Dyslexics

Distribution by Scientific Domains

Terms modified by Dyslexics

  • dyslexic adult
  • dyslexic child

  • Selected Abstracts


    Dyslexia and psycho-social functioning: an exploratory study of the role of self-esteem and understanding

    DYSLEXIA, Issue 4 2009
    Melody M. Terras
    Abstract Individuals with dyslexia may have lower self-esteem and exhibit more emotional and behavioural difficulties than those without reading problems. However, the nature of any relationship between self-esteem and psychopathology remains unknown. This exploratory study assessed levels of self-esteem using the Self-Perception Profile for Children (Manual for the Self-Perception Profile for Children. University of Denver, CO: Denver; 1985) and psycho-social adjustment using the Strengths and Difficulties Questionnaire (J. Child Psychol. Psychiatry, 1997; 38: 581,586) and examined child and parent understanding, attitudes and the perceived impact of reading difficulties on daily life. Sixty-eight children assessed as dyslexic on the basis of discrepancy scores (mean age 11.2 years; 44 male), and their parents, participated. No global self-esteem deficit was found, but the mean score for both child and parent-rated scholastic competence was significantly lower than that of the general population. Rates of social, emotional and behavioural difficulties were significantly higher than in the general population and were correlated with self-esteem. For children who had high global self-worth, both children and their parents had more positive attitudes towards their reading difficulties and were less likely to perceive a negative impact on relationships. The association between academic self-esteem and emotional symptoms is consistent with the proposed link between dyslexia and internalizing difficulties. Good self-esteem and a good understanding of dyslexia may help children avoid some of these difficulties. Further research with larger more representative samples is necessary as understanding the factors that promote successful psycho-social adjustment is essential to the development of effective prevention and intervention strategies. Copyright © 2009 John Wiley & Sons, Ltd. [source]


    Low-level defective processing of non-verbal sounds in dyslexic children

    DYSLEXIA, Issue 2 2009
    Paulino Uclés
    Abstract We compared processing of non-verbal auditory stimuli by dyslexic and non-dyslexic children using electrophysiological methods. The study included 39 children (17 with dyslexia plus 22 controls) assessed via frontal, central, parietal, and temporal electrodes. As an extension of previous P300 event-related potential studies, we analysed variations in the power values of 40-Hz oscillations (gamma-band oscillations involved in cognitive processing) during a specific time window in response to the auditory ,oddball' paradigm that entail target (random 2,kHz) and standard (frequent 1,kHz) stimuli. Dyslexic children differed significantly from controls (P<0.001) in the mean power of the wavelet-transformed 40-Hz oscillation in a time interval starting at 25 ms after stimulus onset up to 50 ms. This means defective processing of sounds. Within groups, standard and target tones elicited significantly different power values (P<0.001). Correlations of values between standard and target responses at each electrode position were not significant within either group, although dyslexics showed a lower correlation than controls. Significant differences in the mean power of these oscillations detected at very early stages of auditory processing in dyslexic children and the wide range of mean values reveal impairment in processing non-verbal sounds in dyslexia. Our results also support recent findings using behavioural and electrophysiological methods suggesting that dyslexia is a general auditory deficit instead of a speech-specific deficit. Copyright © 2008 John Wiley & Sons, Ltd. [source]


    Sensitivity to visual and auditory stimuli in children with developmental dyslexia

    DYSLEXIA, Issue 2 2008
    Bernardine King
    Abstract This study considered the extent to which 23 children with dyslexia differed from 23 reading age (RA) and 23 chronological age (CA) matched controls in their ability to make temporal judgements about auditory and visual sequences of stimuli, and in the speed of their reactions to the onsets and offsets of visual and auditory stimuli. The children with dyslexia were slower (p,=,0.039) than the CA controls in their reactions to non-verbal auditory onsets (tones), were less able to recognize the first stimulus of a sequence of tones (p,=,0.022), and were less accurate in identifying the initial phoneme of a sequence of three (p,<,0.001). These characteristics may be manifestations of an impaired temporal processing system for rapid auditory stimuli. CA controls responded more quickly to tone onsets than to tone offsets (p,=,0.025), but the dyslexic and RA groups showed no significant difference (p,>,0.05) in their reaction times to onsets and offsets of these non-verbal auditory stimuli. Dyslexic readers showed impairment compared with CA controls in responding to the last of a sequence of three non-verbal visual stimuli (shapes), p,=,0.02. Reaction times in the visual and auditory onset and offset tasks were richly intercorrelated in the control groups, but the dyslexic group did not show as many significant correlations in reaction times between the auditory and visual domains, or between the onset and offset RTs within each modality. These results suggest that there may be a less integrated cross-modal and intra-modal temporal system in children with dyslexia than in controls. In many of the measures in this study, the performance of the dyslexic group resembled that of the RA control group but differed from CA controls, which implies a developmental delay. The possibility that such a cognitive delay may be related to an underlying neurological disorder is discussed. Copyright © 2007 John Wiley & Sons, Ltd. [source]


    Dichotic listening and school performance in dyslexia

    DYSLEXIA, Issue 1 2008
    Turid Helland
    Abstract This study focused on the relationship between school performance and performance on a dichotic listening (DL) task in dyslexic children. Dyslexia is associated with impaired phonological processing, related to functions in the left temporal lobe. DL is a frequently used task to assess functions of the left temporal lobe. Due to the predominance of the contralateral neuronal pathways, a right ear advantage in the DL task reflects the superior processing capacity for the right ear stimulus in the left hemisphere (Kimura, 1963). Previous studies using DL in dyslexia are, however, inconclusive, and may reflect degree of severity of dyslexia. The aim of the present study was therefore to investigate lateralized processing in two sub-groups of dyslexia, differing in symptom severity. Two groups of dyslexic 12-year-old children and an age-matched control group were tested with a consonant,vowel DL task. The two dyslexia groups differed in severity through how they responded to training efforts being made in their schools, while otherwise being matched for age, IQ and diagnosis. The D1 (respondent group) group showed a DL performance pattern similar to the control group, i.e. a right ear advantage, while the D2 (non-respondent) group failed to show a right ear advantage on the DL task. The performance on the DL task by the two dyslexia groups may provide better insight as to the degree of reading and writing impairment in dyslexia. ,Cracking the code' and acquiring automatized literacy skills may seem harder for the D2 group children compared to the D1 children. Also, the present study points to the use of DL as a valid assessment tool in clinical work to improve differential diagnoses, particularly in relation to measures of school performance. Copyright © 2007 John Wiley & Sons, Ltd. [source]


    Dichotic listening deficits in children with dyslexia

    DYSLEXIA, Issue 1 2008
    Deborah W. Moncrieff
    Abstract Several auditory processing deficits have been reported in children with dyslexia. In order to assess for the presence of a binaural integration type of auditory processing deficit, dichotic listening tests with digits, words and consonant,vowel (CV) pairs were administered to two groups of right-handed 11-year-old children, one group diagnosed with developmental dyslexia and an age-matched control group. Dyslexic children performed more poorly than controls from their left ears when listening to digits and words and from their right ears when listening to CVs. Direction of ear advantage varied across individuals in both groups when tested with digits and CVs, but ear advantage was stable with words. Several factors that may have contributed to inconsistencies in direction of ear advantage are discussed. When the children were tested in a directed response mode, degree of ear advantage differed significantly between groups with both words and digits. More dyslexic than control children demonstrated clinically significant reductions in dichotic listening performance, but no uniform pattern of deficit emerged. Only the double correct score and the left ear score with CV pairs were predictive of word recognition performance in dyslexic children. Binaural integration deficits are present in some children with dyslexia. Auditory processing disorder assessment may help delineate factors that underlie or are associated with reading impairment in this population. Copyright © 2007 John Wiley & Sons, Ltd. [source]


    The dyslexic student and mathematics in higher education

    DYSLEXIA, Issue 3 2007
    Glynis Perkin
    Abstract Difficulties that are encountered by dyslexic undergraduates with their learning and understanding of mathematics are explored. Specific consideration is given to issues arising through mathematical content, its delivery, the procedures and processes of ,doing' mathematics, and its assessment. Particular difficulties, which have emerged through exploratory and explanatory multiple-case studies, and witnessed through the provision of one-to-one support to a dyslexic and dyspraxic engineering undergraduate, are detailed. Recommendations for the provision of mathematical support to dyslexic students and proposals for future research are given. Copyright © 2007 John Wiley & Sons, Ltd. [source]


    Follow-up of an exercise-based treatment for children with reading difficulties

    DYSLEXIA, Issue 2 2007
    David Reynolds
    Abstract This study reports the results of a long-term follow-up of an exercise-based approach to dyslexia-related disorders (Reynolds, Nicolson, & Hambly, Dyslexia, 2003; 9(1): 48,71). In the initial study, children at risk of dyslexia were identified in 3 years of a junior school. One half then undertook a 6 month, home-based exercise programme. Evaluation after 6 months indicated that the exercise group improved significantly more than the controls on a range of cognitive and motor skills. Critics had suggested that the improvement might be attributable to artifactual issues including Hawthorne effects; an initial literacy imbalance between the groups; and inclusion of non-dyslexic participants. The present study evaluated the issue of whether the gains were maintained over the following 18 months, and whether they were in some sense artifactual as postulated by critics of the original study. Comparison of (age-adjusted) initial and follow-up performance indicated significant gains in motor skill, speech/language fluency, phonology, and working memory. Both dyslexic and non-dyslexic low achieving children benefited. There was also a highly significant reduction in the incidence of symptoms of inattention. Interestingly there were no significant changes in speeded tests of reading and spelling, but there was a significant improvement in (age-adjusted) reading (NFER). It is concluded that the gains were indeed long-lasting, and that the alternative hypotheses based on potential artifacts were untenable, and that the exercise treatment therefore achieved its applied purpose. Further research is needed to determine the underlying reasons for the benefits. Possible (and potentially synergistic) explanations include: improved cerebellar function (neural level); improved learning ability and/or attentional ability (cognitive level); improved self-esteem and self-efficacy (affective level); and improved parental/familial support (social level). Copyright © 2006 John Wiley & Sons, Ltd. [source]


    Language-related differences between discrepancy-defined and non-discrepancy-defined poor readers: a longitudinal study of dyslexia in New Zealand

    DYSLEXIA, Issue 1 2007
    William E. Tunmer
    Abstract Language-related differences between discrepancy-defined and non-discrepancy-defined poor readers were examined in a three-year longitudinal study that began at school entry. The discrepancy-defined (dyslexic) poor readers (n = 19) were identified in terms of poor reading comprehension and average or above average listening comprehension performance, and the non-discrepancy-defined (non-dyslexic) poor readers (n = 19) in terms of both poor reading and listening comprehension performance. The two poor reader groups and a group of normally developing readers (n = 55) were given several oral language, phonological processing, and reading performance measures at six testing occasions. Results indicated that in addition to expected differences on the oral language measures, the non-discrepancy-defined poor readers also showed greater phonological processing deficits than the dyslexic poor readers. The results are discussed in terms of the lack of official recognition of dyslexia in New Zealand, the whole language orientation of classroom reading instruction, and the inadequacy of Reading Recovery for minimizing reading problems. Copyright © 2006 John Wiley & Sons, Ltd. [source]


    Balancing and pointing tasks in dyslexic and control adults

    DYSLEXIA, Issue 4 2006
    Catherine J. Stoodley
    Abstract Developmental dyslexia may affect as much as 15% of the population, but the aetiology of the disorder is still being debated. The cerebellar theory of dyslexia proposes that cerebellar dysfunction could lead to the myriad of symptoms seen in dyslexic individuals, both in literacy and non-literacy domains. The cerebellum is crucial to the fluent performance of motor skills. Previous studies have found that dyslexic children are worse than control children on certain motor and balancing tasks. Here the performance of 28 dyslexic compared to 26 control adults on rapid pointing and balancing measures, tasks which are thought to reflect cerebellar function, was investigated. There were no significant differences between the dyslexic and control participants on the balancing tasks or when the speed and accuracy of pointing were analysed separately. However, when the speed and accuracy of pointing were combined, the dyslexic participants showed poorer performance than the controls (p = 0.045). Furthermore, there were significant relationships between performance on the pointing task and literacy skills, and regression analysis showed that the error and speed of pointing contributed significantly to the variance in literacy skill. The implications for the role of the cerebellum and processing speed in dyslexia are discussed. Copyright © 2006 John Wiley & Sons, Ltd. [source]


    Verbatim and gist recall of sentences by dyslexic and non-dyslexic adults

    DYSLEXIA, Issue 3 2006
    T. R. Miles
    Abstract Forty-eight college students, 24 of them dyslexic, were presented with four sentences of increasing complexity. Participants were asked to repeat each sentence and a record was kept of the number of repetitions required before 100% correct accuracy was achieved. None of the 24 control participants required a total of more than eight repetitions over the four sentences, whereas among the dyslexics the total number of repetitions needed ranged from one to 25. Dyslexic participants were unpredictable in their performance from one level of difficulty to the next and inter-individual variability was far greater in the dyslexic group than in the control group. Overall, despite their relatively poor performance in achieving verbatim accuracy relative to non-dyslexic participants, dyslexic individuals regularly managed to preserve the gist of the sentences. Some theoretical issues arising from these results are discussed. Copyright © 2006 John Wiley & Sons, Ltd. [source]


    Visual, auditory and cross-modal processing of linguistic and nonlinguistic temporal patterns among adult dyslexic readers

    DYSLEXIA, Issue 2 2005
    Ann Meyler
    Abstract This study examined visual, auditory, and cross-modal temporal pattern processing at the nonlinguistic and sublexical linguistic levels, and the relationships between these abilities and decoding skill. The central question addressed whether dyslexic readers are impaired in their perception of timing, as assessed by sensitivity to rhythm. Participants were college-level adult dyslexic and normal readers. The dyslexic adults evidenced generalized impairment in temporal processing: they were less accurate and slower than normal readers when required to detect the temporal gap that differentiated pairs of patterns. Impairment was greatest when processing visual syllables. Temporal pattern processing correlated to decoding ability only among normal readers. It is suggested that high-functioning dyslexics may cope with temporal processing problems by adopting a predominantly holistic, orthographic strategy when decoding. It is proposed that there may be cumulative effects of processing demands from different sources including modality, stimulus complexity, and linguistic demands, and that combinations of these may interact to impact temporal processing ability. Moreover, there may be fundamentally distinct and dissociable temporal processing abilities, each of which may be differently linked developmental dyslexia. Copyright © 2005 John Wiley & Sons, Ltd. [source]


    The characteristics of young and adult dyslexics readers on reading and reading related cognitive tasks as compared to normal readers

    DYSLEXIA, Issue 2 2005
    Shelley Miller-Shaul
    Abstract Most of the research into dyslexia has been carried out among children and has raised the question whether the characteristics of young dyslexics are similar to those of adult dyslexics. The aim of this research was, therefore, to confirm whether the cognitive deficits, which appear among young dyslexics on reading and reading related tasks, are similar among adult dyslexics. Four groups of subjects were tested in this study: two groups of fourth graders, dyslexic and normal readers, and two groups of students, compensated dyslexics and normal readers. A comparison of the differences in research measures between the young dyslexics and their control group, and between the adult dyslexics and their control group, clearly indicates that the difference between regular readers and dyslexics is significantly smaller in the adult group on orthographic tasks, and this difference increases in adults on phonological tasks. The findings of this study reinforce the assumption that dyslexics have particular difficulty with the phonological-auditory channel. Another main finding is the slow speed of processing in verbal and non-verbal tasks. It can be assumed that these problems start at a young age and persist in compensated adult dyslexics. Copyright © 2005 John Wiley & Sons, Ltd. [source]


    Dyslexia in English as a second language

    DYSLEXIA, Issue 1 2005
    Turid Helland
    Abstract This study focused on English as L2 in a group of Norwegian dyslexic 12 year olds, compared to an age and gender matched control group. Norwegian school children learn English from the first grades on. The subjects were assessed with a test battery of verbal and written tasks. First, they were given a comprehension task; second, a model sentence task; third, two pragmatic tasks, and fourth, three tasks of literacy. The verbal tasks were scored according to comprehension, morphology, syntax and semantics, while the literacy tasks were scored by spelling, translation and reading skills. It was hypothesized that the results of the control group and the dyslexia group would differ on all tasks, but that subgrouping the dyslexia group by comprehension skills would show heterogeneity within the dyslexia group. The data analyses confirmed these hypotheses. Significant differences were seen between the dyslexia group and the control group. However, the subgrouping revealed minor differences between the control group and the subgroup with good comprehension skills, and major differences between the control group and the subgroup with poor comprehension skills. Especially morphology and spelling were difficult for the dyslexia group. The results were tentatively discussed within the framework of biological and cognitive models of how to interpret L2 performance in dyslexia, underlining the importance of further research in L2 acquisition in dyslexia. Copyright © 2004 John Wiley & Sons, Ltd. [source]


    Prevalence of persistent primary reflexes and motor problems in children with reading difficulties

    DYSLEXIA, Issue 4 2004
    M. McPhillips
    Abstract It has been shown that some children with reading difficulties have underlying developmental delay and that this may be related to the persistence of primary reflexes. This study investigated the prevalence of persistent primary reflexes in the ordinary primary school population and how this related to other cognitive and social factors. Three groups of 41 children were drawn from a representative, cross-sectional sample of 409 children (aged 9,10 years) attending 11 ordinary primary schools in N. Ireland. The three groups represented the bottom, middle and top 10% respectively of readers from the total sample population. The relative persistence (on a scale of 0 to 4) of the Asymmetrical Tonic Neck Reflex (ATNR) and the prevalence of motor difficulties were assessed for these 3 groups. The rôle of 5 predictor variables (verbal IQ, social deprivation, sex, month of birth and religious affiliation) in determining the reading level of the total sample was also investigated. It was found that the lowest reading group had a significantly higher mean level of ATNR (1.56 [95% CI 1.22,1.90]) compared with the middle reading group (0.56 [0.22,0.90]) and the top reading group (0.59 [0.25,0.92]). 17% of children in the lowest reading group had extremely high levels of the ATNR while 24% showed no presence of ATNR. This contrasted with 0% and 66%, respectively for both middle and top reading groups. It was also found that there was a significant difference between the lowest reading group and the top reading group on a standardised test of motor ability. Furthermore, there was evidence that ATNR persistence but not motor ability was associated with the sex of the child with boys, in particular, at risk. There was no evidence that ATNR persistence or motor ability was significantly associated with social deprivation. It was also found that there were no significant differences between dyslexic and non-dyslexic children with reading difficulties in motor (including balance) performance. This study highlights the high levels of primary reflex persistence in children with reading difficulties and it provides further evidence of the association between reading difficulties and movement difficulties in young children. However, while the implications for intervention are discussed, it is stressed that the persistence of primary reflexes cannot be used as a causal model for reading difficulties, including dyslexia. Copyright © 2004 John Wiley & Sons, Ltd. [source]


    Working memory: Its role in dyslexia and other specific learning difficulties

    DYSLEXIA, Issue 3 2004
    Sharman Jeffries
    Abstract This paper reports a study contrasting dyslexic children against a control group of children without special educational needs (SEN) and a group with varied SENs. Children's abilities were compared on tasks assessing phonological processing, visuo-spatial/motor coordination and executive/inhibitory functioning; being targeted for assessment based on theoretical proposals related to the working memory model. Primary and secondary school level children were tested: 21 assessed as dyslexic with no comorbid difficulties, 26 children assessed with difficulties including dyspraxia, emotional/behavioural problems and attention deficits, 40 children with no known education-related deficits were controls. Results indicated both SEN groups performed worse than controls on working memory phonological loop measures. However, SEN groups could only be differentiated on phonological awareness measures: the dyslexics showing lower scores. Dyslexics performed as well as controls on working memory visuo-spatial scratch pad measures and one of two additional visual,motor coordination tasks, whereas the performance of the other SEN children was lowest on the majority of these measures. Central executive and interference measures engendered mixed performances, both SEN groups showing evidence of deficits in one or more of these areas of functioning, although, of the two SEN groups, the dyslexics seem to have performed the worse when digit name processing was required. Copyright © 2004 John Wiley & Sons, Ltd. [source]


    Evidence for implicit sequence learning in dyslexia

    DYSLEXIA, Issue 1 2002
    Steve W. Kelly
    Abstract Nicolson and Fawcett (Cognition 1990; 35: 159,182) have suggested that a deficit in the automatization of skill learning could account for the general impairments found in dyslexia. Much of the evidence for their claims has been collected via a dual task paradigm, which might allow for alternative explanations of the data. The present study examines automatic skill learning in a single task paradigm and extends previous studies by independently examining the contribution of stimulus-based and response-based learning. The task replicates Mayr's (J. Exp. Psychol.: Learning Memory Cognition 1996; 22: 350,364) methodology in the Serial Reaction Time task by exposing participants to two structured displays, simultaneously. Learning is measured by comparing RT to the learned sequence against RT to a random display. This study demonstrates learning for both dyslexic and control groups for a spatial sequence which was observed and a concurrent non-spatial sequence which was responded to via a keypress. Learning of the sequence did not seem to depend on awareness of the sequence structure. These results suggest that automatic skill learning is intact in dyslexic individuals. Copyright © 2002 John Wiley & Sons, Ltd. [source]


    An examination of the relationship between dyslexia and offending in young people and the implications for the training system

    DYSLEXIA, Issue 2 2001
    Jane Kirk
    Abstract A screening study was undertaken which involved 50 young offenders, serving sentences of various lengths, all from the largest young offenders' institution in Scotland. All 50 were screened for dyslexia and a number received a more detailed follow-up assessment. The results of the screening showed that 25 of the young offenders (50%) were dyslexic to some degree. This finding has implications for professionals, particularly in respect of follow-up assessment and support, and for politicians in relation to issues such as school experience, prison education and staff training. These issues are discussed here in relation to the background and results of the study. Copyright © 2001 John Wiley & Sons, Ltd. [source]


    The magnocellular theory of developmental dyslexia

    DYSLEXIA, Issue 1 2001
    John Stein
    Abstract Low literacy is termed ,developmental dyslexia' when reading is significantly behind that expected from the intelligence quotient (IQ) in the presence of other symptoms,incoordination, left,right confusions, poor sequencing,that characterize it as a neurological syndrome. 5,10% of children, particularly boys, are found to be dyslexic. Reading requires the acquisition of good orthographic skills for recognising the visual form of words which allows one to access their meaning directly. It also requires the development of good phonological skills for sounding out unfamiliar words using knowledge of letter sound conversion rules. In the dyslexic brain, temporoparietal language areas on the two sides are symmetrical without the normal left-sided advantage. Also brain ,warts' (ectopias) are found, particularly clustered round the left temporoparietal language areas. The visual magnocellular system is responsible for timing visual events when reading. It therefore signals any visual motion that occurs if unintended movements lead to images moving off the fovea (,retinal slip'). These signals are then used to bring the eyes back on target. Thus, sensitivity to visual motion seems to help determine how well orthographic skill can develop in both good and bad readers. In dyslexics, the development of the visual magnocellular system is impaired: development of the magnocellular layers of the dyslexic lateral geniculate nucleus (LGN) is abnormal; their motion sensitivity is reduced; many dyslexics show unsteady binocular fixation; hence poor visual localization, particularly on the left side (left neglect). Dyslexics' binocular instability and visual perceptual instability, therefore, can cause the letters they are trying to read to appear to move around and cross over each other. Hence, blanking one eye (monocular occlusion) can improve reading. Thus, good magnocellular function is essential for high motion sensitivity and stable binocular fixation, hence proper development of orthographic skills. Many dyslexics also have auditory/phonological problems. Distinguishing letter sounds depends on picking up the changes in sound frequency and amplitude that characterize them. Thus, high frequency (FM) and amplitude modulation (AM) sensitivity helps the development of good phonological skill, and low sensitivity impedes the acquisition of these skills. Thus dyslexics' sensitivity to FM and AM is significantly lower than that of good readers and this explains their problems with phonology. The cerebellum is the head ganglion of magnocellular systems; it contributes to binocular fixation and to inner speech for sounding out words, and it is clearly defective in dyslexics. Thus, there is evidence that most reading problems have a fundamental sensorimotor cause. But why do magnocellular systems fail to develop properly? There is a clear genetic basis for impaired development of magnocells throughout the brain. The best understood linkage is to the region of the Major Histocompatibility Complex (MHC) Class 1 on the short arm of chromosome 6 which helps to control the production of antibodies. The development of magnocells may be impaired by autoantibodies affecting the developing brain. Magnocells also need high amounts of polyunsaturated fatty acids to preserve the membrane flexibility that permits the rapid conformational changes of channel proteins which underlie their transient sensitivity. But the genes that underlie magnocellular weakness would not be so common unless there were compensating advantages to dyslexia. In developmental dyslexics there may be heightened development of parvocellular systems that underlie their holistic, artistic, ,seeing the whole picture' and entrepreneurial talents. Copyright © 2001 John Wiley & Sons, Ltd. [source]


    Rapid processing of letters, digits and symbols: what purely visual-attentional deficit in developmental dyslexia?

    DEVELOPMENTAL SCIENCE, Issue 4 2010
    Johannes C. Ziegler
    Visual-attentional theories of dyslexia predict deficits for dyslexic children not only for the perception of letter strings but also for non-alphanumeric symbol strings. This prediction was tested in a two-alternative forced-choice paradigm with letters, digits, and symbols. Children with dyslexia showed significant deficits for letter and digit strings but not for symbol strings. This finding is difficult to explain for visual-attentional theories of dyslexia which postulate identical deficits for letters, digits and symbols. Moreover, dyslexics showed normal W-shaped serial position functions for letter and digit strings, which suggests that their deficit is not due to an abnormally small attentional window. Finally, the size of the deficit was identical for letters and digits, which suggests that poor letter perception is not just a consequence of the lack of reading. Together then, our results show that symbols that map onto phonological codes are impaired (i.e. letters and digits), whereas symbols that do not map onto phonological codes are not impaired. This dissociation suggests that impaired symbol-sound mapping rather than impaired visual-attentional processing is the key to understanding dyslexia. [source]


    The role of sensorimotor impairments in dyslexia: a multiple case study of dyslexic children

    DEVELOPMENTAL SCIENCE, Issue 3 2006
    Sarah White
    This study attempts to investigate the role of sensorimotor impairments in the reading disability that characterizes dyslexia. Twenty-three children with dyslexia were compared to 22 control children, matched for age and non-verbal intelligence, on tasks assessing literacy as well as phonological, visual, auditory and motor abilities. The dyslexic group as a whole were significantly impaired on phonological, but not sensorimotor, tasks. Analysis of individual data suggests that the most common impairments were on phonological and visual stress tasks and the vast majority of dyslexics had one of these two impairments. Furthermore, phonological skill was able to account for variation in literacy skill, to the exclusion of all sensorimotor factors, while neither auditory nor motor skill predicted any variance in phonological skill. Visual stress seems to account for a small proportion of dyslexics, independently of the commonly reported phonological deficit. However, there is little evidence for a causal role of auditory, motor or other visual impairments. [source]


    Developmental dyslexia and explicit long-term memory

    DYSLEXIA, Issue 3 2010
    Deny Menghini
    Abstract The reduced verbal long-term memory capacities often reported in dyslexics are generally interpreted as a consequence of their deficit in phonological coding. The present study was aimed at evaluating whether the learning deficit exhibited by dyslexics was restricted only to the verbal component of the long-term memory abilities or also involved visual-object and visual-spatial domain. A further goal of the present study was to investigate the predictive value of non-verbal long-term memory abilities with respect to word and non-word reading in dyslexic children. In accordance with these aims, performances of 60 dyslexic children were compared with that of 65 age-matched normal readers on verbal, visual-spatial and visual-object task. Results documented a generalized impairment of episodic long-term memory capacities in dyslexic children and the results did not vary as a function of children's age. Furthermore, in addition to verbal measures, also individual differences in non-verbal long-term memory tasks turn out to be good predictors of reading difficulties in dyslexics. Our findings indicate that the long-term memory deficit in dyslexia is not limited to the dysfunction of phonological components but also involves visual-object and visual-spatial aspect, thus suggesting that dyslexia is associated to multiple cognitive deficits. Copyright © 2010 John Wiley & Sons, Ltd. [source]


    Effects of dyslexia on postural control in adults

    DYSLEXIA, Issue 2 2010
    M. Patel
    Abstract Dyslexia has been shown to affect postural control. The aim of the present study was to investigate the difference in postural stability measured as torque variance in an adult dyslexic group (n=14, determined using the Adult Dyslexia Checklist (ADCL) and nonsense word repetition test) and an adult non-dyslexic group (n=39) on a firm surface and on a foam block and with eyes open and eyes closed. Another aim was to investigate the correlation between ADCL scores and postural stability. Findings showed that ADCL scores correlated with torque variance in the anteroposterior direction on foam with eyes closed (p=0.001) and in the lateral direction on the foam surface with eyes closed (p=0.040) and open (p=0.010). General Linear Model analysis showed that high dyslexia scores were associated with increased torque variance (p<0.001). However, we found no significant difference between dyslexics and non-dyslexics, though there were indications of larger torque variance in the dyslexics. The findings suggest that adults with high dyslexic ADCL scores may experience sub-clinical balance deficits. Hence, assessing motor ability and postural control in those with high ADCL scores is motivated. Copyright © 2010 John Wiley & Sons, Ltd. [source]


    Low-level defective processing of non-verbal sounds in dyslexic children

    DYSLEXIA, Issue 2 2009
    Paulino Uclés
    Abstract We compared processing of non-verbal auditory stimuli by dyslexic and non-dyslexic children using electrophysiological methods. The study included 39 children (17 with dyslexia plus 22 controls) assessed via frontal, central, parietal, and temporal electrodes. As an extension of previous P300 event-related potential studies, we analysed variations in the power values of 40-Hz oscillations (gamma-band oscillations involved in cognitive processing) during a specific time window in response to the auditory ,oddball' paradigm that entail target (random 2,kHz) and standard (frequent 1,kHz) stimuli. Dyslexic children differed significantly from controls (P<0.001) in the mean power of the wavelet-transformed 40-Hz oscillation in a time interval starting at 25 ms after stimulus onset up to 50 ms. This means defective processing of sounds. Within groups, standard and target tones elicited significantly different power values (P<0.001). Correlations of values between standard and target responses at each electrode position were not significant within either group, although dyslexics showed a lower correlation than controls. Significant differences in the mean power of these oscillations detected at very early stages of auditory processing in dyslexic children and the wide range of mean values reveal impairment in processing non-verbal sounds in dyslexia. Our results also support recent findings using behavioural and electrophysiological methods suggesting that dyslexia is a general auditory deficit instead of a speech-specific deficit. Copyright © 2008 John Wiley & Sons, Ltd. [source]


    The incidence of dyslexia among young offenders in Kuwait

    DYSLEXIA, Issue 2 2009
    Gad Elbeheri
    Abstract This paper investigates the incidence of dyslexia among young offenders in Kuwait. A total of 91 children/young adults from 8 juvenile delinquent welfare centres across Kuwait were interviewed and tested. A measure of non-verbal reasoning ability was used to exclude those with low general ability. The remaining 53 participants were tested on their ability to identify alliteration and rhyme, retain and manipulate sequences of digit and letter names, decode novel letter strings and identify words within letter chains. Participants' reading accuracy, rate of reading, reading comprehension and ability to spell correctly dictated text were also assessed. These measures were used to determine those with indicators of dyslexia. The results indicated that the percentage of individuals presenting evidence of dyslexia was much larger (greater than 20%) in this population of young offenders than would be expected based on the national average (around 6%) of dyslexics in Kuwait derived from a nationwide study (A survey study of dyslexia in Kuwait, Kuwait Dyslexia Association: Kuwait City; 2002). These findings replicate previous evidence for an increased frequency of dyslexia among young offenders. The implications of such findings are discussed in terms of dyslexia awareness, socio-cultural factors, education and intervention, particularly in Kuwait juvenile delinquent welfare centres. Copyright © 2008 John Wiley & Sons, Ltd. [source]


    Phonological and orthographic spelling in high-functioning adult dyslexics

    DYSLEXIA, Issue 2 2009
    Nenagh Kemp
    Abstract Despite a history of reading or spelling difficulties, some adults attain age-appropriate spelling skills and succeed at university. We compared the spelling of 29 such high-functioning dyslexics with that of 28 typical students, matched on general spelling ability, and controlling for vocabulary and non-verbal intelligence. Participants wrote derived real and pseudo words, whose spelling relationship to their base forms was categorized as phonologically simple (apt-aptly), orthographically simple (deceit-deceitful), phonologically complex (ash-ashen), or orthographically complex (plenty-plentiful). Dyslexic participants spelled all word and pseudoword categories more poorly than controls. Both groups spelled simple phonological words best. Dyslexics were particularly poor at spelling simple orthographic words, whose letter patterns and rules must likely be memorized. In contrast, dyslexics wrote more plausible spellings of orthographic than phonological pseudowords, but this might be an artefact of their more variable spelling attempts. These results suggest that high-functioning dyslexics make some use of phonological skills to spell familiar words, but they have difficulty in memorizing orthographic patterns, which makes it difficult to spell unfamiliar words consistently in the absence of sufficient phonological cues or orthographic rules. Copyright © 2008 John Wiley & Sons, Ltd. [source]


    The sources and manifestations of stress amongst school-aged dyslexics, compared with sibling controls

    DYSLEXIA, Issue 4 2008
    Neil Alexander-Passe
    Abstract All school children experience stress at some point in their school careers. This study investigates whether dyslexic children, by way of their educational and social difficulties, experience higher levels of stress at school. The School Situation Survey was used to investigate both the sources and manifestations of stress amongst dyslexic children and non-dyslexic sibling controls. Samples were broken down by gender, age and the size of families. Results suggest significant differences between the groups, with dyslexics in academic years 3,5 experiencing the highest stress levels, specifically in interactions with teachers, worries over academic examinations (SATs) and performance testing, causing emotional (fear, shyness and loneliness) and physiological (nausea, tremors or rapid heart beat) manifestations. Results also suggest that dyslexics in larger families (3,4 sibling families) experience greater stress in interactions with their peers, than those in smaller families (two sibling families),possibly from unfair sibling comparison. Copyright © 2007 John Wiley & Sons, Ltd. [source]


    Verbatim and gist recall of sentences by dyslexic and non-dyslexic adults

    DYSLEXIA, Issue 3 2006
    T. R. Miles
    Abstract Forty-eight college students, 24 of them dyslexic, were presented with four sentences of increasing complexity. Participants were asked to repeat each sentence and a record was kept of the number of repetitions required before 100% correct accuracy was achieved. None of the 24 control participants required a total of more than eight repetitions over the four sentences, whereas among the dyslexics the total number of repetitions needed ranged from one to 25. Dyslexic participants were unpredictable in their performance from one level of difficulty to the next and inter-individual variability was far greater in the dyslexic group than in the control group. Overall, despite their relatively poor performance in achieving verbatim accuracy relative to non-dyslexic participants, dyslexic individuals regularly managed to preserve the gist of the sentences. Some theoretical issues arising from these results are discussed. Copyright © 2006 John Wiley & Sons, Ltd. [source]


    Exploring dyslexics' phonological deficit I: lexical vs sub-lexical and input vs output processes

    DYSLEXIA, Issue 4 2005
    Gayaneh Szenkovits
    Abstract We report a series of experiments designed to explore the locus of the phonological deficit in dyslexia. Phonological processing of dyslexic adults is compared to that of age- and IQ-matched controls. Dyslexics' impaired performance on tasks involving nonwords suggests that sub-lexical phonological representations are deficient. Contrasting nonword repetition vs auditory nonword discrimination suggests that dyslexics are specifically impaired in input phonological processing. These data are compatible with the hypothesis that the deficit initially affects input sub-lexical processes, and further spreads to output and lexical processes in the course of language acquisition. Further longitudinal research is required to confirm this scenario as well as to tease apart the role of the quality of phonological representations from that of verbal short-term memory processes. Copyright © 2005 John Wiley & Sons, Ltd. [source]


    Visual, auditory and cross-modal processing of linguistic and nonlinguistic temporal patterns among adult dyslexic readers

    DYSLEXIA, Issue 2 2005
    Ann Meyler
    Abstract This study examined visual, auditory, and cross-modal temporal pattern processing at the nonlinguistic and sublexical linguistic levels, and the relationships between these abilities and decoding skill. The central question addressed whether dyslexic readers are impaired in their perception of timing, as assessed by sensitivity to rhythm. Participants were college-level adult dyslexic and normal readers. The dyslexic adults evidenced generalized impairment in temporal processing: they were less accurate and slower than normal readers when required to detect the temporal gap that differentiated pairs of patterns. Impairment was greatest when processing visual syllables. Temporal pattern processing correlated to decoding ability only among normal readers. It is suggested that high-functioning dyslexics may cope with temporal processing problems by adopting a predominantly holistic, orthographic strategy when decoding. It is proposed that there may be cumulative effects of processing demands from different sources including modality, stimulus complexity, and linguistic demands, and that combinations of these may interact to impact temporal processing ability. Moreover, there may be fundamentally distinct and dissociable temporal processing abilities, each of which may be differently linked developmental dyslexia. Copyright © 2005 John Wiley & Sons, Ltd. [source]


    The characteristics of young and adult dyslexics readers on reading and reading related cognitive tasks as compared to normal readers

    DYSLEXIA, Issue 2 2005
    Shelley Miller-Shaul
    Abstract Most of the research into dyslexia has been carried out among children and has raised the question whether the characteristics of young dyslexics are similar to those of adult dyslexics. The aim of this research was, therefore, to confirm whether the cognitive deficits, which appear among young dyslexics on reading and reading related tasks, are similar among adult dyslexics. Four groups of subjects were tested in this study: two groups of fourth graders, dyslexic and normal readers, and two groups of students, compensated dyslexics and normal readers. A comparison of the differences in research measures between the young dyslexics and their control group, and between the adult dyslexics and their control group, clearly indicates that the difference between regular readers and dyslexics is significantly smaller in the adult group on orthographic tasks, and this difference increases in adults on phonological tasks. The findings of this study reinforce the assumption that dyslexics have particular difficulty with the phonological-auditory channel. Another main finding is the slow speed of processing in verbal and non-verbal tasks. It can be assumed that these problems start at a young age and persist in compensated adult dyslexics. Copyright © 2005 John Wiley & Sons, Ltd. [source]