Developmental dyslexia in an orthography of intermediate depth: the case of European Portuguese

Fifteen Portuguese children with dyslexia, aged 9–11 years, were compared with reading and chronological age controls with respect to five indicators related to the phonological deficit hypothesis: the effects of lexicality, regularity, and length, implicit and explicit phonological awareness, and rapid naming. The comparison between groups indicates that Portuguese children with dyslexia have a phonological impairment which is revealed by a developmental deficit in implicit phonological awareness and irregular word reading (where younger reading level controls performed better than dyslexics) and by a developmental delay in decoding ability and explicit phonological awareness (where dyslexics matched reading level controls). These results are discussed in relation to the idea that European Portuguese is written in an orthography of intermediate depth.     

Auditory Sensory Processing and Phonological Development in High IQ and Exceptional Readers,Typically Developing Readers,and Children With Dyslexia: A Longitudinal Study

Phonological difficulties characterize children with developmental dyslexia across languages, but whether impaired auditory processing underlies these phonological difficulties is debated. Here the causal question is addressed by exploring whether individual differences in sensory processing predict the development of phonological awareness in 86 English-speaking lower- and middle-class children aged 8 years in 2005 who had dyslexia, or were age-matched typically developing children, some with exceptional reading/high IQ. The predictive relations between auditory processing and phonological development are robust for this sample even when phonological awareness at Time 1 (the autoregressor) is controlled. High reading/IQ does not much impact these relations. The data suggest that basic sensory abilities are significant longitudinal predictors of growth in phonological awareness in children.     

Amplitude envelope perception, phonology and prosodic sensitivity in children with developmental dyslexia

Here we explore relations between auditory perception of amplitude envelope structure, prosodic sensitivity, and phonological awareness in a sample of 56 typically-developing children and children with developmental dyslexia. We examine whether rise time sensitivity is linked to prosodic sensitivity, and whether prosodic sensitivity is linked to phonological awareness. Prosodic sensitivity was measured by two reiterant speech tasks modelled on Kitzen (2001). The children with developmental dyslexia were significantly impaired in the reiterant speech tasks and in the phonological awareness tasks (onset and rime awareness). There were significant predictive relations between basic auditory processing of amplitude envelope structure (in particular, rise time), prosodic sensitivity, phonological awareness, reading, and spelling. The auditory processing difficulties that characterise children with developmental dyslexia appear to impair their sensitivity to phrase-level prosodic cues such as metrical structure as well as to phonology, but in this study phonological and prosodic sensitivity made largely independent contributions to reading.     

Development of dyslexic subgroups:

There is a consensus that dyslexia is on a continuum with normal reading skill and that dyslexics fall at the low end of the normal range in phonological skills. However, there is still substantial variability in phonological skill among dyslexic children. Recent studies have focused on the high end of the continuum of phonological skills in dyslexics, identifying a “surface” dyslexic, or “delayed” profile in which phonological skills are not out of line with other aspects of word recognition. The present study extended this work to a longitudinal context, and explored differences among subgroups of dyslexics on a battery of component reading skills. Third grade dyslexics (n=72) were classified into two subgroups, phonological dyslexics and delayed dyslexics, based on comparisons to younger normal readers at the same reading level (RL group). The children were tested at two points (in third and fourth grade). The results revealed that the classification of dyslexics produced reliable, stable, and valid groups. About 82 percent of the children remained in the same subgroup category when retested a year later. Phonological dyslexics were lower in phoneme awareness and expressive language. Delayed dyslexics tended to be slower at processing printed letters and words but not at rapid automatic naming of letters, and relied more heavily on phonological recoding in reading for meaning than did phonological dyslexics. A subset of the delayed dyslexics with the traditional “surface dyslexic” pattern (relatively high pseudoword and low exception word reading) was also identified. The surface subgroup resembled the RL group on most measures and was not very stable over one year. The results are discussed in light of current models of dyslexia and recent subgrouping schemes, including the Double-Deficit Hypothesis.     

Basic auditory processing and developmental dyslexia in Chinese

The present study explores the relationship between basic auditory processing of sound rise time, frequency, duration and intensity, phonological skills (onset-rime and tone awareness, sound blending, RAN, and phonological memory) and reading disability in Chinese. A series of psychometric, literacy, phonological, auditory, and character processing tasks were given to 73 native speakers of Mandarin with an average age of 9.7 years. Twenty-six children had developmental dyslexia, 29 were chronological age-matched controls (CA controls) and 18 were reading-matched controls (RL controls). Chinese children with dyslexia were significantly poorer than CA controls in almost all phonological tasks, in semantic radical search, and in phonological recoding proficiency. Chinese children with dyslexia also showed significant impairments in most of the basic auditory processing tasks. Regression analyses demonstrated that different auditory measures of rise time discrimination were the strongest predictors of individual differences in Chinese character reading (1 Rise task) and phonological recoding (2 Rise task) respectively, with frequency discrimination also important for nonsense syllable decoding. Our results support the hypothesis that accurate perception of the amplitude envelope of speech is critical for phonological development and consequently reading acquisition across languages.     

Auditory Sensitivity,Speech Perception,and Reading Development and Impairment

While the importance of phonological sensitivity for understanding reading acquisition and impairment across orthographies is well documented, what underlies deficits in phonological sensitivity is not well understood. Some researchers have argued that speech perception underlies variability in phonological representations. Others have investigated the role of more general auditory sensitivity for reading development and reading difficulties, arguing that poor phonological representations may actually be due to broad underlying auditory deficits, which are not restricted to speech stimuli. We argue that these hypotheses are not necessarily mutually exclusive. In this review, we demonstrate that auditory sensitivity and speech perception can be integrated into a single developmental model, in which auditory sensitivity may have an indirect impact on reading; this impact is mediated by speech perception. In the model, we distinguish general auditory sensitivity as falling into at least two general categories: rhythmic and temporal. Correspondingly, speech perception itself can be distinguished as suprasegmental and segmental. Theoretically, the proposed model integrates a broad range of studies on general auditory and speech perception to suggest a developmental trajectory for reading acquisition that can be explored from before birth. Practically, the proposed model points to different ways of understanding and diagnosing reading difficulties and distinguishing reading difficulties across languages and orthographies.     

Investigating the double-deficit hypothesis of developmental dyslexia in an orthography of intermediate depth

The present study aimed to investigate the double-deficit hypothesis (DDH) in an orthography of intermediate depth. Eighty-five European Portuguese-speaking children with developmental dyslexia, aged 7 to 12, were tested on measures of phonological awareness (PA), naming speed (NS), reading, and spelling. The results indicated that PA and NS were not significantly correlated, and that NS predicts reading fluency (but not reading accuracy and spelling) beyond what is accounted for by PA. Although the majority of the children with developmental dyslexia have double deficit (62.4%), some children have a single phonological deficit (24.7%) or a single NS deficit (8.2%). Children with a double deficit were not more impaired in reading fluency, reading accuracy, and spelling than both single-deficit subtypes. In conclusion, the findings of the present study are partially consistent with the DDH and provide evidence for the multifactorial model of developmental dyslexia. Implications of the DDH for an orthography of intermediate depth are emphasized.

     

English phonological specificity predicts early French reading difficulty in emerging bilingual children

The purpose of the present study was to examine the predictive value of a dynamic test of English and French lexical specificity on at-risk reading classification in 13 at-risk and 44 not at-risk emerging English (L1)–French (L2) bilingual Grade 1 children (M = 75.87 months, SD = 3.18) enrolled in an early French immersion program in Canada. Lexical specificity was assessed with a computerized word learning game in which children were taught new English (e.g., “foal” and “sole”) and French (e.g., bac “bin” and bague “ring”) word pairs contrasted by minimal phonological differences. The results indicated that the dynamic test of lexical specificity in English contributed significantly to the prediction of children’s French at-risk reading status at the end of Grade 1 after controlling for French phonological awareness and nonverbal reasoning skills. However, French lexical specificity did not predict children’s reading risk classification in French after controlling for French phonological awareness. Thus, it may be feasible to identify at-risk status in emerging bilinguals using dynamic measures in their stronger language.     

Longitudinal Stability of Phonological and Surface Subtypes of Developmental Dyslexia

Limited evidence supports the external validity of the distinction between developmental phonological and surface dyslexia. We previously identified children ages 8 to 13 meeting criteria for these subtypes (Peterson, Pennington, & Olson, 2013) and now report on their reading and related skills approximately 5 years later. Longitudinal stability of subtype membership was fair and appeared stronger for phonological than surface dyslexia. Phonological dyslexia was associated with a pronounced phonological awareness deficit, but subgroups otherwise had similar cognitive profiles. Subtype did not inform prognosis. Results provide modest evidence for the validity of the distinction, although not for its clinical utility.     

A technique for group screening of dyslexia among adults

This paper reports on the development of a battery of phonological processing tasks to screen adults with dyslexia. The battery consisted of tasks tapping reversed spoonerism, phonological choice, working memory, and vocabulary with confusable alternatives. A self-report questionnaire consisting of two scales, one examining symptoms of dyslexia and the other reading interests, was also constructed. All these tasks showed high discrimination between a group of adults with dyslexia and a control group, all recruited from adult education centers. The tasks also correlated highly with word recognition. The results of the study show that it is possible to develop a sensitive battery of “nonvocalized” tasks to screen adults with dyslexia on a group basis and that self-reports add to the screening. The group administration is both time-saving and cost-effective.     

Motion detection, letter position encoding, and single word reading

Recent research has shown that many people with dyslexia find it unusually difficult to detect flickering or moving visual stimuli, consistent with impaired processing in the magnocellular visual stream. Nonetheless, it remains controversial to suggest that reduced visual sensitivity of this kind might affect reading. We first show that the accuracy of letter position encoding may depend on input from the magnocellular pathway. We then suggest that when children read, impaired magnocellular function may degrade information about where letters are positioned with respect to each other, leading to reading errors which contain sounds not represented in the printed word. We call these orthographically inconsistent nonsense errors letter errors. In an unselected sample of primary school children, we show that the probability of children making “letter” errors in a single word reading task was best explained by independent contributions from motion detection (magnocellular function) and phonological awareness (assessed by a spoonerism task). This result held even when controlling for chronological age, reading ability, and IQ. Together, these findings suggest that impaired magnocellular visual function, as well as phonological deficits, may affect reading.     

Theoretical links among naming speed,precise timing mechanisms and orthographic skill in dyslexia

In this paper, we review several lines of convergent research to discuss the relationship between developmental dyslexia and slow symbol naming speed. We describe the interactive development of orthographic and phonological codes, and we discuss the methodological problems that may have led to underestimating the importance of individual differences in orthographic processing in our account of reading disabilities. Symbol naming speed is typically subsumed under phonological processing, yet it contributes variance to reading, especially to reading fluency, independently of phonological awareness. We speculate that naming speed may reflect precise timing mechanisms necessary to the development of orthographic codes and to their integration with phonological codes. We argue that an understanding of this precise timing dimension is necessary to incorporate in our models of phonological, orthographic, and semantic processes in reading acquisition and reading failure.     

Literacy development in successful men and women with dyslexia

To investigate how, when, and under what conditions individuals with dyslexia manage to develop high literacy levels, an interview and literacy assessment study was conducted with 60 highly successful men and women with dyslexia and 10 peers without dyslexia. The sample with dyslexia included a Nobel laureate, a member of the National Academy of Sciences, and leaders in a variety of fields requiring extensive reading (i.e., medicine, law, business, and the arts and sciences). For both males and females with dyslexia, interest-driven reading was key to the development of high literacy levels. Results showed distinct groups of successful professionals with dyslexia: a compensated group and two partially compensated groups. In each group, literacy development was augmented by avid reading in a content area of passionate personal interest, along with systematic phonics instruction. Through avid reading on a specific topic, the individuals with dyslexia developed knowledge of the specialized vocabulary, typical text structures, concepts, themes, and issues of a particular field. Extensive reading about a favorite subject enhanced the background knowledge of these individuals and enabled them to gain reading practice, which in turn, fostered the development of reading fluency and increasingly sophisticated skills. Although topics and genres of personal interest varied, fascination with a subject area was a common theme among those interviewed. In the literacy assessment, the 60 men and women with dyslexia demonstrated most of the salient characteristics of Chall’s (1983) Stage 5, the highest level of reading development. All participants comprehended sophisticated text, but some, with partially compensated dyslexia, showed continuing lags in basic, lower level “print” skills. Individuals with partially compensated dyslexia fell into two groups: one group showed specific deficits only in spelling, whereas the other group had difficulty in spelling, word recognition, and oral reading. Many, but not all, of the participants with dyslexia showed ongoing lags in reading rate. Gender differences were most apparent in topics of personal interest reading and in mentoring patterns. The study explores how adults with dyslexia, who may continue to lack strong integration of lower level “print” skills, succeed in constructing higher order “meaning” skills. This analysis underscores the need for a balanced approach to literacy instruction that includes both “print” and “meaning” aspects. It emphasizes the need to integrate solid interest-based approaches as a centerpiece of instruction.     

阅读困难儿童语言认知缺陷的干预研究及发展趋势

语言认知缺陷是影响阅读困难儿童阅读能力发展的重要因素,以训练阅读困难儿童的语言认知技能为主要目标的干预研究也备受研究者们的关注,其中,语音意识缺陷干预、阅读流畅性缺陷干预和基于语音意识缺陷和快速命名缺陷的综合干预是当前具有代表性的干预研究.分析、梳理以上干预研究及成效,并展望其发展趋势对阅读困难儿童的干预研究具有非常重要的价值.     

Subtypes of reading disability in a shallow orthography: a double dissociation between accuracy-disabled and rate-disabled readers of Hebrew

Whereas most English language sub-typing schemes for dyslexia (e.g., Castles & Coltheart, 1993) have focused on reading accuracy for words varying in regularity, such an approach may have limited utility for reading disability sub-typing beyond English in which fluency rather than accuracy is the key discriminator of developmental and individual differences in reading ability. The present study investigated the viability of an accuracy/fluency-based typology in a regular orthography, pointed Hebrew. We sought evidence of true or “hard” accuracy/rate subtypes in the strict (double dissociation) sense of selective impairment on only one dimension in the presence of normal levels of performance on the other dimension. In a nationally representative sample of fourth graders, we were able to identify a specific accuracy-disabled sub-group as well as an equally specific rate-disabled subgroup. Validating this subdivision, we show that the nature of reading performance in these subgroups and their converging cognitive/linguistic profiles are unique and distinctive on variables other than the measures used to define them. While the rate-specific disability appeared to reflect a general deficit in speed of processing affecting reading rate, and rapid automatized naming of print-related material, the accuracy-only disability subgroup displayed selective deficits in phonological awareness and morphological knowledge. Biosocial, demographic, and instructional factors, furthermore, did not explain the sub-group differences. It appears that both these subtypes are equally prevalent each counting close to 10% of the population.     

History and significance of rapid automatized naming

In this review, the origins and history of a test of rapid automatized naming (RAN) are traced from nineteenth-century classical brain-behavior analyses of cases of acquired “alexia without agraphia” through adaptations to studies of normal and reading disabled children. The element of speed (of responding verbally to a visual stimulus) was derived from a test of color naming developed over 50 years ago as a bedside measure of recovery from brain injuries. Merging the “visual-verbal” connection essential to reading (specific) with the response time element (general), RAN turned out to be a useful correlate and predictor of reading competence, accounting even for variance beyond that accounted for by timed tests of discrete naming. As one of the two deficits highlighted in the Double Deficit hypothesis with phonological awareness, RAN has emerged as something more than a particularly difficult challenge to a unitary phonological retrieval deficit, and has itself been subjected to further dissection. Coming full circle to its origins, recent research suggests that RAN taps both visual-verbal (language domain) and processing speed (executive domain) contributions to reading.     

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.     

Modeling the Successes and Failures of Interventions for Disabled Readers

A connectionist model of reading development previously used to simulate detailed aspects of developmental dyslexia (Harm & Seidenberg, 1999) was used to explore why certain classes of interventions designed to overcome reading impairments are more effective than others. Previous research has shown that interventions targeting the development of spelling-sound correspondences are more effective at promoting generalization skills than ones designed solely to increase phonological awareness. The simulations broadly replicate the patterns of success and failure found in the developmental literature and provide explicit computational insights into exactly why the interventions that include training on spelling-sound regularities are more effective than those targeting phonological development alone.     

Gender ratio in dyslexia

This paper is based on a study carried out in Great Britain on a national sample of 11,804 ten-year olds. The first section describes an attempt to pick out cases of “specific developmental dyslexia” (Critchley 1970), a constellation or syndrome of difficulties which some believe to be recognizable clinically. When specified criteria for dyslexia were used, 269 children qualified as dyslexic (2.28 percent of the sample). These included 223 boys and 46 girls, for a ratio of 4.51 to 1. Two possible difficulties in interpreting these data are discussed, and a defense is offered of the criteria used. Since some recent research papers report a gender ratio much nearer 1:1 (Shaywitz et al. 1990; Wadsworth et al. 1992; Lubs et al. 1993), those papers were examined for possible differences in procedure; it was found that the definition of dyslexia they used was “poor reading in relation to intelligence.” We carried out a further analysis on our own data using the same criterion. Of the 494 children who qualified as dyslexic on the basis of discrepancy criteria alone (4.19 percent of the sample), 314 were boys and 180 were girls for a ratio of 1.69 to 1. It seems, therefore, that the apparent differences in gender ratio reported in the literature have arisen because different criteria for dyslexia have been used. We argue that the definition based on clinical criteria leads to a more powerful taxonomy and that the widespread equation of “dyslexia” with “poor reading” is a hindrance to progress.