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Reading and spelling disorders: Clinical features and causes
Abstract
Developmental dyslexia (specific reading and specific spelling disorder) is thought to stem from specific features in cognitive processing strongly related to biological maturation of the central nervous system which interact with non-biological learning conditions. The specific learning disorder should not be accounted for by mental age, gross neurological deficits, emotional disturbances or inadequate schooling. As a clinical guideline, the child's level in reading and spelling must be significantly below that expected for the population of children of the same mental age. The persistence rate is high and dyslexia is often associated with psychiatric problems. The etiology is not known. From the biological point of view, dyslexia is supposed to have a neurological basis. Neuroanatomical, neurophysiological, and neuropsychological correlates have been studied by means of autopsy, brain imaging, neurophysiological and neuropsychological methods. There is good evidence that dyslexia is determined by heritable cognitive components of reading and spelling processing. Experimental research focuses on characteristics of brain structure and cognitive skills related to the central nervous systems of auditory-phonological and visual information processing.
... Die geschätzte Prävalenzrate der Lese-und Rechtschreibstörung reicht von 3-10 % (Warnke, 1999;Fawcett & Nicolson, 2007). Die meisten epidemiologischen Studien zeigen eine zwei-bis vierfach höhere Rate des Auftretens einer Lese-und Rechtschreibstörung bei Jungen als bei Mädchen, wohingegen einige Studien auch ein ausgeglichenes Geschlechterverhältnis veranschlagen (Warnke, 1999). ...
... Die geschätzte Prävalenzrate der Lese-und Rechtschreibstörung reicht von 3-10 % (Warnke, 1999;Fawcett & Nicolson, 2007). Die meisten epidemiologischen Studien zeigen eine zwei-bis vierfach höhere Rate des Auftretens einer Lese-und Rechtschreibstörung bei Jungen als bei Mädchen, wohingegen einige Studien auch ein ausgeglichenes Geschlechterverhältnis veranschlagen (Warnke, 1999). ...
... Meist wird die Lese-und (Warnke, 1999). ...
Hintergrund: Die Lese- und Rechtschreibstörung ist mit einer geschätzten Prävalenz von bis zu 10% eine sehr häufige Problematik im Kindes- und Jugendalter. Als Begleitstörungen sind vielfältige psychiatrische Probleme wie Anpassungsstörungen, Verhaltensauffälligkeiten, Störungen des Sozialverhaltens und emotionale Störungen beschrieben. Ziel der vorliegenden Studie war, das psychosoziale Funktionsniveau und die Lebensqualität von Kindern mit Lese- und Rechtschreibstörung zu untersuchen.
Methoden: Es wurde von 23 Kindern mit der Diagnose F 81.0 (Alter 6-13 Jahre, Ø11,3 Jahre.; m:w=17:6) das psychosoziale Funktionsniveau mittels einer Elterneinschätzung anhand eines ICF Core Sets und die Lebensqualität mittels der Eltern- und Kinderversion des ILK erfasst.
Ergebnisse: ICF: Es zeigte sich ein überwiegend gutes psychosoziales Funktionsniveau. Die deutlichsten Einschränkungen im Vergleich zur Normstichprobe zeigten sich - abgesehen von den direkt mit Lesen und Schreiben verbundenen Items - in den Bereichen Temperament und Persönlichkeit, Aufmerksamkeit sowie bei den motorischen Fähigkeiten. ILK: Die gewonnenen Ergebnisse (PR0-7, LQ0-28) deuten auf eine insgesamt gute bis sehr gute Lebensqualität der untersuchten Kinder hin. Sie bewerteten sich nur beim Item Alleine schlechter als die Vergleichsstichproben. Die Eltern sahen die Schule als problematischsten Bereich für die Kinder. Zusätzlich zeigte sich eine starke Belastung der Eltern durch die Probleme ihrer Kinder.
Diskussion: Die überwiegend positiven Ergebnisse für psychosoziales Funktionsniveau und Lebensqualität müssen sicherlich im Zusammenhang mit den Eigenschaften der untersuchten Stichprobe gesehen werden. Dennoch konnte die vorliegende Studie einige Problemfelder aufzeigen, in denen vermehrt Unterstützungsangebote für betroffene Kinder, aber auch für deren Eltern, sinnvoll erscheinen.
... Eine Grundannahme der gegenwärtigen Forschung im Bereich der Neuropsychologie ist, dass LRS primär auf abweichende konstitutionelle Eigenschaften des Gehirns zurückzuführen ist (Habib, 2000;Temple, 2002). Es ist aber auch möglich, dass sie in Interaktion mit nichtbiologischen Faktoren wie psychosozialen, emotionalen und Lernbedingungseinflüssen entstehen (Warnke, 1999 So gibt es zum Beispiel einen Einfluss der Komplexität eines Schriftsystems auf die Prävalenz und Stabilität der LRS, aber auch bei vergleichbar komplexen Schriftsystemen zeigen sich Unterschiede. Die Prävalenzangaben dieser Störungen in der Gesamtbevölkerung variieren beispielsweise von 6 % im spanischsprachigen Raum (Yañez et al., 2002) bis zu 14% (Remschmidt, 1991) im deutschprachigen. ...
... Die Relevanz der wissenschaftlichen Beschäftigung mit dem Phänomen LRS ist auch in gesellschaftlicher Hinsicht nicht zu unterschätzen, denn Menschen mit Lese-Rechtschreib-Beeinträchtigungen weisen eine Tendenz zu zukünftigem antisozialen Verhalten, psychiatrischen Störungen und Delinquenz auf (Warnke, 1999). Außerdem ist bei diesen Menschen eine höhere Prozentrate an Arbeitslosigkeit vorauszusagen. ...
... Die Verbreitung und das Ausmaß der Lesestörungen im englischen Sprachraum scheint im Vergleich zu den übrigen europäischen Sprachen schwerwiegender zu sein (Hierauf wird im Folgenden näher eingegangen werden). Ungeachtet der Überlappung der Lesestörungen mit der Störung des Rechtschreibens (ICD-10, 1993) geht die angloamerikanische Forschung insbesondere auf das Interesse an den Leseprozessen ein, während die Forschung in anderen Ländern auch der Rechtschreibung eine große Bedeutung beimisst (Szczerbiński, 2003;Warnke, 1999). Dies führt zu der Annahme, dass die sozialen Erwartungen, was das Lesen und Schreiben betrifft, ungleich sind. ...
... Dyslexia, which includes difficulties in the acquisition of reading and spelling as core symptoms, is the most common of the learning disabilities (Shaywitz, 1998). Most estimates of prevalence rates range from 3 to 10% of the general population (Baker et al., 1996;Warnke, 1999). Recently, a study on prevalence of dyslexia in The Netherlands has been conducted (Blomert, 2002). ...
... In modern literate societies, dyslexia can have serious implications for both individual and society. Dyslexia is found to be associated, among other things, with the attendance of special schools, lower achieved academic levels, increased vulnerability to unemployment, and lower self-esteem (Beitchman & Young, 1997;Pennington, 1991;Van der Leij, 1991;Warnke, 1999). With the rise of the information society, the burden of dyslexia on both individual and society will be increasingly high. ...
... In most intervention studies, there is only a minor or no attention on spelling skills (Berninger et al., 2000). Both reading and spelling deficits are characteristic symptoms of dyslexia (Hagtvet & Lyster, 2003;Lyon, 1995a;Snowling, 2000;Warnke, 1999). This appears to be a result of the fact that they are secondary language functions derived from spoken language and, consequently, are both dependent on knowledge about how the writing system encodes spoken language (Dietrich & Brady, 2001;Liberman, 1997;Perfetti, 2003). ...
... Die Ergebnisse neuropsychologischer Studien weisen zudem auf Defizite in der Verarbeitungsgeschwindigkeit von visuellen Informationen hin (vgl. Übersicht von Warnke, 1999). ...
... Die Annahme, dass LRS-Kinder schlechter in der schnellen Verarbeitung visueller Stimuli abschneiden als normal lesende Kinder (vgl. Warnke, 1999), lässt sich somit bestätigen. Dass die LRS-Kinder auch schlechtere Leistungen in Aufgaben aufweisen, die visuell-räumliche Fertigkeiten oder eine Figur-Hintergrund-Differenzierung erfassen, kann nicht bewiesen werden. ...
Objective:
Visual perceptual abilities are increasingly being neglected in research concerning reading disabilities. This study measures the visual perceptual abilities of children with disabilities in reading.
Method:
The visual perceptual abilities of 35 children with specific reading disorder and 30 controls were compared using the German version of the Developmental Test of Visual Perception – Adolescent and Adult (DTVP-A).
Results:
11 % of the children with specific reading disorder show clinically relevant performance on the DTVP-A. The perceptual abilities of both groups differ significantly. No significant group differences exist after controlling for general IQ or Perceptional Reasoning Index, but they do remain after controlling for Verbal Comprehension, Working Memory, and Processing Speed Index.
Conclusions:
The number of children with reading difficulties suffering from visual perceptual disorders has been underestimated. For this reason, visual perceptual abilities should always be tested when making a reading disorder diagnosis. Profiles of IQ-test results of children suffering from reading and visual perceptual disorders should be interpreted carefully.
... Die Ergebnisse neuropsychologischer Studien weisen zudem auf Defizite in der Verarbeitungsgeschwindigkeit von visuellen Informationen hin (vgl. Übersicht von Warnke, 1999). ...
... Die Annahme, dass LRS-Kinder schlechter in der schnellen Verarbeitung visueller Stimuli abschneiden als normal lesende Kinder (vgl. Warnke, 1999), lässt sich somit bestätigen. Dass die LRS-Kinder auch schlechtere Leistungen in Aufgaben aufweisen, die visuell-räumliche Fertigkeiten oder eine Figur-Hintergrund-Differenzierung erfassen, kann nicht bewiesen werden. ...
Fragestellung: Die visuellen Wahrnehmungsleistungen werden bei der Erforschung von Lese-Rechtschreibstörungen aktuell weitestgehend vernachlässigt. Diese Studie spezifiziert die visuellen Wahrnehmungsleistungen bei Kindern mit Lese-Rechtschreibstörungen (LRS). Methodik: Die Wahrnehmungsleistungen von 35 Kindern mit LRS und 30 Kontrollgruppenkindern werden anhand des Frostigs Entwicklungstest der visuellen Wahrnehmung – Jugendliche und Erwachsene (FEW-JE) miteinander verglichen. Ergebnisse: 11 % der Kinder mit LRS weisen klinisch auffällige Ergebnisse im FEW-JE auf. Die Wahrnehmungsleistungen der beiden Gruppen unterscheiden sich insgesamt signifikant. Nach Kontrolle des Gesamt-IQ und des Indizes Wahrnehmungsgebundenes Logisches Denken lässt sich kein Effekt durch die Gruppeneinteilung auf die visuellen Wahrnehmungsleistungen nachweisen, jedoch nach Kontrolle der Indizes Sprachverständnis, Arbeitsgedächtnis und Verarbeitungsgeschwindigkeit. Schlussfolgerungen: Die Anzahl der Kinder mit LRS und visuellen Wahrnehmungsstörungen wurde bislang unterschätzt. Im Rahmen der klinischen Diagnostik sollten die visuellen Wahrnehmungsfähigkeiten daher immer überprüft werden. Zudem sollten die IQ-Testprofile von Kindern mit LRS und visuellen Wahrnehmungsstörungen mit Vorsicht interpretiert werden.
... Reading disabilities of all types are developmental in nature and "usually result from impaired phonological processing" (Willcut & Pennington, 2000, p. 1039. Students who have a RD are very likely to suffer from deficiencies in orthographic coding (Warnke, 1999), making automatic reading nearly impossible, which in turn makes comprehension very unlikely. ...
... In addition, lack of sleep causes concentration and brain chemistry difficulties, which both influence the ability to comprehend well. Complicating the matter further is when the presence of a RD, such as dyslexia, makes retrieval of items stored in the long-term memory difficult (Warnke, 1999). ...
... This can affect any part of the reading process (including difficulty with accurate or fluent word recognition, or both), word decoding, reading rate, prosody (oral reading with expression), and reading comprehension. Before the term "dyslexia" came to prominence, it was known as "word blindness" (6). ...
... 15 17 Score is > 11. Hence, this indicates "healthy" eating habits The Mood and Feelings Questionnaire (MFQ) 6 5 Score is < 10; hence, "no difficulty" in mood ...
Objective: The present study seeks to outline a holistic assessment method that was used in understanding problems experienced by an adolescent boy and in designing and implementing an individualized educational program.
Methods: An adolescent child referred for concerns in learning was screened for learning disability using standardized inventories and test batteries. The Connors Parent and Teacher Rating Scales (short forms), Wechsler's Intelligence Scale for Children (WISC), the Vineland Social Maturity Scale (VSMS), and the Kinetic Family Drawing (KFD) test were used to assess the behavior, cognition, and social profile of the child. An individualized educational program was designed and this intervention was provided for 6 months by using parents as co-therapists. Participant and parent interview schedules were used in identifying underlying issues of concern. The child was reassessed 6 months after the intervention was provided.
Results: Findings on the Connors Parent Rating Scale revealed scores that were greater than the 50th percentile on the domains of inattention and cognitive problems. On the Connors Teacher Rating Scale, we observed scores greater than the 50th percentile on the hyperactivity, cognitive problems, and the inattention domains. The WISC revealed that the child had a "Dull Normal" Intellectual functioning and there was also a deficit of 2 years on the social skills as tested by the Vineland Social Maturity Scale (VSMS). The Kinetic Family Drawing Test revealed negative emotions within the child. Post intervention, we noticed a remarkable improvement in the scores across all domains of behavior, social, and cognitive functioning.
Conclusion: Designing an individualized education program that is tailored to the specific needs of the child and using parents as co-therapists proved to be an effective intervention.
... Recruiting populations with dyslexia and other specific diagnoses or traits has a long history of proving difficult, especially in a university setting. The nature of dyslexia and the predominant focus of the education system on reading and writing mean that individuals with medium to severe cases of dyslexia may not be captured when recruiting at the university level, as many have most likely not progressed to this level (Warnke, 1999). Therefore, generalising labbased results to the general population of individuals with dyslexia can become problematic, particularly if based on a WEIRD sample. ...
The combination of a replication crisis, the global COVID-19 pandemic in 2020, and recent technological advances, have accelerated the ongoing transition of research in cognitive psychology and neuroscience to the online realm. When participants cannot be tested in-person, data of acceptable quality can still be collected online. While online research offers many advantages, numerous pitfalls may hinder researchers in addressing their questions appropriately, potentially resulting in unusable data and misleading conclusions. Here, we present an overview of the costs and benefits of conducting online studies in cognitive psychology and neuroscience, coupled with detailed best practice suggestions that span the range from initial study design to the final interpretation of data. These suggestions offer a critical look at issues regarding recruitment of typical and (sub)clinical samples, their comparison, and the importance of context-dependency in each part of a study. We illustrate our suggestions by means of a fictional online study, applicable to traditional paradigms such as research on working memory with a control and treatment group.
... Should professionals choose the font as a tool for public engagement, we recommend that it be highlighted that this font does not resemble how individuals with dyslexia perceive and sample text, but rather is an attempt to induce a more general experience of effortful reading difficulty. As well, it is important to highlight that, in most cases, this font appears to amplify dyslexia-related reading difficulties, keeping in mind the well-educated sample of individuals used in this study, which does not necessarily represent the average individual with dyslexia (Warnke, 1999). Future studies could address whether the Daniel Britton font does however simulate the experience of primary school students at the beginning of their reading practices. ...
Individuals with dyslexia struggle at explaining what it is like to have dyslexia and how they perceive letters and words differently. This led the designer Daniel Britton to create a font that aims to simulate the perceptual experience of how effortful reading can be for individuals with dyslexia (http://danielbritton.info/dyslexia). This font removes forty percent of each character stroke with the aim of increasing reading effort, and in turn empathy and understanding for individuals with dyslexia. However, its efficacy has not yet been empirically tested. In the present study, participants without dyslexia read ten standardized texts from a commercial reading assessment, five texts in Times New Roman and five in the dyslexia simulation font. We compared this group to individuals with dyslexia reading texts from the same reading assessment tool in Times New Roman font. Results show that the simulation font exaggerated the difficulty of reading, surpassing that experienced by adults with dyslexia, as reflected in increased reading time and overall number of eye movements. Reading appeared to be even more laborious for readers reading the simulation font compared to individuals with dyslexia. Future research could compare the performance of the Daniel Britton font against a sample of beginning readers with dyslexia as well as seek to design and empirically test an adapted simulation font with an increased preserved percentage of letter strokes.
... Recruiting populations with dyslexia and other specific diagnoses or traits has a long history of proving difficult, especially in a university setting. The nature of dyslexia and the predominant focus of the education system on reading and writing mean that individuals with medium to severe cases of dyslexia may not be captured when recruiting at the university level, as many have most likely not progressed to this level (Warnke, 1999). Therefore, generalising lab-based results to the general population of individuals with dyslexia can become problematic, particularly if based on a WEIRD sample. ...
The combination of a replication crisis, global COVID-19 pandemic, and recent technological advances have accelerated the on-going transition of research in cognitive psychology and neuroscience to the online realm. When participants cannot be tested in-person, data of acceptable quality can still be collected online. While online research offers many advantages, numerous pitfalls may hinder researchers in addressing their questions appropriately, potentially resulting in unusable data and misleading conclusions. Here, we present a cost-benefit analysis of conducting online studies in cognitive psychology and neuroscience, coupled with detailed best practice suggestions that span the range from initial study design to the final interpretation of data. These suggestions offer a critical look at issues regarding recruitment of typical and (sub)clinical samples, their comparison, and the importance of context-dependency in each part of a study. We illustrate our suggestions by means of a recent online experiment investigating cognitive working memory skills in adults with the learning disorder dyslexia.
... Should professionals choose the font as a tool for public engagement, we recommend that it be highlighted that this font does not resemble how individuals with dyslexia see and sample text, but rather is an attempt to induce the experience of reading difficulty. As well, it is important to highlight that, in most cases, this simulation amplifies dyslexia-related reading difficulties, keeping in mind the well-educated sample of individuals used in this study, which does not necessarily represent the average individual with dyslexia (Warnke, 1999). Future studies could address whether the Daniel Britton font does however simulate the experience of primary school students at the beginning of their reading practices. ...
Individuals with dyslexia struggle at explaining what it is like to have dyslexia and how they perceive letters and words differently. This led the designer Daniel Britton to create a font that aims to simulate the perceptual experience of how effortful reading can be for individuals with dyslexia (http://danielbritton.info/dyslexia). This font removes forty percent of each character stroke with the aim of increasing reading effort, and in turn empathy and understanding for individuals with dyslexia. However, its efficacy has not yet been empirically tested. In the present study, we compared participants without dyslexia reading texts in the dyslexia simulation font to a group of individuals with dyslexia reading the same texts in Times New Roman font. Results suggest that the simulation font amplifies the struggle of reading, surpassing that experienced by adults with dyslexia—as reflected in increased reading time and overall number of eye movements in the majority of typical readers reading in the simulation font. Future research could compare the performance of the Daniel Britton simulation font against a sample of beginning readers with dyslexia as well as seek to design and empirically test an adapted simulation font with an increased preserved percentage of letter strokes.
... "tee" zamiast "tree"); przekręcaniu liter, głosek (np. "b -d", "p -g", "b -p", "u -n") (Stein, Walsh, 1997;Warnke, 1999). Wśród tzw. ...
The basic purpose of this paper is to present selected theoretical and empirical facts concerning dyslexia, taking into account specific reading and spelling disorders experienced by the sighted and the blind who normally use a tactile writing system (braille) to read and write. The article’s content is focused on such key issues as: the terminology (a review of definitions), the symptomatology and etiology of dyslexia. In the light of the collected qualitative data and empirical research findings, dyslexia is likely to occur in blind braille-reading and braille-writing students. The symptoms of dyslexia may be observable in both contracted and uncontracted braille. They may be linked to the phonological processing deficits. The causes of dyslexia in the blind population can be explained in line with the genetic conception and the magnocellular theory by Stein and colleagues. However, it is necessary to design more complex studies on braille dyslexia in the future.
... Yet dyslexics exhibit a strong aversion and compromised reading performance with italic fonts Baeza-Yates, 2016, 2013) compared to non-dyslexics. These deficits are exacerbated when dyslexics are required to read under time pressureas is often the case with many legal documentssince they have difficulties with fast visual information processing (Warnke, 1999) and reading speed (Lefly and Pennington, 1991). As such, the use of italicised font style in particular is discouraged (British Dyslexia Association, 2018). ...
Good reading comprehension is indispensable in many situations including contract-based transactions that have become so prevalent in our everyday lives. People with dyslexia often exhibit impairments in this important cognitive process. Although the effects of italics — a commonly used style for highlighting important content in a range of documents — and font in general, have been explored with behavioural measures, their impact on human brain dynamics remains poorly understood. Here, we used electroencephalography (EEG) to investigate the specific effects of italics in a sentence reading lexical decision task in adult dyslexics and an age-matched non-dyslexia group. Overall, the performance of dyslexics was worse. Cluster-based event-related potential (ERP) analysis revealed that brain responses within the first 300 ms following the decision stimulus differed in amplitude and spatial distribution between dyslexics and non-dyslexics when processing italicised text. An initial ERP component over occipitotemporal electrode sites started to differ between the groups as early as 167 ms following the onset of short italicised decision words. A subsequent ERP component over centrofrontal electrodes showed differences lasting until about 300 ms post-stimulus onset. Inter-individual amplitude differences in this centrofrontal neural signal were predictive of behavioural performance across participants, further highlighting the role of fast post-sensory linguistic processes in lexical decision making. Crucially, our findings emphasise the importance of choosing font style carefully to optimise word processing and reading comprehension by everyone.
... We further postulate that a lack of sensitivity to orthographic errors might contribute to developmental dyslexia (henceforth dyslexia in this paper). Dyslexia is a specific deficit in the acquisition of reading and writing that afflicts between 5-12 % of children ( Shaywitz, 1998, Warnke, 1998, Gustafson and Samuelsson, 1999, Katusic et al., 2001Hasselhorn and Schuchardt, 2006;Landerl and Moll, 2010;Landerl et al., 2013;Moll et al., 2014). A rapid auditory processing deficit has been suggested to underlie dyslexia ( Tallal, 1980, Nicolson et al., 2001). ...
To study the development of orthographic sensitivity during elementary school, we recorded event-related brain potentials (ERPs) from 2nd and 4th grade children who were exposed to line drawing of object or animals upon which the correctly or incorrectly spelled name was superimposed. Stimulus-locked ERPs showed a modulation of a frontocentral negativity between 200 and 500 ms which was larger for the 4th grade children but did not show an effect of correctness of spelling. This effect was followed by a pronounced positive shift which was only seen in the 4th grade children and which showed a modulation of spelling correctness. This effect can be seen as an electrophysiological correlate of orthographic sensitivity and replicates earlier findings in adults. Moreover, response-locked ERPs triggered to the children’s button presses indicating orthographic (in)-correctness showed a succession of waves including the frontocentral error-related negativity and a subsequent negativity with a more posterior distribution. This latter negativity was generally larger for the 4th grade children. Only for the 4th grade children, this negativity was smaller for the false alarm trials suggesting a conscious registration of the error in these children.
... Sie haben also, wie erwartet (vgl. Warnke, 1999), eher Schwierigkeiten in der schnellen Verarbeitung visueller Stimuli als normal lesende Kinder. Die schwächeren Leistungen im "Gestaltschließen" widersprechen allerdings den Ergebnissen von Pache et al. (2004) sowie (Bell et al., 2003). ...
Visual perception is an important cognitive ability with major influence on child development. To support the results of studies published previously the visual perceptual abilities of children suffering from dyslexia, dyscalculia, and developmental coordination disorder as well as children that had a perinatal or early childhood stroke are compared. Different models of visual perceptual processing exist. The present work refers to Frostig´s three level model describing visual perception as an exceptional level between sensation and cognition. As the diagnosis Visual Perceptual Disorder is neither provided by the ICD-10 nor by the DSM-5 the guidelines of the Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften (AWMF) (German working committee of the scientific medical professional associations) are used within the framework of this dissertation. The scores of 241 children aged between 9 and 14 years on the German version of the Developmental Test of Visual Perception - Adolescent and Adult (DTVP-A) are compared. The nonparametric Kruskal-Wallis-H-Test was used for comparative analyses. Furthermore the percentage of children of the different groups who achieved clinical relevant scores and those children who have visual perceptual disorders based on the guidelines of the AWMF are presented. Children with dyslexia achieve superior results compared to children from the other groups. Based on pairwise comparisons results of the main scale General Visual Perception Index tend to differ between the dyscalculia and the dyslexia group. No significant differences between groups are found in the subscale Motor-Reduced Visual Perception Index. In the subscale Visual-Motor Integration Index stroke and dyslexia group differ significantly in pairwise comparisons. Further significant differences are observed in the pairwise group comparisons of the scores in the subtests Form Constancy (dyslexia vs. dyscalculia), Copying (dyscalculia vs. coordination disorder) and Visual-Motor Speed (dyslexia vs. dyscalculia and dyslexia vs. stroke). 39 % of the children suffering from dyscalculia, 36 % of the children who suffered a stroke, 33 % of the children with coordination disorder and 11 % of those with dyslexia achieve clinical relevant scores (= scores at least 1.5 SD below standardized average) on the General Visual Perception Index. Children within the stroke group remarkably often achieve clinical relevant scores in the Visual-Motor Integration Index (43 %) as well as in the subtests Visual Closure and Form Constancy (18 %, respectively). A large amount of children with dyslexia achieve clinical relevant results in the subtests Copying and Visual Closure (17 %, respectively). Within the dyscalculia group a large number of children perform 1.5 SD below average in the subtests Visual Closure (23 %), Form Constancy, Copying and Visual-Motor Search (26 %, respectively). Children with coordination disorder most frequently achieve clinical relevant results in the subtests Copying (38 %), Form Constancy (24 %), Visual Closure (19 %), Figure-Ground and Visual-Motor Search (14 %, respectively). Interestingly, as compared to the other groups children with dyslexia show less overall visual perceptual deficits. A Visual Perceptual Disorder according to the AWMF-criteria (total score 1.5 SD below average on the DTVP-A and 1.5 SD below the General IQ) can be diagnosed for 11 % of the children of the stroke group and for 3 % of the dyslexia as well as the dyscalculia group. When using the Verbal Comprehension Index as reference score instead of the General IQ this pattern changes: 21 % of the stroke, 3 % of the dyslexia and 13 % of the dyscalculia group preserve the diagnosis. Concluding, the results presented in this dissertation thesis show the high incidence of visual perceptual deficits in children with developmental problems. As deficits in visual perceptual abilities differ between groups it seems important to use standardized visual perceptual tests in develop-mental diagnostics and intervention design. Furthermore, the diagnosis Visual Perceptual Disorder has to be defined more precisely. Hence, further studies on the role of visual perceptual deficits in children with developmental disorders such as developmental coordination disorder, dyscalculia, dyslexia and childhood stroke seem necessary. The same holds for studies on the effectiveness of visual perceptual therapies.
... Dyslexie tritt häufig in Kombination mit anderen Störungen auf. Dabei werden vor allem verzögerter oraler Spracherwerb (Dysphasie), Probleme beim Rechnen (Dyskalkulie), Dyspraxie, Probleme bei der zeitlichen Orientierung (Dyschronie) sowie Hyperaktivität (Aufmerksamkeits-Defizit-Hyperaktivitäts-Syndrom, ADHS) beschrieben (Warnke, 1999). Für die Erforschung der Ursachen von Dyslexie bedeutet dies, dass diese Komorbiditäten sorgfältig ausgeschlossen werden müssen, um aus den erhaltenen Ergebnissen möglichst eindeutige Rückschlüsse auf die Ursachen von LRS ziehen zu können. ...
Zusammenfassung: Diese Uberblicksarbeit stellt die wichtigsten neurobiologischen Theorien zu Ursachen der entwicklungsbedingten Lese-Rechtschreib-Schwache und daraus abgeleitete Therapieansatze vor. Es wird zunachst ein kurzer Uberblick uber die Symptomatik und die vermuteten genetischen Grundlagen der Storung gegeben. Die phonologische Defizithypothese als eine allgemein akzeptierte, auf der kognitiven Ebene angesiedelte Theorie wird vorgestellt. Neurobiologische Modelle versuchen zu erklaren, auf welchen neuroanatomischen/physiologischen Ursachen das phonologische Defizit beruht. Die magnozellulare Defizithypothese, die Hypothese eines grundlegenden Verarbeitungsdefizits fur sich zeitlich schnell verandernde Reize, die cerebellare Defizithypothese sowie neuroanatomische Unterschiede zwischen normalen und legasthenen Lesern werden vorgestellt. Neurobiologisch fundierte Therapieansatze der Lese-Rechtschreib-Schwache versuchen, in Erganzung zu traditionellen, eher linguistisch orientierten Therapien die be...
... Konstitutionelle Dyslexie (Lese-Rechtschreib-Schwäche) ist ein spezifisches Defizit beim Erlernen des Lesens und Schreibens, das trotz normaler intellektueller Fähigkeit, angemessener Beschulung und intakter sensorischer Fähigkeiten auftritt (Dilling, Mombour & Schmidt, 1991;Gustafson & Samuelson, 1999;Habib, 2000;Shaywitz, 1998;Warnke, 1999). Die Prävalenz liegt zwischen 5 % und 12 % (Katusic, Colligan, Barbaresi, Schaid & Jacobsen, 2001;Shaywitz, Shaywitz, Fletcher & Escobar, 1990), wobei davon ausgegangen wird, dass mindestens 4 % aller Schüler schwer betroffen sind (British Dyslexia Association, 1995). ...
Zusammenfassung: Unterschiede in der zeitlichen Integration bei praattentiver auditiver Reizverarbeitung wurden bei 12 erwachsenen dyslektischen Lesern und einer Kontrollgruppe untersucht. Dazu wurde die Mismatch-Negativitat (MMN), eine Komponente des auditiven ereigniskorrelierten Hirnpotenzials, die die automatische Entdeckung von Veranderungen der akustischen Umgebung reflektiert, verwendet. Die von gelegentlich auftretenden Tonauslassungen in einer ansonsten regelmasigen Tonfolge evozierte MMN wurde genutzt, um zeitliche Integrationsmechanismen im auditiven System zu untersuchen. In Experiment 1 wurden in einer ansonsten regelmasigen Tonfolge gelegentlich Tone ausgelassen, wobei sich die prasentierten Blocke in ihrem Interstimulus-Intervall unterschieden (120ms, 150ms, 180ms, 200ms, 220ms). In Experiment 2 wurde die Genauigkeit des auditiven Integrationsmechanismus untersucht. Es ergaben sich keine Gruppenunterschiede in Amplitude, Latenz oder Topographie fur die durch Tonauslassungen oder Tonabweichu...
... At the more central processing stages of written language it has been suggested that both spelling and reading share processes that involve the retrieval and storage of lexical and sub-lexical representations. Support for this idea comes from the behavioral literature which suggests that reading and spelling abilities are correlated in typically-developing children and that developmental reading impairments tend to be associated with poor spelling (Henderson, 1980;Morris and Perney, 1984;Ehri and Wilce, 1987;Stevenson et al., 1987;Warnke, 1999;Schulte-Korne, 2001;Berninger et al., 2002). Further, spelling accuracy for words predicts the priming effects on those same words during a lexical decision task, suggesting that reading and spelling may actually share lexical representations (Burt, 2002). ...
In this study we employed a novel technique to examine the neural basis of written spelling by having subjects touch-type single words on an fMRI compatible QWERTY keyboard. Additionally, in the same group of participants we determined if task-related signal changes associated with typed spelling were also co-localized with or separate from those for reading. Of particular interest were the left inferior frontal gyrus, left inferior parietal lobe as well as an area in the left occipitotemporal cortex termed the Visual Word Form Area (VWFA), each of which have been associated with both spelling and reading. Our results revealed that typed spelling was associated with a left hemisphere network of regions which included the inferior frontal gyrus, intraparietal sulcus, inferior temporal/fusiform gyrus, as well as a region in the superior/middle frontal gyrus, near Exner's area. A conjunction analysis of activation associated with spelling and reading revealed a significant overlap in the left inferior frontal gyrus and occipitotemporal cortex. Interestingly, within the occipitotemporal cortex just lateral and superior to the VWFA we identified an area that was selectively associated with spelling, as revealed by a direct comparison of the two tasks. These results demonstrate that typed spelling activates a predominantly left hemisphere network, a subset of which is functionally relevant to both spelling and reading. Further analysis revealed that the left occipitotemporal cortex contains regions with both conjoint and dissociable patterns of activation for spelling and reading.
... Problems in school adjustment or even an increased risk for dropping out of formal schooling have been reported. [In Germany, a number of dyslexic schoolchildren failed to reach class level (Warnke, 1999), many attend schools for special education (Esser & Schmidt, 1993), and less than 2% of the dyslexic students complete high school (Haffner et al., 1998)]. Adult dyslexics may have significant problems in occupational functioning or social mobility. ...
Die vorliegende Arbeit stellt behaviorale und neurophysiologische Aspekte der auditiven Verarbeitung bei Personen mit Dyslexie im Vergleich zu Probanden ohne Lese-Rechtschreibschwäche vor. Empirische Basis waren psychophysikalische und magnetoenzephalographische Untersuchungen zur Verarbeitung von Stopp-Konsonant-Vokal-(KV)-Silben. Als abhängige Variablen dienten das Mismatch Field (MMF) und andere kortikale ereigniskorrelierte Feld-Komponenten (EKF). Die Ergebnisse weisen auf eine atypische Hemisphärenasymmetrie im Temporallappen bei Kindern mit Dyslexie hin. Im Vergleich zu den Kontrollpersonen zeigten sich eine veränderte topographische Verteilung des MMF sowie deutliche Abweichungen in den Quellorten der EKFs. Diese Befunde deuten eine atypische Organisation im primären auditorischen Kortex und angrenzender Gebiete an. Untersuchungen im Querschnitt zeigen auch im Erwachsenenalter noch Auffälligkeiten in der Quellenkonfiguration der magnetischen Antwort um 100 ms nach Silbenbeginn. Allerdings scheinen die Abweichungen in der hemisphärischen Balance durch ein linguistisches Training modifizierbar zu sein. Befunde aus einer Studie an sprachbeeinträchtigten Kindern unterstützen diese Vermutung. Ein Verhaltensexperiment auf der Basis der temporalen Verarbeitungsdefizit-Hypothese suggeriert die Kompensation einer beeinträchtigten auditiven Verarbeitung durch eine gut funktionierende visuelle Modalität. Eine weitere Studie legt zwei Subtypen von Dyslexie nahe, die sich in der akustischen Differenzierungsfähigkeit kurzer und zeitlich verlängerter KV-Silben sowohl auf der Verhaltens- als auch auf der neurophysiologischen Ebene unterscheiden. Insgesamt sprechen die Studien vorwiegend für Auffälligkeiten in der rechten Hemisphäre. Diese Befunde ergänzen Erkenntnisse aus Studien mit bildgebenden Verfahren, die primär auf eine linkshemisphärische Dysfunktion bei Dyslexie hinweisen, und charakterisieren die zeitliche Dynamik dieser Auffälligkeit. The present thesis sought to examine behavioral and neurophysiological aspects of auditory processing in people with dyslexia compared to normally literate controls. To this end, a series of psychophysical experiments and magnetoencephalographic recordings were conducted, involving stop consonant-vowel (CV) syllables. The mismatch field (MMF) and other cortical event-related field (ERF) components served as dependent variables. As an important result, these studies pointed to deviances in hemispheric asymmetry of temporal-lobe sites in children with dyslexia. Signal space analyses revealed an altered topographical distribution of the MMF, while source space analyses showed pronounced deviations in source positions of ERFs. These findings may reflect atypical organization of the primary auditory cortex and adjacent areas, in particular the planum temporale. Cross-sectional investigations indicate that a deviance in source configuration of magnetic waves around 100 ms after syllable presentation continue into adulthood. However, differences in hemispheric balance might be altered following linguistic training as suggested by a study in a small group of language-impaired children with symptoms of dyslexia. A behavioral experiment inspired by the hypothesis of a temporal processing deficit for dyslexia suggests that limitations in auditory processing might be compensated by a well-functioning visual sensory modality. Another study revealed two subgroups of dyslexic individuals differing in their discrimination ability of short and temporally extended CV syllables both at the behavioral and neuronal level. Taken together, the studies indicate predominantly right-hemisphere deviances in children and adults with dyslexia. These observations complement functional neuroimaging studies suggesting mainly a left-hemisphere deficit in dyslexia and characterize the temporal dynamic of the relevant brain processes.
... In a previous study, we found a pathological eye movement pattern for reading words, but not for naming pictures (Trauzettel-Klosinski et al. 2002). This indicates the phonological deficit as one of the main causes of dyslexia (Bradley & Bryant 1978;Tallal 1980;Frith 1981;Golden & Zenhausern 1983;Wimmer 1993;Fox 1994;Rumsey et al. 1997;Swan & Goswami 1997;Shaywitz et al. 1998;Schulte-Ko¨rne et al. 1999;Warnke 1999; [for a review, see von Suchodoletz 1999]). Many studies have found a phonological deficit by means of behavioural, cognitive measures (Snowling 1980(Snowling , 1981Rack et al. 1992;Wimmer 1993;Esser & Schmidt 1994;Wagner et al. 1994), as well as by using brain imaging techniques (Price et al. 1994;Rumsey et al. 1994Rumsey et al. , 1997Salmelin et al. 1996;Demp et al. 1997;Shaywitz et al. 1998;Fiez et al. 1999;Georgiewa et al. 1999;Helenius et al. 1999;Temple et al. 2001). ...
The phonological difficulty and orthographic regularity of a language influence reading strategies. Only a few studies have been conducted in readers of German, which has a high grapheme-phoneme correspondence. The aim of this study was to investigate, firstly, the influence of different levels of phonological difficulty of reading material in German on reading in children and, secondly, to compare the reading strategies of German children with findings in English-speaking readers.
Eye movements in 16 German children with dyslexia and 16 age-matched control children (mean age 9.5±0.35years) in the third and fourth grades of school were recorded by scanning laser ophthalmoscope while they read aloud two texts of differing levels of difficulty.
In the dyslexia group, reading speed was slowed, and the number of saccades and regressions was raised markedly, although the percentage of regressions only slightly. The number of eye movements increased in both groups with increasing text difficulty, although much more in the dyslexia group than in the control group, whereas fixation duration was not influenced.
Phonological difficulty influences reading speed and eye movement pattern: children with dyslexia markedly increase their number of eye movements and analyse the text in smaller units per fixation, but keep fixation duration constant. This strategy reflects their favouring of the indirect, sublexical route of grapheme-phoneme conversion, whereas readers of English-language texts are more likely to prefer the whole-word approach, i.e. the direct, lexical route that is associated with orthographic memory.
... One of the most accepted hypotheses regarding the etiology of dyslexia is a deficit in language processing. Many reports provide evidence for pathologic phonological processing, the decoding from graphemes to phonemes, due to deficits in phonological awareness and/or phonological representation (Bradley & Bryant, 1978; Frith, 1986; Schulte-K€ o orne, Deimel, Bartling, & Remschmidt, 1999; Swan & Goswami, 1997a,b; Wagner & Torgesen, 1987; Warnke, 1999; Wimmer, 1993). Some studies (Snowling et al., 1988; Swan & Goswami, 1997a) have provided evidence that the deficits were based on selective difficulties in retrieving the phonological codes of the words which correspond to the pictograms, which can be based on deficits in encoding as well as processing. ...
We measured pictogram naming (PN) and text reading in dyslexic and normally reading young teenagers. Eye movements were monitored by scanning laser ophthalmoscope, revealing positions of fovea, stimuli on the retina, and speech simultaneously. While text reading speed showed the expected difference between groups, PN speeds overlapped widely. PN was mainly controlled by retrieval time in both groups and correlated with age in dyslexics. During PN, only backward saccades occurred more frequently in dyslexics. We conclude that PN activates visual/eidetic mechanisms that are distinct from the phonemic/analytic pathway necessary for reading. This dual organization leads to a wide range of combinations of performances in PN and text reading.
... On a functional level, reading decoding processes and an attentional deficit have been described in dyslexic readers (Fawcett et al., 1993;Harter et al., 1989;Helenius et al., 1999;Manis et al., 1997;Schulte-K . o orne et al., 1998;Warnke, 1999). Some researchers have used event-related brain potentials (ERPs) to characterize information processing in dyslexic readers. ...
Event-related brain potentials were recorded in two three-stimulus oddball tasks in 13 adult dyslexic and 13 age- and IQ-matched normal readers. The stimuli consisted of a random series of frequent (80%) and non-frequent tones (10%) as well as occasionally inserted novel sounds (10%). The experiment comprised an active (response to the rare target tone) and a passive listening condition. No performance differences were found for dyslexic and normal readers in the active task. In both conditions, novel sounds evoked a centrally distributed P3a-component followed by a P3b-component most prominent at parietal electrodes for target and novel sounds. Additionally, a slow negativity emerged after presentation of novel sounds at frontal electrodes. In the active condition only, peak amplitude of the P3a and the frontal slow negativity to novel stimuli were slightly enlarged for dyslexic readers. These findings indicate a larger distractability of dyslexic readers (enhancement of P3a to novel tones). Furthermore, we propose that dyslexics need to employ more cognitive resources to refocus on the task at hand (as indicated by the enlarged slow frontal negativity).
... The persistent reading and spelling difficulties have serious implications for the social functioning of individuals with dyslexia. Dyslexia is found to be associated with, among other things, the attendance of special schools, and lower achieved academic levels and lower self-esteem (Beitchman & Young, 1997;Pennington, 1991;Warnke, 1999). The persistence of the disorder has led some researchers to conclude that there are biological constraints, preventing intervention from having long-lasting effects (Cossu, 1999;Lyon, 1995;Foorman et al., 1997). ...
Two hundred sixty-seven 10- to 14-year-old Dutch children with dyslexia were randomly assigned to one of two samples that received a treatment for reading and spelling difficulties. The treatment was computer-based and focused on learning to recognise and use the phonological and morphological structure of Dutch words. The inferential algorithmic basis of the program ensured that the instruction was highly structured. The present study examined the reliability of the effects of the treatment, and provided an evaluation of the attained levels of reading and spelling by relating them to normal levels. Both samples revealed large, generalized treatment effects on reading accuracy, reading rate, and spelling skills. Following the treatment, participants attained an average level of reading accuracy and spelling. The attained level of reading rate was comparable to the lower bound of the average range.
In standard educational systems of many countries dyslexic students are considered as a special category of students that should be given special care so that they may be helped with their dyslexia problems. Such opportunities should be given to dyslexic users through educational software as well. In this paper we describe an integrated educational system that supports dyslexic students through multiple facilities.
Developmental learning disorders are known to cause a great amount of psychological and mental stress to the kids and their parents. They affect lives in an adverse manner. Early diagnosis and the right kind of intervention can help the child attain academic standards on par with their peers as seen in this case. [Azra Kirmani , Hanan Ahmad Al-Kadi, Rahila Iftikhar and Yusuf Mayat. A case report of a dyslexic child with an above average IQ, responding to remedial intervention (Dyslexia-Case Report). Life Sci J
Zusammenfassung. Theoretischer Hintergrund: Die klinischen Symptome der LRS ändern sich im Laufe der Entwicklung der Patienten, wobei sich die altersabhängigen Veränderungen der Lesefähigkeit aber von normgerechter Leseentwicklung unterscheiden. Fragestellung: Der Charakter dieser Veränderungen soll anhand der Entwicklung von Lesefertigkeiten in verschiedenen Lebensaltern gezeigt werden. Methoden: 102 Personen mit LRS und 91 normallesenden Kontrollen aus drei Altersgruppen (Kinder, Jugendliche und Erwachsenen) wurden Leseaufgaben vorgegeben, die unterschiedliche phonologische Strategien verlangen: (1) lautes Lesen von Wörtern, (2) von Nonwörtern und (3) Phonemtransformation. Erfasst wurden Lesefehler und -zeiten. Ergebnisse: Eine Verbesserung der Lesefertigkeiten erfolgt kontinuierlich über die drei Altersgruppen. Erwachsene mit LRS erreichen nicht einmal das Wortleseniveau jugendlicher Kontrollen. Beim Nonwortlesen sind sie schlechter als normallesende Kinder und erreichen über die Altersstufen kaum signifikante Verbesserungen. Schlussfolgerungen: In der LRS-Gruppe bilden sich Fähigkeiten zur Graphem-Phonem-Transformation langsamer heraus und bleiben auf niedrigem Niveau. Verbesserungen der Wortlesefähigkeiten scheinen vor allem über lexikalische Strategien (Ganzwortlesen) möglich.
Zusammenfassung Die Verwendung der Computerprogramme Budenberg 1 und 2 und die des Comles-Pakets zur Lese-Rechtschreibförderung brachte nach 1000 Minuten individuellem Trainings für sieben von 16 Kindern Fortschritte im Lesen und für neun Kinder Fortschritte nach zusätzlichen dreieinhalb Monaten Schulbesuch. Beim Rechtschreiben profitierten zusätzlich drei von 16 Kindern, die besonders niedrige Ausgangsleistungen hatten. Dreieinhalb Monate Schulunterricht änderten danach bei fast allen Kindern an den erreichten Rechtschreibleistungen nichts mehr.
Dyslexia is a learning disability that can hinder a person's ability to read, write, spell, and sometimes
speak. Dyslexia is the most common learning disability in children and persists throughout life. The
severity of dyslexia can vary from mild to severe. The sooner dyslexia is treated, the more favorable the
outcome. This paper proposes a prolog based system for dyslexia diagnosis PSDD. PSDD is not only
able to determine the severity degree of this disability but it is also able to propose a treatment plan with
different steps that need to be taken by both teachers and parents. Through their feedback, PSDD is able
to adapt its knowledge in order to give more enhanced treatment plans.
Most children born preterm are considered neurologically normal and free of disability. However in follow-up studies at school age, preterm children, born without major impairment, have been shown to have lower cognitive abilities and associated academic, social and behavioural difficulties. This study investigated the literacy, phonological awareness and language abilities of 169 preterm (<33 weeks gestational age) and 141 fullterm born children aged between 5 and 12 years. Reading, spelling, phonological awareness skills, language and cognitive skills were assessed. The results indicate the preterm children were significantly poorer across all domains assessed in comparison to their fullterm classmates. However, the results of the preterm children do not significantly differ to the standardised assessment populations. Spelling was particularly vulnerable in preterm children and a higher number were identified with speech difficulties. The study also provided further evidence for the strong relationship that exists between language ability, phonological skills and literacy.
The disadvantage dyslexic students suffer at school is not limited to reading and spelling, but it includes mathematical aspects
too. The use of assistive technologies may be particularly beneficial to students with learning disabilities. However they
do have application limits preventing them from being utilized to help the study of scientific subjects. This paper introduces
a research idea in this field, which aims to realise a scientific editor which allows for reading and writing mathematics
with the support of a speech synthesizer.
With the present review, we intend to highlight the importance of considering the age- and development-dependent occurrence of comorbidity in ADHD and to outline distinct trajectories of symptom progression with possible impact on course and outcome of ADHD. The review will focus on introducing the concepts of "developmental epidemiology" and "developmental comorbidity". Psychiatric and non-psychiatric age-dependent comorbidity can be seen in the majority of children, adolescents and adults with ADHD, resulting in a severe impairment of everyday life with considerable functional and psychosocial problems. Concerning the temporal order of occurrence, psychiatric conditions may be present before the appearance of first definite ADHD symptoms ("pre-comorbidity", such as temperament factors, sleep disturbance, autism spectrum disorders and atopic eczema). They may coincide with the time when ADHD symptoms reach a clinically significant level ("simultaneous comorbidity": enuresis, encopresis, developmental dyslexia). The majority of comorbidity, however, appears after the onset of ADHD in the course of disease ("post-comorbidity": tic disorder, depression and suicidality, anxiety disorders, obsessive compulsive disorder, bipolar disorder, conduct and substance use disorders, obesity and personality disorders). The aetio-pathophysiology of ADHD and its comorbid disorders and also the nature of comorbidity itself being highly heterogeneous, we additionally discuss possible models of comorbidity. In the future, longitudinal data on distinct patterns of symptom and comorbidity progression would help to refine disease classification systems, strengthen the power of future genetic studies and finally allow for more specific treatment strategies.
We combined independently the word length and word frequency to examine if the difficulty of reading material affects eye movements in readers of German, which has high orthographic regularity, comparing the outcome with previous findings available in other languages. Sixteen carefully selected German-speaking dyslexic children (mean age, 9.5 years) and 16 age-matched controls read aloud four lists, each comprising ten unrelated words. The lists varied orthogonally in word length and word frequency: high-frequency, short; high-frequency, long; low-frequency, short; low-frequency, long. Eye movements were measured using a scanning laser ophthalmoscope (SLO). In dyslexic children, fixation durations and the number of saccades increased both with word length and word frequency. The percentage of regressions was only increased for low-frequency words. Most of these effects were qualitatively similar in the two groups, but stronger in dyslexic children, pointing to a deficient higher-level word processing, especially phonological deficit. The results indicate that reading eye movements in German children are modulated by the degree of difficulty, and orthographic regularity of the language can determine the nature of modulation. The findings suggest that, similar to Italian but unlike English readers, German children prefer indirect sub-lexical strategy of grapheme-phoneme conversion.
Ziel der Studie war die Exploration von Funktionen des Kurzzeitgedächtnisses bei lese-rechtschreibschwachen Kindern (LRS) im Vergleich zu einer schriftsprachlich normal entwickelten Kontrollgruppe (KG). Gedächtnisfunktionen sollten im Hinblick auf Entwicklungsveränderungen über eine Altersspanne von acht bis dreizehn Jahren untersucht werden. Bei einem möglichen Gedächtnisdefizit sollte überprüft werden, ob dieses sich nur bei schriftsprachähnlichem Material äußerte oder ob es sich um ein allgemeineres Defizit handelte. Insgesamt 65 lese-rechtschreibschwache und schriftsprachlich normal entwickelte Kinder der Altersgruppen 8-9 Jahre, 10-11 Jahre und 12-13 Jahre wurden Aufgaben zur Gedächtnisspanne, zur Benennungsgeschwindigkeit und zur Suchrate unterzogen. In den Aufgaben zur Gedächtnisspanne und zur Benennungsgeschwindigkeit zeigten die lese-rechtschreibschwachen Kinder deutlich schlechtere Leistungen als die Kontrollgruppe, und beide untersuchten Gruppen verbesserten sich in ihren Leistungen mit ansteigendem Alter. Hinweise für ein schriftsprachorientiertes Defizit im Falle der Rechtschreibschwachen ließen sich den Aufgaben zur Gedächtnisspanne und zur Suchrate entnehmen. Zusammenfassend bestätigen die vorliegenden Ergebnisse Defizite in Funktionen des Kurzzeitgedächtnisses bei LRS. Über die untersuchte Altersspanne hinweg kam es nicht zu einer Annäherung der Leistungen der Rechtschreibschwachen an die der Kontrollgruppe, was für ein bleibendes Defizit im Fall der LRS spricht. Um zu eindeutigen Ergebnissen hinsichtlich der Schriftsprachabhängigkeit der Gedächtnisdefizite bei LRS kommen zu können, müssen weitere Studien abgewartet werden.
Zusammenfassung Die retrospektive Datenanalyse dreier Gruppen à 20 Kinder im Alter von 8-12 Jahren mit hyperkinetischen Störungen und/oder einer Lese-Rechtschreibstörung der Klinik und Poliklinik für Kinder- und Jugendpsychiatrie und Psychotherapie der Universität Würzburg ergab die nachfolgenden Ergebnisse. Die Ergebnisse der vorliegenden Studie finden sich in der Literatur wieder. Kognitive Fähigkeiten Im kognitiven Bereich fanden sich wenige Unterschiede zwischen den Gruppen. Nachteile ergaben sich aus der Tatsache heraus, dass die Studie retrospektiv durchgeführt wurde und die Fallzahlen daher teils sehr klein waren. Sozial-emotionaler Bereich Für den sozial-emotionalen Bereich fanden sich plausible Ergebnisse. Den Kindern mit einer Aufmerksamkeitsdefizit-/ Hyperaktivitätsstörung (ADHS) waren vermehrt expansive Verhaltensweisen nachzuweisen wie zum Beispiel ein gestörtes Regelverhalten, oppositionelles Verhalten, Aggressivität, Probleme mit Gleichaltrigen, Einzelgängerdasein oder Auffälligkeiten in der Vorschule. Bei den Kindern mit Lese-Rechtschreibstörung fanden sich vielmehr introversive Merkmale wie beispielsweise eine emotionale Störung, ein mangelndes Selbstwertgefühl oder Schulangst. Psychosoziale Situation Die Auswertung des Psychosozialen Bereiches der Kinder mittels Achse V und VI des multiaxialen Klassifikationsschemas für psychische Störungen des Kindes- und Jugendalters ergab eine Belastung der Kinder mit hyperkinetischen Störungen vor allem durch eine abweichende Elternsituation und eine negativ veränderte familiäre Beziehung durch neue Familienmitglieder. Die Kinder mit Lese-Rechtschreibstörung waren besonders betroffen von einer chronischen zwischenmenschlichen Belastung in Zusammenhang mit der Schule sowie von der Herabsetzung der Selbstachtung.
In a recent study on picture naming and word reading in dyslexics and control children we found a combination of normal picture retrieval times and severe reading impairments in dyslexics. Therefore, we hypothesize that brain response patterns differ between patients and controls during word reading, but are similar in picture naming as a non-letter mediated task.
Time course of brain activation was investigated by magnetoencephalography during word reading and picture naming in 9 dyslexic children and 13 age-matched controls (aged 9-10 years).
We found 5 consecutive activations spreading from occipito-parietal to temporo-frontal sites. Group differences occurred only during reading: a delayed response in temporal superior and angular gyri at 235-285 ms and absence of activation in anterior temporal and inferior frontal regions at 430-530 ms for dyslexics.
Problems in phonological processing are reflected in delay of early activity and absence of late activity in language related brain regions. From the lack of group differences during picture naming, we conclude the presence of two pathways: a phonological/orthographic one for word reading, which is disturbed in dyslexics, and a visual one for picture naming, which can be unaffected in dyslexics.
Evidence is provided for different pathways for the processing of letter-mediated and visual-eidetic information. This knowledge may be important for dyslexics in the context of coping with everyday demands and for training of relevant skills.
In this study, we examined the characteristics of reading disability (RD) in the seventh grade of the Greek educational system and the corresponding diagnostic practice. We presented a clinically administered assessment battery, composed of typically employed tasks, and a fully automated, computer-based assessment battery that evaluates some of the same constructs. In all, 261 children ages 12 to 14 were tested. The results of the traditional assessment indicated that RD concerns primarily slow reading and secondarily poor reading and spelling accuracy. This pattern was matched in the domains most attended to in expert student evaluation. Automatic (computer-based) screening for RD in the target age range matched expert judgment in validity and reliability in the absence of a full clinical evaluation. It is proposed that the educational needs of the middle and high school population in Greece will be best served by concentrating on reading and spelling performance--particularly fluency--employing widespread computer-based screening to partially make up for expert-personnel shortage.
This article is concerned with a review of empirical research and own findings on the role of auditory information processing for reading and spelling disability. Reading and spelling disabled children and adults are characterised by deficits in phonological processing and speech perception. The results concerning the perception of non-speech stimuli presented in rapid succession are controversial. For diagnosis and treatment the phonological awareness and speech perception should be regarded as relevant.
Researchers have taken two somewhat different views regarding the nature and development of orthographic and phonological knowledge in spelling and reading. A strongly integrative view holds that development in both areas depends on a common underlying knowledge base. For example, Ehri (1989, 1992) has argued that alphabetic “orthographic images” involved in both reading and spelling are amalgamated with the phonological information pertaining to the word (see also, Barron, 1986; Goswami & Bryant, 1990; Stuart & Coltheart, 1988). A more separatist view is represented in “dual-route” theories that emphasize the independence of two routes to the lexicon; an indirect phonological-decoding route operating through the reader’s knowledge of grapheme-phoneme correspondences, and a direct “visual” route that uses orthographic knowledge to access the lexicon without phonological mediation (Coltheart, 1978; Morton, 1969). The “dual-route” view has been very influential in attempts to account for individual differences in acquired and developmental reading disorders (Boder, 1973; Castles & Coltheart, 1993; Coltheart, Curtis, Atkins, & Haller, 1993; Mitterer, 1982; Patterson, Marshal, & Coltheart, 1985; Seymour, 1986), as well as individual differences across the normal continuum of reading ability (Baron, 1979; Baron & Strawson, 1976; Freebody & Byrne, 1988; Treiman, 1984). In this chapter we selectively review earlier research and present new behavioral-genetic evidence on the degree of developmental independence between disabled readers’ skills in the indirect (phonological) and direct (orthographic) routes for the identification of printed words.
The existence of a phonemic deficit that is predictive of, and probably causal to, many cases of reading difficulty is well established. Tallal (1984) has suggested that this phonemic deficit is in fact a symptom of an underlying auditory temporal processing deficit. Our purpose in this paper is to evaluate the plausibility of this hypothesis. The various components that might constitute sequential (or temporal) processing are described. Our review of the literature reveals considerable evidence for a deficit in dyslexics in stimulus individuation tasks (e.g., gap detection) and temporal order judgments in both the auditory and visual modalities. The possibility that a general temporal processing deficit is associated with dyslexia, as suggested by Tallal (1984), is explored, and possible etiologies for such a deficit are discussed. The possibility of a causal link between temporal processing deficits and some reading disabilities is demonstrated, and converging evidence from morphological studies is reviewed. It is concluded that a temporal processing deficit does appear to be present in many developmental dyslexics, and strategies are suggested for further research aimed at evaluating the hypothesis that this deficit may be the root cause of a number of cases of dyslexia itself.
Zusammenfassung: Die Lese-Rechtschreibstörung (LRS) ist eine der häufigsten Entwicklungsstörungen. Die Ursachen dieser komplexen Störung sind bisher nur kaum verstanden. Familienuntersuchungen zeigen, dass die LRS familiär gehäuft auftritt und dass das Risiko für ein Geschwisterkind, eine LRS zu entwickeln, ca. 3,5fach erhöht ist. Verschiedene kognitive Fähigkeiten sind mit der LRS korreliert. Hierzu gehören die phonologische Bewusstheit, orthographisches Wissen, phonologisches Dekodieren, auditives Kurzzeitgedächtnis und schnelles Benennen. Eine familiäre Häufung dieser mit der LRS korrelierten Dimensionen und eine hohe Erblichkeit (Heritabilität) wurden wiederholt gefunden. Die Heritabilität für die Lesefähigkeit liegt zwischen 50-60%, für die Rechtschreibstörung zwischen 50 und 70%. Durch genomweite Kopplungsuntersuchungen wurden bisher 9 Kandidatengenregionen (DYX1-9) identifiziert. Vier Kandidatengene, DCDC2, KIAA0319, ROBO1 und DYX1C1 wurden kürzlich beschrieben. Diese beeinflussen die neuronale Migration und sind daher funktionell aussichtsreiche Kandidatengene für die LRS. Allerdings konnte bisher keine funktionell relevante Mutation gefunden werden. Die Komorbidität zwischen LRS und ADHD sowie LRS und Sprachentwicklungsstörungen könnte zum Teil durch gemeinsame genetische Faktoren erklärt werden. In der Zukunft wird es für die Ursachenforschung der LRS entscheidend sein, möglichst alle ursachenrelevanten Dimensionen gemeinsam an ausreichend großen Stichproben zu untersuchen. Neben den relevanten neurobiologischen Faktoren sollten auch Umweltfaktoren und die verschiedenen Interaktionen, wie z.B. Gen-Umwelt und Gen-Gen-Interaktionen untersucht werden. In einem europäischen, kollaborativen Forschungsvorhaben (NeuroDys) wird weltweit die größte Stichprobe von Kindern mit einer LRS gesammelt und untersucht, um durch ein verbessertes Ursachenverständnis unter Einschluss der Identifikation von genetischen Risikofaktoren die Komplexität des Störungsbildes besser zu verstehen und perspektivisch spezifische Therapien zu entwickeln.
In this paper we present evidence supporting the hypothesis that a basic temporal processing impairment in language-impaired children underlies their inability to integrate sensory information that converges in rapid succession in the central nervous system. We provide data showing that this deficit is pansensory; that is, affects processing in multiple sensory modalities, and also affects motor output within the millisecond time frame. We also provide data that links these basic temporal integration deficits to specific patterns of speech perception and speech production deficits in language-impaired children. We suggest that these basic temporal deficits cause a cascade of effects starting with disruption of the normal development of an otherwise effective and efficient phonological system. We propose further that these phonological processing deficits result in subsequent failure to learn to speak and to read normally. That is, both the language and reading problems have their basis in deficiently established phonological processing and decoding. Finally we use data derived from our ongoing behavioral studies with language-impaired children to address some fundamental issues pertaining to the neurobiological basis of speech perception and production (e.g., hemispheric specialization) underlying these processes. We suggest that results from magnetic resonance imaging (MRI) and positron emission tomography (PET) studies, as well as studies of behavioral performance in normal adults and adults with acquired lesions, combined with more recent results from animal studies, all support the view that a left-hemispheric specialization for speech initially developed through evolution as a specialization for processing and producing sensory and motor events that occur in rapid succession.
This paper reports a research which examined the relationship between dyslexia and eye movement control in Spanish speaking children. The study compared the eye movements recordings of 30 dyslexic, 30 retarded and 30 normal readers, aged between 7 and 14, in one ocular tracking task and two reading tasks which differed in their degree of reading difficulty. Within each group the subjects were divided into 3 subgroups of 10 in accordance with the following chronological ages: 7–9, 10–11 and 12 years and above. Dependent variables were saccadics (number, size and fixation pause), regressives (number, size and fixation pause), total number of movements and percentage of regressives over the total number of movements. The following results were obtained: (1) In the two reading tasks significant differences were found between dyslexic and normal readers and between retarded and normal readers in most of the parameters, no differences being found between dyslexic and retarded readers except in a few parameters; (2) in the ocular tracking task significant differences both between dyslexic and normal readers and between dyslexic and retarded readers were found in all dependent variables, no differences being found between retarded and normal readers at all, and (3) the age factor produced a significant main effect in the two reading tasks indicating a general improvement of eye movements as age increases but an interaction effect with reading disability in the ocular tracking task-indicating a deterioration in eye movements in the dyslexic group as a function of age-was also found. The results are discussed in the context of alternative theoretical explanations of developmental dyslexia.
To address the question of a possible magnocellular visual deficit in children with reading problems (dyslexia), we examined
pattern ERG and VEP responses to stimulation with checks of 24′, 49′ and 180′ in size and of 5%, 42% and 100% contrast level.
Neurophysiological difference between children with reading problems and those without them was found confined to VEP which
showed a significant prolongation of P100 wave in dyslexic children at highest contrast (100%) and smallest checks (24′).
Pattern ERG was normal. These results support the assumption of a visual deficit in dyslexic children. However, they are not
consistent with an isolated deficit of the magnocellular function, which, theoretically, would cause VEP changes to lower
contrast and largest check stimuli.
In order to investigate the relationship between dyslexia and central auditory processing, 19 children with spelling disability and 15 controls at grades 5 and 6 were examined using a passive oddball paradigm. Mismatch negativity (MMN) was determined for tone and speech stimuli. While there were no group differences for the tone stimuli, we found a significantly attenuated MMN in the dyslexic group for the speech stimuli. This finding leads to the conclusion that dyslexics have a specific speech processing deficit at the sensory level which could be used to identify children at risk at an early age.
There exist many theories of the evolution of language, and many were produced in the 19th Century. These theories tried to account for the production of language. They all lead to a paradox. If a mutation occurred which made a man capable of speech, he would have no language to speak nor anyone to understand him. If a mutation made a man capable of comprehension what language would he learn and who would speak it? The possibility of simultaneous mutations in two men in contact seems highly unlikely. More recent theories which stress the origin of language through gesture face exactly the same paradox.
In attempting to gain a better understanding of the pathogenesis of developmental dysphasia, research has focused on the associated characteristics of language-disordered children. These studies initially focused on the most obvious surface symptomatology, that is the linguistic dysfunction of these children. Subsequent studies have focused on nonlinguistic characteristics which commonly are associated with or accompany the language disorder, such as neuropsychological (perceptual, motor, memory, cognitive) dysfunction or social and emotional disturbance.
Mit der vorliegenden Trainingsstudie wird der Versuch unternommen, Ergebni e eines Förderprograrnms zur sprachlichen Bewußtheit (Lundberg, Frost & Petersen 1988) im deutschsprachigen Raum zu validieren. An unserer Replikationsstudie nahmen insgesamt 371 Kinder teil, von denen 205 Kinder einer Trainingsgruppe und 166 Kinder einer Kontrollgruppe zugewiesen wurden. Das Förderprograrnm bestand aus Sprachspielen, die über einen Zeitraum von zirka 6 Monaten täglich 15 Minuten in den Kindergartengruppen durchgeführt wurden. Die Kontrollgruppe erhielt keine spezielle Förderung, sondern nahm am regulären Kindergartenprogramm teil. Indikatoren der sprachlichen Bewußtheit und weitere metalinguistische und kognitive Variablen wurden unmittelbar vor und nach der Förderung erhoben. Zu Beginn des ersten Schuljahres wurde ein metalinguistischer Transfertest, gegen Ende dann ein Rechtschreibtest durchgeführt. Die Befunde replizieren die Ergebnisse der dänischen Ausgangsstudie insofern, als kurz- und langfristige Trainingseffekte gesichert werden konnten. Sie verdeutlichen jedoch zusätzlich, daß die Qualität der Förderung für die Langzeitwirkung entscheidend war.
Twenty years ago, ocular disturbances (hyperopia, exophoria, weakness of convergence) were discussed as a possible cause of developmental dyslexia. Recently disturbances in the cerebral areas of the visual pathway and of the visual center have been suggested. Nevertheless, the correction of refractive errors and the treatment of ocular motility disorders have shown significant positive effects. Reading material must be produced in high-quality print and dyslectic pupils should be given additional time in school tests. Finally, therapies without scientifically verified effectiveness are discussed.
The role of eye movement control in dyslexia has been controversially discussed during the past. Recent studies, however, have shown that many dyslexics show poor saccadic control in sequential and single target tasks. In normally reading children the ability to suppress reflexive eye movements to a suddenly appearing visual stimulus and to generate voluntary saccades instead, strongly develops during school age. In the present study, we investigated whether the poor saccadic performance observed in dyslexic subjects could be related to a deficit in the voluntary control of saccade generation. 108 subjects aged between 8 and 18 years were classified into two age-matched sub-groups of dyslexics and andage-matched control group. All subjects performed an overlap standard (pro) and a gap anti-saccade task with 100 trials to each side in random order. The results show that saccadic control improves with age both in control and dyslexic subjects in a parallel manner, with the dyslexics remaining worse in the anti-task: they have great difficulties in suppressing reflexive saccades to the suddenly presented stimulus. In the standard overlap task, as compared to control subjects, their saccadic reaction times (SRT) scatter more and they make a significantly higher number of anticipatory saccades (SRT < 80 ms). All other variables in the anti-task did not differentiate between dyslexics and control subjects as a group. This saccadic performance is similar to that observed in patients with prefrontal lesions and, in particular, in ADHD children, where it has been interpreted as a disruption of fixation controllmechanisms. The abnormal saccadic behaviour in dyslexics could be alternatively explained either by a general frontal or parietal problem in saccadic triggering or by an erroneous visual-attentional strategy induced to cope the visual processing problems dyslexics experience during reading. In any case, it is necessary to improve impaired eye movement control. This is possible today by daily practice of specified visual tasks requiring almost perfect fixation and/or saccade control.
Genetic factors contribute significantly to developmental dyslexia. A gene locus on chromosome 15 has been identified in some families. These families show an autosomal dominant inheritance with incomplete penetrance.
The predictive contribution of phonological skills at school entry to reading and spelling performance at the end of Grade 1 was examined with a sample of about 560 boys. The main concern was the coincidence between poor phonological skills and later problems in reading or spelling. Various analyses consistently indicated a rather feeble association between phonological skills and literacy achievement. Most of the children with poor phonological skills were able to read and to spell within the normal range at the end of Grade 1. As a possible reason for the low predictive value of phonological skills in the present study the early assessment of reading and spelling along with a very slowly progressing phonologically oriented instruction is discussed.
Objective.
—There is strong evidence that developmental dyslexia is both familial and heritable, but the mode of genetic transmission has remained unclear. In this article, we examine specific genetic hypotheses about the mode of transmission of developmental dyslexia by performing complex segregation analyses.Design.
—A family study method was applied, whereby the relatives of dyslexic probands were examined for dyslexia. The families studied represent four independently ascertained samples.Setting.
—The four samples of families were primarily from rural and suburban communities of Colorado, Washington State, and Iowa.Participants.
— A total of 204 families and 1698 individuals in the four samples combined.
Main Outcome Measures.
—The complex segregation program, POINTER, was used to test competing genetic hypotheses of how a categorical trait (dyslexia) is transmitted in families.Results.
—The results were consistent with major locus transmission in three of four samples and with polygenic transmission in the fourth. In these three samples, the estimates of penetrance for the AA, Aa, and aa genotypes (where A is the abnormal allele) were, respectively, 1.000, 1.000, and 0.001 to 0.039 in males, and 0.560 to 1.000, 0.550 to 0.897, and 0.000 in females. The estimated gene frequency of the major locus was between 3% and 5%.Conclusions.
—Sex-influenced, additive, or dominant transmission occurs in a significant proportion of dyslexic families. Other evidence indicates, however, that dyslexia is etiologically heterogeneous and that there is genetic heterogeneity even among families selected for apparent dominant transmission. Thus, while no single major locus may account for all of dyslexia, it is important to pursue potential major loci for dyslexia using linkage techniques.(JAMA. 1991;266:1527-1534)
Eight brains, six male and two female, of reliably diagnosed cases of developmental dyslexia have been analyzed in this laboratory thus far. Common to all the specimens is the absence of ordinary asymmetry in the planum temporale, a language relevant area of the temporal lobe. In addition, the male cases and one female case displayed multiple focal areas of malformation of the cerebral cortex, located variably in the language relevant perisylvian regions and to a greater or lesser extent bilaterally. Both female cases and, to a mild degree, one of the males display focal areas of cortical scarring dated to the end of pregnancy through to the end of the second year of life at the latest. The scarring tends to be located in the vascular watershed territories.
Experimental animal research suggests that symmetry may represent absence of the necessary developmental pruning of neural networks required for specific functions such as language. This diminished pruning results in excessive neurons and (at least interhemispheric) connections.
Additional modeling in experimental animals suggests that cortical malformations and scarring similar to those seen in the dyslexic brains may represent early focal injury that could be attributed to congenital disorders of the immune system.
The purpose of this study was to determine the reliability and validity of tests that have been used to operationalize the concept of phonemic awareness. Ninety-six kindergarten children were given 10 tests of phonemic awareness and a test of the rate at which they learned to decode novel words. The reliability, validity, and relative difficulty of each test were determined. A principal factor analysis with oblique rotation revealed that two highly related factors underlie phonemic awareness tests. A multiple regression analysis indicated that a combination of two tests, one related to each factor, has greater predictive validity for the beginning steps in reading acquisition than does any test alone. /// [French] Cette recherche avait pour but de vérifier la fidélité et la validité de tests utilisés pour opérationnaliser le concept de conscience phonémique. L'auteur a fait subir à 96 enfants de maternelle 10 tests de conscience phonémique et un test pour évaluer leur rapidité de décodage de mots nouveaux. La fidélité, la validité et la difficulté relative de chaque test ont ensuite été évaluées. Une analyse factorielle principale avec rotation oblique a révélé que les tests de conscience phonémique s'appuient sur deux facteurs étroitement reliés. L'analyse de régression multiple a par ailleurs, indiqué, qu'une combinaison deux à deux de deux tests, présente une plus grande validité prédictive des premières étapes de l'apprentissage de la lecture que chaque test pris isolément. /// [Spanish] El propósito de este estudio fue determinar la confiabilidad y validez de los tests que han sido usados para definir operacionalmente el concepto de alerta fonémica (phonemic awareness). A 96 niños de jardín se les administraron 10 tests de alerta fonémica y un test de la velocidad a la que aprendían a decodificar palabras nuevas. Se determinó la confiabilidad, validez y dificultad relativa de cada test. Un análisis factorial principal con rotación oblicua reveló que hay dos factores altamente relacionados que subyacen a los tests de alerta fonémica. Un análisis de regresión múltiple indicó que una combinación de dos tests, uno relacionado con cada factor, tiene mayor validez predictiva para los pasos iniciales en la adquisición de la lectura que cualquier test por sí solo. /// [German] Der zweck dieser Studie war, die Verläßlichkeit und Gültigkeit von Tests festzulegen, welche benutzt wurden, das Konzept phonemischer Erkenntnis einzusetzen. Neunundsechzig Fünfjährige wurden 10 phonemische Erkenntnis-Tests gegeben und ein Test auf die Schnelligkeit hin, mit der sie lernten, neue Wörter zu entschlüsseln. Die Verläßlichkeit, Gültigkeit und verhältnismäßige Schwierigkeit von jedem Test wurden festgelegt. Eine Hauptfaktor-Analyse mit versteckter Rotation zeigte, daß zwei stark verbundene Faktoren phonemischen Erkenntnis-Tests zugrundeliegen. Eine Mehrfach-Regressions-Analyse zeigte auf, daß die Kombination von zwei Tests, jeweils auf einen der beiden Faktoren eingehend, eine bessere Voraussage-Gültigkeit für die Anfangsschritte beim Lesen hat als jeder Test für sich allein.
This study examined whether the characteristic reading speed impairment of German dyslexic children results from a general skill-automatization deficit sensu Nicolson and Fawcett (1990) or from more specific deficits in visual naming speed and phonological skills. The hypothesized skill-automatization deficit was assessed by balancing, peg moving, and visual search. Rapid "automatized" naming tasks served as measures of impaired visual naming speed, and the phonological deficit was assessed by speech perception, phonological sensitivity, and phonological memory tasks. Dyslexic German children and age-matched control children (all boys) were tested at the end of Grade 2 and as participants of a longitudinal study also at the beginning of Grade 1. No evidence for a skill-automatization deficit was found, as the dyslexic children did not differ at all on the balancing tasks and little on the other nonverbal skill tasks. However, the dyslexic children showed impaired visual naming speed and impaired phonological memory performance that were observed not only in Grade 2 but also before learning to read. Overall, the findings support the conclusion that, even in regular orthographies, difficulties in learning to read are due to a phonological deficit and not to a general skill-automatization deficit.
A comprehensive cognitive appraisal of elementary school children with learning disabilities showed that within the language sphere, deficits associated with reading disability are selective Phonological deficits consistently accompany reading problems whether they occur in relatively pure form or in the presence of coexisting attention deficit or arithmetic disability Although reading-disabled children were also deficient in production of morphologically related forms, this difficulty stemmed in large part from the same weakness in the phonological component that underlies reading disability In contrast, tests of syntactic knowledge did not distinguish reading-disabled children from those with other cognitive disabilities, nor from normal children after covarying for intelligence
This report summarizes a few of the main findings from a programme of inter related educational and psychiatric studies of school age children on the Isle of Wight. The appended bibliography gives details of all published books and papers on the project. However, the main findings of the series of investigations reported here are being brought together in three books currently in preparation. One summarizes the reading studies, one the adolescent social and psychiatric studies and the third describes the Isle of Wight-London comparative studies.
It has long been recognized that there are certain children who have a more or less selective difficulty in learning to read. The earlier observers of this condition, among them Berkhan,1 in 1885, apparently assumed that it was related to a general mental defect and described such cases as partial imbeciles (halbidiote). A more or less complete inability to learn to read, particularly when it is associated as it often is with atrocious handwriting and poor spelling, naturally enough would incline the uncritical observer to assume that the child was, if not truly defective, at least not as bright as he should be to accomplish his school tasks. Very often the logic of this explanation forms a typical vicious circle. The child is said to be feebleminded because he cannot learn to read, and his inability to learn to read is said to be because he is feebleminded. Gradually,
describe the converging evidence from psychophysical and physiological investigations showing that a large proportion of disabled readers are deficient in transient visual processing / referring to studies of visual masking, they report that the nature of the deficit involves the time course of visual processing; the transient system of disabled readers responds less efficiently than that of normal readers, resulting in a less effective pattern of inhibition of the sustained visual channel response / outline recent studies indicating that temporal aspects of transient system functioning can be affected by the physical properties of the text—namely wavelength / [suggest] that a normal pattern of visual processing in disabled readers can be reestablished depending on the wavelength properties of text (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The consistency of reports of an association between reading disability and various problem behaviours both over time and across different types of samples suggests that the relationship is robust. What is not clear is the nature of the relationship or 'what leads to what.' However, this is an important question because of its implications for intervention.
This chapter first reviews findings from longitudinal studies of reading and behavior and reading disabilities and juvenile delinquency. The authors then summarise the results of a longitudinal analysis of data from the Dunedin (New Zealand) multidisciplinary health and development study on the association between reading disability and problem behaviour in boys and girls from age 5 to 11 yrs. They also report the results of a follow-up of reading-disabled boys and girls at age 13, with an emphasis on juvenile delinquency and attitudes to schooling and education.
The evidence from the Dunedin study suggest a long-term association between reading disability and behaviour problems in both boys and girls. Furthermore, the results are consistent with the hypothesis that the behaviour problems of most of the reading-disabled children arose as a consequence of a failure to learn to read rather than vice-versa. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Results from a longitudinal correlational study of 244 children from kindergarten through 2nd grade indicate that young children's phonological processing abilities are well-described by 5 correlated latent abilities: phonological analysis, phonological synthesis, phonological coding in working memory, isolated naming, and serial naming. These abilities are characterized by different developmental rates and remarkably stable individual differences. Decoding did not exert a causal influence on subsequent phonological processing abilities, but letter-name knowledge did. Causal relations between phonological processing abilities and reading-related knowledge are bidirectional: Phonological processing abilities exert strong causal influences on word decoding; letter-name knowledge exerts a more modest causal influence on subsequent phonological processing abilities. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Data from two studies on large samples of 7-, 11- and 13-year-old children were used to estimate the regression relationship between reading, spelling and maths achievement and IQ. Using these regression equations the number of children obtaining achievement scores more than two standard deviations below that expected were identified. It was found that there was a significant excess of underachievers for reading and spelling at 11 years but not for maths. This ‘hump’ was also found for the reading of non-words. It was concluded that the issue of whether such a ‘hump’ can be found is only a minor facet of the debate about the nature of reading failure, and that more direct studies of the processing of written text are likely to prove more decisive.
In an attempt to delineate causal factors in dyslexia, 113 children and young adults (age‐range eight to 18 years) were divided into three groups: those with brain damage who could read (n = 31), those with brain damage who were dyslexic (n = 53), and those without brain damage who were dyslexic (n = 29). A battery of neuropsychological tests was presented to each participant.
No significant differences were found between the two dyslexic groups. Three syndromes ‐language disorder, articulation and graphomotor dysco‐ordination, and visuo‐perceptual disorder—were found among the great majority of those with dyslexia. The results support a model of dyslexia as being caused by multiple independent defects in higher cortical functioning, as opposed to the theory of a single causal defect. A clinical description of each syndrome is given and models of dyslexia are discussed. The authors stress the desirability of including brain‐damaged readers as a control group in any future study on causal factors in dyslexia.
RÉSUMÉ
Dyslexie chez les enfants et les adolescents: trois syndromes neuropsychologiques indépendants
Dans le but de déterminer les facteurs en cause dans la dyslexie, 113 enfants et adolescents (ágés de 8 à 18 ans) ont été divises en trois groupes: ceux qui pouvaient lire malgré une lésion cérébrale (n = 31), ceux qui présentaient une lésion cérébrale et une dyslexie (n = 53) et ceux qui sans lésion cérébrale avaient une dyslexie (n 29). Une batterie de tests neuropsychologiques ont été proposes a chaque sujet.
Aucune différence significative n'a été trouvée entre les deux groupes dyslexiques. Trois syndromes: troubles du langage, incoordination de l'articulation et de la graphomotricité, et troubles visuo‐perceptif ont été notés chez la grande majorité des dyslexiques. Ces résultats sont en faveur d'une conception de la dyslexie causée par de multiples facteurs indépendants dans le fonctionnement cortical haut et non d'une conception d'une cause unique. Une description clinique de chaque syndrome est donnée et des modèles de dyslexie sont discutés. Les auteurs insistent sur la nécessité d'inclure des lecteurs atteints de troubles cérébraux comme groupe contrôle dans toute étude ultérieure sur les facteurs en cause dans la dyslexie.
ZUSAMMENFASSUNG
Leseschwäche bei Kindern und Heraimachsenden: drei unabhängige neuropsychologische Syndrome
Um die Kausalfaktoren der Dyslexie zu beschreiben, wurden 113 Kinder und Heran‐wachsende (Alter 8–18 Jahre) in der Untersuchung in drei Gruppen geteilt: solche mit Hirnschaden, die aber lesen konnten (n = 31), solche mit Hirnschaden und Dyslexie (n = 53) und solche ohne Hirnschaden mit Dyslexie (n = 29). Jeder Versuchsteilnehmer wurde einer Reihe neuropsychologischer Tests unterzogen.
Zwischen den leseschwachen Gruppen fand sich keine signifikante Differenz. Bei der großen Mehrheit derer mit Dyslexie fanden sich drei Symtome—Sprachstörungen, Artikulations‐ und graphomotorische Dyskoordination und visuell‐perzeptive Störungen. Die Ergebnisse unterstützen eine Modellvorstellung der Dyslexie, die sie durch multiple voneinander unabhängige Defekte höherer corticaler Funktionen verursacht ansieht, im Gegensatz zu der Theorie eines einzelnen kausalen Defekts. Es wird eine klinische Beschreibung eines jeden Syndroms gegeben und Modelle der Dyslexie werden diskutiert. Die Autoren betonen, daß es wünschenswert ist bei jeder weiteren Studie über Kausalfaktoren der Dyslexie Hirngeschädigte, die lesen können, als eine Kontrollgruppe mit einzubeziehen.
RESUMEN
Dislexia en ninos y jóvenes adultos: Tres sindromes neuropsicológicos independientes
En un intento de delinear los factores causales en la dislexia, 113 niños y adultos jóvenes (de edad entre 8 y 18 años) fueron divididos en tres grupos: Unos con lesión cerebral y que podian leer (n = 31), otros con lesión cerebral pero que eran disléxicos (n = 53) y otros sin lesión cerebral y que eran disléxicos (n = 29). A cada participante se le presentó una bateria de tests neuropsicológicos.
No se halló ninguna diferencia significativa entre los dos grupos disléxicos. Tres sindromes (alteración en el lenguaje, discoordinación de la articulacion y grafomotora y alteracion visuo‐perceptiva) fueron hallados en la gran mayoria de los que padecian dislexia. Los resultados apoyan la idea de que la dislexia está causada por mûltiples defectos independientes de las funciones corticales superiores, en oposición a la teoría de un único defecto causal. Se da una descripción clinica de cada sindrome y se discuten los modelos de dislexia. Los autores subrayan el deseo de incluir a los lectores con lesión cerebral como un grupo control en estudios futuros que se hagan sobre los factores causales de la dislexia.
This study examined the familial aggregation of spelling disability in a sample of 32 German school-aged children and their relatives. The influence of two different diagnostic criteria (low-achievement criterion, and regression-based IQ-discrepancy criterion) on the rate of affectedness was investigated. Results revealed that 52.3-61.9% of the sibs and 26-34% of the parents were spelling disabled. Little evidence was found for an influence of the diagnostic criterion on the rate of affectedness.
Genetic influences on reading are investigated in a sample of 285, 13 year old twins. Using a multiple regression procedure, the heritability of disability (h
g2) for Reading Recognition was found to be non-significant. However the h
g2 for spelling disability was found to be 0.58 (P<0.05), after controlling for individual differences in IQ. The twins in this study were an unselected sample from the general population. Therefore it was possible to estimate h
g2 for differing degrees of severity of disability. These analyses showed that for spelling but not for Reading Recognition or Reading Composite, there were substantial genetic contributions to all levels of disability. For indices of Orthographic Coding there were no significant values of h
g2. In contrast measures of Phonological Coding and Homophone Recognition have consistently high values of h
g2. More detailed analyses suggested that there were possibly two independent aspects of phonological ability, each influenced by genetic factors.
This paper reports on a longitudinal study dealing with the development of literacy in young children. A total of 163 children
were first tested during their last year in kindergarten using a variety of tasks that tapped phonological processing, memory
capacity, early literacy, and intelligence. Children’s word decoding, reading comprehension, and spelling skills were assessed
in elementary school several years later. As a main result, all of the predictor domains had a significant impact on the acquisition
of literacy in elementary school, although the contribution of each domain differed as a function of the criterion measure.
An attempt to identify children-at-risk using a kindergarten screening test provided encouraging results. Nonetheless, it
was shown that whereas group predictions of reading and spelling performance can be quite accurate, the individual prognosis
of school problems is far from perfect.
This special issue grew out of the XVI International Rodin Remediation Scientific Conference held in Boulder, Colorado in
September, 1990 which was devoted to the topic of genetic and neurological influences on dyslexia, or reading disability (RD).
This conference would not have been possible without the vision and generosity of Per Udden and the Rodin Remediation Foundation,
who have been unique catalysts in fostering an interdisciplinary understanding of dyslexia or RD.
The hypothesis that in developmental dyslexia the integration of visually presented information and language processing is dysfunctional is tested. Results of processing visually presented letter strings during EEG recordings are presented. The task difficulty of the letter strings was standardised individually and automatically by a computer program. EEG was recorded during rest conditions and different levels of reading performance. 30 developmental dyslexic boys who met the Denckla criteria of "dyslexia pure" and 28 matched control subjects were investigated. The main replicated results were: (1) There was a delay in dyslexic children in processing visually presented letter information, (2) there was no deficit in sustained attention in developmental dyslexics, (3) increasing cognitive activation and reading performance resulted in a faster attenuation of relative alpha power in dyslexics compared to controls, and (4) the dyslexic group did not reveal characteristic focal EEG features when task difficulty was standardised individually.
The basic multiple regression model for the analysis of selected twin data (DeFries and Fulker 1985, 1988) was fitted to spelling data from 100 pairs of MZ twins and 71 pairs of same-sex DZ twins tested in the Colorado Reading Project (DeFries, Olson, Pennington and Smith 1991), and to data from 12 pairs of MZ twins and 15 pairs of same-sex DZ twins tested in the London twin study of reading disability (Stevenson, Graham, Fredman and McLoughlin 1984, 1987). Estimates of h
g
2
obtained from analyses of these data suggest that about 60% of the deficit of probands is due to heritable influences in both samples. When a regression model was fitted separately to data from males and females in the combined Colorado and London samples, resulting estimates of h
g
2
were 0.660.18 and 0.560.19, respectively, a nonsignificant difference. Collaborative analyses of data from additional twin studies of reading disability would facilitate more rigorous tests of hypotheses of differential genetic etiology as a function of group membership.
Pattern reversal visually evoked potentials were examined in a group of 16 boys with developmental dyslexia and 17 controls matched for sex, age and intelligence. Delineation of hypothesis was done with an independent pilot study. Wave form differences between groups could be observed over the left central lead in the pilot and replication study. Only 44% of the dyslexies showed a negative component between 110 and 215 ms after stimulus onset in comparison to more than 80% of the controls. The lack of this component was most prominent in dyslexies whose spelling scores were more than 1.5 standard deviations below their intelligence score.
Genetic linkage analysis is a means of localizing genes to specific chromosomal regions. Localization of genes influencing specific reading disability (dyslexia) can lead to characterization of the phenotypic effects of each gene and to early diagnosis of children at risk. Previous studies using the family study LOD score method of linkage analysis have identified two chromosomal regions that may contain genes influencing dyslexia. The present study examines the sib pair method of linkage analysis, which has several advantages over the LOD score method. In particular, the mode of inheritance does not need to be specified and diagnosis of parents is not required, but it is a less powerful technique. Using the same population as the previous studies (with less than 200 sib pairs) and two different means of diagnosis of dyslexia, the sib pair analysis was able to detect the same suggested linkages as the LOD score method, plus a possible third region. This confirms that the sib pair method is an effective means of screening for linkage with reasonable sample sizes.