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.     

Reversing letters and reading transformed text in dyslexia: A reassessment

The visual deficit hypothesis of development dyslexia has largely been abandoned because many of the phenomena that initially motivated it could not be replicated under controlled experimental conditions, while phonological processing deficits were found to provide a better explanation for the replicable phenomena. Nevertheless, many teachers and special educators continue to subscribe to the hypothesis that deficits of visual perception are a major cause of reading failure in dyslexia. As part of a larger family study, we reexamined the questions (1) whether probands and affected relatives in dyslexia families reverse easily confused letters more frequently under experimental conditions than normal readers from the same families, and (2) whether they show unusual facility in reading geometrically transformed text. The findings indicated that young dyslexia students reverse easily confused letters more often than normal readers. Reading group differences of letter reversal were significant in children from 7–10 years but not thereafter; and virtually no subject reversed letters when spelling whole words. Furthermore, dyslexic persons in every age group from 7–60 years actually took longer than normal readers to decode geometrically transformed text; and the time to decode transformed texts increased progressively with age after adolescence in both dyslexic persons and normal readers. Thus, reading group differences in decoding easily confused letters and reading geometrically transformed text do not support the visual deficit hypothesis and probably do not help to clarify the etiology of developmental dyslexia.     

Timing precision and rhythm in developmental dyslexia

Current research on the etiology ofdevelopmental dyslexia is generally informed byeither of two major hypotheses. One of theseassumes that the phonological processing ofconsonants and vowels at a segmental levelidentifies the core deficit in developmentaldyslexia and that it cannot be reduced todomain-general deficits of temporal informationprocessing. The other hypothesis holds thatphonological processing deficits aresymptomatic of an underlying, domain-generaldysfunction; and that at least some dyslexiasubtypes are causally related to domain generaldeficits of temporal information processing forauditory and visual stimuli. This report startsfrom the assumption that the terms temporal information processing andphonological processing as applied in currentdyslexia research, are frequently conflated. Further, it assumes that the conflated termsmust be decomposed into their concretebehavioral referents before the causalsignificance of either can be investigatedsystematically.The studies to be summarized in thisreport represents one step toward suchdecomposition. The findings indicated thatduring a motor sequencing task, dyslexicstudents anticipated the signal of anisochronic pacing metronome by intervals thatwere two or three times as long as those ofage matched normal readers or normal adults.These group differences were significant whenparticipants tapped with the preferred indexfinger alone or with both fingers in unison.Dyslexic students also took significantlylonger than normal readers did to recalibratetheir tapping responses when the metronome ratewas experimentally changed in the middle of atrial.In addition, dyslexic students, bycontrast to normal readers, had inordinatedifficulty reproducing simple motor rhythms byfinger tapping, and similar difficultyreproducing the appropriate speech rhythm oflinguistically neutral nonsense syllables.These difficulties were exaggerated whenparticipants had to synchronize theirperformance to an external pacing metronome.The implications of the findings for temporalinformation processing deficits on one hand,and impaired phonological processing on theother, are discussed.     

Developmental dyslexia,neurolinguistic theory and deviations in brain morphology

Although some form of central nervous system involvement is presumed, evidence establishing a relationship between dyslexia and neurological dysfunction has been correlational. Recently, neuroimaging and postmortem studies have begun to provide direct evidence implicating neuropathological structures in dyslexia. This article reviews computed tomography (CT) and magnetic resonance imaging (MRI) studies examining deviations in brain morphology which appear to be associated with neurolinguistic functioning. Methodological and technical issues are discussed. Based on their own and others research, the authors conclude that dyslexics show variations in specific brain regions, namely, reversed or symmetrical plana temporale (LR), smaller insular length bilaterally, and symmetrical frontal regions. Moreover, recent studies by the senior author and colleagues suggest that specific reading tasks are associated with specific variations in brain morphology. Symmetrical frontal widths was related to poorer passage comprehension, and reversed frontal area symmetry was related to poor word attack skills. Though many conceptual and technical issues remain unresolved, neuroimaging procedures appear to provide direct evidence supporting the importance of deviations in normal patterns of brain morphology in dyslexia.     

The representation and attainment of students with dyslexia in UK higher education

Using a database of allstudents in higher education in the UK in1995–1996, students with dyslexia and those withno reported disability were compared in termsof demographic properties, programmes of studyand academic attainment. Students with dyslexiaconstituted 0.42% of all students resident inthe UK. Their representation varied with age,gender, ethnicity and entrance qualificationsand with their level, mode and subject ofstudy. Students with dyslexia were more likelyto withdraw during their first year of studyand were less likely to complete theirprogrammes of study, although with appropriatesupport the completion rate of students withdyslexia can match that of students with nodisabilities. In addition, students withdyslexia who completed first-degree programmestended to gain a poorer class of honours thanstudents with no reported disability, but 40%obtained first-class or upper second-classhonours. In short, dyslexia may havedeleterious consequences for progression,completion and achievement in higher education,but it is by no means incompatible with a highlevel of success, given appropriate commitmenton the part of the students and appropriateresources on the part of their institution.     

Artificial grammar learning in primary school children with and without developmental dyslexia

This paper explores implicit learning in typically developing and primary school children (9–12 years old) with developmental dyslexia using an artificial grammar learning (AGL) task. Two experiments were conducted, which differed in time of presentation and nature of the instructional set (experiment 1—implicit instructions vs experiment 2—explicit instructions). Repeated measures analysis of variance (group × grammaticality × chunk strength) showed a group effect only in experiment 1 (implicit instructions), with only the typically developing children showing evidence of AGL. There was a grammaticality effect (adherence to the rules) for both groups in the two experimental situations. We suggest that the typically developing children exhibited intact implicit learning as manifested in AGL performance, whereas children with developmental dyslexia failed to provide such evidence due to possible mediating cognitive developmental factors.     

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.     

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.     

Developmental dyslexia,cerebellar/vestibular brain function and possible links to exercise-based interventions: a review

The Phonological Processing Deficit (PPD) hypothesis remains the most influential theory to explain why some children fail to acquire appropriate reading skills. However, current research suggests that there may be other deficits operating, and that the phonological processing deficit may be just one manifestation of a deeper underlying anatomical syndrome that originates in the cerebellar or vestibular areas of the brain. Claims that exercise regimes or programmes of vestibular stimulation may provide a ‘cure’ for developmental dyslexia (specific reading difficulties) prompt scepticism among the scientific community and raise concerns about the exploitation of vulnerable parents. The paper provides a review of research into the causes of specific reading difficulties at the behavioural, cognitive and biological level of explanation, and considers whether or not there is any theoretical basis for the use of exercise-based intervention programmes. Following consideration of recent findings from a range of scientific disciplines, it is concluded that such ‘unconventional’ methods of intervention may draw some theoretical support from the scientific literature, although researchers are cautioned to be wary of comorbidity issues. It is also concluded that more rigorous and independent evaluations of the success (or otherwise) of exercise-based interventions are needed.     

Coexisting problem behaviour in severe dyslexia

A small group of children and young adolescent with dyslexia has severely impaired reading skills despite prolonged special education. These are the students in focus. In dyslexia, problem behaviour, internalised as well as externalised, has previously been reported, so also for the participants with dyslexia in this study. The aim of the present study was to obtain more in‐depth knowledge of the behaviour problems from various informants, representing different settings. This kind of information is imperative for identifying problem behaviour, and for planning and implementing remedial programmes. A clinical group of 70 students with severe dyslexia, due to phonological problems, and a control group of 70 without reading problems participated. The two groups were pair‐wise matched on age, gender, cognitive level and whether they lived in rural or urban areas. Mean age was 150 months, and mean IQ was approximately 100 in both groups. Parents, teachers and participants provided information on behaviour through the Achenbach questionnaires Child Behavior Checklist, Teacher's Report Form and Youth Self Report. Behaviour is, in these questionnaires, divided into eight syndrome areas called Withdrawn, Somatic Complaints, Anxious/Depressed, Social Problems, Thought Problems, Attention Problems, Delinquent Behavior and Aggressive Behavior. The three informant groups reported significantly more problems in the dyslexia group than in the controls in all the syndrome areas. Parents reported more children with dyslexia to be anxious and depressed, and have social problems and attention problems than teachers. They also reported suicidal ideations in nine participants with dyslexia. In addition, parents rated more internalising and total problems in the dyslexia group than teachers.     

Secondary symptoms of dyslexia: a comparison of self-esteem and anxiety profiles of children with and without dyslexia

The secondary symptoms of individuals with dyslexia, such as high anxiety and low self-esteem, have aroused various debates not only in the educational, but also in the clinical context. Since pro and contra arguments are supported by a more or less equal number of empirical findings, no final conclusion could be drawn for this specific phenomenon. The current study aims to contribute more data in this respect and offers a possible explanation for both sides that either support or reject the relationship between dyslexia and its secondary symptoms. The main investigation of this study is the comparison of anxiety and self-esteem profiles of children with and without dyslexia. Participants are 124 school children aged between eight and 11 years. Their IQ as well as their reading and writing ability were also measured and used as control variables. All data were collected and analysed using a quantitative approach. Effect sizes are also provided in order to facilitate meta-analysis in the future and to confirm the results of a significant test. The results indicate that children with dyslexia have anxiety and self-esteem issues in the specific context or domain. However, their general anxiety and self-esteem were not impaired. A discussion regarding the possibility and/or the necessity of the secondary symptoms of dyslexia is also provided.     

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.     

Auditory and motor rhythm awareness in adults with dyslexia

Children with developmental dyslexia appear to be insensitive to basic auditory cues to speech rhythm and stress. For example, they experience difficulties in processing duration and amplitude envelope onset cues. Here we explored the sensitivity of adults with developmental dyslexia to the same cues. In addition, relations with expressive and receptive rhythm tasks, such as tempi recognition and manual tapping to a metronome, were explored. Our goal was to investigate whether the auditory deficits seen in dyslexia are specific to cues to speech rhythm and stress, or are part of a wider rhythmic awareness problem. A group of 19 undergraduate students with dyslexia were compared with 20 age‐ and ability‐matched controls. The findings confirmed a relationship between auditory rhythm sensitivity and literacy in adults, as well as showing an association with metronome inter‐tap‐interval variability.     

快速命名与汉语发展性阅读障碍的研究综述

近年来快速命名与发展性阅读障碍的研究,主要讨论了快速命名对发展性阅读障碍产生预测性作用的主要原因:语音能力、正字法能力和任意性的形音联结.虽然鲜有研究涉及任意性的形音联结,但这个因素在形音关系不透明的汉语中,可能与阅读过程和快速命名都存在很大的相关性.今后应设立一个有效的统一的鉴别发展性阅读障碍儿童的标准,逐渐形成中文阅读发展的体系.     

Identifying dyslexia with confirmatory latent profile analysis

Confirmatory latent profile analysis (CLPA) was used with the normative sample from the Kaufman Test of Educational Achievement, 3rd ed. (KTEA‐3) to determine whether it was possible to identify a latent class of individuals whose scores were consistent with the academic strengths and weaknesses related to dyslexia. The CLPA identified a class of individuals consistent with dyslexia across four‐grade level groups (first–second, third–fifth, sixth–eighth, and ninth–twelfth). The results of the CLPA were applied to the KTEA‐3 clinical samples of those with known clinical diagnoses. Individuals with Specific Learning Disorder in Reading and/or Written Expression had a higher probability of being in the dyslexia latent class. The use of CLPA as a tool for learning disability diagnosis appears plausible, though much more research is needed. The strengths, limitations, and future directions for the use of CLPA in diagnosis are discussed.     

The impact of dyslexia on pupils' self‐esteem

This study investigates the factors that affect the self‐esteem of learners with dyslexia. It provides a brief overview of some of the key literature in this area and then describes a small‐scale study conducted in two mainstream secondary schools in the north of England. Data were collected using semi‐structured interviews with secondary‐aged pupils who had received an official diagnosis of dyslexia. Nine pupils volunteered to be interviewed. The study considers the impact of factors such as comparisons made against other students and the impact of teachers, peers and family on pupils' self‐esteem. The results of the study indicate that these factors contribute significantly to self‐esteem for pupils with dyslexia. However, the study found that the most significant factor that contributed to students' self‐esteem was a positive diagnosis of ‘dyslexia’ and ownership of the label. The study concludes that an early diagnosis of dyslexia is essential for creating a positive self‐image and recommends that further research is necessary into the significance of the diagnosis for these learners.     

Screening for multiple genes influencing dyslexia

Genetic linkage analysis is a means of localizing genes to specific chromosomal regions. Localization of genes influencing specific reading disability (dyslexia) can lead to characterization of the phenotypic effects of each gene and to early diagnosis of children at risk. Previous studies using the family study LOD score method of linkage analysis have identified two chromosomal regions that may contain genes influencing dyslexia. The present study examines the sib pair method of linkage analysis, which has several advantages over the LOD score method. In particular, the mode of inheritance does not need to be specified and diagnosis of parents is not required, but it is a less powerful technique. Using the same population as the previous studies (with less than 200 sib pairs) and two different means of diagnosis of dyslexia, the sib pair analysis was able to detect the same suggested linkages as the LOD score method, plus a possible third region. This confirms that the sib pair method is an effective means of screening for linkage with reasonable sample sizes.