The development of reading skill and bases of developmental dyslexia were explored using connectionist models. Four issues were examined: the acquisition of phonological knowledge prior to reading, how this knowledge facilitates learning to read, phonological and non phonological bases of dyslexia, and effects of literacy on phonological representation. Compared with simple feedforward networks, representing phonological knowledge in an attractor network yielded improved learning and generalization. Phonological and surface forms of developmental dyslexia, which are usually attributed to impairments in distinct lexical and nonlexical processing “routes,” were derived from different types of damage to the network. The results provide a computationally explicit account of many aspects of reading acquisition using connectionist principles.

This monograph discusses research, theory, and practice relevant to how children learn to read English. After an initial overview of writing systems, the discussion summarizes research from developmental psychology on children's language competency when they enter school and on the nature of early reading development. Subsequent sections review theories of learning to read, the characteristics of children who do not learn to read (i.e., who have developmental dyslexia), research from cognitive psychology and cognitive neuroscience on skilled reading, and connectionist models of learning to read. The implications of the research findings for learning to read and teaching reading are discussed. Next, the primary methods used to teach reading (phonics and whole language) are summarized. The final section reviews laboratory and classroom studies on teaching reading. From these different sources of evidence, two inescapable conclusions emerge: (a) Mastering the alphabetic principle (that written symbols are associated with phonemes) is essential to becoming proficient in the skill of reading, and (b) methods that teach this principle directly are more effective than those that do not (especially for children who are at risk in some way for having difficulty learning to read). Using whole-language activities to supplement phonics instruction does help make reading fun and meaningful for children, but ultimately, phonics instruction is critically important because it helps beginning readers understand the alphabetic principle and learn new words. Thus, elementary -school teachers who make the alphabetic principle explicit are most effective in helping their students become skilled, independent readers.

A multiple case study was conducted in order to assess three leading theories of developmental dyslexia: (i) the phonological theory, (ii) the magnocellular (auditory and visual) theory and (iii) the cerebellar theory. Sixteen dyslexic and 16 control university students were administered a full battery of psychometric, phonological, auditory, visual and cerebellar tests. Individual data reveal that all 16 dyslexics suffer from a phonological deficit, 10 from an auditory deficit, four from a motor deficit and two from a visual magnocellular deficit. Results suggest that a phonological deficit can appear in the absence of any other sensory or motor disorder, and is sufficient to cause a literacy impairment, as

This article focuses on applying the SERIOL model of orthographic processing to dyslexia. The model is extended to include a phonological route and reading acquisition. We propose that the temporal alignment of serial orthographic and phonological representations is a key aspect of learning to read, driving the formation of a phonemic encoding. The phonemic encoding and the serial representations are mutually reinforcing, leading to automatic, proficient processing of letter strings. A breakdown in any component of this system leads to the failure to form stringspecific phonological and visual representations, resulting in impaired reading ability. Following the pioneering work of Liberman and colleagues (1974), research into dyslexia has focused on phonological deficits. As discussed by Castles and Colheart (2004), there is a wide range of evidence that dyslexics are impaired in phonological awareness tasks, such as phoneme deletion, phoneme counting and phoneme lending. This correlation has largely been taken to reflect causality. That is, impaired phonological awareness is thought to reflect abnormal phonological representations, which are thought to be the fundamental cause of dyslexia. However, a causal relationship between phonological awareness and

This article reports an extended `case series' of studies comparing performance of three age groups of dyslexic and matched control children on primitive skills. The dyslexic children showed deficits in most of the skills, with fundamental deficits (worse performance than reading age controls) on phonological skill, naming speed, bead threading, and on some balance tasks. Furthermore, there was no evidence of sub-types of dyslexia, with all dyslexic children showing deficits in at least two skill modalities. The results, which have considerable theoretical and applied significance, demonstrate that the difficulties of dyslexic children are not limited to phonological skills. Dyslexia is more than a phonological disability May 17, 1995 --- 2 --- Introduction The Editor of this Journal has set contributors a considerable, but worthy, challenge in asking us not only to attain the theoretical high ground but also to bring out the relevance of dyslexia theory to dyslexia practice. In thi...

Studies of developmental dyslexia using functional imaging techniques have found disrupted activation of the left angular gyrus, and functional connectivity analyses have demonstrated functional disconnection of this region in dyslexia. I review evidence suggesting that this disconnection may reflect disruption of white-matter tracts in the brain, which subserve communication between disparate regions of the cerebral cortex. A novel magnetic resonance imaging technique known as diffusion tensor imaging has been used to demonstrate a correlation between white matter structure and reading ability in both dyslexic and normal adults. These results could reflect either epigeneticallydetermined differences in white-matter structure or experience-dependent plasicity of white matter structure. The relation of white matter structure and reading ability may be mediated by the role of myelinated white matter in the rapid transmission of neural signals. Poldrack -- DTI and dyslexia 3 Reading is...

Developmental dyslexia and specific language impairment (SLI) were for many years treated as distinct disorders but are now often regarded as different manifestations of the same underlying problem, differing only in severity or developmental stage. The merging of these categories has been motivated by the reconceptualization of dyslexia as a language disorder in which phonological processing is deficient. The authors argue that this focus underestimates the independent influence of semantic and syntactic deficits, which are widespread in SLI and which affect reading comprehension and impair attainment of fluent reading in adolescence. The authors suggest that 2 dimensions of impairment are needed to conceptualize the relationship between these disorders and to capture phenotypic features that are important for identifying neurobiologically and etiologically coherent subgroups. Specific language impairment (SLI) and developmental dyslexia (also known as specific reading disability; SRD) are common developmental disorders that have a serious impact on a child’s educational and psychosocial outcome. SLI affects around 3%– 10 % of children (Tomblin et al., 1997) and is diagnosed when oral language lags behind other areas of development for no apparent

this paper will be to review the scientific studies that led to 5 the development of these new remediation techniques, based on neuroplasticity research, as well as the outcome data derived from controlled laboratory studies and field trials aimed at assessing the efficacy of these new training methods. Early studies focusing on the etiology of developmental language impairments date back to the early 1960s. In a classic paper, Benton (1964) hypothesized that central auditory processing deficits may characterize many children with developmental dysphasia, now referred to as specific language impairment (SLI). Subsequent studies focused on one aspect of central auditory processing, that is, sequencing or temporal order judgement (TOJ) deficits. Pursuing these early studies, Tallal and Piercy (1973 a; 1973 b) set out to investigate further the auditory perceptual abilities of children with developmental dysphasia. In addition to an experimental temporal order judgement (TOJ) task, they included a frequency discrimination task as a control condition. In both the TOJ and the frequency discrimination task the identical set of stimuli were presented. Stimuli consisted of two 75 msec duration complex tones that differed in fundamental frequency (100Hz vs 305Hz). All possible combinations of these two stimuli were presented in pairs. The two tones in the pair were separated by a silent interval of varying duration (inter-stimulus interval -- ISI). In the TOJ task the child was trained to press two response buttons, to indicate the temporal order of the two tones. If the same tone was presented twice, the button representing that tone was pressed twice. If two different 6 tones were presented, the child was trained to indicate which one came first and which second, using the...

y ability in children are primarily associated with problems in phonological processing, whereas deficits in rapid visual ability in children are primar- ily associated with problems in orthographic processing (Farmer & Klein, 1995). In contrast to the children, the adults showed a strong relation between rapid auditory ability and both orthographic and phonological processing. These results suggest that continued deficits in auditory ability may have a pervasive and negative impact on word processing in general. In addition, adults did not exhibit a relation between rapid visual ability and orthographic-processing problems. Orthographic-processing deficits may Requests for reprints should be sent to James R. Booth, Department of Communication Sciences and Disorders, Northwestern University, 2299 North Campus Drive, Evanston, IL 60208-3560. E-mail: j-booth@nwu.edu ORTHOGRAPHIC AND PHONOLOGICAL PROCESSING 103 102 BOOTH ET AL.<F11.86

It is now well-established that there is a causal connection between children’s phonological skills and their acquisition of reading and spelling. Here we study low-level auditory processes that may underpin the development of phonological representations in children. Dyslexic and control children were given a battery of phonological tasks, reading and spelling tasks and auditory processing tasks. Potential relations between deficits in dyslexic performance in the auditory processing tasks and phonological awareness were explored. It was found that individual differences in auditory tasks requiring amplitude envelope rise time processing explained significant variance in phonological processing. It is argued that developmentally, amplitude envelope cues may be primary in establishing well-specified phonological representations, as these cues should yield important rhythmic and syllable-level information about speech.