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.     

Persistence of phonological awareness deficits in older children with dyslexia

Three groups of children with dyslexia, with mean age 8, 13 and 17 years, together with three groups of normally achieving children matched for age and IQ with the dyslexic groups, undertook tests of sound categorization and phoneme deletion. The design allowed comparison not only across chronological age but also across reading age. The children with dyslexia performed significantly worse even than their reading age controls on both tasks. Indeed, overall performance of the 17 year old children with dyslexia was closest, but inferior, to that of the 8 year old controls. Since the sound categorization task was designed to minimize working memory load, the results extend previous findings on the phonological awareness deficits in dyslexia by dissociating the deficit from memory load and by showing that it persists at least into late adolescence.     

Early phonological and lexical markers of reading disabilities

Phonological and lexical characteristics of 30-month-old children’s spontaneous language samples were examined as indicators of later reading outcome. Participants were 27 children, 10 children with reading disability and 17 children without reading disability. Of the non-disabled readers, 7 were at high familial risk for reading disability, and 10 came from families with no history of reading difficulties. Children later identified as reading disabled at second grade and beyond demonstrated narrower lexical diversity and simpler phonological forms as compared to the normal reading participants. Implications of reduced phonological complexity in the productive lexicons of reading disabled children are discussed.     

Theoretical and methodological pitfalls in making comparisons between developmental and acquired dyslexia: Some comments on A. Castles & M. Coltheart (1993)

On the basis of a study of the reading skills of 56 developmental dyslexics, Castles & Coltheart (1993) have proposed that there are at least two varieties of dyslexia in children. In the first, there is an impairment of lexical reading and in the second, the operation of the sublexical procedure is impaired. We take issue with their, proposal on theoretical grounds and argue that methodologlcal weaknesses in their study seriously weaken their claims.     

Structural invariance in the associations of naming speed,phonological awareness,and verbal reasoning in good and poor readers: A test of the double deficit hypothesis

The associations of multiple measures of speeded naming, phonological awareness, and verbal intelligence with word reading were examined in 51 poor readers and 74 good readers in third and fourth grade. Structural equation modeling was used to determine the extent to which these two groups exhibited structurally invariant patterns of associations among the constructs. Results revealed that for poor readers, both speeded naming and phonological awarencess were significantly associated with word reading, but verbal intelligence had no association with it. In contrast, for good readers, phonological awareness and verbal intelligence were significantly associated with word reading, but naming speed was not. Findings are discussed in light of the double deficit hypothesis.     

Subtypes of developmental dyslexia: The influence of definitional variables

The purpose of this study was to investigate the hypothesis that the manner in which a reading disability is defined will influence the conclusions that are made about the characteristics of the disability. To test this hypothesis, learning disabled and normally achieving children, aged 6 to 14, were administered tasks measuring grammatical, shortterm memory, phonological, reading, and visual-spatial skills. The poor readers were divided into groups of poor readers with

Comparing the phonological and double deficit hypotheses for developmental dyslexia

This study tested the predictions of thephonological and double deficit hypotheses byexperimentally examining speech perception,phoneme awareness, lexical retrieval (serialand discrete), articulatory speed, and verbalSTM in school age child (N = 35) and adolescent(N = 36) dyslexics, and both chronological age(CA) and reading age (RA) controls. Theresults confirmed the findings of previousstudies of a deficit in phoneme awareness indevelopmental dyslexia. At both age levels,dyslexics performed significantly more poorlythan both their CA and RA controls. Althoughdeficits in the other processes investigated,particularly in rapid serial naming, were alsoapparent, they were not as clear-cut as thedeficit in phoneme awareness. In general,definite evidence of a deficit in rapid serialnaming was limited to the more severelyimpaired dyslexics. Furthermore, although rapidserial naming contributed independent variationto various literacy skills, its contributionwas modest relative to the contribution ofphoneme awareness, regardless of whether theliteracy skill relied more or less heavily onphonological or orthographic coding skills. Further analyses suggested that variation inrapid serial skill is particularly importantfor fluent reading of text, whereas phonemeawareness is particularly important for thedevelopment of the ability to read byphonologically recoding letters or groups ofletters in words into their phonological codes.This explains the relatively strongcontribution of phoneme awareness to readingand spelling ability in general. In sum, thephonological hypothesis offers a moreparsimonious account of the present resultsthan the double deficit hypothesis.     

The contribution of orthographic and phonological processes to word reading in young Norwegian readers

The dissociation between phonological and orthographic processes in word reading was investigated in a study involving 147 children in grade 3. The criterion measure was a timed word reading test. Two tasks assessed phonological skills and two tasks assessed orthographical skills. Orthographic ability accounted for variance in word reading even after phonological ability had been controlled. Poor readers differed from skilled readers in the way phonological and orthographic factors were balanced. The relationship between the two factors was fairly strong among poor readers, whereas the correlation was low for more skilled readers. Furthermore, phonological factors played a much stronger role in explaining the variance in word reading among poor readers, while on the other hand, orthographic factors were more powerful among skilled readers.     

The Universal and the unique in dyslexia: A cross-linguistic investigation of reading and reading fluency in Hebrew-and English-speaking children with reading disorders

Cross-linguistic studies provide a unique tool for the identification of universal processes in oral and written language, both in development and in breakdown (Annual Review of psychology, 52, 369–396). Examining the differential strengths and weaknesses of children with dyslexia in contrasting orthographies can help illumine both the more universal aspects of reading disabilities, as well as their individual language-specific attributes. The aim of this study, was to investigate the shared and distinctive characteristics of readers with dyslexia on reading and reading fluency across Hebrew and English orthographies. Differences between 60 Hebrew and English-speaking children with dyslexia on a battery of cognitive, linguistic, and reading measures will be discussed along with theoretical implications.     

The role of visual and phonological representations in the processing of written words by readers with diagnosed dyslexia: evidence from a working memory task

The aim of the study was to elucidate the nature and efficiency of the strategies that readers with phonological dyslexia use for temporary retention of written words in Working Memory (WM). Data was gathered through a paradigm whereby participants had to identify serially presented written (target) words from within larger word pools according to their presentation order, with word pools containing code-specific distracter (CSD) words and non-code-specific distracter (NCSD) words. Analyses focused on three aspects of performance: (1) false recognition of target words; (2) correct recognition of target words; and (3) retention of word presentation order. Participants were readers with diagnosed phonological dyslexia (n = 20, mean grade level = 9.05 [0.89]) and a control group of regular readers (n = 25, mean grade level = 9.00 [0.76]). Results provide direct evidence that the dyslexic readers and the regular readers used essentially different memory coding strategies for the temporary retention of written words, with the former predominantly relying on a visual strategy and the latter on a phonological strategy. Findings further pinpointed a notably impoverished ability of the dyslexic readers to retain word presentation order. The implication of these findings is discussed in relation to theories predicting the acquisition and mastery of reading.

Sound links in reading and spelling with discrepancy-defined dyslexics and children with moderate learning difficulties

This study reports the effects of a highly structuredindividually administered remedial teaching programmefor children with reading difficulties. Thephonological awareness, reading accuracy and spellingattainments of 28 children diagnosed as having low IQ(Mean IQ = 66, SD = 5.3) were compared with those of29 children diagnosed as having discrepancy defineddyslexia (Mean IQ = 95, SD = 8.4). The responsivenessto intervention of each group was also compared withteacher-referred reading-delayed children matched forinitial literacy skills. For reading accuracy andphonological awareness the dyslexic group respondedmore successfully than the low IQ group. The twogroups did not differ significantly on spelling. It isargued that the reading accuracy and phonologicalawareness results are in keeping with thephonological-core variable-difference (Stanovich &Siegel 1994) model of reading disability and that thegains of all groups on all measures were such thatthere is no obvious benefit in using IQ to selectchildren for a programme of individual teaching whichcombines reading with phonological awarenesstraining.     

Letter names, letter sounds and phonological awareness: an examination of kindergarten children across letters and of letters across children

In this study 149 kindergarten children were assessed for knowledge of letter names and letter sounds, phonological awareness, and cognitive abilities. Through this it examined child and letter characteristics influencing the acquisition of alphabetic knowledge in a naturalistic context, the relationship between letter-sound knowledge and letter-name knowledge, and the prediction of Grade 1 phonological awareness and word identification from these variables. Knowledge of letter sounds was better for vowels and for letters with consonant–vowel names than for those with vowel–consonant names or names bearing little relationship to their sounds. However, there were anomalies within each category reflecting characteristics of the individual letters. Structural equation modelling showed that cognitive ability, comprising receptive vocabulary, non-verbal reasoning, rapid automatized naming of colours, and phonological memory significantly contributed to alphabetic knowledge and phonological awareness. In turn, letter-name knowledge but not phonological awareness predicted letter-sound knowledge and subsequent reading skill.This research was supported by a grant from the Social Sciences and Humanities Research Council of Canada to the first author. Thank you is extended to the participating schools and children and to Ian Newby-Clark for his orientation to AMOS. Michelle Bell, Shelly Moretti and Jodi Page have since graduated from the University of Guelph     

Asynchrony of visual-orthographic and auditory-phonological word recognition processes: An underlying factor in dyslexia

This study investigated whether asynchrony ofspeed of processing (SOP) betweenvisual-orthographic and auditory-phonologicalmodalities can account for word recognitiondeficits among dyslexic readers. SOP amongelementary school dyslexic readers was comparedto that of chronologically age-matched normalreaders. SOP was assessed using nonlinguisticand linguistic auditory and visual low-leveltasks and higher-level orthographic andphonological tasks. Behavioral andelectrophysiological (ERP) measures of SOP wereobtained. Data indicated that dyslexic readerswere significantly slower than control readersin most of the experimental tasks. Moreover,dyslexics revealed a systematic SOP gap betweenthe auditory-phonological and thevisual-orthographic modalities. This gap wasfound in both P200 and P300 latencies, andexplained most of the variance in wordrecognition. A theory is proposed suggestingthat asynchrony between the processing rates ofthe visual and the auditory modalities may bean underlying cause of dyslexia.     

The role of naming speed within a model of reading acquisition

That symbol naming speed is an importantcorrelate of reading skill has been generallyacknowledged. Just what contribution it makesand why is a much more difficult question. Wesuggest that the search for such answers isbest developed within a broad model of readingskill acquisition. We propose an informalmodel and review evidence for several of itslinks. The major lines of influence arehypothesized to flow from cognitive abilities(mediated by instructional factors) tointermediate and final reading outcomes. Theoutcomes at each level, however, are affectedby outcomes at other levels, and in other wayscombine to complicate the picture. Use of sucha model may focus our research questions morefinely and lead to a more preciseconceptualization of the basis for naming speed– reading relationships.     

The Processing of Inflectional Morphology: A Comparison of Children with and without Dyslexia

Children aged 11–12 years with a diagnosis of dyslexia (DR) were compared to chronological and reading-age matched poor readers (PR), and two normal reader groups, age-matched (CA) and spelling and reading-age matched (SA–RA), on their processing of inflectional morphology. In comparison to SA–RAs and PRs, the DRs made more spelling errors on regular past tense verb endings relative to irregular past tense verbs and non-verbs. In reading, the DRs took longer than the other groups to make decisions in the written but not oral condition of a tense judgement task. In addition, they were less affected than the PR and SA–RA groups by case altered disruption to the morpheme boundary of inflected verbs. The findings suggest dyslexic children do not show deficits in morphological processing in spoken language, but they are slower at reading and less accurate at spelling regularly inflected verbs compared with normally developing younger children. This difference could plausibly be accommodated within the Phonological Deficit Hypothesis of dyslexia.     

Phonological and visual processing deficits can dissociate in developmental dyslexia: Evidence from two case studies

The present study describes two Frenchteenagers with developmental reading andwriting impairments whose performance wascompared to that of chronological age andreading age matched non-dyslexic participants.Laurent conforms to the pattern of phonologicaldyslexia: he exhibits a poor performance inpseudo-word reading and spelling, producesphonologically inaccurate misspellings butreads most exception words accurately. Nicolas,in contrast, is poor in reading and spelling ofexception words but is quite good atpseudo-word spelling, suggesting that hesuffers from surface dyslexia and dysgraphia.The two participants were submitted to anextensive battery of metaphonological tasks andto two visual attentional tasks. Laurentdemonstrated poor phonemic awareness skills butgood visual processing abilities, while Nicolasshowed the reverse pattern with severedifficulties in the visual attentional tasksbut good phonemic awareness. The presentresults suggest that a visual attentionaldisorder might be found to be associated withthe pattern of developmental surface dyslexia.The present findings further show thatphonological and visual processing deficits candissociate in developmental dyslexia.     

The role of question type and reading ability in reading comprehension

Performance on a standardized reading comprehension test reflects the number of correct answers readers select from a list of alternate choices, but fails to provide information about how readers cope with the various cognitive demands of the task. The aim of this study was to determine whether three groups of readers: normally achieving (NA), poor comprehenders (CD), with no decoding disability, and reading disabled (RD), poor comprehenders with poor decoding skills, differed in their ability to cope with reading comprehension task demands. Three task variables reflected in the question-answer relations that appear on standardized reading comprehension tests were identified.Passage Independent (PI) question can be answered with reasonable accuracy based on the reader's prior knowledge of the passage content.Inference (INFER) questions required the reader to generate an inference at the local or global test level.Locating (LOCAT) questions require the reader to match the correct answer choice to a detail explicitly stated in the text either verbatim or in paraphrase form. The relations among reader characteristics, cognitive task factors and reading comprehension test scores were analyzed using a structural relations equation with LISREL. It was found that the three reading groups differed with respect to the underlying relationship between their performance on specific question-answer types and their standardized reading comprehension score. For the NA group, a high score on PI was likely to be accompanied by a low score on INFER, whereas in the CD and RD groups, PI and INFER are positively related. The finding of a negative relationship between background knowledge and inference task factors for normally achieving readers suggests that even normal readers may have comprehension difficulties that go undetected on the basis of a standardized scores. This study indicates that current comprehension assessments may not be adequate for assessing specific reading difficulties and that more precise diagnostic tools are needed.     

Levels of phonological awareness and learning to read

The paper reports studies of segmentation performance by a Nursery group of children, who had not yet started to learn to read, and by Primary 1 and 2 groups, who were in the early stages of learning by a standard method of whole word acquisition combined with letter-sound learning. Rhyme and alliteration production tasks were applied, together with segmentation tasks requiring division of monosyllabic words or non-words of simple or complex structure into two parts, three parts, or as many parts as possible. Performance was related to the hierarchical model of the syllable which distinguishes a two-dimensional (2D) level (onset/rime), a three-dimensional (3D) level (initial consonants, vowel, terminal consonants) and many-dimensional (nD) level (phonemes). The hypothesis that phonological awareness (PA) normally develops down the hierarchy, from larger to smaller units, predicts that segmentation ability should emerge in the sequence 2D 3D nD. In practice, the reverse of this order was found. The results are discussed in relation to theories of the relationship between literacy development and the different levels of PA.