Lexical decision with left,right and center visual field presentation: a comparison between dyslexic and regular readers by means of electrophysiological and behavioral measures

This study examined the differences in processing between regular and dyslexic readers in a lexical decision task in different visual field presentations (left, right, and center). The research utilized behavioral measures that provide information on accuracy and reaction time and electro-physiological measures that permit the examination of brain activity during cognitive processing. Two groups of university students, regular and dyslexic readers, were matched on age, gender, intelligence, socioeconomic status, and handedness. A lexical decision task was used in order to examine the processes during word recognition. Subjects were required to decide whether a sequence of letters constituted a real word existing in spoken language or whether the stimulus seen was not an accurate word. For the behavioral measures, it was found that the dyslexics read slower and with more errors than the regular readers. Moreover, the ERP components appeared later in dyslexics as compared to regular readers in this task. The performance of the dyslexics improved and even approached that of the regular readers when the stimuli were presented to the left visual field. Thus, it seems that the dyslexics were relying more on their right hemisphere for linguistic processing, whereas the regular readers were relying more on their language areas in the left hemisphere.     

The relationship between phonological codes on memory and spelling tasks for students with and without learning disabilities.

The purpose of the study was to determine the degree to which 31 (23 boys and 8 girls) 13-year-old children with learning disabilities from Grades 7, 8, and 9 were comparable to younger (9-year-old) reading- and spelling-matched controls in (a) phonological similarity effects, (b) phonetically based misspellings, and (c) relationships between memory and spelling performance. Children with reading disabilities and reading-recognition-matched controls, subgrouped by spelling ability, were compared on their memory for phonetically similar and dissimilar word lists and types of spelling errors. The results indicate that children with reading disabilities who are matched to younger children on both reading recognition and spelling ability exhibit normal phonological effects on memory and spelling measures. Within each reading group, low spellers produced more semiphonetic errors than high spellers, and high spellers produced more phonetic errors than low spellers. Significant correlations between memory and spelling error measures were more frequent for children with reading disabilities when compared to controls matched on reading and spelling ability. It was concluded that the phonological performance of reading/spelling-matched children with reading disabilities is characterized by an overreliance on phonological codes, whereas their counterparts' performance reflects independent and less generalizable use of phonological substrates across tasks.     

What can spelling errors tell us about the causes and treatment of dyslexia?

Until recently the majority of research undertaken into dyslexia focused on English‐speaking dyslexics, who tend to make significantly more phonological than visual errors. This led to a major assumption about the possible cause of dyslexia being a lack of phonological awareness. According to the phonological deficit theory, the level of phonological consistency of a language determines not only the reading speed but also the amount and types of reading and spelling errors made by dyslexic people. This theory has been seriously challenged by the results of a number of studies in more phonologically consistent languages, such as Greek, Italian and Japanese, where morphology seemed to play a more crucial role than the phonological structure of a language per se. The 116 dyslexic people who took part in this experiment were matched on age, sex, IQ and psycho‐educational performance. A total of 58 US English‐speaking dyslexic people were compared to 58 Greek dyslexic people. Both groups met the diagnostic criteria. Results demonstrated that Greek dyslexics were found to make significantly fewer phonological errors (11.0%) than the US dyslexics (85.5%, p < .000), but comparatively more visual (66.8% to US 14.0%, P < .000) and grammatical errors (22.2% to US 0.1%, p < .000) than their English‐speaking counterparts. These data showed highly significant quantitative and qualitative spelling differences. Greek dyslexics could be accurately differentiated from the US English dyslexics based on the three types of spelling errors.     

Unexpectedly Poor Spelling and Phonological-Processing Skill

This study investigated the phonological skills of university students who were unexpectedly poor spellers relative to their word reading accuracy. Compared with good spellers, unexpectedly poor spellers showed no deficits in phonological memory, selection of appropriate graphemes for phonemes in word misspellings and nonword spellings, and phoneme awareness. In contrast, poor readers–poor spellers performed worse than the other groups at all but the last of these tasks. Although unexpectedly poor spellers misread nonwords more often than good spellers and took longer to begin pronouncing long, difficult-to-spell words, they took no longer to begin pronouncing shorter words and the names of corresponding pictures. The difficulty with reading nonwords and long words was thus interpreted as arising at the stage of identifying and parsing the orthographic input rather than phonological retrieval. The findings indicate that unexpectedly poor spellers of the type studied here do not have a mild phonological deficit.     

Qualitative and quantitative differences among dyslexic,normal, and nondyslexic poor readers

This study tested the hypothesis that when a stringent criterion of normal IQ is applied in the selection of dyslexic readers, and when dyslexics, nondyslexic poor readers, and normal readers are matched on reading comprehension — rather than word reading — significant differences among these groups can be demonstrated. Two groups of poor readers from primary grades, one with normal IQ (dyslexics) and the other with below-average IQ (nonspecific reading disabled, NSRD) were matched for reading comprehension with a group of younger normal readers. The dyslexic group was found to be inferior to the other two groups in tests of decoding and spelling. The dyslexic readers were more context-dependent for word recognition than the other two groups. The NSRD group did not differ from the normal readers in these aspects but had the worst performance on a test of inferential comprehension. It was concluded that dyslexics differ from normal readers and low-IQ poor readers in word and nonword reading skills and context-dependency for reading. A group of six adult dyslexics were also found to be deficient in decoding skills. A lack of unanimity in the use of certain terminology, a substantial age difference between low-IQ poor readers and normals, and the difference in the criteria used for matching the different groups could be factors that can explain the disagreements seen between the findings of the present study and those reported by some other studies. Potential problems associated with reading-age matched experimental design are discussed.     

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.     

Developmental dyslexia: Heterogeneity without discrete subgroups

Is the dual route model of word recognition useful in explaining individual differences in reading behaviors for most developmental dyslexics? Many past case studies of surface and phonological acquired dyslexics and a few similar studies of developmental dyslexia have suggested this might be so. The present study investigated individual differences among a group of 65 dyslexics, age 10 to 13, in reading, phonemic segmentation, and word retrieval. The dyslexics’ performance was compared to that of 65 reading age controls and 17 age-matched good readers. The research questions were: (1) Are there discrete subgroups of developmental dyslexics as suggested by the case studies? (2) How do oral language measures relate to the various reading tasks? The data indicated there were no discrete subgroups within the group of dyslexics; in addition, the variability in performance on reading tasks was quite similar for the dyslexic and reading age-control groups. A few dyslexics resembled phonological dyslexics and surface dyslexics, but these subjects were still part of a continuum. We also report the relationship between phonemic segmentation and word retrieval and various reading tasks. It appears that dyslexics at extreme ends of the continuum may exhibit quite different patterns from each other in their oral language task performance as well as in their reading.     

Dyslexia: Symbol processing difficulty in the Kannada language

The purpose of this study was to investigate whether among children who speak Kannada, a Dravidian language from South India, there are those who show the same pattern of specific dyslexia as has been found to occur in children who speak European languages. The performances of 14 dyslexic children, aged between 8 and 10 years, whose native language was Kannada, were compared on a variety of tasks with fourteen normal readers and fourteen non-dyslexic poor readers. There were no significant differences between the three groups on tests of visual discrimination, visual recognition, visual recall, memory for shapes in sequence, or auditory discrimination. There were differences, however, between the dyslexics and the normal readers on tests of recall of auditorily presented digits, word analysis, word synthesis, and on two tests of visual-verbal association. The non-dyslexic poor readers were more similar to the dyslexics on recall of auditorily presented digits and word synthesis but more similar to the normal readers on word analysis and on the two tests of visual-verbal association. It is argued that these results are evidence of a consistent pattern in specific dyslexia which does not depend on any one writing system or geographical location.     

Do dyslexics misread a ROWS for a ROSE?

Insufficient knowledge of the subtle relations between words’ spellings and their phonology is widely held to be the primary limitation in developmental dyslexia. In the present study the influence of phonology on a semantic-based reading task was compared for groups of readers with and without dyslexia. As many studies have shown, skilled readers make phonology-based false-positive errors to homophones and pseudohomophones in the semantic categorization task. The basic finding was extended to children, teens, and adults with dyslexia from familial and clinically-referred samples. Dyslexics showed the same overall pattern of phonology errors and the results were consistent across dyslexia samples, across age groups, and across experimental conditions using word and nonword homophone foils. The dyslexic groups differed from chronological-age matched controls by having elevated false-positive homophone error rates overall, and weaker effects of baseword frequency. Children with dyslexia also made more false-positive errors to spelling control foils. These findings suggest that individuals with dyslexia make use of phonology when making semantic decisions both to word homophone and non-word pseudohomophone foils and that dyslexics lack adequate knowledge of actual word spellings, compared to chronological-age and reading-level matched control participants.     

Spelling difficulties in Spanish-speaking children with dyslexia / Dificultades de escritura en niños españoles con dislexia

In addition to reading difficulties, a significant proportion of developmental dyslexics have spelling problems, which persist into adulthood. Studies carried out in languages with opaque orthographies have found that dyslexics frequently make phonological substitutions when spelling and have difficulties in developing orthographic representations of irregular words. Those errors seem to derive from an excessive use of phonological codes when writing. Minimal research in Spanish (relatively transparent orthography) about the relationship between dyslexia and spelling difficulties has been carried out to date. In this study, 19 Spanish-speaking developmental dyslexics (from 7 to 11 years old) and 28 controls (from 6 to 11 years old, distributed in two groups, one matched for age and the other for reading level with the dyslexics) performed a dictation task of 80 stimuli with different levels of orthographic consistency, in order to discover the codes they use in the writing process. Results showed that Spanish children with dyslexia made significantly more spelling errors, especially among the ruled and irregular words. These findings are consistent with the idea that these children have difficulties in developing orthographic representations and use phonological codes more frequently than non-dyslexics, resulting in phonologically plausible errors when writing irregular words. These results have important implications for the treatment of spelling difficulties in children with dyslexia, highlighting the need to focus on the correct acquisition of grapheme-phoneme conversion rules as well as the development of appropriate orthographic representations.     

语境与语义——谈英译汉词义的准确表达

翻译中的失误往往是由于词义的选择错误所致.在英译汉时,词义的准确选择很大程度上依赖于它所处的语境.语境使词义的褒贬含义和词的搭配关系在具体的上下文中更加明确,从而为译者确定词义提供了依据.因此说离开语境,翻译将无从谈起.     

Unexpectedly Poor Spelling in University Students

University students who were unexpectedly poor spellers relative to above average spellers revealed less extensive word-specific knowledge in their misspellings but not inferior knowledge of phoneme-grapheme correspondences, indicating that many of their orthographic representations lack word-specific graphemic information. Performance on deceptive nonwords in a printed lexical decision task showed that the poorer spellers did not place particular reliance on word beginnings as the basis for identification. However, because they could classify accurately many words for which they did not know the precise spelling, they may make greater use of partial cues when identifying words. They were also slower at making lexical decisions and slower and more error-prone at making same/different judgments on pairs of common words presented intact or with misordered letters. These effects showed that the poorer spellers were inferior at rapid orthographic analysis. The origin of their disadvantage in orthographic knowledge and orthographic-processing skill was not explained by more limited print exposure.     

Reading and spelling error analysis of native

This study was an investigation of reading and spelling errors of dyslexic Arabic readers (n=20) compared with two groups of normal readers: a young readers group, matched with the dyslexics by reading level (n=20) and an age-matched group (n=20). They were tested on reading and spelling of texts, isolated words and pseudowords. Two research questions were the focus of this study: What are the reading and spelling profile errors of dyslexic native Arabic speakers? What is the effect of the Arabic orthography on these types of errors? The results of the reading error analysis revealed a clear contribution of the uniqueness of the Arabic orthography to the types of errors made by the three different groups. In addition, the error profiles of the dyslexic readers were similar to the error profiles made by the younger reading-level-matched group in percentages and in quality. The most prominent types of errors were morphological and semiphonetic, which highlighted the contribution of the Arabic orthography to these types of errors. Consistently, the profile of the spelling errors was similar in percentages and quality among the dyslexics and the reading-level-matched group but different from the age-matched group on the spelling measures. The analysis of the spelling errors revealed that the dominant type of error was mostly phonetic due to the limited orthographic lexicon. In addition, the Arabic orthography also contributed to these types of errors because many spelling mistakes were made due to poor knowledge of the spelling rules. The results of the reading and spelling errors are discussed from a reading development point of view. Further, two models are suggested, one for reading and one for spelling, to illustrate the cognitive processes that underlie the reading and spelling mistakes in this type of orthography.     

Visual and Auditory Information Processing in Dyslexia: The Possibility of Subtypes

THIS DOUBLE‐BLIND experiment investigated various aspects of visual and auditory problems related to dyslexia. Seventeen children with dyslexia aged 7.25 to 10.25 years were compared with 17 normal readers matched for CA and intellectual ability. A speech perception task which measured the subjects’ auditory threshold level significantly separated the two groups. No difference was found when this task was performed at 35 dB above individual threshold levels. A significant difference between groups was found for the Form Constancy Subtest of the Frostig Developmental Test of Visual Perception (DTVP) (1966). A significant negative correlation found between these measures for the dyslexics, but not for the normal readers, supports previous evidence for auditory and visual subtypes in dyslexia. Various optometric measures were also examined. Four dyslexics, but no normal readers, suffered fixation disparity. This difference was significant. Six representative subjects of each group were compared for eye tracking in reading. The word span of the dyslexics was significantly smaller than that of the normal readers. A multiple discriminant analysis incorporating the auditory threshold task, form constancy, fusional reserves (distance, negative), accommodation right eye and heterophoria significantly discriminated the two reading groups. The perceptual variables were more heavily weighted than the optometric measures. It was concluded that while eye tracking and binocular fusion problems should always be considered in the assessment of dyslexics, factors involved in information processing in auditory and visual perception appear to be those which are more highly implicated.     

The semantic effect on retrieval of radicals in logographic characters

This study examined the semantic effect on retrieval of radicals ofJapanese kanji. In the retrieval task, a stimulus word written inhiragana (Japanese syllabary) was presented one by one on a display, andparticipants quickly named the left radical of the target kanjicharacter that corresponded to the stimulus hiragana word. It was foundthat the mean naming latency was shorter and fewer errors were made whenthe left radicals were semantically related to the target kanji thanwhen they were not. Also remarkable was a momentary retrieval failure(i.e., no response) characterized as a `tip-of-the-pen' state which evena high-frequency word precipitated more often in the semanticallyunrelated condition. These results highlight a critical role thatmeaning plays in the activation of orthographic forms of kanji. Somecharacteristic features of writing in kanji are discussed.     

Spelling of Deaf Children Who Use Cochlear Implants

The spellings of 39 profoundly deaf users of cochlear implants, aged 6 to 12 years, were compared with those of 39 hearing peers. When controlled for age and reading ability, the error rates of the 2 groups were not significantly different. Both groups evinced phonological spelling strategies, performing better on words with more typical sound–spelling correspondences and often making misspellings that were phonologically plausible. However, the magnitude of these phonological effects was smaller for the deaf children than for hearing children of comparable reading and spelling ability. Deaf children with cochlear implants made the same low proportion of transposition errors as hearing children. The findings indicate that deaf children do not rely primarily on visual memorization strategies, as suggested by previous studies. However, deaf children with cochlear implants use phonological spelling strategies to a lesser degree than hearing peers.     

Comprehension,recall, and dyslexia: A proposal for the application of schema theory

Evidence suggesting that dyslexia is a multifaceted syndrome is beginning to accumulate. Furthermore, a reexamination of some literature suggests that in addition to having word recognition problems, some dyslexics may also have problems understanding language. Whereas there is a rather extensive literature on word recognition, and even on word understanding, few studies have examined the problems dyslexics may have in understanding and remembering connected discourse. This paper explores issues related to certain possible problems of comprehension and recall among dyslexics and proposes a new direction for research through the application of schema theory. A version of this paper was presented at the meeting of the New England Branch of the Orton Society, Boston, May 1978. Preparation of this paper was supported in part by a grant from Harvard University with funds supplied by the Spencer Foundation. The opinions expressed do not necessarily reflect the position or policy of Harvard or the Spencer Foundation, and no official endorsement should be inferred.     

Morphological,phonological, and orthographic differences between the spelling of normally achieving children and basic literacy adults

In this study, we compared 41 adults in a basic literacy class with 92 achievement-level-matched children on their use of English print conventions, as inferred by a qualitative analysis of spelling errors. The two groups followed similar patterns in their mastery of basic spelling features, including letter reversals, consonant blends, and short vowels, with the adults showing relatively more advanced skill in using orthographic patterns. However, the adults made a preponderance of misspellings that were rarely made by the children, including omissions, substitutions, and additions of derivational and inflectional morphemes, and neglect of word endings in general. The findings indicate clear morphological difficulties along with more subtle phonological coding deficits. We suggest that low literacy adults would benefit from specific direct instruction in linguistic analysis, with particular attention to the morphological principles underlying inflections and derivations. Such instruction should be based on a careful assessment of reading and spelling knowledge.     

Phonemic and graphemic consistency: Effects on decoding for German and American children

Speed, accuracy, and types of errors in decoding lists of words and pseudo words and performance in two phonemic awareness tasks were assessed for German and American children in the first and second grades. German children were significantly better than American children only in pseudo word decoding measures across grades. Between group analyses showed that American children committed more vowel and word substitution errors in both decoding accuracy tasks than German children. Word substitution errors were more likely in word decoding than in pseudo word decoding for children in both languages. Within group analyses indicate that variance in decoding errors and speed accounted for by word substitution versus nonword and vowel versus consonant errors differed dependent on grade and whether real or pseudo words were read. Results suggest successful reading in English depends upon more complex grapheme to phoneme correspondence rules than does reading in German.