with at least 2 dyslexic family members, and families where probands were the only affected family members. Half of affected relatives had motor coordination deficits; and they came from families in which probands also showed impaired motor coordination. By contrast, affected relatives without motor deficits came from dyslexia families where probands did not have motor deficits. Motor coordination deficits were more common and more severe among affected offspring in families where both parents were affected than among affected offspring in families where only one parent was affected. However, motor coordination deficits were also more common and more severe in affected parents when both parents were affected than among affected parents in families where only one parent was affected. We conclude that impaired temporal resolution in motor action identifies a behavioral phenotype in some subtypes of developmental dyslexia. The observed pattern of transmission for motor deficits and reading impairment in about half of dyslexia families was most congruent with a genetic model of dyslexia in which 2 codominant major genes cosegregate in dyslexia pedigrees where the proband is also motorically impaired. 54 refs., 5 figs., 5 tabs.
Ho, Connie Suk-Han; Chan, David Wai-Ock; Lee, Suk-Han; Tsang, Suk-Man; Luan, Vivian Hui
The present study examined the cognitive profile and subtypes of developmental dyslexia in a nonalphabetic script, Chinese. One hundred and forty-seven Chinese primary school children with developmental dyslexia were tested on a number of literacy and cognitive tasks. The results showed that rapid naming deficit and orthographic deficit were the two most dominant types of cognitive deficits in Chinese developmental dyslexia, and that rapid naming and orthographic processing had significant unique contributions to literacy performance. Seven subtypes of dyslexia--global deficit, orthographic deficit, phonological memory deficit, mild difficulty, and three other subtypes with rapid-naming-related deficits--were identified using scores of the cognitive tasks as classification measures in cluster analyses. These subtypes were validated with a behaviour checklist and three literacy measures. The authors suggested that orthographic and rapid naming deficits in Chinese dyslexic children might pose an interrelated problem in developing orthographic knowledge and representation. Therefore, orthographic-related difficulties may be the crux of the problem in Chinese developmental dyslexia.
Papagiannopoulou, Eleni A.; Lagopoulos, Jim
Dyslexia is a neurodevelopmental disorder estimated to affect between 4 and 7% of the population. It is often referred to as a learning disability and is characterized by deficits in the linguistic system. To better understand the neural underpinnings of dyslexia, we examined the electroencephalography (EEG) power spectra between pre-adolescents with dyslexia and neurotypical control children during eyes closed state. We reported the differences in spontaneous oscillatory activity of each major EEG band (delta, theta, alpha, and beta) adopting a global as well as in a region-by-region and hemispheric approach to elucidate whether there are changes in asymmetry in children with dyslexia compared to controls. We also examined the relationship between EEG power spectra and clinical variables. The findings of our study confirm the presence of an atypical linguistic network, evident in children with dyslexia. This abnormal network hallmarked by a dominance of theta activity suggests that these abnormalities are present prior to these children learning to read, thus implicating delayed maturation and abnormal hypoarousal mechanisms. PMID:26942169
Jiménez-Fernández, Gracia; Gutiérrez-Palma, Nicolás; Defior, Sylvia
The role of segmental phonology in developmental dyslexia (DD) is well established (e.g., deficit in phonological awareness), but the role of suprasegmental phonology (prosody) has been less widely investigated. Stress is one of the main prosodic features and refers to the relative prominence of syllables (strong/weak) within a word. The aim of the present study is to examine stress awareness in children with dyslexia and the possible mediation of phonemic awareness on suprasegmental phonological skills. Thirty-one Spanish children with DD and 31 chronological age-control children participated. Two stress awareness tasks were administrated, one with words and another with pseudowords. Results show that the children with dyslexia performed more poorly on both tasks than control children. The pattern of results in accuracy and reaction time suggest that, while children without difficulties use different strategies depending on the type of item, the children with dyslexia employ the same strategy to resolve the two tasks without any benefit of lexical knowledge about stress. Even so, this strategy did not work so efficiently as it did in the control group, which led the group with dyslexia to make a greater number of mistakes. It was also found that, when phonemic awareness was entered as a covariate, accuracy differences disappeared, but only in the word stress task. However, when lexical knowledge was not necessary (as in the pseudoword stress task) differences still remained statistically significant. Implications on the importance of suprasegmental processing in reading acquisition disabilities are discussed.
Papagiannopoulou, Eleni A; Lagopoulos, Jim
Dyslexia is a neurodevelopmental disorder estimated to affect between 4 and 7% of the population. It is often referred to as a learning disability and is characterized by deficits in the linguistic system. To better understand the neural underpinnings of dyslexia, we examined the electroencephalography (EEG) power spectra between pre-adolescents with dyslexia and neurotypical control children during eyes closed state. We reported the differences in spontaneous oscillatory activity of each major EEG band (delta, theta, alpha, and beta) adopting a global as well as in a region-by-region and hemispheric approach to elucidate whether there are changes in asymmetry in children with dyslexia compared to controls. We also examined the relationship between EEG power spectra and clinical variables. The findings of our study confirm the presence of an atypical linguistic network, evident in children with dyslexia. This abnormal network hallmarked by a dominance of theta activity suggests that these abnormalities are present prior to these children learning to read, thus implicating delayed maturation and abnormal hypoarousal mechanisms.
Selenius, Heidi; Hellström, Ake; Belfrage, Henrik
Dyslexia does not cause criminal behaviour, but it may worsen aggressive behaviour tendencies. In this study, aggressive behaviour and risk of future violence were compared between forensic psychiatric patients with and without dyslexia. Dyslexia was assessed using the Swedish phonological processing battery 'The Pigeon'. The patients filled in the Aggression Questionnaire, and trained assessors performed the risk assessments using HCR-20 version 2. Patients with dyslexia self-reported more aggressive behaviour compared with those without dyslexia. There was only a nearly significant tendency (p = 0.06) for the patients with dyslexia to receive higher scores in the HCR-20 compared with the patients without dyslexia, and phonological processing skills did not significantly predict aggression or risk of future violence. However, regression analyses demonstrated that poor phonological processing skills are a significant predictor of anger, which in turn significantly predicts risk of future violence.
Lindgrén, Signe-Anita; Laine, Matti
High-performing adults with compensated dyslexia pose particular challenges to dyslexia diagnostics. We compared the performance of 20 multilingual Finnish university students with suspected dyslexia with 20 age-matched and education-matched controls on an extensive test battery. The battery tapped various aspects of reading, writing, word retrieval, phonological processing and other cognitive functions relevant for dyslexia. Reading and writing were examined in the two domestic languages, Swedish and Finnish. The most prominent group differences in reading and writing emerged on accuracy measures in both languages (reading text aloud, proofreading, writing to dictation, free writing). The dyslexia group also performed less well on speeded segmentation of written input, complex speeded naming and complex phoneme manipulation. The pattern of results fits the phonological deficit hypothesis of dyslexia and indicates the presence of pervasive underlying defects in compensated dyslexia.
Sharma, Anita; Gothecha, Vinod K.; Ojha, Nisha K.
Dyslexia is one of the commonest learning disability. It is defined as a disorder where a child, in spite of all the classroom teaching, is not able to attain the language skills of reading, writing and spelling according to their level of intelligence. Dyslexia individuals often have difficulty in relating to the association between sound and their respective letters. Reversing or transposing the letters while writing is characteristic with letters such as b and d, P and q, etc., The prevalence among school children is reported as 9.87% and in the selected families, it is 28.32%. Dyslexia significantly interferes with academic achievement or activities of daily life and are not primarily due to sensory, motor or mentally handicaps. About 40% of dyslexic children and adolescents dropout of schools. According to Ayurveda, learning is a result of successive and complex interaction of Indriyas (cognitive and motor organs), Indriyartha (sense organs), Mana (psyche), Atma and Buddhi (intellect). Above all, the functioning of these factors is governed by Tridosha (vata, pitta and kapha) and Triguna (Sattva, Raja and Tama) in a specific coordination and balance Any disturbance in these Tridosha and Triguna will cause disordered functioning of Indriya, Mana and Buddhi leading to impaired learning or Dyslexia Ayurvedic drugs can help in the management of dyslexia by making these Tridosha and Triguna in well-balanced state and also by providing Medhya (intellect promoting) drugs to improve the learning ability in these children. PMID:23723664
Sharma, Anita; Gothecha, Vinod K; Ojha, Nisha K
Dyslexia is one of the commonest learning disability. It is defined as a disorder where a child, in spite of all the classroom teaching, is not able to attain the language skills of reading, writing and spelling according to their level of intelligence. Dyslexia individuals often have difficulty in relating to the association between sound and their respective letters. Reversing or transposing the letters while writing is characteristic with letters such as b and d, P and q, etc., The prevalence among school children is reported as 9.87% and in the selected families, it is 28.32%. Dyslexia significantly interferes with academic achievement or activities of daily life and are not primarily due to sensory, motor or mentally handicaps. About 40% of dyslexic children and adolescents dropout of schools. According to Ayurveda, learning is a result of successive and complex interaction of Indriyas (cognitive and motor organs), Indriyartha (sense organs), Mana (psyche), Atma and Buddhi (intellect). Above all, the functioning of these factors is governed by Tridosha (vata, pitta and kapha) and Triguna (Sattva, Raja and Tama) in a specific coordination and balance Any disturbance in these Tridosha and Triguna will cause disordered functioning of Indriya, Mana and Buddhi leading to impaired learning or Dyslexia Ayurvedic drugs can help in the management of dyslexia by making these Tridosha and Triguna in well-balanced state and also by providing Medhya (intellect promoting) drugs to improve the learning ability in these children.
Kershner, John R
Extant neurobiological theories of dyslexia appear fractional in focusing on isolated brain regions, mechanisms, and functional pathways. A synthesis of current research shows support for an Interactive Specialization (IS) model of dyslexia involving the dysfunctional orchestration of a widely-distributed, attentionally-controlled, hierarchical, and interhemispheric circuit of intercommunicating neuronal networks. This circuitry is comprised principally of the frontostriatal-parietal cognitive control system of networks, the posterior corpus callosum, and the left arcuate fasciculus. During development, the coalescence of these functionally specialized regions, acting together, may be essential to preventing the core phonemic and phonological processing deficits defining the dyslexic phenotype. Research demonstrating an association of each with processing phonology presents the foundational outline for a comprehensive, integrative theory of dyslexia and suggests the importance of inclusive remedial efforts aimed at promoting interactions among all three networking territories.
Bishop, D. V. M.
Developmental dyslexia runs in families, and twin studies have confirmed that there is a substantial genetic contribution to poor reading. The way in which discoveries in molecular genetics are reported can be misleading, encouraging us to think that there are specific genes that might be used to screen for disorder. However, dyslexia is not a classic Mendelian disorder that is caused by a mutation in a single gene. Rather, like many other common disorders, it appears to involve combined effects of many genes and environmental factors, each of which has a small influence, possibly supplemented by rare variants that have larger effects but apply to only a minority of cases. Furthermore, to see clearer relationships between genotype and phenotype, we may need to move beyond the clinical category of dyslexia to look at underlying cognitive deficits that may be implicated in other neurodevelopmental disorders. PMID:25854887
Mundy, Ian R; Carroll, Julia M
The current experiment investigated conflicting predictions regarding the effects of spelling-stress regularity on the lexical decision performance of skilled adult readers and adults with developmental dyslexia. In both reading groups, lexical decision responses were significantly faster and significantly more accurate when the orthographic structure of a word ending was a reliable as opposed to an unreliable predictor of lexical stress assignment. Furthermore, the magnitude of this spelling-stress regularity effect was found to be equivalent across reading groups. These findings are consistent with intact phoneme-level regularity effects also observed in dyslexia. The paper discusses how findings of intact spelling-sound regularity effects at both prosodic and phonemic levels, as well as other similar results, can be reconciled with the obvious difficulties that people with dyslexia experience in other domains of phonological processing.
Sireteanu, Ruxandra; Goebel, Claudia; Goertz, Ralf; Werner, Ingeborg; Nalewajko, Magdalena; Thiel, Aylin
In order to test the hypothesis of attentional deficits in dyslexia, we investigated the performance of children with developmental dyslexia on a number of visual search tasks. When tested with conjunction tasks for orientation and form using complex, letter-like material, dyslexic children showed an increased number of errors accompanied by faster reaction times in comparison to control children matched to the dyslexics on age, gender, and intelligence. On conjunction tasks for orientation and color, dyslexic children were also less accurate, but showed slower reaction times than the age-matched control children. These differences between the two groups decreased with increasing age. In contrast to these differences, the performance of dyslexic children in feature search tasks was similar to that of control children. These results suggest that children with developmental dyslexia present selective deficits in complex serial visual search tasks, implying impairment in goal-directed, sustained visual attention.
Al-Shidhani, Thuraya Ahmed; Arora, Vinita
Dyslexia is a specific learning disability that is neurological in origin, with an estimated overall worldwide prevalence of 5–10% of the population. It is characterised by difficulties in reading, accuracy, fluency, spelling and decoding abilities. The majority of publications reviewed indicated that screening is performed at the preschool level. Screening can also be conducted at birth or the first year of life. Understanding human development theory, for example, Piaget’s human development theory, may help determine at which stage of childhood development dyslexia is more detectable, and therefore guide the management of this disability. The objective of this review is to provide a brief and updated overview of dyslexia and its management in children through human development issues. PMID:23269949
Bishop, D V M
Developmental dyslexia runs in families, and twin studies have confirmed that there is a substantial genetic contribution to poor reading. The way in which discoveries in molecular genetics are reported can be misleading, encouraging us to think that there are specific genes that might be used to screen for disorder. However, dyslexia is not a classic Mendelian disorder that is caused by a mutation in a single gene. Rather, like many other common disorders, it appears to involve combined effects of many genes and environmental factors, each of which has a small influence, possibly supplemented by rare variants that have larger effects but apply to only a minority of cases. Furthermore, to see clearer relationships between genotype and phenotype, we may need to move beyond the clinical category of dyslexia to look at underlying cognitive deficits that may be implicated in other neurodevelopmental disorders.
Ronchi, Roberta; Algeri, Lorella; Chiapella, Laura; Gallucci, Marcello; Spada, Maria Simonetta; Vallar, Giuseppe
Right-brain-damaged patients may show a reading disorder termed neglect dyslexia. Patients with left neglect dyslexia omit letters on the left-hand-side (the beginning, when reading left-to-right) part of the letter string, substitute them with other letters, and add letters to the left of the string. The aim of this study was to investigate the pattern of association, if any, between error types in patients with left neglect dyslexia and recurrent perseveration (a productive visuo-motor deficit characterized by addition of marks) in target cancellation. Specifically, we aimed at assessing whether different productive symptoms (relative to the reading and the visuo-motor domains) could be associated in patients with left spatial neglect. Fifty-four right-brain-damaged patients took part in the study: 50 out of the 54 patients showed left spatial neglect, with 27 of them also exhibiting left neglect dyslexia. Neglect dyslexic patients who showed perseveration produced mainly substitution neglect errors in reading. Conversely, omissions were the prevailing reading error pattern in neglect dyslexic patients without perseveration. Addition reading errors were much infrequent. Different functional pathological mechanisms may underlie omission and substitution reading errors committed by right-brain-damaged patients with left neglect dyslexia. One such mechanism, involving the defective stopping of inappropriate responses, may contribute to both recurrent perseveration in target cancellation, and substitution errors in reading. Productive pathological phenomena, together with deficits of spatial attention to events taking place on the left-hand-side of space, shape the manifestations of neglect dyslexia, and, more generally, of spatial neglect.
Tamboer, P; Vorst, H C M; Ghebreab, S; Scholte, H S
Meta-analytic studies suggest that dyslexia is characterized by subtle and spatially distributed variations in brain anatomy, although many variations failed to be significant after corrections of multiple comparisons. To circumvent issues of significance which are characteristic for conventional analysis techniques, and to provide predictive value, we applied a machine learning technique--support vector machine--to differentiate between subjects with and without dyslexia. In a sample of 22 students with dyslexia (20 women) and 27 students without dyslexia (25 women) (18-21 years), a classification performance of 80% (p < 0.001; d-prime = 1.67) was achieved on the basis of differences in gray matter (sensitivity 82%, specificity 78%). The voxels that were most reliable for classification were found in the left occipital fusiform gyrus (LOFG), in the right occipital fusiform gyrus (ROFG), and in the left inferior parietal lobule (LIPL). Additionally, we found that classification certainty (e.g. the percentage of times a subject was correctly classified) correlated with severity of dyslexia (r = 0.47). Furthermore, various significant correlations were found between the three anatomical regions and behavioural measures of spelling, phonology and whole-word-reading. No correlations were found with behavioural measures of short-term memory and visual/attentional confusion. These data indicate that the LOFG, ROFG and the LIPL are neuro-endophenotype and potentially biomarkers for types of dyslexia related to reading, spelling and phonology. In a second and independent sample of 876 young adults of a general population, the trained classifier of the first sample was tested, resulting in a classification performance of 59% (p = 0.07; d-prime = 0.65). This decline in classification performance resulted from a large percentage of false alarms. This study provided support for the use of machine learning in anatomical brain imaging.
Jordan, Julie-Ann; McGladdery, Gary; Dyer, Kevin
This study examined levels of mathematics and statistics anxiety, as well as general mental health amongst undergraduate students with dyslexia (n = 28) and those without dyslexia (n = 71). Students with dyslexia had higher levels of mathematics anxiety relative to those without dyslexia, while statistics anxiety and general mental health were comparable for both reading ability groups. In terms of coping strategies, undergraduates with dyslexia tended to use planning-based strategies and seek instrumental support more frequently than those without dyslexia. Higher mathematics anxiety was associated with having a dyslexia diagnosis, as well as greater levels of worrying, denial, seeking instrumental support and less use of the positive reinterpretation coping strategy. By contrast, statistics anxiety was not predicted by dyslexia diagnosis, but was instead predicted by overall worrying and the use of denial and emotion focused coping strategies. The results suggest that disability practitioners should be aware that university students with dyslexia are at risk of high mathematics anxiety. Additionally, effective anxiety reduction strategies such as positive reframing and thought challenging would form a useful addition to the support package delivered to many students with dyslexia.
Wang, Li-Chih; Yang, Hsien-Ming
This present study focuses on classifying developmental dyslexia by combining two famous models, the dual-route model and the triangle model of Chinese reading, re-examining validity of the subtypes, and observing the error types of word recognition for each subtype. Sixty-sixth graders with dyslexia in Chinese and 45 sixth graders who were matched by age and IQ with the dyslexic group were involved in the present study. Twelve (20%) sixth graders from the dyslexic group were classified as having phonological dyslexia, 11 (18.3%) were classified as surface dyslexia, 12 (20%) were classified as deep dyslexia, and five (8.3%) of them were classified as displaying more than one kind of deficit. Besides, still more than half (31; 51.7%) of the dyslexic group did not belong to any subtypes here. These subtypes had a good validity based on comparison of their phonological awareness, orthography, and semantics. Finally, for their error types of word recognition, both children with multiple-deficit dyslexia and children with non-subtype dyslexia showed a proportional pattern of six kinds of errors. Children with phonological dyslexia showed more phonetic errors and analogy errors, children with surface dyslexia showed more visual errors and analogy errors, and children with deep dyslexia showed more semantic errors and selective errors.
Snowling, M J
This paper reviews evidence in support of the phonological deficit hypothesis of dyslexia. Findings from two experimental studies suggest that the phonological deficits of dyslexic children and adults cannot be explained in terms of impairments in low-level auditory mechanisms, but reflect higher-level language weaknesses. A study of individual differences in the pattern of reading skills in dyslexic children rejects the notion of 'sub-types'. Instead, the findings suggest that the variation seen in reading processes can be accounted for by differences in the severity of individual children's phonological deficits, modified by compensatory factors including visual memory, perceptual speed and print exposure. Children at genetic risk who go on to be dyslexic come to the task of reading with poorly specified phonological representations in the context of a more general delay in oral language development. Their prognosis (and that of their unaffected siblings) depends upon the balance of strengths and difficulties they show, with better language skills being a protective factor. Taken together, these findings suggest that current challenges to the phonological deficit theory can be met.
Aleci, Carlo; Piana, Giulio; Piccoli, Marzia; Bertolini, Marco
According to wide literature, a global impairment in the temporal and spatial domains as well as an increased crowding effect is common of dyslexics. The aim of the study was to evaluate if such subjects suffer from a more general impairment of spatial relationship perception (SRP) and in particular from anomalous spatial relationship anisotropy (SRA) thus accounting both for their global perceptual distortions and abnormal crowding. SRP of 39 young disabled readers and 23 normal subjects were measured by a specifically designed psychophysical technique based on circular and elliptical target recognitions. A general impairment of SRP characterized by increased horizontal/vertical anisotropy was found in the dyslexic sample compared to the controls. In the second part of the experiment, reading efficiency and reading time were measured by MNREAD(©) reading cards in standard conditions and after increasing horizontal spatial extension of the sentence by different values. We suppose this modification could well compensate the abnormal anisotropy found in dyslexics. Data obtained in the two groups were compared. A strong correlation between reading efficiency (a parameter we have specifically devised) and horizontal spatial text relationship values were present in the patients (r=.87, p<.01), but not in the controls. The same was found taking into consideration mean reading time (r=-.82, p<.01). We therefore gather that an alteration of SRP, characterized by an increased anisotropy may be involved in developmental dyslexia.
Thiessen, Erik D.; Holt, Lori L.
Purpose Developmental dyslexia (DD) is commonly thought to arise from phonological impairments. However, an emerging perspective is that a more general procedural learning deficit, not specific to phonological processing, may underlie DD. The current study examined if individuals with DD are capable of extracting statistical regularities across sequences of passively experienced speech and nonspeech sounds. Such statistical learning is believed to be domain-general, to draw upon procedural learning systems, and to relate to language outcomes. Method DD and control groups were familiarized with a continuous stream of syllables or sine-wave tones, the ordering of which was defined by high or low transitional probabilities across adjacent stimulus pairs. Participants subsequently judged two 3-stimulus test items with either high or low statistical coherence as being the most similar to the sounds heard during familiarization. Results As with control participants, the DD group was sensitive to the transitional probability structure of the familiarization materials as evidenced by above-chance performance. However, the performance of participants with DD was significantly poorer than controls across linguistic and nonlinguistic stimuli. In addition, reading-related measures were significantly correlated with statistical learning performance of both speech and nonspeech material. Conclusion Results are discussed in light of procedural learning impairments among participants with DD. PMID:25860795
Friedmann, Naama; Gvion, Aviah; Nisim, Roni
We explored morphological decomposition in reading, the locus in the reading process in which it takes place and its nature, comparing different types of morphemes. We assessed these questions through the analysis of letter position errors in readers with letter position dyslexia (LPD). LPD is a selective impairment to letter position encoding in the early stage of word reading, which results in letter migrations (such as reading "cloud" for "could"). We used the fact that migrations in LPD occur mainly in word-interior letters, whereas exterior letters rarely migrate. The rationale was that if morphological decomposition occurs prior to letter position encoding and strips off affixes, word-interior letters adjacent to an affix (e.g., signs-signs) would become exterior following affix-stripping and hence exhibit fewer migrations. We tested 11 Hebrew readers with developmental LPD and 1 with acquired LPD in 6 experiments of reading aloud, lexical decision, and comprehension, at the single word and sentence levels (compared with 25 age-matched control participants). The LPD participants read a total of 12,496 migratable words. We examined migrations next to inflectional, derivational, or bound function morphemes compared with migrations of exterior letters. The results were that root letters adjacent to inflectional and derivational morphemes were treated like middle letters, and migrated frequently, whereas root letters adjacent to bound function morphemes patterned with exterior letters, and almost never migrated. Given that LPD is a pre-lexical deficit, these results indicate that morphological decomposition takes place in an early, pre-lexical stage. The finding that morphologically complex nonwords showed the same patterns indicates that this decomposition is structurally, rather than lexically, driven. We suggest that letter position encoding takes place before morphological analysis, but in some cases, as with bound function morphemes, the complex word is re
Friedmann, Naama; Gvion, Aviah; Nisim, Roni
We explored morphological decomposition in reading, the locus in the reading process in which it takes place and its nature, comparing different types of morphemes. We assessed these questions through the analysis of letter position errors in readers with letter position dyslexia (LPD). LPD is a selective impairment to letter position encoding in the early stage of word reading, which results in letter migrations (such as reading “cloud” for “could”). We used the fact that migrations in LPD occur mainly in word-interior letters, whereas exterior letters rarely migrate. The rationale was that if morphological decomposition occurs prior to letter position encoding and strips off affixes, word-interior letters adjacent to an affix (e.g., signs-signs) would become exterior following affix-stripping and hence exhibit fewer migrations. We tested 11 Hebrew readers with developmental LPD and 1 with acquired LPD in 6 experiments of reading aloud, lexical decision, and comprehension, at the single word and sentence levels (compared with 25 age-matched control participants). The LPD participants read a total of 12,496 migratable words. We examined migrations next to inflectional, derivational, or bound function morphemes compared with migrations of exterior letters. The results were that root letters adjacent to inflectional and derivational morphemes were treated like middle letters, and migrated frequently, whereas root letters adjacent to bound function morphemes patterned with exterior letters, and almost never migrated. Given that LPD is a pre-lexical deficit, these results indicate that morphological decomposition takes place in an early, pre-lexical stage. The finding that morphologically complex nonwords showed the same patterns indicates that this decomposition is structurally, rather than lexically, driven. We suggest that letter position encoding takes place before morphological analysis, but in some cases, as with bound function morphemes, the complex word
Texas Education Agency, Austin.
This handbook, available in English and Spanish, contains the Texas State Board of Education's approved procedures concerning dyslexia and related disorders and information regarding the state's dyslexia statutes and their relation to the federal Rehabilitation Act of 1973, Section 504, and the Individuals with Disabilities Education Act. Chapters…
Melby-Lervag, Monica; Lervag, Arne
We present a meta-analysis reviewing studies that have focused on the relationship between dyslexia and nonword repetition. The results show that children with dyslexia have poorer nonword repetition skills when compared to both chronological-age and reading-level controls. However, the severity of the nonword repetition problem varies…
Background Evidence has been synthesized to determine hindering and facilitating factors associated with the work participation of adults with developmental dyslexia (DD), classified according to the International Classification of Functioning, Disability and Health (ICF). Methods A systematic literature review has been performed. Two search strings were used to determine the population and the context of work. The ICF was expanded with two subdivisions: one that made the environmental factors more work-related and a subdivision of personal factors. For data extraction the method known as qualitative metasummary was used and the manifest frequency effect size (MFES) for each category in the ICF was calculated. Results From 33 included studies 318 factors have been extracted and classified in the ICF. In the classification the frequency of occurrences and the consistency in direction (i.e., hindering or facilitating) have been made visible. The ICF categories with the highest MFES were mental functions with factors like feelings and emotions about dyslexia; activities like reading or writing/spelling; participation with factors like acquiring and keeping a job; social relationships at work where the attitudes and support of the employer and co-workers are important; working conditions with factors like the availability of assistive technology and accommodations on the job; and personal factors like self-disclosure and coping strategies. Conclusions In the context of work DD affects nearly all domains of functioning, mostly in a negative way. Within each domain the impact of DD increases over the course of life. To overcome that negative influence, many forms of adaptation, compensation, or coping are mentioned. Also notable is the lack of positive attitudes toward DD of the participants with DD—with the exception of the attitudes of teachers with DD—as well as on the part of colleagues, supervisors, and employers. PMID:24460949
Iribarren, I. Carolina; Jarema, Gonia; Lecours, Andre Roch
Discusses two monolingual Spanish-speaking patients who were able to read words but showed great difficulty reading nonwords, a pattern of behavior known as phonological dyslexia. Contradicts the hypothesis that lexical reading is not an option for Spanish readers, because Spanish orthography is highly irregular, and supports the view that…
Szmalec, Arnaud; Loncke, Maaike; Page, Mike P. A.; Duyck, Wouter
The present study offers an integrative account proposing that dyslexia and its various associated cognitive impairments reflect an underlying deficit in the long-term learning of serial-order information, here operationalized as Hebb repetition learning. In nondyslexic individuals, improved immediate serial recall is typically observed when one…
Monaghan, Padraic; Shillcock, Richard
There are several causal explanations for dyslexia, drawing on distinctions between dyslexics and control groups at genetic, biological, or cognitive levels of description. However, few theories explicitly bridge these different levels of description. In this paper, we review a long-standing theory that some dyslexics' reading impairments are due…
Ziegler, Johannes C.; Pech-Georgel, Catherine; George, Florence; Lorenzi, Christian
Speech perception deficits in developmental dyslexia were investigated in quiet and various noise conditions. Dyslexics exhibited clear speech perception deficits in noise but not in silence. "Place-of-articulation" was more affected than "voicing" or "manner-of-articulation." Speech-perception-in-noise deficits persisted when performance of…
Noordenbos, Mark W.; Serniclaes, Willy
Speech perception in dyslexia is characterized by a categorical perception (CP) deficit, demonstrated by weaker discrimination of acoustic differences between phonemic categories in conjunction with better discrimination of acoustic differences within phonemic categories. We performed a meta-analysis of studies that examined the reliability of the…
Li, Wing-Sze; Ho, Connie Suk-Han
This study examined the extent and nature of lexical tone deficit in Chinese developmental dyslexia. Twenty Cantonese-speaking Chinese dyslexic children (mean age 8 ; 11) were compared to twenty average readers of the same age (CA control group, mean age 8 ; 11), and another twenty younger average readers of the same word reading level (RL control…
Diraä, Nadia; Engelen, Jan; Ghesquière, Pol; Neyens, Koen
The Katholieke Universiteit Leuven (K.U.Leuven) has a tradition of supporting students with a disability in order to guarantee equal opportunities to achieve their educational, personal and vocational goals. The K.U.Leuven policy is working towards inclusive education in the long term, by improving facilities and accommodation for certain target groups in the short term. Efforts have also been directed to make the learning environment more accessible for all kind of students, especially over the last few years. One of the target groups that has increasing numbers are students with learning disabilities (including dyslexia, dyscalculia, ...). To accommodate these students, the K.U.Leuven set off a project to evaluate the use of assistive technology (AT) for dyslexia. This small-scale study examined the experiences of two groups of students with dyslexia using 2 different software programs specifically developed to support this group of students. It was apparent that for students with dyslexia, reading and studying presents additional limitations which AT could facilitate to some extent.
Ziegler, Johannes C.; Pech-Georgel, Catherine; George, Florence; Foxton, Jessica M.
This study investigated global versus local pitch pattern perception in children with dyslexia aged between 8 and 11 years. Children listened to two consecutive 4-tone pitch sequences while performing a same/different task. On the different trials, sequences either preserved the contour (local condition) or they violated the contour (global…
Georgiou, George K.; Papadopoulos, Timothy C.; Zarouna, Elena; Parrila, Rauno
The purpose of this study was to examine if children with dyslexia learning to read a consistent orthography (Greek) experience auditory and visual processing deficits and if these deficits are associated with phonological awareness, rapid naming speed and orthographic processing. We administered measures of general cognitive ability, phonological…
Snowling, Margaret J.
This paper reviews current proposals concerning the definition of dyslexia and contrasts it with reading comprehension impairment. We then discuss methods for early identification and review evidence that teacher assessments and ratings may be valid screening tools. Finally, we argue that interventions should be theoretically motivated and…
Anderson, Peggy L., Ed.; Meier-Hedde, Regine, Ed.
Dyslexia is a disability that exists in all countries that have high expectations for literacy. The inability to read in spite of normal intellectual potential represents one of the most puzzling educational challenges for literate societies, regardless of the culture or language. This book examines medical, psychological, educational, and…
Tobia, Valentina; Marzocchi, Gian Marco
The aim of this study was to investigate verbal and nonverbal cognitive deficits in Italian students with developmental dyslexia. The performances of 32 dyslexic students, 64 age-matched typically reading controls, and 64 reading age-matched controls were compared on tests of lexical knowledge, phonological awareness, rapid automatized naming,…
van Viersen, Sietske; de Bree, Elise H.; Kroesbergen, Evelyn H.; Slot, Esther M.; de Jong, Peter F.
This study investigated risk and protective factors associated with dyslexia and literacy development, both at the group and individual level, to gain more insight in underlying cognitive profiles and possibilities for compensation in high-IQ children. A sample of 73 Dutch primary school children included a dyslexic group, a gifted-dyslexic group,…
Agus, Trevor R.; Carrión-Castillo, Amaia; Pressnitzer, Daniel; Ramus, Franck
Purpose: A phonological deficit is thought to affect most individuals with developmental dyslexia. The present study addresses whether the phonological deficit is caused by difficulties with perceptual learning of fine acoustic details. Method: A demanding test of nonverbal auditory memory, "noise learning," was administered to both…
Peterson, Robin L.; Pennington, Bruce F.; Olson, Richard K.; Wadsworth, Sally J.
Limited evidence supports the external validity of the distinction between developmental phonological and surface dyslexia. We previously identified children ages 8 to 13 meeting criteria for these subtypes (Peterson, Pennington, & Olson, 2013) and now report on their reading and related skills approximately 5 years later. Longitudinal…
Vickers, Melana Zyla
Universities are providing extra time on tests, quiet exam rooms, in-class note-takers, and other assistance to college students with modest learning disabilities. But these policies are shrouded in secrecy. This paper, "Accommodating College Students with Learning Disabilities: ADD, ADHD, and Dyslexia," by Melana Zyla Vickers, examines…
Coffield, Mary; O'Neill, Jenny
The Durham County Policy Document on Specific Learning Difficulties (dyslexia and dyspraxia) has been developed over a period of years as a countywide response to ensure that children's specific learning difficulties are identified and that schools are equipped to offer a range of appropriate interventions. The content of the policy document is…
This review discusses the important contribution made by one particular theoretical model of reading--the dual route model--to the identification and understanding of different varieties of developmental dyslexia. The model itself is first outlined, and the particular types of reading disorder that would be predicted to occur based on this model…
Lorusso, Maria Lulsa; Facoetti, Andrea; Bakker, Dirk J.
In this study, 123 children with a diagnosis of developmental dyslexia were assigned to different treatment groups, either variations of Bakker's intervention program based on the balance model or a control, a specific reading training group. Thorough cognitive and neuropsychological assessment allowed determination of the subtype of dyslexia…
Ise, Elena; Schulte-Korne, Gerd
Orthographic spelling is a major difficulty in German-speaking children with dyslexia. The aim of the present study was to evaluate the effectiveness of an orthographic spelling training in spelling-disabled students (grade 5 and 6). In study 1, ten children (treatment group) received 15 individually administered weekly intervention sessions (60…
Wright, Craig M; Conlon, Elizabeth G; Dyck, Murray
The aim of this study was to investigate the theory that visual magnocellular deficits seen in groups with dyslexia are linked to reading via the mechanisms of visual attention. Visual attention was measured with a serial search task and magnocellular function with a coherent motion task. A large group of children with dyslexia (n = 70) had slower serial search times than a control group of typical readers. However, the effect size was small (η(p)(2) = 0.05) indicating considerable overlap between the groups. When the dyslexia sample was split into those with or without a magnocellular deficit, there was no difference in visual search reaction time between either group and controls. The data suggest that magnocellular sensitivity and visual spatial attention weaknesses are independent of one another. They also provide more evidence of heterogeneity in response to psychophysical tasks in groups with dyslexia. Alternative explanations for poor performance on visual attention tasks are proposed along with avenues for future research.
Singleton, Chris; Henderson, Lisa-Marie
Visual stress--a condition in which unpleasant visual symptoms are experienced when reading--has been reported to be more prevalent in dyslexic individuals but at the present time the relationship between dyslexia and visual stress remains controversial. ViSS, a computerized visual stress screener that incorporates reading-like visual search, has…
Bacon, Alison M; Parmentier, Fabrice B R; Barr, Polly
Impairments in working memory are suggested to be one of the defining characteristics of dyslexia, and deficits in verbal recall are well documented. However, the situation regarding visuospatial memory is less clear. In a widely used measure, the Corsi blocks task, sequences of visuospatial locations can be recalled forwards, in the order presented (CF), or backwards, in reverse order (CB). Previous research has suggested that, while CF draws on spatial-sequential resources, CB may load executive and distinctly visual processes. While people with dyslexia typically show no deficit on CF, CB is rarely presented. We present three studies which indicate a consistent dyslexic deficit on CB that can be ameliorated by visual strategy instructions. Our data suggest that, without instruction, people with dyslexia are unable to adopt an effective CB strategy and this is consistent with a deficit in executive function. These results have implications for our understanding of visuospatial memory in dyslexia, and also in terms of the administration of the Corsi task to special populations.
Menghini, D.; Finzi, A.; Benassi, M.; Bolzani, R.; Facoetti, A.; Giovagnoli, S.; Ruffino, M.; Vicari, S.
The aim of this study was to investigate the role of several specific neurocognitive functions in developmental dyslexia (DD). The performances of 60 dyslexic children and 65 age-matched normally reading children were compared on tests of phonological abilities, visual processing, selective and sustained attention, implicit learning, and executive…
Veispak, Anneli; Ghesquiere, Pol
A proportion of children with visual impairments have specific reading difficulties that cannot be easily explained. This article reviews the data on problems with braille reading and interprets them from the framework of the temporal-processing deficit theory of developmental dyslexia.
Singleton, Chris; Henderson, Lisa-Marie
Visual stress-a condition in which unpleasant visual symptoms are experienced when reading-has been reported to be more prevalent in dyslexic individuals but at the present time the relationship between dyslexia and visual stress remains controversial. ViSS, a computerized visual stress screener that incorporates reading-like visual search, has recently shown promise in studies with unselected samples of primary and secondary school children. This study investigated the use of ViSS with dyslexic children. Dyslexic children identified as having high visual stress showed significantly higher per cent increases in reading rate with a coloured overlay and reported significantly higher critical symptoms of visual stress, compared to dyslexic children with low visual stress. The same results were found for reading-age controls, indicating that ViSS can be equally effective with normal readers as well as with children with dyslexia. Compared to reading-age controls, dyslexic children were found to have significantly higher susceptibility to visual stress, significantly larger per cent increases in reading rate with an overlay, and significantly higher critical and non-critical symptoms of visual stress. Extrapolated to unselected population samples, the data also suggest that visual stress is more likely to be found in people with dyslexia than in people who do not have dyslexia. These results, which point to an important link between the two conditions, are discussed in relation to current theories that attribute visual stress to either a magnocellular dysfunction or cortical hyperexcitability.
Washburn, Erin K.; Joshi, R. Malatesha; Binks-Cantrell, Emily S.
Roughly one-fifth of the US population displays one or more symptoms of dyslexia: a specific learning disability that affects an individual's ability to process written language. Consequently, elementary school teachers are teaching students who struggle with inaccurate or slow reading, poor spelling, poor writing, and other language processing…
Bosse, Marie-Line; Tainturier, Marie Josephe; Valdois, Sylviane
The visual attention (VA) span is defined as the amount of distinct visual elements which can be processed in parallel in a multi-element array. Both recent empirical data and theoretical accounts suggest that a VA span deficit might contribute to developmental dyslexia, independently of a phonological disorder. In this study, this hypothesis was…
Orsolini, Margherita; Fanari, Rachele; Cerracchio, Sara; Famiglietti, Luisa
In this study we explore the development of phonological and lexical reading in dyslexic children. We tested a group of 14 Italian children who have been diagnosed with dyslexia and whose reading age is end of grade 1. We compared this group with a group of 70 typically developing children who have been tested for reading at the end of grade 1.…
Conlon, Elizabeth G.; Lilleskaret, Gry; Wright, Craig M.; Power, Garry F.
The aim of the experiments was to investigate how manipulating the contrast of the signal and noise dots in a random dot kinematogram (RDK), influenced on motion coherence thresholds in adults with dyslexia. In the first of two experiments, coherent motion thresholds were measured when the contrasts of the signal and noise dots in an RDK were…
Elbeheri, Gad; Everatt, John; Malki, Mohammad Al
This paper investigates the incidence of dyslexia among young offenders in Kuwait. A total of 91 children/young adults from 8 juvenile delinquent welfare centres across Kuwait were interviewed and tested. A measure of non-verbal reasoning ability was used to exclude those with low general ability. The remaining 53 participants were tested on their…
Dunson, Walter E.
"School Success for Kids With Dyslexia and Other Reading Difficulties" provides parents and teachers with goals that will meet the needs of students who are struggling with reading, leading them to work through their difficulties and enjoy reading. It includes information, assessments, and techniques that parents, teachers, and school…
Wang, Xiaochen; Georgiou, George K.; Das, J. P.; Li, Qing
The purpose of the present study was twofold: (a) to examine the extent to which Chinese dyslexic children experience deficits in phonological and orthographic processing skills and (b) to examine if Chinese dyslexia is associated with deficits in Planning, Attention, Simultaneous, and Successive (PASS) processing. A total of 27 Grade 4 children…
Ingesson, S. Gunnel
Interviews with 75 teenagers and young adults were performed to investigate how young people with dyslexia experienced school in terms of well-being, educational achievement, self-esteem, peer relations and belief in their future. Results from earlier studies suggest that secondary emotional problems are common. The first six grades in school were…
Smith, Allan B.; Locke, John L.; Farkas, Laurie
The conversational timing patterns of three year old children who were at a high familial risk for dyslexia were examined in the course of their interaction with adults. Findings indicated that previously documented differences in speech timing surface as subtle differences in spontaneous child-adult conversation as early as three years of age.
New Texas literacy laws mandate continuing education requirements for educators who teach dyslexic students. Close to twenty percent of the US population display one or more symptoms of dyslexia (Washburn, Joshi, & Binks-Cantrell, 2011), and teachers must be equipped to adapt instruction to meet these students' needs. The purpose of this…
The current research is an examination of the nature of reading difficulties in dyslexic readers of Hindi. The reading performance of children with dyslexia was compared with that of reading-age (RA) and chronological-age (CA) matched controls on word and non word reading of items of different length. The results showed that the dyslexic children…
Women with children have been depicted as struggling to justify themselves in the shadow of intensive mothering ideology. However, little is said about women who have a disability such as dyslexia, and how disability may intersect with intensive mothering ideology to present additional challenges. In this paper, life-story interviews are drawn…
Scerri, Thomas S.; Paracchini, Silvia; Morris, Andrew; MacPhie, I. Laurence; Talcott, Joel; Stein, John; Smith, Shelley D.; Pennington, Bruce F.; Olson, Richard K.; DeFries, John C.; Monaco, Anthony P.
Background Six independent studies have identified linkage to chromosome 18 for developmental dyslexia or general reading ability. Until now, no candidate genes have been identified to explain this linkage. Here, we set out to identify the gene(s) conferring susceptibility by a two stage strategy of linkage and association analysis. Methodology/Principal Findings Linkage analysis: 264 UK families and 155 US families each containing at least one child diagnosed with dyslexia were genotyped with a dense set of microsatellite markers on chromosome 18. Association analysis: Using a discovery sample of 187 UK families, nearly 3000 SNPs were genotyped across the chromosome 18 dyslexia susceptibility candidate region. Following association analysis, the top ranking SNPs were then genotyped in the remaining samples. The linkage analysis revealed a broad signal that spans approximately 40 Mb from 18p11.2 to 18q12.2. Following the association analysis and subsequent replication attempts, we observed consistent association with the same SNPs in three genes; melanocortin 5 receptor (MC5R), dymeclin (DYM) and neural precursor cell expressed, developmentally down-regulated 4-like (NEDD4L). Conclusions Along with already published biological evidence, MC5R, DYM and NEDD4L make attractive candidates for dyslexia susceptibility genes. However, further replication and functional studies are still required. PMID:21060895
Schiff, Rachel; Cohen, Miki; Ben-Artzi, Elisheva; Sasson, Ayelet; Ravid, Dorit
The aim of the present study is to examine the morphological knowledge of readers with developmental dyslexia compared to chronological age and reading-level matched controls. The study also analyzes the errors dyslexics make and their metamorphological awareness compared to controls. Participants included 31 seventh-grade dyslexic children and…
Kahta, Shani; Schiff, Rachel
The aim of the present study was to investigate implicit learning processes among adults with developmental dyslexia (DD) using a visual linguistic artificial grammar learning (AGL) task. Specifically, it was designed to explore whether the intact learning reported in previous studies would also occur under conditions including minimal training…
Donfrancesco, Renato; Iozzino, Roberto; Caruso, Barbara; Ferrante, Laura; Mugnaini, Daniele; Talamo, Alessandra; Miano, Silvia; Dimitri, Andrea; Masi, Gabriele
Different moderators/mediators of risk are involved in developmental dyslexia (DD), but data are inconsistent. We explored the prevalence of season of birth and its association with gender and age of school entry in an Italian sample of dyslexic children compared to an Italian normal control group. The clinical sample included 498 children (345…
Taroyan, Naira A.; Nicolson, Roderick I.; Buckley, David
Coherent motion perception was tested in nine adolescents with dyslexia and 10 control participants matched for age and IQ using low contrast stimuli with three levels of coherence (10%, 25% and 40%). Event-related potentials (ERPs) and behavioural performance data were obtained. No significant between-group differences were found in performance…
Kohnen, Saskia; Nickels, Lyndsey; Castles, Anne; Friedmann, Naama; McArthur, Genevieve
We report the first three cases of selective developmental letter position dyslexia in English. Although the parents and teachers of the children were concerned about these children's reading, standard tests did not reveal their deficit. It was only when the appropriate target words were presented, in this case, migratable words, that their letter…
Semenza, Carlo; Arcara, Giorgio; Facchini, Silvia; Meneghello, Francesca; Ferraro, Marco; Passarini, Laura; Pilosio, Cristina; Vigato, Giovanna; Mondini, Sara
Reading compound words was studied in neglect dyslexia in order to assess the influence of "headedness". The "head" of a compound is the component that determines the grammatical category, the syntactic (e.g., the gender) and the semantic properties of the compound as a whole. For example, in the word "blackberry" "berry" is the compound's head.…
Rastle, Kathleen; Tyler, Lorraine K.; Marslen-Wilson, William
Morphological errors in reading aloud (e.g., "sexist" [right arrow] "sexy") are a central feature of the symptom-complex known as deep dyslexia, and have historically been viewed as evidence that representations at some level of the reading system are morphologically structured. However, it has been proposed (Funnell, 1987) that morphological…
Schulte-Körne, Gerd; Bruder, Jennifer
Neurophysiological studies on children and adults with dyslexia provide a deeper understanding of how visual and auditory processing in dyslexia might relate to reading deficits. The goal of this review is to provide an overview of research findings in the last two decades on motion related and contrast sensitivity visual evoked potentials and on auditory event related potentials to basic tone and speech sound processing in dyslexia. These results are particularly relevant for three important theories about causality in dyslexia: the magnocellular deficit hypothesis, the temporal processing deficit hypothesis and the phonological deficit hypothesis. Support for magnocellular deficits in dyslexia are primarily provided from evidence for altered visual evoked potentials to rapidly moving stimuli presented at low contrasts. Consistently ERP findings revealed altered neurophysiological processes in individuals with dyslexia to speech stimuli, but evidence for deficits processing certain general acoustic information relevant for speech perception, such as frequency changes and temporal patterns, are also apparent.
Gangadharan, Geethu; Criton, Sebastian; Surendran, Divya
Acquired idiopathic generalized anhidrosis is a rare condition, where the exact pathomechanism is unknown. We report a case of acquired idiopathic generalized anhidrosis in a patient who later developed lichen planus. Here an autoimmune-mediated destruction of sweat glands may be the probable pathomechanism.
laboratory- acquired mycoses . Insofar as possible, the etiological fungus, type of laboratory, classification of personnel, type of work conducted, and other...pertinent data have been listed in this study. More than 288 laboratory- acquired mycoses are described here, including 108 cases of
Low literacy is termed 'developmental dyslexia' when reading is significantly behind that expected from the intelligence quotient (IQ) in the presence of other symptoms--incoordination, left-right confusions, poor sequencing--that characterize it as a neurological syndrome. 5-10% of children, particularly boys, are found to be dyslexic. Reading requires the acquisition of good orthographic skills for recognising the visual form of words which allows one to access their meaning directly. It also requires the development of good phonological skills for sounding out unfamiliar words using knowledge of letter sound conversion rules. In the dyslexic brain, temporoparietal language areas on the two sides are symmetrical without the normal left-sided advantage. Also brain 'warts' (ectopias) are found, particularly clustered round the left temporoparietal language areas. The visual magnocellular system is responsible for timing visual events when reading. It therefore signals any visual motion that occurs if unintended movements lead to images moving off the fovea ('retinal slip'). These signals are then used to bring the eyes back on target. Thus, sensitivity to visual motion seems to help determine how well orthographic skill can develop in both good and bad readers. In dyslexics, the development of the visual magnocellular system is impaired: development of the magnocellular layers of the dyslexic lateral geniculate nucleus (LGN) is abnormal; their motion sensitivity is reduced; many dyslexics show unsteady binocular fixation; hence poor visual localization, particularly on the left side (left neglect). Dyslexics' binocular instability and visual perceptual instability, therefore, can cause the letters they are trying to read to appear to move around and cross over each other. Hence, blanking one eye (monocular occlusion) can improve reading. Thus, good magnocellular function is essential for high motion sensitivity and stable binocular fixation, hence proper
Representatives DOD SCHOOLS Additional Reporting Could Improve Accountability for Academic Achievement of Students with Dyslexia December...Could Improve Accountability for Academic Achievement of Students with Dyslexia 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...Students with Dyslexia Highlights of GAO-08-70, a report to the Chairman, Committee on Science and Technology, House of Representatives Many of our
Alves, Débora Cristina; Casella, Erasmo Barbante; Ferraro, Alexandre Arcanjo
Purpose to analyze and classify the spelling performance according to the semiology of spelling error of children with developmental dyslexia (DD) and with developmental dyslexia associated to attention deficit disorder and hyperactivity(DD and ADHD) comparing them to a group of children without learning process complaints. Methods Seventy students, from the third to fifth grade, participated in this study divided as follows: 32 children without complaints of learning difficulties (GI), mean age 9.5 years; 22 students with developmental dyslexia (GII), mean age 10 years; 16 scholars with developmental dyslexia associated to attention deficit disorders and hyperactivity (GIII), mean age 9.9. Spelling skills were assessed through a standardized word dictation task. Results Data indicated that GII and GIII children presented lower performance when compared with typically developed children. There was no statistical difference between the performance of GII and GIII children regarding the score reached in spelling, although GIII children presented the lowest performance. We observed differences between GII and GIII only in the type of misspelling. Conclusion Data from this research contribute to develop better programs for intervention in the studied population.
The secondary symptoms of individuals with dyslexia, such as high anxiety and low self-esteem, have aroused various debates not only in the educational, but also in the clinical context. Since pro and contra arguments are supported by a more or less equal number of empirical findings, no final conclusion could be drawn for this specific…
Gersons-Wolfensberger, D C; Ruijssenaars, W A
A committee of the Health Council of the Netherlands prepared a report on the definition and treatment of dyslexia at the request of the Minister of Health, Welfare, and Sport (see Note). The Health Council, as charged by the Health Act, is to inform the government on the state of science with respect to public health issues. The Council is entirely funded by the government but otherwise completely independent (an independence guaranteed by law). The committee was formed to answer questions regarding the provisions and funds needed for the treatment of persons with dyslexia, neuropsychological treatment modalities, in particular, and the role of speech and language therapists. Definitive decision making about reimbursement by the Dutch National Health Service for treatment by speech and language therapists in cases of dyslexia was on hold, pending the committee's report. Specific attention was requested for the following aspects: the definition of dyslexia (the characteristic symptoms of this category of developmental language disabilities); the consequences of the proposed definition for indication and treatment; the appropriate methods of treatment; the involvement of several possible professionals (e.g., neuropsychologist, remedial teacher, speech and language therapist), as well as the role of the neurologist during and in relation to the treatment process; and those situations in which treatment should be the responsibility of the health care system. This article summarizes the committee's considerations and conclusions on these different aspects.
Cicchini, Guido Marco; Marino, Cecilia; Mascheretti, Sara; Perani, Daniela; Morrone, Maria Concetta
Dyslexia is a specific impairment in reading that affects 1 in 10 people. Previous studies have failed to isolate a single cause of the disorder, but several candidate genes have been reported. We measured motion perception in two groups of dyslexics, with and without a deletion within the DCDC2 gene, a risk gene for dyslexia. We found impairment for motion particularly strong at high spatial frequencies in the population carrying the deletion. The data suggest that deficits in motion processing occur in a specific genotype, rather than the entire dyslexia population, contributing to the large variability in impairment of motion thresholds in dyslexia reported in the literature.
Bo, Ola O.
Investigation of the connection between hand dominance and dyslexia are not at all conclusive. This may be due to the fact that the term dyslexia is used in different ways in different investigations. (Author)
Colangelo, Annette; Buchanan, Lori; Westbury, Chris
Deep dyslexia is an acquired reading disorder that involves the production of semantic errors and the inability to read aloud nonwords successfully. Several explanations for this reading impairment posit multiple loci of damage to account for the various error types produced in deep dyslexia. In contrast, the failure of inhibition hypothesis suggests that damage in the phonological output lexicon alone can explain these errors. Specifically, this hypothesis proposes normal processing via orthographic and phonological reading routes, as well as an intact semantic system. However, slowed or reduced inhibitory connections result in the failure to suppress spuriously activated neighbours in the phonological output lexicon, where neighbourhood can be defined in terms of phonology, orthography, or semantics. Given a failure to inhibit semantically related candidates, semantic reading errors occur. Important to the test of this hypothesis is that it evolves several predictions that are contrary to performance observed in the normal population. In particular, semantic errors are predicted to be greater in conditions where words are blocked according to semantic category than in random presentations. In addition, a semantic interference effect is expected. The results of semantic blocking were consistent with these predictions and lend support to the failure of inhibition hypothesis.
Tamboer, Peter; Scholte, H Steven; Vorst, Harrie C M
In voxel-based morphometry studies of dyslexia, the relation between causal theories of dyslexia and gray matter (GM) and white matter (WM) volume alterations is still under debate. Some alterations are consistently reported, but others failed to reach significance. We investigated GM alterations in a large sample of Dutch students (37 dyslexics and 57 non-dyslexics) with two analyses: group differences in local GM and total GM and WM volume and correlations between GM and WM volumes and five behavioural measures. We found no significant group differences after corrections for multiple comparisons although total WM volume was lower in the group of dyslexics when age was partialled out. We presented an overview of uncorrected clusters of voxels (p < 0.05, cluster size k > 200) with reduced or increased GM volume. We found four significant correlations between factors of dyslexia representing various behavioural measures and the clusters found in the first analysis. In the whole sample, a factor related to performances in spelling correlated negatively with GM volume in the left posterior cerebellum. Within the group of dyslexics, a factor related to performances in Dutch-English rhyme words correlated positively with GM volume in the left and right caudate nucleus and negatively with increased total WM volume. Most of our findings were in accordance with previous reports. A relatively new finding was the involvement of the caudate nucleus. We confirmed the multiple cognitive nature of dyslexia and suggested that experience greatly influences anatomical alterations depending on various subtypes of dyslexia, especially in a student sample.
Ziegler, Johannes C; Perry, Conrad; Zorzi, Marco
The most influential theory of learning to read is based on the idea that children rely on phonological decoding skills to learn novel words. According to the self-teaching hypothesis, each successful decoding encounter with an unfamiliar word provides an opportunity to acquire word-specific orthographic information that is the foundation of skilled word recognition. Therefore, phonological decoding acts as a self-teaching mechanism or 'built-in teacher'. However, all previous connectionist models have learned the task of reading aloud through exposure to a very large corpus of spelling-sound pairs, where an 'external' teacher supplies the pronunciation of all words that should be learnt. Such a supervised training regimen is highly implausible. Here, we implement and test the developmentally plausible phonological decoding self-teaching hypothesis in the context of the connectionist dual process model. In a series of simulations, we provide a proof of concept that this mechanism works. The model was able to acquire word-specific orthographic representations for more than 25 000 words even though it started with only a small number of grapheme-phoneme correspondences. We then show how visual and phoneme deficits that are present at the outset of reading development can cause dyslexia in the course of reading development.
Ziegler, Johannes C.; Perry, Conrad; Zorzi, Marco
The most influential theory of learning to read is based on the idea that children rely on phonological decoding skills to learn novel words. According to the self-teaching hypothesis, each successful decoding encounter with an unfamiliar word provides an opportunity to acquire word-specific orthographic information that is the foundation of skilled word recognition. Therefore, phonological decoding acts as a self-teaching mechanism or ‘built-in teacher’. However, all previous connectionist models have learned the task of reading aloud through exposure to a very large corpus of spelling–sound pairs, where an ‘external’ teacher supplies the pronunciation of all words that should be learnt. Such a supervised training regimen is highly implausible. Here, we implement and test the developmentally plausible phonological decoding self-teaching hypothesis in the context of the connectionist dual process model. In a series of simulations, we provide a proof of concept that this mechanism works. The model was able to acquire word-specific orthographic representations for more than 25 000 words even though it started with only a small number of grapheme–phoneme correspondences. We then show how visual and phoneme deficits that are present at the outset of reading development can cause dyslexia in the course of reading development. PMID:24324240
Ensrud, E R; Krivickas, L S
The acquired demyelinating neuropathies can be divided into those with an acute onset and course and those with a more chronic course. The acute neuropathies present as Guillain-Barré syndrome and include acute inflammatory demyelinating polyradiculoneuropathy (AIDP), Miller Fisher syndrome, acute motor axonal neuropathy (AMAN), acute motor and sensory axonal neuropathy (AMSAN), and acute pandysautonomia. The chronic neuropathies are collectively known as chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and include MADSAM (multifocal acquired demyelinating sensory and motor neuropathy, also know as Lewis-Sumner syndrome) and DADS (distal acquired demyelinating symmetric neuropathy) as variants. The clinical features, pathology, pathogenesis, diagnosis, treatment, rehabilitation, and prognosis of these neuropathies are discussed.
Simunovic, Matthew P
Acquired color vision deficiency occurs as the result of ocular, neurologic, or systemic disease. A wide array of conditions may affect color vision, ranging from diseases of the ocular media through to pathology of the visual cortex. Traditionally, acquired color vision deficiency is considered a separate entity from congenital color vision deficiency, although emerging clinical and molecular genetic data would suggest a degree of overlap. We review the pathophysiology of acquired color vision deficiency, the data on its prevalence, theories for the preponderance of acquired S-mechanism (or tritan) deficiency, and discuss tests of color vision. We also briefly review the types of color vision deficiencies encountered in ocular disease, with an emphasis placed on larger or more detailed clinical investigations.
Hakvoort, Britt; de Bree, Elise; van der Leij, Aryan; Maassen, Ben; van Setten, Ellie; Maurits, Natasha; van Zuijen, Titia L.
Purpose: This study assessed whether a categorical speech perception (CP) deficit is associated with dyslexia or familial risk for dyslexia, by exploring a possible cascading relation from speech perception to phonology to reading and by identifying whether speech perception distinguishes familial risk (FR) children with dyslexia (FRD) from those…
Sumner, Emma; Connelly, Vincent; Barnett, Anna L.
It is commonly assumed that children with dyslexia are slower at handwriting than other children. However, evidence of slow handwriting in children with dyslexia is very mixed. Thirty-one children with dyslexia, aged 9 years, were compared to both age-matched children and younger spelling-ability matched children. Participants completed an…
Laasonen, Marja; Leppamaki, Sami; Tani, Pekka; Hokkanen, Laura
The project Adult Dyslexia and Attention Deficit Disorder in Finland (Project DyAdd) compares adults (n = 119, 18-55 years) with dyslexia, attention-deficit/hyperactivity disorder (ADHD), dyslexia together with ADHD (comorbid), and healthy controls with neuropsychological, psychophysical, and biological methods. The focus of this article is on the…
Torppa, Minna; Eklund, Kenneth; van Bergen, Elsje; Lyytinen, Heikki
This study focuses on the stability of dyslexia status from Grade 2 to Grade 8 in four groups: (a) no dyslexia in either grade (no-dyslexia, n = 127); (b) no dyslexia in Grade 2 but dyslexia in Grade 8 (late-emerging, n = 18); (c) dyslexia in Grade 2 but not in Grade 8 (resolving, n = 15); and (d) dyslexia in both grades (persistent-dyslexia, n = 22). We examined group differences from age 3.5 to age 14 in (a) reading, vocabulary, phonology, letter knowledge, rapid naming, IQ, verbal memory; (b) familial and environmental risk and supportive factors; and (c) parental skills in reading, phonology, rapid naming, verbal memory, and vocabulary. Our findings showed group differences both in reading and cognitive skills of children as well as their parents. Parental education, book-reading frequency, and children's IQ, however, did not differentiate the groups. The children in the persistent-dyslexia group exhibited widespread language and cognitive deficits across development. Those in the resolving group had problems in language and cognitive skills only prior to school entry. In the late-emerging group, children showed clearly compromised rapid naming. Additionally, their parents had the most severe difficulties in rapid naming, a finding that suggests strong genetic liability. The findings show instability in the diagnosis of dyslexia. The members of the late-emerging group did not have a distinct early cognitive profile, so late-emerging dyslexia appears difficult to predict. Indeed, these children are at risk of not being identified and not receiving required support. This study suggests the need for continued monitoring of children's progress in literacy after the early school years.
Zhao, Hua; Zhang, Baoping; Chen, Yun; Zhou, Xiang
Background Several studies have been conducted to explore risk factors for dyslexia. However, most studies examining dyslexia have been skewed toward Western countries, and few have considered two nationalities simultaneously. This study focused on differences in dyslexia prevalence and potential environmental risk factors between Han and Uyghur children. Methods A cross-sectional study was conducted in Kashgar and Aksu, cities in Xinjiang province, China. A two-stage sampling strategy was used to recruit 2,854 students in grades 3–6 from 5 primary schools in 5 districts; 2,348 valid student questionnaires were included in the analysis. Dyslexia checklists for Chinese and Uyghur children and pupil rating scales were used to identify children with dyslexia. Questions related to the home literacy environment and reading ability were used to evaluate potential environmental risk factors. Single factor analysis and multivariate logistic regression were used to examine prevalence and risk factors for dyslexia. Results Dyslexia prevalence differed significantly between Han (3.9%) and Uyghur (7.0%) children (P < 0.05), and the boy-to-girl diagnosis ratio was almost 2:1. Multiple logistic regression analysis showed that ethnic differences in dyslexia prevalence between Han and Uyghur children could have occurred because of factors such as mother’s occupation (P = 0.02, OR = 0.04, 95% CI = 0.01–0.68) and the frequency with which parents told stories (P = 0.00, OR = 4.50, 95% CI = 1.67–12.11). Conclusions The prevalence of dyslexia was high in all children, particularly those in the Uyghur group. Environmental factors could have been responsible for some of the differences observed. The results contribute to the early identification and management of dyslexia in children from these two groups and research examining developmental dyslexia and differences in racial genetics. PMID:27416106
Mather, David S; Milford, Todd M; Mcrae, Lona M
The purpose of this theoretical analysis and synthesis is to indicate how left-eye sighting dominance may lead to reading failure through dysfunctional right hemisphere letter encoding. Differing compensatory strategies are postulated to lead to outcomes that include the development of the phonologically impaired and phonologically proficient subtypes of dyslexia as well as specific spelling disability. Evidence is presented indicating that these disorders might be prevented by delaying the introduction of letter writing until the age of 8 years. Early childhood speech categorization in children genetically at-risk of developing dyslexia is also considered from this perspective. Convergent support for this premature writing hypothesis is provided by a comparison with the development of the left-hand inverted writing posture.
Suárez Coalla, Paz; Cuetos Vega, Fernando
Several studies have shown that a phonological deficit is the origin of developmental dyslexia, because dyslexics have important difficulties in mapping orthographic to phonological codes. However, visual criteria are still used for the diagnosis of dyslexia and to develop methods of intervention. This study attempts to determine whether there are visual problems in dyslexic children. To this aim, dyslexic children and children without reading difficulties, matched by chronological age, participated in two experiments. One study was based on the Reversal test and the other was a visual decision task in which participants had to decide whether two letters were the same or different. There were 40 pairs of letters, to measure reaction times and mistakes. The results showed that dyslexics had similar performance to controls in the detection of different visual stimuli. Developmental dyslexics do not appear to have visual perceptual problems, but a particular difficulty to retrieve the phonological code of graphemes.
Lee, Byung Hwa; Suh, Mee Kyung; Kim, Eun-Joo; Seo, Sang Won; Choi, Kyung Mook; Kim, Gyeong-Moon; Chung, Chin-Sang; Heilman, Kenneth M.; Na, Duk L.
Patients with right hemisphere injury often omit or misread words on the left side of a page or the beginning letters of single words (neglect dyslexia). Our study involving a large sample of acute right hemisphere stroke investigated (1) the frequency of neglect dyslexia (ND), (2) the association between ND and other types of contralesional…
Researchers have found that teachers seem to lack information about dyslexia which can influence teaching efficacy and behavior. Because inclusion has caused children with dyslexia to spend the majority of their day in general education classrooms, general education teachers are mainly responsible for educating these students. These teachers must…
Rochelle, Kim S. H.; Talcott, Joel B.
Background: Developmental dyslexia is typically defined by deficits in phonological skills, but it is also associated with anomalous performance on measures of balance. Although balance assessments are included in several screening batteries for dyslexia, the association between impairments in literacy and deficits in postural stability could be…
De Clercq-Quaegebeur, Maryse; Casalis, Severine; Lemaitre, Marie-Pierre; Bourgois, Beatrice; Getto, Marie; Vallee, Louis
This study examined the pattern of results on the "Wechsler Intelligence Scale for Children" (WISC-IV; French version) for 60 French children with dyslexia, from 8 to 16 years of age. Although use of WISC-III failed to clearly identify typical profiles and cognitive deficits in dyslexia, WISC-IV offers an opportunity to reach these…
Goswami, Usha; Mead, Natasha; Fosker, Tim; Huss, Martina; Barnes, Lisa; Leong, Victoria
Prosodic patterning is a key structural element of spoken language. However, the potential role of prosodic awareness in the phonological difficulties that characterise children with developmental dyslexia has been little studied. Here we report the first longitudinal study of sensitivity to syllable stress in children with dyslexia, enabling the…
Bigozzi, Lucia; Tarchi, Christian; Pinto, Giuliana; Accorti Gamannossi, Beatrice
We conducted this prospective cohort study to explore the predictability of dyslexia from 1st-grade literacy skills in Italian students. We followed 407 Italian students in primary school from the 1st through the 3rd grades. Students were diagnosed with dyslexia in the 3rd grade. We retrospectively tested participants' 1st-grade performance in…
Boets, Bart; De Smedt, Bert; Cleuren, Leen; Vandewalle, Ellen; Wouters, Jan; Ghesquiere, Pol
This longitudinal study examined the development of phonology and literacy in Dutch-speaking children at family risk of dyslexia and in matched controls. Measures were administered in kindergarten (before the start of formal reading instruction), in first and in third grade. Children, diagnosed with dyslexia in third grade, showed impaired…
Hazan, Valerie; Messaoud-Galusi, Souhila; Rosen, Stuart; Nouwens, Suzan; Shakespeare, Bethanie
Purpose: This study investigated whether adults with dyslexia show evidence of a consistent speech perception deficit by testing phoneme categorization and word perception in noise. Method: Seventeen adults with dyslexia and 20 average readers underwent a test battery including standardized reading, language and phonological awareness tests, and…
Poelmans, Hanne; Luts, Heleen; Vandermosten, Maaike; Boets, Bart; Ghesquiere, Pol; Wouters, Jan
The etiology of developmental dyslexia remains widely debated. An appealing theory postulates that the reading and spelling problems in individuals with dyslexia originate from reduced sensitivity to slow-rate dynamic auditory cues. This low-level auditory deficit is thought to provoke a cascade of effects, including inaccurate speech perception…
Francisco, Ana A.; Jesse, Alexandra; Groen, Margriet A.; McQueen, James M.
Purpose: Because reading is an audiovisual process, reading impairment may reflect an audiovisual processing deficit. The aim of the present study was to test the existence and scope of such a deficit in adult readers with dyslexia. Method: We tested 39 typical readers and 51 adult readers with dyslexia on their sensitivity to the simultaneity of…
Tobia, Valentina; Bonifacci, Paola; Ottaviani, Cristina; Borsato, Thomas; Marzocchi, Gian Marco
The aim of this study was to investigate physiological activation during reading and control tasks in children with dyslexia and typical readers. Skin conductance response (SCR) recorded during four tasks involving reading aloud, reading silently, and describing illustrated stories aloud and silently was compared for children with dyslexia (n =…
Bogliotti, C.; Serniclaes, W.; Messaoud-Galusi, S.; Sprenger-Charolles, L.
Previous studies have shown that children suffering from developmental dyslexia have a deficit in categorical perception of speech sounds. The aim of the current study was to better understand the nature of this categorical perception deficit. In this study, categorical perception skills of children with dyslexia were compared with those of…
Cameron, Harriet; Nunkoosing, Karl
The aim of this study was to explore lecturers' experiences with and perspectives on dyslexia and dyslexic students to inform the wider debate about the issues of dyslexia support in higher education. Data were collected and analysed using an abbreviated constructivist grounded theory method. Participants were categorised as "positive",…
Macdonald, Stephen J.
Since the 1960s, studies in the psycho-sciences have implied that people with dyslexia are at increased risk of engaging in criminal behaviours. There are two common themes that have emerged from this research. Firstly, studies that employ a psycho-medical model imply that the correlation between dyslexia and crime is embedded within neurological…
Nelson, Kent Peter
Many of the symptoms of dyslexia--such as difficulties with decoding written symbols, phonemic awareness, physical coordination, and readable handwriting--may adversely affect music learning. Despite challenges, some individuals with dyslexia succeed in music. The purpose of this study was to examine the perceptions of five professional musicians…
Warmington, Meesha; Stothard, Susan E.; Snowling, Margaret J.
Although there are a number of standardised measures to assess dyslexia in children, there are comparatively fewer instruments suitable for the assessment of dyslexia in adults. Given the growing number of students entering UK higher education institutions, there is a need to develop reliable tools for assessing the additional needs of those with…
Rose, L. Todd; Rouhani, Parisa
Most research on dyslexia to date has focused on early childhood, while comparatively little is known about the nature of dyslexia in adolescence. The current study had two objectives. The first was to investigate the relative contributions of several cognitive and linguistic factors to connected-text oral reading fluency in a sample of…
Howland, Karole A.; Liederman, Jacqueline
Purpose: To examine how adults with dyslexia versus adults with typical reading form lexical representations during pseudoword learning. Method: Twenty adults with dyslexia and 20 adults with typical reading learned meanings, spellings, and pronunciations of 16 pictured pseudowords, (half with regular and half with irregular grapheme-phoneme…
Stampoltzis, Aglaia; Tsitsou, Elisavet; Plesti, Helen; Kalouri, Rani
Introduction: Dyslexia is a learning difficulty which affects people in different ways. During the last decades the number of students with dyslexia entering higher education increased steadily. Method: This paper reports a pilot study exploring the attitudes, views and experiences of faculty members at one small size Greek university regarding…
Callens, Maaike; Tops, Wim; Stevens, Michaël; Brysbaert, Marc
An increasing number of students with dyslexia register in higher education. As a consequence, information on their pattern of strengths and weaknesses is essential to construct adequate assessment and diagnostic protocols. In a sample of 100 first-year bachelor students with dyslexia and 100 control students, a large pool of cognitive skills were…
Nigro, Luciana; Jiménez-Fernández, Gracia; Simpson, Ian C.; Defior, Sylvia
One of the hallmarks of dyslexia is the failure to automatise written patterns despite repeated exposure to print. Although many explanations have been proposed to explain this problem, researchers have recently begun to explore the possibility that an underlying implicit learning deficit may play a role in dyslexia. This hypothesis has been…
The present study aimed at exploring the educational, social and emotional experiences of individuals with dyslexia both during school and tertiary education. For this purpose, semi-structured interviews were conducted with ten Greek students with dyslexia who were enrolled in higher education institutions. The data analysis was carried out with…
Wong, Anita M.-Y.; Ho, Connie S.-H.; Au, Terry K.-F.; Kidd, Joanna C.; Ng, Ashley K.-H.; Yip, Lesley P.-W.; Lam, Catherine C.-C.
Specific language impairment (SLI) and dyslexia are found to co-occur in school-aged children learning Chinese, a non-alphabetic language (Wong, Kidd, Ho, & Au in "Sci Stud Read" 14:30--57, 2010). This paper examined the "Distinct" hypothesis--that SLI and dyslexia have different cognitive deficits and behavioural…
Serry, Tanya Anne; Hammond, Lorraine
The purpose of this study was to examine Australian learning difficulties specialists' knowledge about, and the use of, the term dyslexia. An online survey was constructed based on a current definition of, and evidence about, dyslexia and distributed to members of relevant professional associations. A total of 179 participants responded to the…
van Bergen, Elsje; de Jong, Peter F.; Plakas, Anna; Maassen, Ben; van der Leij, Aryan
Background: The present study concerns literacy and its underlying cognitive skills in Dutch children who differ in familial risk (FR) for dyslexia. Previous studies with FR-children were inconclusive regarding the performance of FR-children without dyslexia as compared to the controls. Moreover, van Bergen et al. (2011) recently showed that…
Gooch, Debbie; Snowling, Margaret; Hulme, Charles
Background: Deficits in time perception (the ability to judge the duration of time intervals) have been found in children with both attention-deficit/hyperactivity disorder (ADHD) and dyslexia. This paper investigates time perception, phonological skills and executive functions in children with dyslexia and/or ADHD symptoms (AS). Method: Children…
Ramus, Franck; Marshall, Chloe R.; Rosen, Stuart; van der Lely, Heather K. J.
An on-going debate surrounds the relationship between specific language impairment and developmental dyslexia, in particular with respect to their phonological abilities. Are these distinct disorders? To what extent do they overlap? Which cognitive and linguistic profiles correspond to specific language impairment, dyslexia and comorbid cases? At…
Nelson, Kent Peter; Hourigan, Ryan M.
Many of the characteristics of dyslexia--such as difficulties with decoding written symbols, phonemic awareness, physical coordination, and readable handwriting--may adversely affect music learning. Despite challenges, individuals with dyslexia can succeed in music. The purpose of this study was to examine the perceptions of five professional…
Stampoltzis , Aglaia; Tsitsou, Elisavet; Plesti, Helen; Kalouri, Rani
Dyslexia is the most common declared disability at universities which primarily affects reading, writing, speed of processing and organization. Many students with dyslexia have "invisible" difficulties that require different types of accommodations. The aim of this study is to give voice to the learning experiences of ten students with…
Padget, S. Yancey
Specific reading disability/dyslexia is examined as the one type of learning disability for which research results are consistent enough to suggest a model. The implications of this model are considered and three types of learning disabilities are discussed: specific language impairments, specific reading disability/dyslexia, and specific math…
Mascheretti, Sara; Marino, Cecilia; Simone, Daniela; Quadrelli, Ermanno; Riva, Valentina; Cellino, Maria Rosaria; Maziade, Michel; Brombin, Chiara; Battaglia, Marco
Although dyslexia runs in families, several putative risk factors that cannot be immediately identified as genetic predict reading disability. Published studies analyzed one or a few risk factors at a time, with relatively inconsistent results. To assess the contribution of several putative risk factors to the development of dyslexia, we conducted…
Kerkhoff, Annemarie; de Bree, Elise; de Klerk, Maartje; Wijnen, Frank
This study tests the hypothesis that developmental dyslexia is (partly) caused by a deficit in implicit sequential learning, by investigating whether infants at familial risk of dyslexia can track non-adjacent dependencies in an artificial language. An implicit learning deficit would hinder detection of such dependencies, which mark grammatical…
Foreman-Sinclair, Kimberly Ann
The purpose of this mixed research study was to investigate early assessment and identification for dyslexia in kindergarten through second grade, and to examine whether teachers' knowledge and beliefs lead to the practice of retaining students in grade rather than recommending formal dyslexia assessment. This study investigated both kindergarten…
Gray, Erika S.
Dyslexia is a congenital disorder characterized by unexpected difficulties in learning to read and spell in relation to one's verbal intelligence, motivation, and educational opportunities (Aylward et al., 2003; Morgan, 1896). Because dyslexia can affect 1.5-5% of the population (Aylward et al., 2003; Vellutino et al., 1996), understanding how to…
Nichols, S. A.; McLeod, J. S.; Holder, R. L.; McLeod, H. S. T.
This study reports a comparison of screening tests for dyslexia, dyspraxia and Meares-Irlen (M-I) syndrome in a Higher Education setting, the University of Worcester. Using a sample of 74 volunteer students, we compared the current tutor-delivered battery of 15 subtests with a computerized test, the Lucid Adult Dyslexia Screening test (LADS), and…
White, Sarah; Milne, Elizabeth; Rosen, Stuart; Hansen, Peter; Swettenham, John; Frith, Uta; Ramus, Franck
This study attempts to investigate the role of sensorimotor impairments in the reading disability that characterizes dyslexia. Twenty-three children with dyslexia were compared to 22 control children, matched for age and non-verbal intelligence, on tasks assessing literacy as well as phonological, visual, auditory and motor abilities. The dyslexic…
Tsermentseli, Stella; O'Brien, Justin M.; Spencer, Janine V.
A large body of research has reported visual perception deficits in both people with dyslexia and autistic spectrum disorders. In this study, we compared form and motion coherence detection between a group of adults with high-functioning autism, a group with Asperger's disorder, a group with dyslexia, and a matched control group. It was found that…
Marinelli, Chiara Valeria; Angelelli, Paola; Di Filippo, Gloria; Zoccolotti, Pierluigi
Although developmental dyslexia is often referred to as a cross-modal disturbance, tests of different modalities using the same stimuli are lacking. We compared the performance of 23 children with dyslexia and 42 chronologically matched control readers on reading versus repetition tasks and visual versus auditory lexical decision using the same…
Alden, Sandy; Pollock, Venda Louise
It is generally accepted that art and design related disciplines attract a higher proportion of students with dyslexia than traditional academic counterparts. Combined with this is a prevalent perception that dyslexia predominantly affects students' writing and linguistic ability and it is this, as well as an increased visual-spatial sensibility,…
Berninger, Virginia W.; Abbott, Robert D.; Thomson, Jennifer; Wagner, Richard; Swanson, H. Lee; Wijsman, Ellen M.; Raskind, Wendy
Recent theoretical advances in working memory guided analyses of cognitive measures in 122 children with dyslexia and their 200 affected biological parents in families with a multigenerational history of dyslexia. Both children and adults were most severely impaired, on average, in three working memory components- phonological word-form storage,…
Odegard, Timothy N.; Ring, Jeremiah; Smith, Stephanie; Biggan, John; Black, Jeff
Developmental dyslexia is associated with functional abnormalities within reading areas of the brain. For some children diagnosed with dyslexia, phonologically based remediation programs appear to rehabilitate brain function in key reading areas (Shaywitz et al., Biological Psychiatry 55: 101-110, 2004; Simos et al., Neuroscience 58: 1203-1213,…
Ptak, Radek; Di Pietro, Marie; Schnider, Armin
Neglect dyslexia--a peripheral reading disorder generally associated with left spatial neglect--is characterized by omissions or substitutions of the initial letters of words. Several observations suggest that neglect dyslexia errors are independent of viewer-centered coordinates; the disorder is therefore thought to reflect impairment at the…
Goswami, Usha; Wang, H.-L. Sharon; Cruz, Alicia; Fosker, Tim; Mead, Natasha; Huss, Martina
Studies in sensory neuroscience reveal the critical importance of accurate sensory perception for cognitive development. There is considerable debate concerning the possible sensory correlates of "phonological processing", the primary cognitive risk factor for developmental dyslexia. Across languages, children with dyslexia have a specific…
Williams Carawan, Lena; Nalavany, Blace
Reflexive photography for individual interviews and the use of art with focus groups provides a valuable method for exploring the psychosocial issues encountered by adults with dyslexia. Reflexive photography and art is particularly appropriate when interviewing adults with dyslexia who may have difficulty expressing and focusing on what they want…
Fiset, Stephanie; Arguin, Martin; Fiset, Daniel
We attempted to simulate the main features of letter-by-letter (LBL) dyslexia in normal readers through stimulus degradation (i.e. contrast reduction and removal of high spatial frequencies). The results showed the word length and the letter confusability effects characteristic of LBL dyslexia. However, the interaction of letter confusability and…
Skottun, Bernt C.; Skoyles, John R.
Dyslexia has been widely held to be associated with deficient temporal processing. It is, however, not established that the slower visual processing of dyslexic readers is not a secondary effect of task difficulty. To illustrate this we re-analyze data from Liddle et al. (2009) who studied temporal order judgment in dyslexia and plotted the…
In the diversity of an international school, many children for whom dyslexia is a barrier to literacy skill development may not have formally been identified as dyslexic; however, it does not mean that their needs do not require to be met. This paper considers the elements necessary to support the learners with dyslexia. Teaching Reading Through…
Coleman, Chris; Gregg, Noel; McLain, Lisa; Bellair, Leslie W.
In this study, the authors analyzed 2,056 spelling errors produced by 130 young adults (65 with dyslexia, 65 typically achieving), which came from two sources: a standardized spelling test and an impromptu essay-writing task. Students with dyslexia exhibited higher spelling error rates across both tasks. To characterize the inaccurate spelling…
Laycock, Robin; Crewther, David P.; Crewther, Sheila G.
Controversy still exists over whether there is a magnocellular deficit associated with developmental dyslexia. Here we utilised a magnocellular system-biased phantom contour form discrimination task defined by high temporal frequency contrast reversals to compare contrast sensitivity in a group of children with dyslexia and an age- and nonverbal…
McCardle, Peggy, Ed.; Miller, Brett, Ed.; Lee, Jun Ren, Ed.; Tzeng, Ovid J. L., Ed.
What causes dyslexia, and how does it manifest across languages? As bilingualism becomes increasingly important globally, these questions have never been more critical--and this comprehensive volume from The Dyslexia Foundation explores them in unprecedented depth. Bringing together the best brain-based, genetics, and behavioral research in the…
Snowling, Margaret J.; Muter, Valerie; Carroll, Julia
Background: This study is the follow-up in early adolescence of children born to families with a history of dyslexia ( Gallagher, Frith, & Snowling, 2000). Methods: Fifty young people with a family history of dyslexia and 20 young people from control families were assessed at 12-13 years on a battery of tests of literacy and language skills, and…
Berninger, Virginia W.; Lee, Yen-Ling; Abbott, Robert D.; Breznitz, Zvia
To identify effective treatment for both the spelling and word decoding problems in dyslexia, 24 students with dyslexia in grades 4 to 9 were randomly assigned to treatments A (n = 12) or B (n = 12) in an after-school reading-writers' workshop at the university (thirty 1-h sessions twice a week over 5 months). First, both groups received step 1…
Skottun, Bernt C.; Parke, Lesley A.
Examines the assumption that the parvocellular system is suppressed by the magnocellular system during saccadic eye movements and that this visual deficit is associated with dyslexia. Evidence from six studies indicates the magnocellular system is suppressed during saccadic eye movements, disproving the magnocellular deficit theory of dyslexia.…
Tressoldi, Patrizio E.; Stella, Giacomo; Faggella, Marzia
Development of reading speed in Italian children with dyslexia was estimated using individualized growth curves for 38 children with dyslexia tested longitudinally from 2nd-8th grade and compared with controls. Their reading speed development followed a linear trend of .3 syllables per second per grade, half the increment observed in controls.…
Buchholz, Judy; McKone, Elinor
We examine the visual processing of high-functioning adults with developmental dyslexia (mean Performance IQ=126.5) and current phonological problems. In comparison to an age- and IQ-matched control group, the group with dyslexia showed deficits in two tasks associated with magnocellular/dorsal pathway function. For the "frequency doubling"…
Ziegler, Johannes C.; Pech-Georgel, Catherine; Dufau, Stephane; Grainger, Jonathan
Visual-attentional theories of dyslexia predict deficits for dyslexic children not only for the perception of letter strings but also for non-alphanumeric symbol strings. This prediction was tested in a two-alternative forced-choice paradigm with letters, digits, and symbols. Children with dyslexia showed significant deficits for letter and digit…
Mahe, Gwendoline; Bonnefond, Anne; Gavens, Nathalie; Dufour, Andre; Doignon-Camus, Nadege
Efficient reading relies on expertise in the visual word form area, with abnormalities in the functional specialization of this area observed in individuals with developmental dyslexia. We have investigated event related potentials in print tuning in adults with dyslexia, based on their N170 response at 135-255 ms. Control and dyslexic adults…
Guttorm, Tomi K.; Leppanen, Paavo H. T.; Richardson, Ulla; Lyytinen, Heikki
This study examined event-related potentials (ERPs) to synthetic consonant-vowel syllables from 26 newborns with familial risk for dyslexia and 23 control infants participating in a longitudinal study of dyslexia. Results indicated that the cortical electric activation evoked by speech elements differed between children with and without risk for…
Casserly, Ann Marie
This paper reports on a four-year research project examining the experiences of children with dyslexia in mainstream schools and reading schools/classes. The focus of this paper is on the socio-emotional effects of dyslexia on a group of children attending a reading school/class for a specific duration before returning to mainstream. The findings…
van Bergen, Elsje; de Jong, Peter F.; Maassen, Ben; Krikhaar, Evelien; Plakas, Anna; van der Leij, Aryan
Do children who go on to develop dyslexia show normal verbal and nonverbal development before reading onset? According to the aptitude-achievement discrepancy model, dyslexia is defined as a discrepancy between intelligence and reading achievement. One of the underlying assumptions is that the general cognitive development of children who fail to…
Eklund, Kenneth; Torppa, Minna; Aro, Mikko; Leppänen, Paavo H. T.; Lyytinen, Heikki
This study followed the development of reading speed, reading accuracy, and spelling in transparent Finnish orthography in children through Grades 2, 3, and 8. We compared 2 groups of children with familial risk for dyslexia--1 group with dyslexia (Dys _FR, n = 35) and 1 group without (NoDys_FR, n = 66) in Grade 2--with a group of children without…
Lorusso, Maria Luisa; Facoetti, Andrea; Molteni, Massimo
Aim of the study is to analyze the contributions of hemispheric, attentional, and processing speed factors to the effects of neuropsychological treatment of developmental dyslexia. Four groups of dyslexic children (M-type dyslexia) were treated over a period of four months. A first group (n=9) underwent Bakker's Hemisphere-Specific Stimulation,…
Reid, Gavin; Strnadova, Iva; Cumming, Therese
This paper discusses the role of mobile technology in supporting people with dyslexia within the theoretical framework of Universal Design for Learning. The authors discuss how students with dyslexia can use mobile technology to address a diverse range of academic needs (such as reading, composing text, notetaking, metacognition and studying…
Laasonen, Marja; Virsu, Veijo; Oinonen, Suvi; Sandbacka, Mirja; Salakari, Anita; Service, Elisabet
We investigated whether poor short-term memory (STM) in developmental dyslexia affects the processing of sensory stimulus sequences in addition to phonological material. STM for brief binary non-verbal stimuli (light flashes, tone bursts, finger touches, and their crossmodal combinations) was studied in 20 Finnish adults with dyslexia and 24…
Dickie, Catherine; Ota, Mitsuhiko; Clark, Ann
This study investigates whether developmental dyslexia involves an impairment in implicit phonological representations, as distinct from orthographic representations and metaphonological skills. A group of adults with dyslexia was matched with a group with no history of speech/language/literacy impairment. Tasks varied in the demands made on…
Annett, M; Eglinton, E; Smythe, P
The prediction of the right shift theory that there are two types of dyslexia with different distributions of handedness was examined in a large cohort of school children. Dyslexics with poor phonology were less biased to dextrality than controls, while dyslexics without poor phonology tended to be more dextral than controls on measures of hand preference and hand skill. Relatives also differed for handedness, as expected if phonological dyslexics were less likely than nonphonological dyslexics and controls to carry the hypothesized rs + gene.
Öqvist Seimyr, Gustaf; Ygge, Jan; Pansell, Tony; Rydberg, Agneta; Jacobson, Christer
Dyslexia is a neurodevelopmental reading disability estimated to affect 5–10% of the population. While there is yet no full understanding of the cause of dyslexia, or agreement on its precise definition, it is certain that many individuals suffer persistent problems in learning to read for no apparent reason. Although it is generally agreed that early intervention is the best form of support for children with dyslexia, there is still a lack of efficient and objective means to help identify those at risk during the early years of school. Here we show that it is possible to identify 9–10 year old individuals at risk of persistent reading difficulties by using eye tracking during reading to probe the processes that underlie reading ability. In contrast to current screening methods, which rely on oral or written tests, eye tracking does not depend on the subject to produce some overt verbal response and thus provides a natural means to objectively assess the reading process as it unfolds in real-time. Our study is based on a sample of 97 high-risk subjects with early identified word decoding difficulties and a control group of 88 low-risk subjects. These subjects were selected from a larger population of 2165 school children attending second grade. Using predictive modeling and statistical resampling techniques, we develop classification models from eye tracking records less than one minute in duration and show that the models are able to differentiate high-risk subjects from low-risk subjects with high accuracy. Although dyslexia is fundamentally a language-based learning disability, our results suggest that eye movements in reading can be highly predictive of individual reading ability and that eye tracking can be an efficient means to identify children at risk of long-term reading difficulties. PMID:27936148
Scerri, Thomas S; Brandler, William M; Paracchini, Silvia; Morris, Andrew P; Ring, Susan M; Richardson, Alex J; Talcott, Joel B; Stein, John; Monaco, Anthony P
Approximately 90% of humans are right-handed. Handedness is a heritable trait, yet the genetic basis is not well understood. Here we report a genome-wide association study for a quantitative measure of relative hand skill in individuals with dyslexia [reading disability (RD)]. The most highly associated marker, rs11855415 (P = 4.7 × 10(-7)), is located within PCSK6. Two independent cohorts with RD show the same trend, with the minor allele conferring greater relative right-hand skill. Meta-analysis of all three RD samples is genome-wide significant (n = 744, P = 2.0 × 10(-8)). Conversely, in the general population (n = 2666), we observe a trend towards reduced laterality of hand skill for the minor allele (P = 0.0020). These results provide molecular evidence that cerebral asymmetry and dyslexia are linked. Furthermore, PCSK6 is a protease that cleaves the left-right axis determining protein NODAL. Functional studies of PCSK6 promise insights into mechanisms underlying cerebral lateralization and dyslexia.
Bonifacci, Paola; Montuschi, Martina; Lami, Laura; Snowling, Margaret J
Within a dimensional view of reading disorders, it is important to understand the role of environmental factors in determining individual differences in literacy outcome. In the present study, we compared a group of 40 parents of children with dyslexia (PDys) with a group of 40 parents of typically developing children. The two parent groups did not differ in socioeconomic status or nonverbal IQ. Participants were assessed on cognitive (IQ, digit span) and literacy (reading fluency and accuracy) tasks, phonological awareness and verbal fluency measures. Questionnaires addressed reading history, parental distress, family functioning, anxiety and depression. The PDys group performed worse in all literacy measures and more frequently reported a history of poor reading; they also showed more parental distress. There were no differences between the two groups in depression or family functioning and no differences between mothers and fathers. Findings indicate that PDys show a cognitive profile consistent with the broader phenotype of dyslexia (i.e. reading impairment and poor phonological awareness), whereas, considering the emotional profile, the impact of dyslexia on the family system is limited to parental distress associated with the perception of having a child with specific needs.
McArthur, Genevieve; Castles, Anne; Kohnen, Saskia; Larsen, Linda; Jones, Kristy; Anandakumar, Thushara; Banales, Erin
The aims of this study were to (a) compare sight word training and phonics training in children with dyslexia, and (b) determine if different orders of sight word and phonics training have different effects on the reading skills of children with dyslexia. One group of children (n = 36) did 8 weeks of phonics training (reading via grapheme-phoneme correspondence rules) and then 8 weeks of sight word training (reading irregular words as a whole), one group did the reverse (n = 36), and one group did phonics and sight word training simultaneously for two 8-week periods (n = 32). We measured the effects of phonics and sight word training on sight word reading (trained irregular word reading accuracy, untrained irregular word reading accuracy), phonics reading (nonword reading accuracy, nonword reading fluency), and general reading (word reading fluency, reading comprehension). Sight word training led to significant gains in sight word reading measures that were larger than gains made from phonics training, phonics training led to statistically significant gains in a phonics reading measure that were larger than gains made from sight word training, and both types of training led to significant gains in general reading that were similar in size. Training phonics before sight words had a slight advantage over the reverse order. We discuss the clinical implications of these findings for improving the treatment and assessment of children with dyslexia.
Bacon, Alison M; Handley, Simon J
Recent research has suggested that individuals with dyslexia rely on explicit visuospatial representations for syllogistic reasoning while most non-dyslexics opt for an abstract verbal strategy. This paper investigates the role of visual processes in relational reasoning amongst dyslexic reasoners. Expt 1 presents written and verbal protocol evidence to suggest that reasoners with dyslexia generate detailed representations of relational properties and use these to make a visual comparison of objects. Non-dyslexics use a linear array of objects to make a simple transitive inference. Expt 2 examined evidence for the visual-impedance effect which suggests that visual information detracts from reasoning leading to longer latencies and reduced accuracy. While non-dyslexics showed the impedance effects predicted, dyslexics showed only reduced accuracy on problems designed specifically to elicit imagery. Expt 3 presented problems with less semantically and visually rich content. The non-dyslexic group again showed impedance effects, but dyslexics did not. Furthermore, in both studies, visual memory predicted reasoning accuracy for dyslexic participants, but not for non-dyslexics, particularly on problems with highly visual content. The findings are discussed in terms of the importance of visual and semantic processes in reasoning for individuals with dyslexia, and we argue that these processes play a compensatory role, offsetting phonological and verbal memory deficits.
Gooch, Debbie; Hulme, Charles; Nash, Hannah M; Snowling, Margaret J
Background Comorbidity among developmental disorders such as dyslexia, language impairment, attention deficit/hyperactivity disorder and developmental coordination disorder is common. This study explores comorbid weaknesses in preschool children at family risk of dyslexia with and without language impairment and considers the role that comorbidity plays in determining children’s outcomes. Method The preschool attention, executive function and motor skills of 112 children at family risk for dyslexia, 29 of whom also met criteria for language impairment, were assessed at ages 3 ½ and 4 ½. The performance of these children was compared to the performance of children with language impairment and typically developing controls. Results Weaknesses in attention, executive function and motor skills were associated with language impairment rather than family risk status. Individual differences in language and executive function are strongly related in the preschool period and preschool motor skills predicted unique variance (4%) in early reading skills over and above children’s language ability. Conclusion Comorbidity between developmental disorders can be observed in the preschool years: children with language impairment have significant and persistent weaknesses in motor skills and executive function compared to those without language impairment. Children’s early language and motor skills are predictors of children’s later reading skills. PMID:24117483
Casini, Laurence; Pech-Georgel, Catherine; Ziegler, Johannes C
Temporal processing in French children with dyslexia was evaluated in three tasks: a word identification task requiring implicit temporal processing, and two explicit temporal bisection tasks, one in the auditory and one in the visual modality. Normally developing children matched on chronological age and reading level served as a control group. Children with dyslexia exhibited robust deficits in temporal tasks whether they were explicit or implicit and whether they involved the auditory or the visual modality. First, they presented larger perceptual variability when performing temporal tasks, whereas they showed no such difficulties when performing the same task on a non-temporal dimension (intensity). This dissociation suggests that their difficulties were specific to temporal processing and could not be attributed to lapses of attention, reduced alertness, faulty anchoring, or overall noisy processing. In the framework of cognitive models of time perception, these data point to a dysfunction of the 'internal clock' of dyslexic children. These results are broadly compatible with the recent temporal sampling theory of dyslexia.
Besser, Martin W; MacDonald, Stephen G
Acquired hypofibrinogenemia is most frequently caused by hemodilution and consumption of clotting factors. The aggressive replacement of fibrinogen has become one of the core principles of modern management of massive hemorrhage. The best method for determining the patient’s fibrinogen level remains controversial, and particularly in acquired dysfibrinogenemia, could have major therapeutic implications depending on which quantification method is chosen. This review introduces the available laboratory and point-of-care methods and discusses the relative advantages and limitations. It also discusses current strategies for the correction of hypofibrinogenemia. PMID:27713652
Falguera, M; Ramírez, M F
This article not only reviews the essential aspects of community-acquired pneumonia for daily clinical practice, but also highlights the controversial issues and provides the newest available information. Community-acquired pneumonia is considered in a broad sense, without excluding certain variants that, in recent years, a number of authors have managed to delineate, such as healthcare-associated pneumonia. The latter form is nothing more than the same disease that affects more frail patients, with a greater number of risk factors, both sharing an overall common approach.
Washburn, Erin K; Binks-Cantrell, Emily S; Joshi, R Malatesha
The purpose of the study was to examine the knowledge base of preservice teachers from the USA and the UK of dyslexia as a language-based learning disability. A survey (both US and UK versions) was constructed using current research-based understandings of dyslexia as a language-based learning disability. One hundred and one preservice teachers from the USA and 70 preservice teachers from the UK were administered the survey. Results indicated that participants in the two groups demonstrated some similar accurate knowledge about dyslexia as well as displaying some common misunderstandings about dyslexia. Recommendations concerning preservice teacher preparation and professional development for in-service teachers about dyslexia as well as future research directions are discussed.
Mascheretti, Sara; Marino, Cecilia; Simone, Daniela; Quadrelli, Ermanno; Riva, Valentina; Cellino, Maria Rosaria; Maziade, Michel; Brombin, Chiara; Battaglia, Marco
Although dyslexia runs in families, several putative risk factors that cannot be immediately identified as genetic predict reading disability. Published studies analyzed one or a few risk factors at a time, with relatively inconsistent results. To assess the contribution of several putative risk factors to the development of dyslexia, we conducted a case-control study of 403 Italian children, 155 with dyslexia, by implementing a stepwise logistic regression applied to the entire sample, and then to boys and girls separately. Younger parental age at child's birth, lower parental education, and risk of miscarriage significantly increased the odds of belonging to the dyslexia group (19.5% of the variation). These associations were confirmed in the analyses conducted separately by sex, except for parental education, which significantly affected only males. These findings support reading disabilities as a multifactorial disorder and may bear some importance for the prevention and/or early detection of children at heightened risk for dyslexia.
MacCullagh, Lois; Bosanquet, Agnes; Badcock, Nicholas A
People with dyslexia are vastly under-represented in universities (Katusic et al., , Richardson & Wydell, ; Stampoltzis & Polychronopoulou, ). This situation is of concern for modern societies that value social justice. This study was designed to explore learning experiences of university students with dyslexia and factors that could contribute to their success. Thirteen students with dyslexia and 20 non-dyslexic peers were interviewed about their university learning experiences using a semi-structured qualitative approach. Students with dyslexia described engaging in learning activities intensively, frequently and strategically. They reported challenges and strengths relating to study skills, lectures, assessments, technology and support services. They also described helpful strategies including self-directed adaptive techniques, provisions from lecturers and assistance from the university. These findings suggest that students with dyslexia experience broad challenges at university, but helpful strategies may be available. Copyright © 2016 John Wiley & Sons, Ltd.
Parhiala, P; Torppa, M; Eklund, K; Aro, T; Poikkeus, A-M; Heikkilä, R; Ahonen, T
This longitudinal study compares developmental changes in psychosocial functioning during the transition into school of children with and without dyslexia. In addition, it examines the effects of gender and family risk for dyslexia in terms of the associations between dyslexia and psychosocial functioning. Children's psychosocial functioning (social skills, inattention and externalizing and internalizing problems) was evaluated by their parents at ages 4, 6 and 9, and diagnosis for dyslexia was made at age 8 (in grade 2). The findings indicated that children with dyslexia were already rated as having poorer social skills and being more inattentive than were typical readers before their entry into school. Significant interactions of gender and diagnosis of dyslexia emerged for social skills and inattention. The social skills of boys with dyslexia improved after school entry as compared to the level of girls without dyslexia, whereas the social skills of girls with dyslexia did not improve. Boys with dyslexia were rated as showing a high level of inattention both prior to and after school entry, whereas, for girls with dyslexia, inattention ratings increased after school entry, eventually matching the boys' levels.
Schwartz, Stacey Hunter
This paper reviews the Acquired Brain Injury (ABI) Program at Coastline Community College (California). The ABI Program is a two-year, for-credit educational curriculum designed to provide structured cognitive retraining for adults who have sustained an ABI due to traumatic (such as motor vehicle accident or fall) or non-traumatic(such as…
Daini, Roberta; Albonico, Andrea; Malaspina, Manuela; Martelli, Marialuisa; Primativo, Silvia; Arduino, Lisa S
Although omission and substitution errors in neglect dyslexia (ND) patients have always been considered as different manifestations of the same acquired reading disorder, recently, we proposed a new dual mechanism model. While omissions are related to the exploratory disorder which characterizes unilateral spatial neglect (USN), substitutions are due to a perceptual integration mechanism. A consequence of this hypothesis is that specific training for omission-type ND patients would aim at restoring the oculo-motor scanning and should not improve reading in substitution-type ND. With this aim we administered an optokinetic stimulation (OKS) to two brain-damaged patients with both USN and ND, MA and EP, who showed ND mainly characterized by omissions and substitutions, respectively. MA also showed an impairment in oculo-motor behavior with a non-reading task, while EP did not. The two patients presented a dissociation with respect to their sensitivity to OKS, so that, as expected, MA was positively affected, while EP was not. Our results confirm a dissociation between the two mechanisms underlying omission and substitution reading errors in ND patients. Moreover, they suggest that such a dissociation could possibly be extended to the effectiveness of rehabilitative procedures, and that patients who mainly omit contralesional-sided letters would benefit from OKS.
McMahon, Christine M; Cuker, Adam
The development of thrombocytopenia is common in hospitalized patients and is associated with increased mortality. Frequent and important causes of thrombocytopenia in hospitalized patients include etiologies related to the underlying illness for which the patient is admitted, such as infection and disseminated intravascular coagulation, and iatrogenic etiologies such as drug-induced immune thrombocytopenia, heparin-induced thrombocytopenia, posttransfusion purpura, hemodilution, major surgery, and extracorporeal circuitry. This review presents a brief discussion of the pathophysiology, distinguishing clinical features, and management of these etiologies, and provides a diagnostic approach to hospital-acquired thrombocytopenia that considers the timing and severity of the platelet count fall, the presence of hemorrhage or thrombosis, the clinical context, and the peripheral blood smear. This approach may offer guidance to clinicians in distinguishing among the various causes of hospital-acquired thrombocytopenia and providing management appropriate to the etiology.
Stahley, Sara N.; Kowalczyk, Andrew P.
Desmosomes are cell-cell junctions that mediate adhesion and couple the intermediate filament cytoskeleton to sites of cell-cell contact. This architectural arrangement functions to integrate adhesion and cytoskeletal elements of adjacent cells. The importance of this robust adhesion system is evident in numerous human diseases, both inherited and acquired, that occur when desmosome function is compromised. This review focuses on autoimmune and infectious diseases that impair desmosome function. In addition, we discuss emerging evidence that desmosomal genes are often misregulated in cancer. The emphasis of our discussion is placed on how human diseases inform our understanding of basic desmosome biology, and in turn, how fundamental advances in the cell biology of desmosomes may lead to new treatments for acquired diseases of the desmosome. PMID:25795143
Stahley, Sara N; Kowalczyk, Andrew P
Desmosomes are cell-cell junctions that mediate adhesion and couple the intermediate filament cytoskeleton to sites of cell-cell contact. This architectural arrangement integrates adhesion and cytoskeletal elements of adjacent cells. The importance of this robust adhesion system is evident in numerous human diseases, both inherited and acquired, which occur when desmosome function is compromised. This review focuses on autoimmune and infectious diseases that impair desmosome function. In addition, we discuss emerging evidence that desmosomal genes are often misregulated in cancer. The emphasis of our discussion is placed on the way in which human diseases can inform our understanding of basic desmosome biology and in turn, the means by which fundamental advances in the cell biology of desmosomes might lead to new treatments for acquired diseases of the desmosome.
Ghisi, Marta; Bottesi, Gioia; Re, Anna M.; Cerea, Silvia; Mammarella, Irene C.
Dyslexia is a permanent condition characterized by reading difficulties that include inaccurate or slow and effortful word reading, poor decoding, and poor spelling abilities. People with dyslexia may have psychological and psychopathological issues such as low self-esteem, poor resilience, and symptoms of depression and anxiety. They may also develop social problems and emotional issues, as well as low academic and social self-efficacy. The present study aimed to assess the psychological features of a sample of 28 Italian university students with dyslexia, comparing them with a control group of typically developing students matched for gender, education, and academic discipline, to enhance our knowledge of dyslexia outcomes in an Italian setting. The results show that university students with dyslexia experience higher levels of somatic complaints, social and attentional problems, lower self-esteem, and higher depression scores than controls, while no difference emerged between the two groups’ resilience scores. In conclusion, the present findings suggest that university students with dyslexia report more psychological issues than students without dyslexia and could benefit from intervention to improve their psychological and physical well-being. PMID:27065220
Smith-Spark, James H; Zięcik, Adam P; Sterling, Christopher
Short-term and working memory problems in dyslexia are well-documented, but other memory domains have received little empirical scrutiny, despite some evidence to suggest that they might be impaired. Prospective memory is memory for delayed intentions, whilst retrospective memory relates to memory for personally experienced past events. To gain an understanding of subjective everyday memory experience, a self-report measure designed to tap prospective and retrospective memory was administered to 28 adults with dyslexia and 26 IQ-matched adults without dyslexia. Adults with dyslexia reported experiencing significantly more frequent problems with memory than the adults without dyslexia. Group differences were found across seven out of the eight questionnaire scales. Further to these analyses, the participants' own ratings were compared with proxy ratings provided by close associates. The perception of poorer memory abilities in the participants did not differ between respondent types. The self-reported difficulties are, thus, unlikely to be the result of lowered self-esteem or metacognitive awareness. More frequent difficulties with both types of memory would seem, therefore, to be experienced by adults with dyslexia in everyday life. Further laboratory-based research is recommended to explore both memory domains in dyslexia and to identify the cognitive mechanisms by which these problems occur. Copyright © 2016 John Wiley & Sons, Ltd.
Firth, Nola; Frydenberg, Erica; Steeg, Charlotte; Bond, Lyndal
A dyslexia coping programme entitled Success and Dyslexia was implemented in two primary schools within a whole-class coping programme and whole-school dyslexia professional development context. One hundred and two year 6 students, 23 of whom had dyslexia, undertook surveys pretest, post-test and at 1-year follow-up. Effectiveness of the coping programme and maintenance of effects for the students after transition to secondary school were investigated. Inclusion of contrast group data in the follow-up year suggested significant positive changes at first and second follow-ups in locus of control and nonproductive coping may also be associated with increase in age. Most trends were in the expected direction, especially for students with dyslexia. At follow-up, students with dyslexia reported similar perceived control and adaptive coping to students without dyslexia rather than a decrease in these areas as is usually the case. A larger sample and an ongoing control group are needed to confirm these results.
Tamboer, Peter; Vorst, Harrie C M
The validity of a Dutch self-report inventory of dyslexia was ascertained in two samples of students. Six biographical questions, 20 general language statements and 56 specific language statements were based on dyslexia as a multi-dimensional deficit. Dyslexia and non-dyslexia were assessed with two criteria: identification with test results (Sample 1) and classification using biographical information (both samples). Using discriminant analyses, these criteria were predicted with various groups of statements. All together, 11 discriminant functions were used to estimate classification accuracy of the inventory. In Sample 1, 15 statements predicted the test criterion with classification accuracy of 98%, and 18 statements predicted the biographical criterion with classification accuracy of 97%. In Sample 2, 16 statements predicted the biographical criterion with classification accuracy of 94%. Estimations of positive and negative predictive value were 89% and 99%. Items of various discriminant functions were factor analysed to find characteristic difficulties of students with dyslexia, resulting in a five-factor structure in Sample 1 and a four-factor structure in Sample 2. Answer bias was investigated with measures of internal consistency reliability. Less than 20 self-report items are sufficient to accurately classify students with and without dyslexia. This supports the usefulness of self-assessment of dyslexia as a valid alternative to diagnostic test batteries.
Wilcke, Arndt; Müller, Bent; Schaadt, Gesa; Kirsten, Holger; Boltze, Johannes
Dyslexia is a developmental disorder characterized by severe problems in the acquisition of reading and writing skills. It has a strong neurobiological basis. Genetic influence is estimated at 50-70%. One of the central problems with dyslexia is its late diagnosis, normally not before the end of the 2nd grade, resulting in the loss of several years for early therapy. Currently, research is focusing on the development of early tests for dyslexia, which may be based on EEG and genetics. Our aim was to determine the acceptance of such a future test among parents. We conducted a representative survey in Germany with 1000 parents of children aged 3-7 years, with and without experience of dyslexia. 88.7% of the parents supported the introduction of an early test for dyslexia based on EEG and genetics; 82.8% would have their own children tested, and 57.9% were willing to pay for the test if health insurance did not cover the costs. Test acceptance was significantly higher if parents had prior experience with dyslexia. The perceived benefits of such a test were early recognition and remediation and, preventing deficits. Concerns regarded the precision of the test, its potentially stigmatizing effect and its costs. The high overall support for the test leads to the conclusion that parents would accept a test for dyslexia based on EEG and genetics.
Macdonald, Stephen J
The aim of this study is to develop perceptual knowledge of dyslexia from adults diagnosed with this condition. Historically, the dominant conceptual frameworks used to study dyslexia stem from psychological or educational practice. These disciplines predominantly draw on professional neuro-biological or educational knowledge that can be broadly summarized within a medical or educational model approach. Both the medical and educational models view dyslexia as resulting from a neurological and learning dysfunction. As such, only a small amount of research has attempted to locate dyslexia within a sociological context. This paper analyses the life narratives of adults diagnosed with dyslexia using the social model of disability. The author investigates the impact that disabling barriers have in education and employment for people with dyslexia. The implications of this are discussed, particularly how issues of disabling barriers and social-class structures affect the lives of people with dyslexia. The paper argues that social-class positioning and institutional discrimination (in the form of disabling barriers) shape the experiences of people living with this condition.
Goswami, Usha; Barnes, Lisa; Mead, Natasha; Power, Alan James; Leong, Victoria
Children with developmental dyslexia are characterized by phonological difficulties across languages. Classically, this 'phonological deficit' in dyslexia has been investigated with tasks using single-syllable words. Recently, however, several studies have demonstrated difficulties in prosodic awareness in dyslexia. Potential prosodic effects in short-term memory have not yet been investigated. Here we create a new instrument based on three-syllable words that vary in stress patterns, to investigate whether prosodic similarity (the same prosodic pattern of stressed and unstressed syllables) exerts systematic effects on short-term memory. We study participants with dyslexia and age-matched and younger reading-level-matched typically developing controls. We find that all participants, including dyslexic participants, show prosodic similarity effects in short-term memory. All participants exhibited better retention of words that differed in prosodic structure, although participants with dyslexia recalled fewer words accurately overall compared to age-matched controls. Individual differences in prosodic memory were predicted by earlier vocabulary abilities, by earlier sensitivity to syllable stress and by earlier phonological awareness. To our knowledge, this is the first demonstration of prosodic similarity effects in short-term memory. The implications of a prosodic similarity effect for theories of lexical representation and of dyslexia are discussed. © 2016 The Authors. Dyslexia published by John Wiley & Sons Ltd.
Hachmann, Wibke M; Bogaerts, Louisa; Szmalec, Arnaud; Woumans, Evy; Duyck, Wouter; Job, Remo
Recent findings suggest that people with dyslexia experience difficulties with the learning of serial order information during the transition from short- to long-term memory (Szmalec et al. Journal of Experimental Psychology: Learning, Memory, & Cognition 37(5): 1270-1279, 2011). At the same time, models of short-term memory increasingly incorporate a distinction of order and item processing (Majerus et al. Cognition 107: 395-419, 2008). The current study is aimed to investigate whether serial order processing deficiencies in dyslexia can be traced back to a selective impairment of short-term memory for serial order and whether this impairment also affects processing beyond the verbal domain. A sample of 26 adults with dyslexia and a group of age and IQ-matched controls participated in a 2 × 2 × 2 experiment in which we assessed short-term recognition performance for order and item information, using both verbal and nonverbal material. Our findings indicate that, irrespective of the type of material, participants with dyslexia recalled the individual items with the same accuracy as the matched control group, whereas the ability to recognize the serial order in which those items were presented appeared to be affected in the dyslexia group. We conclude that dyslexia is characterized by a selective impairment of short-term memory for serial order, but not for item information, and discuss the integration of these findings into current theoretical views on dyslexia and its associated dysfunctions.
Kronschnabel, Jens; Brem, Silvia; Maurer, Urs; Brandeis, Daniel
The classical phonological deficit account of dyslexia is increasingly linked to impairments in grapho-phonological conversion, and to dysfunctions in superior temporal regions associated with audiovisual integration. The present study investigates mechanisms of audiovisual integration in typical and impaired readers at the critical developmental stage of adolescence. Congruent and incongruent audiovisual as well as unimodal (visual only and auditory only) material was presented. Audiovisual presentations were single letters and three-letter (consonant-vowel-consonant) stimuli accompanied by matching or mismatching speech sounds. Three-letter stimuli exhibited fast phonetic transitions as in real-life language processing and reading. Congruency effects, i.e. different brain responses to congruent and incongruent stimuli were taken as an indicator of audiovisual integration at a phonetic level (grapho-phonological conversion). Comparisons of unimodal and audiovisual stimuli revealed basic, more sensory aspects of audiovisual integration. By means of these two criteria of audiovisual integration, the generalizability of audiovisual deficits in dyslexia was tested. Moreover, it was expected that the more naturalistic three-letter stimuli are superior to single letters in revealing group differences. Electrophysiological and hemodynamic (EEG and fMRI) data were acquired simultaneously in a simple target detection task. Applying the same statistical models to event-related EEG potentials and fMRI responses allowed comparing the effects detected by the two techniques at a descriptive level. Group differences in congruency effects (congruent against incongruent) were observed in regions involved in grapho-phonological processing, including the left inferior frontal and angular gyri and the inferotemporal cortex. Importantly, such differences also emerged in superior temporal key regions. Three-letter stimuli revealed stronger group differences than single letters. No
Zuk, Jennifer; Bishop-Liebler, Paula; Ozernov-Palchik, Ola; Moore, Emma; Overy, Katie; Welch, Graham; Gaab, Nadine
Previous research has suggested a link between musical training and auditory processing skills. Musicians have shown enhanced perception of auditory features critical to both music and speech, suggesting that this link extends beyond basic auditory processing. It remains unclear to what extent musicians who also have dyslexia show these specialized abilities, considering often-observed persistent deficits that coincide with reading impairments. The present study evaluated auditory sequencing and speech discrimination in 52 adults comprised of musicians with dyslexia, nonmusicians with dyslexia, and typical musicians. An auditory sequencing task measuring perceptual acuity for tone sequences of increasing length was administered. Furthermore, subjects were asked to discriminate synthesized syllable continua varying in acoustic components of speech necessary for intraphonemic discrimination, which included spectral (formant frequency) and temporal (voice onset time [VOT] and amplitude envelope) features. Results indicate that musicians with dyslexia did not significantly differ from typical musicians and performed better than nonmusicians with dyslexia for auditory sequencing as well as discrimination of spectral and VOT cues within syllable continua. However, typical musicians demonstrated superior performance relative to both groups with dyslexia for discrimination of syllables varying in amplitude information. These findings suggest a distinct profile of speech processing abilities in musicians with dyslexia, with specific weaknesses in discerning amplitude cues within speech. Because these difficulties seem to remain persistent in adults with dyslexia despite musical training, this study only partly supports the potential for musical training to enhance the auditory processing skills known to be crucial for literacy in individuals with dyslexia. (PsycINFO Database Record
Chen, Yun; Zhao, Hua; Zhang, Yi-xin; Zuo, Peng-xiang
Developmental dyslexia is a complex reading and writing disorder with strong genetic components. In previous genetic studies about dyslexia, a number of candidate genes have been identified. These include DCDC2, which has repeatedly been associated with developmental dyslexia in various European and American populations. However, data regarding this relationship are varied according to population. The Uyghur people of China represent a Eurasian population with an interesting genetic profile. Thus, this group may provide useful information about the association between DCDC2 gene polymorphisms and dyslexia. In the current study, we examined genetic data from 392 Uyghur children aged 8–12 years old from the Xinjiang Uyghur Autonomous Region of China. Participants included 196 children with dyslexia and 196 grade-, age-, and gender-matched controls. DNA was isolated from oral mucosal cell samples and fourteen single nucleotide polymorphisms (rs6456593, rs1419228, rs34647318, rs9467075, rs793862, rs9295619, rs807701, rs807724, rs2274305, rs7765678, rs4599626, rs6922023, rs3765502, and rs1087266) in DCDC2 were screened via the SNPscan method. We compared SNP frequencies in five models (Codominant, Dominant, Recessive, Heterozygote advantage, and Allele) between the two groups by means of the chi-squared test. A single-locus analysis indicated that, with regard to the allele frequency of these polymorphisms, three SNPs (rs807724, rs2274305, and rs4599626) were associated with dyslexia. rs9467075 and rs2274305 displayed significant associations with developmental dyslexia under the dominant model. rs6456593 and rs6922023 were significantly associated with developmental dyslexia under the dominant model and in the heterozygous genotype. Additionally, we discovered that the T-G-C-T of the four-marker haplotype (rs9295619-rs807701-rs807724-rs2274305) and the T-A of the two-marker haplotype (rs3765502-1087266) were significantly different between cases and controls. Thus
Skottun, Bernt C
A number of authors have postulated a "magnocellular-dorsal stream" deficit in dyslexia. Combining the magnocellular system and the dorsal stream into a single entity in this context faces the problem that contrast sensitivity data do not point to a magnocellular deficiency linked to dyslexia, while, on the other hand, motion perception data are largely consistent with a dorsal stream dysfunction. Thus, there are data both for and against a "magnocellular-dorsal stream" deficit in connection with dyslexia. It is here pointed out that this inconsistency is abolished once it is recognized that the magnocellular system and the dorsal stream are separate entities.
de Carvalho, Carolina A. F.; Kida, Adriana de S. B.; Capellini, Simone A.; de Avila, Clara R. B.
Purpose: To investigate parameters related to fluency, reading comprehension and phonological processing (operational and short-term memory) and identify potential correlation between the variables in Dyslexia and in the absence of reading difficulties. Method: One hundred and fifteen students from the third to eighth grade of elementary school were grouped into a Control Group (CG) and Group with Dyslexia (GDys). Reading of words, pseudowords and text (decoding); listening and reading comprehension; phonological short-term and working memory (repetition of pseudowords and Digit Span) were evaluated. Results: The comparison of the groups showed significant differences in decoding, phonological short-term memory (repetition of pseudowords) and answers to text-connecting questions (TC) on reading comprehension, with the worst performances identified for GDys. In this group there were negative correlations between pseudowords repetition and TC answers and total score, both on listening comprehension. No correlations were found between operational and short-term memory (Digit Span) and parameters of fluency and reading comprehension in dyslexia. For the sample without complaint, there were positive correlations between some parameters of reading fluency and repetition of pseudowords and also between answering literal questions in listening comprehension and repetition of digits on the direct and reverse order. There was no correlation with the parameters of reading comprehension. Conclusion: GDys and CG showed similar performance in listening comprehension and in understanding of explicit information and gap-filling inference on reading comprehension. Students of GDys showed worst performance in reading decoding, phonological short-term memory (pseudowords) and on inferences that depends on textual cohesion understanding in reading. There were negative correlations between pseudowords repetition and TC answers and total score, both in listening comprehension. PMID
Molinaro, Nicola; Lizarazu, Mikel; Lallier, Marie; Bourguignon, Mathieu; Carreiras, Manuel
Developmental dyslexia is a reading disorder often characterized by reduced awareness of speech units. Whether the neural source of this phonological disorder in dyslexic readers results from the malfunctioning of the primary auditory system or damaged feedback communication between higher-order phonological regions (i.e., left inferior frontal regions) and the auditory cortex is still under dispute. Here we recorded magnetoencephalographic (MEG) signals from 20 dyslexic readers and 20 age-matched controls while they were listening to ∼10-s-long spoken sentences. Compared to controls, dyslexic readers had (1) an impaired neural entrainment to speech in the delta band (0.5-1 Hz); (2) a reduced delta synchronization in both the right auditory cortex and the left inferior frontal gyrus; and (3) an impaired feedforward functional coupling between neural oscillations in the right auditory cortex and the left inferior frontal regions. This shows that during speech listening, individuals with developmental dyslexia present reduced neural synchrony to low-frequency speech oscillations in primary auditory regions that hinders higher-order speech processing steps. The present findings, thus, strengthen proposals assuming that improper low-frequency acoustic entrainment affects speech sampling. This low speech-brain synchronization has the strong potential to cause severe consequences for both phonological and reading skills. Interestingly, the reduced speech-brain synchronization in dyslexic readers compared to normal readers (and its higher-order consequences across the speech processing network) appears preserved through the development from childhood to adulthood. Thus, the evaluation of speech-brain synchronization could possibly serve as a diagnostic tool for early detection of children at risk of dyslexia. Hum Brain Mapp 37:2767-2783, 2016. © 2016 Wiley Periodicals, Inc.
Hirai, Daisuke; Yamashita, Yugo; Masunaga, Nobutoyo; Katsura, Toshiaki; Akao, Masaharu; Okuno, Yoshiaki; Koyama, Hiroshi
Inhibitors directed against factor V rarely occur, and the clinical symptoms vary. We herein report the case of a patient who presented with a decreased factor V activity that had decreased to <3 %. We administered vitamin K and 6 units of fresh frozen plasma, but she thereafter developed an intracerebral hemorrhage. It is unclear whether surgery >10 years earlier might have caused the development of a factor V inhibitor. The treatment of acquired factor V inhibitors is mainly the transfusion of platelet concentrates and corticosteroids. Both early detection and the early initiation of the treatment of factor V inhibitor are thus considered to be important. PMID:27746446
Taroyan, Naira A; Nicolson, Roderick I; Buckley, David
Coherent motion perception was tested in nine adolescents with dyslexia and 10 control participants matched for age and IQ using low contrast stimuli with three levels of coherence (10%, 25% and 40%). Event-related potentials (ERPs) and behavioural performance data were obtained. No significant between-group differences were found in performance accuracy and response latencies of correct responses, for early (P1, N1, and P2) or late (P3) ERP peaks. However, attenuated early ERPs in the 10% coherent condition correlated significantly with lower performance accuracy (r = -.66) and with the magnitude of literacy deficit (r = -.46).
Warrington, E K; Langdon, D
A patient with spelling dyslexia read both words and text accurately but slowly and laboriously letter by letter. Her performance on a test of lexical decision was slow. She had great difficulty in detecting a 'rogue' letter attached to the beginning or end of a word--for example, ksong--or in parsing two unspaced words, such as applepeach. By contrast she was immune to the effects of interpolating extraneous coloured letters in a word, a manipulation that affects normal readers. Therefore it is argued that this patient had damage to an early stage in the reading process, to the visual word form itself. Images PMID:8126508
Acquired coagulation factor inhibitors are an autoimmune disease causing bleeding symptoms due to decreases in the corresponding factor (s) which result from the appearance of autoantibodies against coagulation factors (inhibitor). This disease is quite different from congenital coagulation factor deficiencies based on genetic abnormalities. In recent years, cases with this disease have been increasing, and most have anti-factor VIII autoantibodies. The breakdown of the immune control mechanism is speculated to cause this disease since it is common in the elderly, but the pathology and pathogenesis are presently unclear. We herein describe the pathology and pathogenesis of factor VIII and factor V inhibitors. Characterization of these inhibitors leads to further analysis of the coagulation process and the activation mechanisms of clotting factors. In the future, with the development of new clotting examination method (s), we anticipate that further novel findings will be obtained in this field through inhibitor analysis. In addition, detailed elucidation of the coagulation inhibitory mechanism possibly leading to hemostatic treatment strategies for acquired coagulation factor disorders will be developed.
Tomasino, Barbara; Marin, Dario; Maieron, Marta; D'Agostini, Serena; Fabbro, Franco; Skrap, Miran; Luzzatti, Claudio
Neuropsychological data about acquired impairments in reading and writing provide a strong basis for the theoretical framework of the dual-route models. The present study explored the functional neuroanatomy of the reading and spelling processing system. We describe the reading and writing performance of patient CF, an Italian native speaker who developed an extremely selective reading and spelling deficit (his spontaneous speech, oral comprehension, repetition and oral picture naming were almost unimpaired) in processing double letters associated with surface dyslexia and dysgraphia, following a tumor in the left temporal lobe. In particular, the majority of CF's errors in spelling were phonologically plausible substitutions, errors concerning letter numerosity of consonants, and syllabic phoneme-to-grapheme conversion (PGC) errors. A similar pattern of impairment also emerged in his reading behavior, with a majority of lexical stress errors (the only possible type of surface reading errors in the Italian language, due the extreme regularity of print-to-sound correspondence). CF's neuropsychological profile was combined with structural neuroimaging data, fiber tracking, and functional maps and compared to that of healthy control participants. We related CF's deficit to a dissociation between impaired ventral/lexical route (as evidenced by a fractional anisotropy - FA decrease along the inferior fronto-occipital fasciculus - IFOF) and relatively preserved dorsal/phonological route (as evidenced by a rather full integrity of the superior longitudinal fasciculus - SLF). In terms of functional processing, the lexical-semantic ventral route network was more activated in controls than in CF, while the network supporting the dorsal route was shared by CF and the control participants. Our results are discussed within the theoretical framework of dual-route models of reading and spelling, emphasize the importance of the IFOF both in lexical reading and spelling, and offer
De Clercq-Quaegebeur, Maryse; Casalis, Séverine; Lemaitre, Marie-Pierre; Bourgois, Béatrice; Getto, Marie; Vallée, Louis
This study examined the pattern of results on the Wechsler Intelligence Scale for Children (WISC-IV; French version) for 60 French children with dyslexia, from 8 to 16 years of age. Although use of WISC-III failed to clearly identify typical profiles and cognitive deficits in dyslexia, WISC-IV offers an opportunity to reach these objectives with new indexes and subtests. The mean performance analysis showed a Working Memory Index (WMI) at a limit level, significantly lower compared to the three other indexes. The WMI was the lowest index for 68% of the population studied and was significantly weaker for children with phonological dyslexia compared to children with surface dyslexia. WISC-IV evidenced preserved language and reasoning abilities in contrast to limited verbal working memory efficiency. Theoretical and clinical implications are discussed.
Duranovic, Mirela; Sehic, Sabina
A group of children with dyslexia (mean ages 9 and 14 years) was studied, together with group of children without dyslexia matched for age. Participants were monolingual native speakers of the Bosnian language with transparent orthography. In total, the diagnostic tests were performed with 41 children with dyslexia and 41 nondyslexic children. The participants were asked to produce monosyllables, /pa/, /ta/, and /ka/, and the trisyllable /pataka/, as fast as possible. Analysis was undertaken in four ways: (1) time of occlusion duration for plosives (duration of stop), (2) voice onset time for plosives, (3) diadochokinetic rate--articulators rate measured by pronunciation of monosyllables and the trisyllable, and (4) time of moving articulators from one gesture to another-time of interval length (from the explosion of one plosive to the start of the explosion of another plosive). The results suggest that children with dyslexia have significant problems with the speed of articulatory movements involved in speech production.
Bogliotti, C; Serniclaes, W; Messaoud-Galusi, S; Sprenger-Charolles, L
Previous studies have shown that children suffering from developmental dyslexia have a deficit in categorical perception of speech sounds. The aim of the current study was to better understand the nature of this categorical perception deficit. In this study, categorical perception skills of children with dyslexia were compared with those of chronological age and reading level controls. Children identified and discriminated /do-to/ syllables along a voice onset time (VOT) continuum. Results showed that children with dyslexia discriminated among phonemically contrastive pairs less accurately than did chronological age and reading level controls and also showed higher sensitivity in the discrimination of allophonic contrasts. These results suggest that children with dyslexia perceive speech with allophonic units rather than phonemic units. The origin of allophonic perception in the course of perceptual development and its implication for reading acquisition are discussed.
Gabay, Yafit; Gabay, Shai; Schiff, Rachel; Ashkenazi, Sarit; Henik, Avishai
Previous research has shown that individuals with DD (developmental dyslexia) demonstrated a left mini neglect on visual line (VL) bisection tasks, which has been commonly referred to as right parietal dysfunction. However, insufficient reading experience characterizes dyslexia and may call into question the validity of this interpretation, since the VL bisection task has been found to be influenced by reading habits. The current study investigated whether altered performance of individuals with DD on bisection tasks may be attributed to impaired attentional mechanisms or to insufficient reading exposure. DD and control groups performed visual and mental number line bisection tasks, which have been shown to be modulated differently by reading habits. In both tasks, the magnitude of left bisection errors was significantly larger in the DD group compared with controls. This finding suggests attentional mechanisms act differently in dyslexia and supports evidence linking dyslexia to decreased function of the left hemisphere.
Galaburda, Albert M.
This paper summarizes research currently being conducted on the biologic underpinnings of learning disorders, particularly dyslexia. The research findings discussed are derived from studying neuroanatomic, neurophysiologic, neurogenetic, neuroimaging, and behavioral characteristics in animal models that exhibit developmental brain anomalies and…
Rogers, Heather D; Macgregor, Jennifer L; Nord, Kristin M; Tyring, Stephen; Rady, Peter; Engler, Danielle E; Grossman, Marc E
Epidermodysplasia verruciformis (EV) is a rare autosomal recessive genodermatosis with an increased susceptibility to specific human papillomavirus (HPV) genotypes. Classically, this viral infection leads to the development of tinea versicolor-like macules on the trunk, neck, arms, and face during childhood, and over time, these lesions can progress to squamous cell carcinoma. More recently, an EV-like syndrome has been described in patients with impaired cell-mediated immunity. We describe two cases of EV-like syndrome in HIV-positive patients, review all previously reported cases of EV in patients with impaired cell-mediated immunity, introduce the term "acquired epidermodysplasia verruciformis" to describe EV developing in the immunocompromised host and examine the limited treatment options for these patients.
Gilmore, N. J.; Beaulieu, R.; Steben, M.; Laverdière, M.
Acquired immunodeficiency syndrome, or AIDS, is a new illness that occurs in previously healthy individuals. It is characterized by immunodeficiency, opportunistic infections and unusual malignant diseases. Life-threatening single or multiple infections with viruses, mycobacteria, fungi or protozoa are common. A rare neoplasm, Kaposi's sarcoma, has developed in approximately one third of patients with AIDS. More than 800 cases of AIDS have been reported in North America, over 24 of them in Canada. The majority of patients are male homosexuals, although AIDS has also developed in abusers of intravenously administered drugs, Haitian immigrants, individuals with hemophilia, recipients of blood transfusions, prostitutes, and infants, spouses and partners of patients with AIDS. The cause of AIDS is unknown, but the features are consistent with an infectious process. Early diagnosis can be difficult owing to the nonspecific symptoms and signs of the infections and malignant diseases. Therefore, vigilance by physicians is of utmost importance. PMID:6342737
Gilmore, N.J.; Beaulieu, R.; Steben, M.; Laverdière, M.
Acquired immunodeficiency syndrome, or AIDS, is a new illness that occurs in previously healthy individuals. It is characterized by immunodeficiency, opportunistic infections and unusual malignant diseases. Life-threatening single or multiple infections with viruses, mycobacteria, fungi or protozoa are common. A rare neoplasm, Kaposi's sarcoma, has developed in approximately one third of patients with AIDS. More than 800 cases of AIDS have been reported in North America, over 24 of them in Canada. The majority of patients are male homosexuals, although AIDS has also developed in abusers of intravenously administered drugs, Haitian immigrants, individuals with hemophilia, recipients of blood transfusions, prostitutes, and infants, spouses and partners of patients with AIDS. The cause of AIDS is unknown, but the features are consistent with an infectious process. Early diagnosis can be difficult owing to the nonspecific symptoms and signs of the infections and malignant diseases. Therefore, vigilance by physicians is of the utmost importance. PMID:1544049
Flaugnacco, Elena; Lopez, Luisa; Terribili, Chiara; Zoia, Stefania; Buda, Sonia; Tilli, Sara; Monasta, Lorenzo; Montico, Marcella; Sila, Alessandra; Ronfani, Luca; Schön, Daniele
Rhythm organizes events in time and plays a major role in music, but also in the phonology and prosody of a language. Interestingly, children with developmental dyslexia-a learning disability that affects reading acquisition despite normal intelligence and adequate education-have a poor rhythmic perception. It has been suggested that an accurate perception of rhythmical/metrical structure, that requires accurate perception of rise time, may be critical for phonological development and subsequent literacy. This hypothesis is mostly based on results showing a high degree of correlation between phonological awareness and metrical skills, using a very specific metrical task. We present new findings from the analysis of a sample of 48 children with a diagnosis of dyslexia, without comorbidities. These children were assessed with neuropsychological tests, as well as specifically-devised psychoacoustic and musical tasks mostly testing temporal abilities. Associations were tested by multivariate analyses including data mining strategies, correlations and most importantly logistic regressions to understand to what extent the different auditory and musical skills can be a robust predictor of reading and phonological skills. Results show a strong link between several temporal skills and phonological and reading abilities. These findings are discussed in the framework of the neuroscience literature comparing music and language processing, with a particular interest in the links between rhythm processing in music and language.
Bacon, Alison M; Handley, Simon J
Effective reasoning is fundamental to problem solving and achievement in education and employment. Protocol studies have previously suggested that people with dyslexia use reasoning strategies based on visual mental representations, whereas non-dyslexics use abstract verbal strategies. This research presents converging evidence from experimental and individual differences perspectives. In Experiment 1, dyslexic and non-dyslexic participants were similarly accurate on reasoning problems, but scores on a measure of visual memory ability only predicted reasoning accuracy for dyslexics. In Experiment 2, a secondary task loaded visual memory resources during concurrent reasoning. Dyslexics were significantly less accurate when reasoning under conditions of high memory load and showed reduced ability to subsequently recall the visual stimuli, suggesting that the memory and reasoning tasks were competing for the same visual cognitive resource. The results are consistent with an explanation based on limitations in the verbal and executive components of working memory in dyslexia and the use of compensatory visual strategies for reasoning. There are implications for cognitive activities that do not readily support visual thinking, whether in education, employment or less formal everyday settings.
Arduino, Lisa S; Vallar, Giuseppe; Burani, Cristina
The present study investigated the effects of the duration of the stimulus on the reading performance of right-brain-damaged patients with left neglect dyslexia. Three Italian patients read aloud words and nonwords, under conditions of unlimited time of stimulus exposure and of timed presentation. In the untimed condition, the majority of the patients' errors involved the left side of the letter string (i.e., neglect dyslexia errors). Conversely, in the timed condition, although the overall level of performance decreased, errors were more evenly distributed across the whole letter string (i.e., visual - nonlateralized - errors). This reduction of neglect errors with a reduced time of presentation of the stimulus may reflect the read out of elements of the letter string from a preserved visual storage component, such as iconic memory. Conversely, a time-unlimited presentation of the stimulus may bring about the rightward bias that characterizes the performance of neglect patients, possibly by a capture of the patients' attention by the final (rightward) letters of the string.
De Vos, Astrid; Vanvooren, Sophie; Vanderauwera, Jolijn; Ghesquière, Pol; Wouters, Jan
A fundamental deficit in the synchronization of neural oscillations to temporal information in speech could underlie phonological processing problems in dyslexia. In this study, the hypothesis of a neural synchronization impairment is investigated more specifically as a function of different neural oscillatory bands and temporal information rates in speech. Auditory steady-state responses to 4, 10, 20 and 40Hz modulations were recorded in normal reading and dyslexic adolescents to measure neural synchronization of theta, alpha, beta and low-gamma oscillations to syllabic and phonemic rate information. In comparison to normal readers, dyslexic readers showed reduced non-synchronized theta activity, reduced synchronized alpha activity and enhanced synchronized beta activity. Positive correlations between alpha synchronization and phonological skills were found in normal readers, but were absent in dyslexic readers. In contrast, dyslexic readers exhibited positive correlations between beta synchronization and phonological skills. Together, these results suggest that auditory neural synchronization of alpha and beta oscillations is atypical in dyslexia, indicating deviant neural processing of both syllabic and phonemic rate information. Impaired synchronization of alpha oscillations in particular demonstrated to be the most prominent neural anomaly possibly hampering speech and phonological processing in dyslexic readers.
Altarelli, Irene; Leroy, François; Monzalvo, Karla; Fluss, Joel; Billard, Catherine; Dehaene-Lambertz, Ghislaine; Galaburda, Albert M; Ramus, Franck
Among the various asymmetrical structures of the human brain, the planum temporale, an anatomical region associated with a variety of auditory and language-related processes, has received particular attention. While its surface area has been shown to be greater in the left hemisphere compared to the right in about two-thirds of the general population, altered patterns of asymmetry were revealed by post mortem analyses in individuals with developmental dyslexia. These findings have been inconsistently replicated in magnetic resonance imaging studies of this disorder. In this report, we attempt to resolve past inconsistencies by analyzing the T1-weighted MR images of 81 children (mean age: 11 years, sd: 17 months), including 46 control (25 boys) and 35 dyslexic children (20 boys). We manually outlined Heschl's gyri, the planum temporale and the posterior rami of the Sylvian fissure on participants' brain images, using the same anatomical criteria as in post mortem studies. Results revealed an altered pattern of asymmetry of the planum temporale surface area in dyslexic boys only, with a greater proportion of rightward asymmetrical cases among dyslexic boys compared to control boys. Additionally, analyses of cortical thickness showed no asymmetry differences between groups for any of the regions of interest. Finally, a greater number of Heschl's gyrus full duplications emerged for the right hemisphere of dyslexic boys compared to controls. The present findings confirm and extend early post mortem observations. They also stress the importance of taking gender into account in studies of developmental dyslexia.
Bishop, Dorothy V. M.
Uta Frith has made a major contribution to our understanding of developmental disorders, especially autism and dyslexia. She has studied the cognitive and neurobiological bases of both disorders and demonstrated distinctive impairments in social cognition and central coherence in autism, and in phonological processing in dyslexia. In this enterprise she has encouraged psychologists to work in a theoretical framework that distinguishes between observed behaviour and the underlying cognitive and neurobiological processes that mediate that behaviour. PMID:18038335
Tops, Wim; Callens, Maaike; Desoete, Annemie; Stevens, Michaël; Brysbaert, Marc
We examined whether academic and professional bachelor students with dyslexia are able to compensate for their spelling deficits with metacognitive experience. Previous research suggested that students with dyslexia may suffer from a dual burden. Not only do they perform worse on spelling but in addition they are not as fully aware of their difficulties as their peers without dyslexia. According to some authors, this is the result of a worse feeling of confidence, which can be considered as a form of metacognition (metacognitive experience). We tried to isolate this metacognitive experience by asking 100 students with dyslexia and 100 matched control students to rate their feeling of confidence in a word spelling task and a proofreading task. Next, we used Signal Detection Analysis to disentangle the effects of proficiency and criterion setting. We found that students with dyslexia showed lower proficiencies but not suboptimal response biases. They were as good at deciding when they could be confident or not as their peers without dyslexia. They just had more cases in which their spelling was wrong. We conclude that the feeling of confidence in our students with dyslexia is as good as in their peers without dyslexia. These findings go against the Dual Burden theory (Krüger & Dunning, 1999), which assumes that people with a skills problem suffer twice as a result of insufficiently developed metacognitive competence. As a result, there is no gain to be expected from extra training of this metacognitive experience in higher education students with dyslexia. PMID:25192428
Tops, Wim; Callens, Maaike; Desoete, Annemie; Stevens, Michaël; Brysbaert, Marc
We examined whether academic and professional bachelor students with dyslexia are able to compensate for their spelling deficits with metacognitive experience. Previous research suggested that students with dyslexia may suffer from a dual burden. Not only do they perform worse on spelling but in addition they are not as fully aware of their difficulties as their peers without dyslexia. According to some authors, this is the result of a worse feeling of confidence, which can be considered as a form of metacognition (metacognitive experience). We tried to isolate this metacognitive experience by asking 100 students with dyslexia and 100 matched control students to rate their feeling of confidence in a word spelling task and a proofreading task. Next, we used Signal Detection Analysis to disentangle the effects of proficiency and criterion setting. We found that students with dyslexia showed lower proficiencies but not suboptimal response biases. They were as good at deciding when they could be confident or not as their peers without dyslexia. They just had more cases in which their spelling was wrong. We conclude that the feeling of confidence in our students with dyslexia is as good as in their peers without dyslexia. These findings go against the Dual Burden theory (Krüger & Dunning, 1999), which assumes that people with a skills problem suffer twice as a result of insufficiently developed metacognitive competence. As a result, there is no gain to be expected from extra training of this metacognitive experience in higher education students with dyslexia.
Temple, Elise; Deutsch, Gayle K.; Poldrack, Russell A.; Miller, Steven L.; Tallal, Paula; Merzenich, Michael M.; Gabrieli, John D. E.
Developmental dyslexia, characterized by unexplained difficulty in reading, is associated with behavioral deficits in phonological processing. Functional neuroimaging studies have shown a deficit in the neural mechanisms underlying phonological processing in children and adults with dyslexia. The present study examined whether behavioral remediation ameliorates these dysfunctional neural mechanisms in children with dyslexia. Functional MRI was performed on 20 children with dyslexia (8–12 years old) during phonological processing before and after a remediation program focused on auditory processing and oral language training. Behaviorally, training improved oral language and reading performance. Physiologically, children with dyslexia showed increased activity in multiple brain areas. Increases occurred in left temporo-parietal cortex and left inferior frontal gyrus, bringing brain activation in these regions closer to that seen in normal-reading children. Increased activity was observed also in right-hemisphere frontal and temporal regions and in the anterior cingulate gyrus. Children with dyslexia showed a correlation between the magnitude of increased activation in left temporo-parietal cortex and improvement in oral language ability. These results suggest that a partial remediation of language-processing deficits, resulting in improved reading, ameliorates disrupted function in brain regions associated with phonological processing and produces additional compensatory activation in other brain regions. PMID:12604786
Noordenbos, M W; Segers, E; Serniclaes, W; Mitterer, H; Verhoeven, L
There is ample evidence that individuals with dyslexia have a phonological deficit. A growing body of research also suggests that individuals with dyslexia have problems with categorical perception, as evidenced by weaker discrimination of between-category differences and better discrimination of within-category differences compared to average readers. Whether the categorical perception problems of individuals with dyslexia are a result of their reading problems or a cause has yet to be determined. Whether the observed perception deficit relates to a more general auditory deficit or is specific to speech also has yet to be determined. To shed more light on these issues, the categorical perception abilities of children at risk for dyslexia and chronological age controls were investigated before and after the onset of formal reading instruction in a longitudinal study. Both identification and discrimination data were collected using identical paradigms for speech and non-speech stimuli. Results showed the children at risk for dyslexia to shift from an allophonic mode of perception in kindergarten to a phonemic mode of perception in first grade, while the control group showed a phonemic mode already in kindergarten. The children at risk for dyslexia thus showed an allophonic perception deficit in kindergarten, which was later suppressed by phonemic perception as a result of formal reading instruction in first grade; allophonic perception in kindergarten can thus be treated as a clinical marker for the possibility of later reading problems.
Dåderman, Anna M; Meurling, Ann Wirsén; Levander, Sten
Previous neuropsychiatric studies suggest a relationship between reading disability and cognitive impulsivity. This relationship is not entirely explained by the high comorbidity between reading disability and attention deficit hyperactivity disorder (ADHD), as children with a co-occurrence of these disorders tend to be more impulsive than those with ADHD only. Other research has demonstrated that poor verbal skill (irrespective of the presence of dyslexia) deficits in executive functions and impulsivity are important risk factors for criminal behaviour. The present study bridges these two research traditions by examining whether patients undergoing forensic psychiatric investigation who also have dyslexia, have a cognitive style characterized by impulsivity. Male forensic patients (mean age 27 years, range 16-35) with (n = 9) and without (n = 13) dyslexia were evaluated on the computerized EuroCog test battery. The findings suggest that patients with dyslexia tend to use a cognitive impulsive style and suggest a more direct link between dyslexia and cognitive impulsivity that is not mediated by the presence of ADHD. In order to identify treatment needs and tailor treatment accordingly, forensic patients should be assessed with respect to poor verbal skill, dyslexia and impulsivity.
The error-detection mechanism aids in preventing error repetition during a given task. Electroencephalography demonstrates that error detection involves two event-related potential components: error-related and correct-response negativities (ERN and CRN, respectively). Dyslexia is characterized by slow, inaccurate reading. In particular, individuals with dyslexia have a less active error-detection mechanism during reading than typical readers. In the current study, we examined whether a reading training programme could improve the ability to recognize words automatically (lexical representations) in adults with dyslexia, thereby resulting in more efficient error detection during reading. Behavioural and electrophysiological measures were obtained using a lexical decision task before and after participants trained with the reading acceleration programme. ERN amplitudes were smaller in individuals with dyslexia than in typical readers before training but increased following training, as did behavioural reading scores. Differences between the pre-training and post-training ERN and CRN components were larger in individuals with dyslexia than in typical readers. Also, the error-detection mechanism as represented by the ERN/CRN complex might serve as a biomarker for dyslexia and be used to evaluate the effectiveness of reading intervention programmes. Copyright © 2016 John Wiley & Sons, Ltd.
Ma, Yujun; Wang, Enguo; Yuan, Tian; Zhao, Guo Xiang
As the reading process is inseparable from working memory, inhibition, and other higher cognitive processes, the deep cognitive processing defects that are associated with dyslexia may be due to defective distraction inhibition systems. In this study, we used event-related potential technology to explore the source of negative priming effects in children with developmental dyslexia and in a group of healthy children for comparison. We found that the changes in the average response times in the negative priming and control conditions were consistent across the two groups, while the negative priming effects differed significantly between the groups. The magnitude of the negative priming effect was significantly different between the two groups, with the magnitude being significantly higher in the control group than it was in the developmental dyslexia group. These results indicate that there are deficits in distraction inhibition in children with developmental dyslexia. In terms of the time course of processing, inhibition deficits in the dyslexia group appeared during early-stage cognition selection and lasted through the response selection phase. Regarding the cerebral cortex locations, early-stage cognition selection was mainly located in the parietal region, while late-stage response selection was mainly located in the frontal and central regions. The results of our study may help further our understanding of the intrinsic causes of developmental dyslexia.
Reynolds, Andrea Elaine; Caravolas, Markéta
The Bangor Dyslexia Test (BDT) is a short, easy-to-administer screener for use with a broad age range, which has been in use in the UK for over three decades. A distinctive feature of the battery is its focus on skills requiring aspects of verbal and phonological processing without, however, measuring literacy skills per se. Despite its longstanding existence and usage, there has been no evaluation of the psychometric properties of the battery as an adult dyslexia screener. We examined the psychometric properties of the BDT and evaluated its capacity to discriminate between adults with and without dyslexia. A large archival sample of university students with dyslexia (n = 193) and students with no reported literacy difficulties (n = 40) were compared on the BDT as well as on literacy and cognitive measures. Statistical analyses revealed the BDT to be a reliable (α = .72) and valid dyslexia screening tool with the capacity to effectively identify adults at risk of the disorder with an overall classification rate of 94% (sensitivity 96.4% and specificity 82.5%). In addition, higher indices of dyslexia risk on the BDT were associated with lower scores on standardized measures of literacy.
Helland, Turid; Plante, Elena; Hugdahl, Kenneth
This study focused on predicting dyslexia in children ahead of formal literacy training. Because dyslexia is a constitutional impairment, risk factors should be seen in preschool. It was hypothesized that data gathered at age 5 using questions targeting the dyslexia endophenotype should be reliable and valid predictors of dyslexia at age 11. A questionnaire was given to caretakers of 120 5-year-old children, and a risk index score was calculated based on questions regarding health, laterality, motor skills, language, special needs education and heredity. An at-risk group (n = 25) and matched controls (n = 24) were followed until age 11, when a similar questionnaire and literacy tests were administered to the children who participated in the follow-up study (22 at risk and 20 control). Half of the at-risk children and two of the control children at age 5 were identified as having dyslexia at age 11 (8 girls and 5 boys). It is concluded that it is possible to identify children at the age of 5 who will have dyslexia at the age of 11 through a questionnaire approach.
Majerus, Steve; Cowan, Nelson
Verbal short-term memory (STM) impairment is one of the most consistent associated deficits observed in developmental reading disorders such as dyslexia. Few studies have addressed the nature of this STM impairment, especially as regards the ability to temporarily store serial order information. This question is important as studies in typically developing children have shown that serial order STM abilities are predictors of oral and written language development. Associated serial order STM deficits in dyslexia may therefore further increase the learning difficulties in these populations. In this mini review, we show that specific serial order STM impairment is frequently reported in both dyslexic children and adults with a history of dyslexia. Serial order STM impairment appears to occur for the retention of both verbal and visuo-spatial sequence information. Serial order STM impairment is, however, not a characteristic of every individual dyslexic subject and is not specific to dyslexia. Future studies need to determine whether serial order STM impairment is a risk factor which, in association with phonological processing deficits, can lead to dyslexia or whether serial order STM impairment reflects associated deficits causally unrelated to dyslexia. PMID:27752247
van Bergen, Elsje; de Jong, Peter F; Maassen, Ben; Krikhaar, Evelien; Plakas, Anna; van der Leij, Aryan
Do children who go on to develop dyslexia show normal verbal and nonverbal development before reading onset? According to the aptitude-achievement discrepancy model, dyslexia is defined as a discrepancy between intelligence and reading achievement. One of the underlying assumptions is that the general cognitive development of children who fail to learn to read has been normal. The current study tests this assumption. In addition, we investigated whether possible IQ deficits are uniquely related to later reading or are also related to arithmetic. Four-year-olds (N = 212) with and without familial risk for dyslexia were assessed on 10 IQ subtests. Reading and arithmetic skills were measured 4 years later, at the end of Grade 2. Relative to the controls, the at-risk group without dyslexia had subtle impairments only in the verbal domain, whereas the at-risk group with dyslexia lagged behind across IQ tasks. Nonverbal IQ was associated with both reading and arithmetic, whereas verbal IQ was uniquely related to later reading. The children who went on to develop dyslexia performed relatively poorly in both verbal and nonverbal abilities at age 4, which challenges the discrepancy model. Furthermore, we discuss possible causal and epiphenomenal models explaining the links between early IQ and later reading.
Barbiero, Chiara; Lonciari, Isabella; Montico, Marcella; Monasta, Lorenzo; Penge, Roberta; Vio, Claudio; Tressoldi, Patrizio Emanuele; Ferluga, Valentina; Bigoni, Anna; Tullio, Alessia; Carrozzi, Marco; Ronfani, Luca
Background Although dyslexia is one of the most common neurobehavioral disorders affecting children, prevalence is uncertain and available data are scanty and dated. The objective of this study is to evaluate the prevalence of dyslexia in an unselected school population using clearly defined and rigorous diagnostic criteria and methods. Methods Cross sectional study. We selected a random cluster sample of 94 fourth grade elementary school classes of Friuli Venezia Giulia, a Region of North Eastern Italy. We carried out three consecutive levels of screening: the first two at school and the last at the Neuropsychiatry Unit of a third level Mother and Child Hospital. The main outcome measure was the prevalence of dyslexia, defined as the number of children positive to the third level of screening divided by the total number of children enrolled. Results We recruited 1774 children aged 8–10 years, of which 1528 received parents’ consent to participate. After applying exclusion criteria, 1357 pupils constituted the final working sample. The prevalence of dyslexia in the enrolled population ranged from 3.1% (95% CI 2.2–4.1%) to 3.2% (95% CI 2.4–4.3%) depending on different criteria adopted. In two out of three children with dyslexia the disorder had not been previously diagnosed. Conclusions This study shows that dyslexia is largely underestimated in Italy and underlines the need for reliable information on prevalence, in order to better allocate resources both to Health Services and Schools. PMID:23118930
Gabay, Yafit; Vakil, Eli; Schiff, Rachel; Holt, Lori L.
Objective Developmental dyslexia is presumed to arise from specific phonological impairments. However, an emerging theoretical framework suggests that phonological impairments may be symptoms stemming from an underlying dysfunction of procedural learning. Method We tested procedural learning in adults with dyslexia (n=15) and matched-controls (n=15) using two versions of the Weather Prediction Task: Feedback (FB) and Paired-associate (PA). In the FB-based task, participants learned associations between cues and outcomes initially by guessing and subsequently through feedback indicating the correctness of response. In the PA-based learning task, participants viewed the cue and its associated outcome simultaneously without overt response or feedback. In both versions, participants trained across 150 trials. Learning was assessed in a subsequent test without presentation of the outcome, or corrective feedback. Results The Dyslexia group exhibited impaired learning compared with the Control group on both the FB and PA versions of the weather prediction task. Conclusions The results indicate that the ability to learn by feedback is not selectively impaired in dyslexia. Rather it seems that the probabilistic nature of the task, shared by the FB and PA versions of the weather prediction task, hampers learning in those with dyslexia. Results are discussed in light of procedural learning impairments among participants with dyslexia. PMID:25730732
Keohane, Elaine M
Acquired aplastic anemia (AA) is a disorder characterized by a profound deficit of hematopoietic stem and progenitor cells, bone marrow hypocellularity, and peripheral blood pancytopenia. It primarily affects children, young adults, and those over 60 years of age. The majority of cases are idiopathic; however, idiosyncratic reactions to some drugs, chemicals, and viruses have been implicated in its etiology. An autoimmune T-cell reaction likely causes the stem cell depletion, but the precise mechanism, as well as the eliciting and target antigens, is unknown. Symptoms vary from severe life-threatening cytopenias to moderate or non-severe disease that does not require transfusion support. The peripheral blood typically exhibits pancytopenia, reticulocytopenia, and normocytic or macrocytic erythrocytes. The bone marrow is hypocellular and may exhibit dysplasia of the erythrocyte precursors. First line treatment for severe AA consists of hematopoietic stem cell transplantation in young patients with HLA identical siblings, while immunosuppression therapy is used for older patients and for those of any age who lack a HLA matched donor. Patients with AA have an increased risk of developing paroxysmal nocturnal hemoglobinuria (PNH), myelodysplastic syndrome (MDS), or acute leukemia. Further elucidation of the pathophysiology of this disease will result in a better understanding of the interrelationship among AA, PNH, and MDS, and may lead to novel targeted therapies.
Effect of Atomoxetine Treatment on Reading and Phonological Skills in Children with Dyslexia or Attention-Deficit/Hyperactivity Disorder and Comorbid Dyslexia in a Randomized, Placebo-Controlled Trial
Shaywitz, Bennett; Wietecha, Linda; Wigal, Sharon; McBurnett, Keith; Williams, David; Kronenberger, William G.; Hooper, Stephen R.
Abstract Objectives: Evaluated the effects of atomoxetine on the reading abilities of children with dyslexia only or attention-deficit/hyperactivity disorder (ADHD) and comorbid dyslexia. Methods: Children aged 10–16 years (N = 209) met Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR) criteria for dyslexia only (n = 58), ADHD and comorbid dyslexia (n = 124), or ADHD only (n = 27) and were of normal intelligence. Patients were treated with atomoxetine (1.0–1.4 mg/kg/day) or placebo in a 16-week, randomized, placebo-controlled, double-blind trial. The dyslexia-only and ADHD and comorbid dyslexia groups were randomized 1:1; the ADHD-only group received atomoxetine in a blinded manner. Reading abilities were measured with the Woodcock Johnson III (WJIII), Comprehensive Test of Phonological Processing (CTOPP), Gray Oral Reading Tests-4, and Test of Word Reading Efficiency. Results: Atomoxetine-treated dyslexia-only patients compared with placebo patients had significantly greater improvement (p < 0.02) with moderate to approaching high effect sizes (ES) on WJIII Word Attack (ES = 0.72), Basic Reading Skills (ES = 0.48), and Reading Vocabulary (ES = 0.73). In the atomoxetine-treated ADHD and comorbid dyslexia group, improvement on the CTOPP Elision measure (ES = 0.50) was significantly greater compared with placebo (p < 0.02). Total, inattentive, and hyperactive/impulsive ADHD symptom reductions were significant in the atomoxetine-treated ADHD and comorbid dyslexia group compared with placebo, and from baseline in the ADHD-only group (p ≤ 0.02). ADHD symptom improvements in the ADHD and comorbid dyslexia group were not correlated with improvements in reading. Conclusions: Atomoxetine treatment improved reading scores in patients with dyslexia only and ADHD and comorbid dyslexia. Improvements for patients with dyslexia only were in critical components of reading, including
Wennas Brante, Eva
Better understanding of the diverse reading abilities of people with dyslexia is necessary for the design of more effective learning situations, which are vital both to students with dyslexia and to their teachers. Seven individuals with dyslexia currently or formerly in higher education were interviewed about their reading experiences to learn…
Wong, Simpson W. L.; McBride-Chang, Catherine; Lam, Catherine; Chan, Becky; Lam, Fanny W. F.; Doo, Sylvia
This study sought to examine factors that are predictive of future developmental dyslexia among a group of 5-year-old Chinese children at risk for dyslexia, including 62 children with a sibling who had been previously diagnosed with dyslexia and 52 children who manifested clinical at-risk factors in aspects of language according to testing by…
Davis, J. M.; Deponio, P.
This paper draws from our experiences of an EU Life Long Learning Programme Project: GATE Understanding Dyslexia Phenomena Between Pre-Primary And Primary (2009-2011) to discuss different conceptual positions concerning dyslexia. It compares medical notions of dyslexia with perspectives from childhood and disability studies to question the ways in…
Xia, Zhichao; Hoeft, Fumiko; Zhang, Linjun; Shu, Hua
An increasing body of studies has revealed neuroanatomical impairments in developmental dyslexia. However, whether these structural anomalies are driven by dyslexia (disorder-specific effects), absolute reading performance (performance-dependent effects), and/or further influenced by age (maturation-sensitive effects) remains elusive. To help disentangle these sources, the current study used a novel disorder (dyslexia vs. control) by maturation (younger vs. older) factorial design in 48 Chinese children who were carefully matched. This design not only allows for direct comparison between dyslexics versus controls matched for chronological age and reading ability, but also enables examination of the influence of maturation and its interaction with dyslexia. Voxel-based morphometry (VBM) showed that dyslexic children had reduced regional gray matter volume in the left temporo-parietal cortex (spanning over Heschl's gyrus, planum temporale and supramarginal gyrus), middle frontal gyrus, superior occipital gyrus, and reduced regional white matter in bilateral parieto-occipital regions (left cuneus and right precuneus) compared with both age-matched and reading-level matched controls. Therefore, maturational stage-invariant neurobiological signatures of dyslexia were found in brain regions that have been associated with impairments in the auditory/phonological and attentional systems. On the other hand, maturational stage-dependent effects on dyslexia were observed in three regions (left ventral occipito-temporal cortex, left dorsal pars opercularis and genu of the corpus callosum), all of which were previously reported to be involved in fluent reading and its development. These striking dissociations collectively suggest potential atypical developmental trajectories of dyslexia, where underlying mechanisms are currently unknown but may be driven by interactions between genetic and/or environmental factors. In summary, this is the first study to disambiguate
Xia, Zhichao; Hoeft, Fumiko; Zhang, Linjun; Shu, Hua
An increasing body of studies has revealed neuroanatomical impairments in developmental dyslexia. However, whether these structural anomalies are driven by dyslexia (disorder-specific effects), absolute reading performance (performance-dependent effects), and/or further influenced by age (maturation-sensitive effects) remains elusive. To help disentangle these sources, the current study used a novel disorder (dyslexia vs. control) by maturation (younger vs. older) factorial design in 48 Chinese children who were carefully matched. This design not only allows for direct comparison between dyslexics versus controls matched for chronological age and reading ability, but also enables examination of the influence of maturation and its interaction with dyslexia. Voxel-based morphometry (VBM) showed that dyslexic children had reduced regional gray matter volume in the left temporo-parietal cortex (spanning over Heschl’s gyrus, planum temporale and supramarginal gyrus), middle frontal gyrus, superior occipital gyrus, and reduced regional white matter in bilateral parieto-occipital regions (left cuneus and right precuneus) compared with both age-matched and reading-level matched controls. Therefore, maturational stage-invariant neurobiological signatures of dyslexia were found in brain regions that have been associated with impairments in the auditory/phonological and attentional systems. On the other hand, maturational stage-dependent effects on dyslexia were observed in three regions (left ventral occipito-temporal cortex, left dorsal pars opercularis and genu of the corpus callosum), all of which were previously reported to be involved in fluent reading and its development. These striking dissociations collectively suggest potential atypical developmental trajectories of dyslexia, where underlying mechanisms are currently unknown but may be driven by interactions between genetic and/or environmental factors. In summary, this is the first study to disambiguate
Fei, Chengwen; Wang, Yao; Gong, Yu; Xu, Hui; Yu, Qian; Shi, Yuling
Abstract Background: Reactive perforating collagenosis (RPC) is a rare form of transepithelial elimination, in which altered collagen is extruded through the epidermis. There are 2 types of RPC, acquired RPC (ARPC) and inherited RPC, while the latter is extremely rare. Here we report on 1 case of ARPC. Methods: A 73-year-old female was presented with strongly itchy papules over her back and lower limbs for 3 months. She denied the history of oozing or vesiculation. A cutaneous examination showed diffusely distributed multiple well-defined keratotic papules, 4 to 10 mm in diameter, on the bilateral lower limbs and back as well as a few papules on her chest and forearm. Scratching scars were over the resolved lesions while Koebner phenomenon was negative. The patient had a history of type 2 diabetes for 15 years. Laboratory examinations showed elevated blood glucose level. Skin lesion biopsy showed a well-circumscribed area of necrosis filled with a keratotic plug. Parakeratotic cells and lymphocytic infiltration could be seen in the necrosed area. In dermis, sparse fiber bundles were seen perforating the epidermis. These degenerated fiber bundles were notarized as collagen fiber by elastic fiber stain, suggesting a diagnosis of RPC. Results: Then a diagnosis of ARPC was made according to the onset age and the history of diabetes mellitus. She was treated with topical application of corticosteroids twice a day and oral antihistamine once a day along with compound glycyrrhizin tablets 3 times a day. And the blood glucose was controlled in a satisfying range. Two months later, a significant improvement was seen in this patient. Conclusion: Since there is no efficient therapy to RPC, moreover, ARPC is considered to be associated with some systemic diseases, the management of the coexisting disease is quite crucial. The patient in this case received a substantial improvement due to the control of blood glucose and application of compound glycyrrhizin tablets. PMID
Hayek, Maisam; Dorfberger, Shoshi; Karni, Avi
Children with developmental dyslexia (DD) may differ from typical readers in aspects other than reading. The notion of a general deficit in the ability to acquire and retain procedural ('how to') knowledge as long-term procedural memory has been proposed. Here, we compared the ability of elementary school children, with and without reading difficulties (DD, typical readers), to improve their tactile discrimination with practice and tested the children's ability to retain the gains. Forty 10-11-year-olds practiced the tactile discrimination of four braille letters, presented as pairs, while blindfolded. In a trial, participants were asked to report whether the target stimuli were identical or different from each other. The structured training session consisted of six blocks of 16 trials each. Performance was re-tested at 24 hours and two weeks post-training. Both groups improved in speed and in accuracy. In session 1, children with DD started as significantly less accurate and were slower than the typical readers but showed rapid learning and successfully closed the gap. Only two children with DD failed to benefit from training and were not included in subsequent data analyses. At 24 hours post-training both groups showed effective retention of the gains in speed and accuracy. Importantly, children with DD were able to retain the gains in speed and accuracy, over a two-week interval as effectively as typical readers. Thus, children with DD were as effective in the acquisition and retention of tactile discrimination of braille letters as typical readers of the same age. The results do not support the notion of a general procedural learning disability in DD.
Reznick, Julia; Friedmann, Naama
This study examined whether and how the morphological structure of written words affects reading in word-based neglect dyslexia (neglexia), and what can be learned about morphological decomposition in reading from the effect of morphology on neglexia. The oral reading of 7 Hebrew-speaking participants with acquired neglexia at the word level—6 with left neglexia and 1 with right neglexia—was evaluated. The main finding was that the morphological role of the letters on the neglected side of the word affected neglect errors: When an affix appeared on the neglected side, it was neglected significantly more often than when the neglected side was part of the root; root letters on the neglected side were never omitted, whereas affixes were. Perceptual effects of length and final letter form were found for words with an affix on the neglected side, but not for words in which a root letter appeared in the neglected side. Semantic and lexical factors did not affect the participants' reading and error pattern, and neglect errors did not preserve the morpho-lexical characteristics of the target words. These findings indicate that an early morphological decomposition of words to their root and affixes occurs before access to the lexicon and to semantics, at the orthographic-visual analysis stage, and that the effects did not result from lexical feedback. The same effects of morphological structure on reading were manifested by the participants with left- and right-sided neglexia. Since neglexia is a deficit at the orthographic-visual analysis level, the effect of morphology on reading patterns in neglexia further supports that morphological decomposition occurs in the orthographic-visual analysis stage, prelexically, and that the search for the three letters of the root in Hebrew is a trigger for attention shift in neglexia. PMID:26528159