Neuropsychological treatment of dyslexia in the classroom setting

The purpose of this study was to validate Bakker's (1990, 1992) clinical neuropsychological balance model of dyslexia when implemented in a traditional general education classroom environment. The sample included 45 middle school, right-handed boys and girls (mean age = 12.78) with L-type dyslexia (excessively fast readers who make substantive reading errors), P-type dyslexia (displaying accurate but slow and laborious reading), and M-type dyslexia (readers who commit a combination of L-type and P-type dyslexia errors). The experimental groups (L and P type dyslexia) were presented with hemisphere specific stimulation (HSS) and hemispheric alluding stimuli (HAS). HSS involves the presentation of words into the right visual field (RVF) or the left visual field (LVF) or through tactile exercises with the right or left hand. HAS is achieved by constructing semantically and phonetically challenging letters and words. The children with M-type dyslexia served as a control group and received traditional decoding and comprehension exercises. The readers were exposed to a specific treatment model for 16 weeks, depending on their reading accuracy and comprehension. Statistical analyses indicated that, although there were no significant changes in word recognition for the dyslexia subtypes, the readers with L-type, P-type, and M-type dyslexia exhibited significant improvement in reading accuracy and comprehension as assessed by results from pretest to posttest. These results suggest that Bakker's clinical neuropsychological intervention can be effectively applied to the general education setting as well.     

Hemisphere-specific treatment of dyslexia subtypes: a field experiment

Evidence is discussed to show that so-called L- and P-type dyslexia result from deviations in the development of hemispheric subservience in learning to read. Investigations into the validity of the L/P classification are reviewed, as are laboratory experiments on the effects of so-called hemisphere-specific stimulation (HSS). In the present field experiment, 28 L-dyslexic children (mean chronological and reading age 10.6 and 7.5 years, respectively) received HSS of the right hemisphere by the presentation of words to the fingers of the left hand, and 26 P-dyslexic children (mean chronological and reading age 9.4 and 7.2 years, respectively) received HSS of the left hemisphere by the presentation of words to the fingers of the right hand. Control L and P subjects were treated according to the discretion of the remedial teacher. The results underscore the findings of previous laboratory experiments in that (a) HSS-treated L-dyslexics, relative to controls, tended to show larger improvement of accuracy in text reading; and (b) HSS-treated P-dyslexics, relative to controls, showed larger improvement of fluency in word reading.     

Learning strategies and study approaches of postsecondary students with dyslexia

The present study describes the self-reported learning strategies and study approaches of college and university students with and without dyslexia and examines the relationship of those characteristics with reading ability. Students with (n = 36) and without (n = 66) dyslexia completed tests measuring reading rate, reading comprehension, reading history, learning strategies, and learning approaches. The results indicated that students without dyslexia obtained significantly higher scores than students with dyslexia in their reported use of selecting main ideas and test taking strategies. Students with dyslexia reported significantly greater use of study aids and time management strategies in comparison to students without dyslexia. Moreover, university students with dyslexia were significantly more likely to report a deep approach to learning in comparison to university students without dyslexia. Reading ability correlated positively with selecting main ideas and test taking strategies and negatively with use of study aids. The authors interpret the learning strategy results as consequences of and compensations for the difficulties that students with dyslexia have in word reading.     

The balance model of dyslexia and remedial training: an evaluative study

The aim of this study was to test the validity of Bakker's (1983, 1990) theory and treatment paradigm of dyslexia. Twenty-one children (mean age = 9.9 years) categorized as P-type dyslexics (showing accurate but slow and fragmented reading) and 19 children (mean age = 9.7 years) categorized as L-type dyslexics (fast but inaccurate readers) were presented with hemisphere-specific stimulation (HSS) and hemisphere-alluding stimulation (HAS). HSS was produced by presenting words to either the left or the right visual half-field, or to the left or right hand of the participant. HAS training was achieved through the presentation of either semantically/phonetically demanding or perceptually demanding text. Participants were given either a treatment program that was specifically designed for their particular dyslexia subtype, or a program that had been deliberately chosen to be inconsistent with their subtype. Contrary to predictions, participants made gains on all of the reading measures, regardless of the type of treatment given. On the basis of these findings it is suggested that treatment gains made are due to nonspecific training effects and not to the specific nature of Bakker's remedial strategies.     

Visual stress in adults with and without dyslexia

The relationship between dyslexia and visual stress (sometimes known as Meares‐Irlen syndrome) is uncertain. While some theorists have hypothesised an aetiological link between the two conditions, mediated by the magnocellular visual system, at the present time the predominant theories of dyslexia and visual stress see them as distinct, unrelated conditions, a view that has received some support from studies with children. Studies of visual stress in adults are rare, yet recent reports of a high incidence of this phenomenon amongst university students with diagnosed dyslexia call for further investigation of the issue. This study sought to clarify the relationship between visual stress and dyslexia by comparing the reading performance of dyslexic and non‐dyslexic adults with, and without, colour. Degree of susceptibility to visual stress was determined by means of a symptom rating scale. Optimal colour was determined using an Intuitive Colorimeter, which was also employed to assess reading speed under the two experimental conditions. Only the dyslexic students with high visual stress showed significant gains in reading speed when using optimal colour. The use of response to treatment (rather than symptomatology) as a diagnostic criterion for visual stress is questioned, especially when applied to adults, as this may give misleading findings. On the basis of reported symptomatology, students who experience high levels of visual stress are more likely to show improvements in reading rate with optimal colour if they also have dyslexia than if they do not have dyslexia. Although not establishing an aetiological link, these findings imply an interaction between the two conditions with major implications for theory, diagnosis and treatment.     

Sound-symbol learning in children with dyslexia

This study evaluated the effect of sound-symbol association training on visual and phonological memory in children with a history of dyslexia. Pretests of phonological and visual memory, a sound-symbol training procedure, and phonological and visual memory posttests were administered to children with dyslexia, to children whose dyslexia had been compensated through remedial training, and to age- and reading level-matched comparison groups. Deficits in visual and phonological memory and memory for sound-symbol associations were demonstrated in the dyslexia group. For children with dyslexia and children whose dyslexia had been remediated, the sound-symbol training scores were significantly associated with word and pseudoword reading scores and were significantly lower than those of the comparison groups. Children with dyslexia and children whose dyslexia had been compensated showed significantly less facilitation of phonological memory following the training than did typical readers. Skilled readers showed some reduction in accuracy of visual memory following the training, which may be the result of interference of verbalization with a predominantly visual task. A parallel decrease was not observed in the children with dyslexia, possibly because these children did not use the verbal cues. Children with dyslexia and children whose dyslexia had been compensated seemed to have difficulty encoding the novel sounds in memory. As a result, they derived less phonological memory advantage and less visual memory interference from the training than did typical readers. Children in the compensated dyslexia group scored lower on sound-symbol training than their age peers. In other respects, the scores of these children were equivalent to those of the typically reading comparison groups. Children in the compensated dyslexia group exhibited higher phonological rehearsal, iconic memory, and associative memory scores than children in the dyslexia group. Implications for the remediation of dyslexia are discussed.     

Electrophysiological correlates of dyslexic subtypes.

The construct validity of Boder's typology of dyslexia was investigated using quantified EEG. Thirty-nine children, ranging in age from 7-0 to 10-11, were recorded during a contextual reading task and at rest. During reading, children with dyslexia were expected to show increased theta and beta amplitude compared to nondisabled readers. These differences were expected in regions of presumed strength for each subtype as a sign of overengagement in task. Children with phonological deficits (dysphonetic dyslexia) were expected to adopt visuospatial processing strategies (right occipital-parietal activation), those with orthographic deficits (dyseidetic dyslexia) to emphasize phonetic strategies (left temporal-parietal activation). Results supported beta frequency differences in anticipated regions by subtype during the reading task. However, the direction of difference hypothesis was not supported. Decreased amplitudes in both groups with dyslexia compared to normally achieving readers suggest reconceptualization of the theoretical base for the Boder subtyping system.     

The neural basis of developmental dyslexia

Until recently, many thought developmental dyslexia was a behavioral disorder that primarily affected reading. In fact, it is a partly heritable condition, the clinical manifestations of which are extremely complex including deficits in reading, working memory, sensorimotor coordination, and early sensory processing. Even though extensive research has characterized these behavioral abnormalities carefully, the biological mechanisms of the clinical manifestations still are poorly understood. Recent research into both the nature of the structural and functional abnormalities in developmental dyslexia and the functional neuroanatomy of reading have rapidly advanced our understanding of the localization of the processes responsible for the signs and symptoms of dyslexia. This paper reviews recent evidence supporting a biological basis for developmental dyslexia. This article was made possible by grant NICHD HD36461 from The Charles A. Dana Foundation and The International Dyslexia Association.     

Gender differences in the severity of adult familial dyslexia

Thirty seven adults with a three generation family history of dyslexia and a strong personal history of reading/spelling problems were administered a psychoeducational battery to confirm the diagnosis of dyslexia. Males were not disproportionately represented in the dyslexic sample although they exhibited a more severe profile of reading impairment relative to females. Severity of dyslexia is discussed as a possible mechanism of the reported higher prevalence of dyslexia among males.     

Antecedents to reading disability: Preschool language development and literacy experiences of children from dyslexic families

In a longitudinal study of the relation between preschool development and later reading abilities, children with dyslexic parents and/or older siblings were compared to children with no family incidence of dyslexia. Many children from dyslexic families developed reading problems by the end of the second grade, and these poor readers were characterized chiefly by weaker early syntactic and phonological skills and by less frequent exposure to books during their preschool years than the preschoolers who became normal readers. Some implications of the results for etiological theories of dyslexia are discussed.     

Neuropsychological intervention in kindergarten children with subtyped risks of reading retardation

Kindergarten children at risk of developing language problems were administered the Florida Kindergarten Screening Battery. A principal components analysis revealed a verbal and a visual-spatial component and subsequent discriminant function analyses a high verbal/low visual-spatial group (LAL: Latent L) and a high visual-spatial/low verbal group (LAP: Latent P). LAL- and LAP-children were considered at risk for developing an L- or P-type of dyslexia, respectively. As is common practice with children suffering from manifest L- or P- dyslexia, the LAL- and LAP-kindergartners received right and left hemisphere stimulation, respectively. The outcomes were compared with those of bilateral hemispheric stimulation and no intervention. Reading tests were administered in primary school Grades 1 and 5/6; teachers’ evaluation of reading took place in Grade 5/6. Overall, the LAL- and LAP- groups showed significant backwardness in word and text reading, both at early and late primary school. Types of intervention made a difference though: not significantly backward in early word, late word, and late text reading were the LAL-children who had received right hemisphere stimulation. Nonintervened LAP-children did not show significant backwardness in early word reading and late text reading, nor did LAP-children who had received left hemisphere or bilateral stimulation. Early text reading was not affected by any treatment. Teacher’s evaluations were in support of these findings.     

Integration of the visual and auditory networks in dyslexia: a theoretical perspective

In addition to an intrinsic difficulty in reading and spelling, one of the defining characteristics of dyslexia is an enduring and pervasive difficulty in phonological coding, such that dyslexic readers find it particularly challenging to process and manipulate the constituent sounds of a language. Coexistent with this finding is the evidence that some dyslexic readers also demonstrate subtle sensory coding problems in the visual and auditory domains. Few theories have been proposed to unite these different findings within a coherent model of reading. Here the evidence for visual, auditory and phonological coding problems in dyslexia is briefly reviewed, and a hypothesis is proposed for how adequate early sensory coding may be intrinsic to phonological awareness and subsequent reading ability. In this hypothesis, a cortical network is assumed that incorporates the visual, auditory and phonological skills of reading. The visual sub‐component of the network is mediated by the dorsal visual pathway, which is responsible for the accurate spatial encoding of letters, words and text. The auditory component of the network in pre‐readers is intrinsic to the development of phonological sensitivity, and then grapheme‐phoneme assimilation as reading skills develop. In this hypothesis, some of the symptoms of dyslexia may result from subtle problems in the encoding of both visual and auditory information and their role in maintaining the synchronicity of the reading network.     

The role of morpheme recognition and morphological awareness in dyslexia

This paper begins by presenting theoretical arguments and empirical evidence to support the idea that morpheme analysis strategies play a part in word recognition in reading, and in dyslexia in particular. The results of two studies are presented which indicate that dyslexic adolescents use recognition of root morphemes as a compensatory strategy in reading of both single words and coherent text. Furthermore, the evidence is reviewed that the use of morpheme recognition as a strategy in reading to some extent depends on the linguistic awareness of morphemes in spoken language. Finally, results from a pilot study of the effects of morphological awareness training of dyslexic students are presented which suggest that it may be possible to improve the awareness of morphology independently of phoneme awareness, and that such a training may have positive effects on reading of coherent text and on the accurate spelling of morphologically complex words.     

Reading-related behavioral characteristics of chinese children with dyslexia: The use of the teachers’ behavior checklist in Hong Kong

Primary school teachers rated the frequency of occurrence of 65 reading-related behavioral characteristics of Grade 1 to Grade 6 Chinese school children in Hong Kong. An item factor analysis based on ratings on 554 students yielded two major dimensions of behavioral characteristics on reading and writing problems, and sequencing and spatial difficulties. In predicting the literacy and cognitive skills of a separate sample of 184 school children, gender, age, and the two empirical scales developed on the basis of factor analysis were used as predictors in regression analyses. The findings indicated that reading and writing problems emerged as the most predominant predictor of various literacy and cognitive deficits. The two mean scores of behavioral characteristics for children with dyslexia were significantly elevated as compared with those for children without dyslexia. Implications of the findings for screening dyslexia and predicting specific cognitive deficits using classroom-based behavior checklists are discussed.     

Observations on the temporal correlates of reading failure

The definitions of developmental dyslexia andtemporal processing are discussed and severalconstruals of what a temporal processingdeficit might entail are illustrated. Then,using a framework developed by Farmer & Klein(1995), the proposal that a temporal processingdeficit (in vision, audition, or both) might bethe root cause of some proportion of cases ofdevelopmental dyslexia is introduced andvarious research strategies for testing thisproposal are identified. The symposium paperswhich address this general question using arange of these strategies are then criticallyreviewed. It is noted that whereas reading isa recent artifact not yet subject to any directselection pressure, its normal performancerequires the use of, and connections between,the highly evolved modules for visual patternrecognition and language. Within vision andlanguage redundant coding, which permitsperformance in the face of injuries anddegraded input, also makes it difficult todetect subtle deficits (whether temporal, ornot) unless precise tests are used. Yet suchdeficits may degrade performance on tasks (suchas reading) which require the non-copiousconnections between vision and language. Theefficacy of this pathway, I suggest, ismeasured by performance on the rapidautomatized naming (RAN) test.     

Tennessee meets the challenge of dyslexia

In 1993, the Tennessee General Assembly voted funds to establish a model unit of integrated services and research to address the full scope of issues associated with dyslexia. Dyslexia is characterized as significant difficulty in reading and spelling individual words. In the Tennessee Center for the Study and Treatment of Dyslexia, these problems are presumed to be the consequence of a phonological core deficit. When compared to typical readers, matched for age or reading level, dyslexic readers evidence average listening comprehension, a relative strength in reading comprehension, deficits in word recognition and spelling, and severe deficits in word analysis as well as in awareness and manipulation of phonemes. Integration of this information yields a diagnostic profile that may be applied in the differential diagnosis of dyslexia both in clinical and school settings. This paper presents an overview of the Tennessee Center for Dyslexia and the services it provides as well as its guidelines for interpreting the results of norm-referenced tests and criterion-referenced measures to diagnose dyslexia and plan appropriate intervention. Frith’s (1985, 1986) developmental framework for reading acquisition is integrated with the assessment data to outline an instructional plan that addresses mastery of skills within and across the hierarchical phases—logographic, alphabetic, and orthographic—of reading development.     

发展性阅读障碍的神经机制及其对第二语言学习的影响

研究表明拼音文字系统的发展性阅读障碍者与以中文为代表的表意文字系统的发展性阅读障碍者在阅读过程中大脑的激活部位存在差异。关于母语阅读障碍儿童对第二语言学习的影响是近年来发展性阅读障碍研究的热点。双语发展性阅读障碍的理论假设主要有两种语言相互依赖假设和正字法依赖假设。前者认为母语的阅读障碍可以自动迁移到第二语言的学习中;后者认为母语的阅读障碍是否会迁移到第二语言的学习中,要依赖两种语言的正字法特征。我们认为这两种理论不是相互矛盾的,阅读障碍是否会同时出现在两种语言中可能取决于这两种语言是否共用了相同的有缺陷的神经系统。     

Adults with dyslexia: how can they achieve academic success despite impairments in basic reading and writing abilities? The role of text structure sensitivity as a compensatory skill

The aim of this study was to investigate (1) whether a sample of highly educated individuals with dyslexia living under optimal personal, educational, cultural, and socioeconomic conditions continues to display core deficits in reading and writing skills during adulthood (extending prior results in Dutch, English, Hebrew, and Spanish to the Portuguese writing system); (2) whether these individuals can compensate for the effects of persistent core deficits when reading complex academic texts; (3) which cognitive resources, such as reading strategies, are used as compensatory mechanisms; and (4) whether quality of life is affected in these individuals. These questions were examined in a sample of 28 adults with dyslexia (DG) and 28 control participants (CG) paired by sex, age, education, and occupation, with a mean of 15 years of formal education. Participants completed measures of phonological awareness; decoding of syllables, words, and pseudowords; writing; reading comprehension (inferential and literal questions, recall, and sensitivity to the rhetorical structure of the target text); and quality of life. Results showed that (1) core deficits associated with dyslexia persisted into adulthood: participants with dyslexia performed worse than control subjects at all levels of phonological awareness, reading (except word reading accuracy), and spelling; (2) the groups did not differ on any measures of reading comprehension, suggesting a compensation of core deficits; (3) three compensatory mechanisms were identified: slower reading, use of text structure, and verbal ability; (4) participants with dyslexia required more family support and professional help throughout their educational careers, and had more depressive symptoms than control subjects.     

汉语阅读障碍儿童与普通儿童朗读错误研究

为反映汉语阅读障碍儿童朗读的特点,采用错误分析技术,对10名汉语阅读障碍儿童和10名普通儿童的朗读错误进行了系统的分析.结果发现:汉语阅读障碍儿童朗读流畅性与准确性都低于普通儿童,朗读中的替代错误、添加错误、省略错误都显著多于普通儿童.而二者在颠倒错误上的差异不显著.在替代错误中,音似、形似、语义及无关替代显著地多于普通儿童.与普通儿童相比,汉语阅读障碍儿童的朗读问题主要表现为错误数量更多,而不是表现为错误类型上的特点.最后结合研究发现对阅读障碍的诊断与干预提出了建议.