Visuospatial superiority in developmental dyslexia: Myth or reality?

Anecdotal evidence indicates that dyslexia is positively associated with superior visuospatial ability but empirical evidence is inconsistent. We explicitly tested the hypothesis that dyslexia is associated with visuospatial advantage in 20 dyslexic and 21 unimpaired adult readers using paper-and-pencil measures and tests of 'everyday' visuospatial ability. We found no main effect of group on visuospatial task performance but did observe a series of significant sex × group interactions. Relative to dyslexic and unimpaired women, dyslexic men were significantly better at identifying shapes in ambiguous figures, reproducing complex figures, reproducing designs using coloured blocks, and recalling the direction of the Queen's head on a postage stamp. They were also significantly faster and more accurate than unimpaired men at navigating and recreating a virtual environment. These data suggest that visuospatial advantage in dyslexia may be confined to men. Possible explanations for this are discussed.     

Cognitive brain potentials in kindergarten children with subtyped risks of reading retardation

Cognition-related brain responses to meaningful and meaningless figures were registered in 5-year-old kindergarten children who either had been subtyped as being at-risk of developing an L- or P-type dyslexia (LAL versus LAP) or who were not at-risk. While identifying, naming, or categorizing pictures, event-related potentials (ERP) were registered. Three cognition-related components were found: the N460, the P780, and the Slow Wave (SW). LAP-children produced weak N460 activity across tasks, whereas LAL children, and to a lesser degree, non-risk children produced robust task-dependent activity. This finding may indicate that LAP-children lack semantic input while processing the figures. P780 latencies to frequently occurring figures were found hemisphere-dependent: LAP-children showed longer latencies in the right than in the left hemisphere, whereas the distribution was reversed in the LAL and non-risk children. It was also found that the right hemisphere is generally responsible for a lion's share of the processing of figures and therefore it seems that the right hemisphere of LAP-children invests ample time in doing so. Whereas LAP-children showed largest SW amplitude differences between frequent and infrequent stimuli at posterior locations, LAL children did so at frontal locations. Assuming that the SW represents working-memory processes, it may be that working-memory in LAP-children deals with figure-relevant visual-spatial information and with figure-derived concepts in LAL children. Overall, the findings suggest that LAL and LAP represent two different groups of kindergartners at risk of dyslexia and that these differences, to some degree, fit with the presumed etiology of L- and P-type dyslexia.     

Performance of children with developmental dyslexia on high and low topological entropy artificial grammar learning task

Graph complexity as measured by topological entropy has been previously shown to affect performance on artificial grammar learning tasks among typically developing children. The aim of this study was to examine the effect of graph complexity on implicit sequential learning among children with developmental dyslexia. Our goal was to determine whether children’s performance depends on the complexity level of the grammar system learned. We conducted two artificial grammar learning experiments that compared performance of children with developmental dyslexia with that of age- and reading level-matched controls. Experiment 1 was a high topological entropy artificial grammar learning task that aimed to establish implicit learning phenomena in children with developmental dyslexia using previously published experimental conditions. Experiment 2 is a lower topological entropy variant of that task. Results indicated that given a high topological entropy grammar system, children with developmental dyslexia who were similar to the reading age-matched control group had substantial difficulty in performing the task as compared to typically developing children, who exhibited intact implicit learning of the grammar. On the other hand, when tested on a lower topological entropy grammar system, all groups performed above chance level, indicating that children with developmental dyslexia were able to identify rules from a given grammar system. The results reinforced the significance of graph complexity when experimenting with artificial grammar learning tasks, particularly with dyslexic participants.     

Phonological and Surface Subtypes among University Students with Dyslexia

The prevalence of phonological and surface dyslexia subtypes among Swedish university students with dyslexia (n = 40) was examined using both the regression method, developed by Castles and Coltheart, and latent profile analysis. When an academic‐level control group was used as a reference group in a regression, eight students with phonological dyslexia and 15 students with surface dyslexia were identified. In contrast, 17 students with phonological dyslexia and two students with surface dyslexia were identified when the subtypes were defined by reference to a reading‐level control group, indicating a deviant profile among the students with phonological dyslexia and delayed development among those with surface dyslexia. The latent profile analysis was based on five phonological and four orthographic tasks. Seven profiles were obtained, of which none exhibited deficits in orthographic but not in phonological skills or vice versa. Thus, the analysis further supported the phonological deficit hypothesis of dyslexia.     

Temporal processing in dyslexia

The temporal processing capabilities of 15 children with dyslexia versus 15 age-matched and 15 reading-matched controls in a word identification task were examined. The hypothesis underlying the present experiment was that word recognition would be inferior in children with dyslexia, relative to controls, when the task demanded the temporal integration (sequencing) of two-syllable words. Such a hypothesis must predict that one-syllable word recognition does not distinguish between these two populations and that these effects cannot be accounted for in terms of eye movement differences. To test this hypothesis, one- and two-syllable words displayed for 100, 300, and 3,000 msec were required to be identified. The results yielded evidence of decreased accuracy of word identification by the children with dyslexia in the two-syllable, 300-msec condition, as predicted. A second experiment was unable to uncover any differences in eye movement behaviors that could account for the effects observed in the first experiment. The results are discussed in terms of potential sequential processing deficits in individuals with dyslexia.     

Children with dyslexia are slow writers because they pause more often and not because they are slow at handwriting execution

It is commonly assumed that children with dyslexia are slower at handwriting than other children. However, evidence of slow handwriting in children with dyslexia is very mixed. Thirty-one children with dyslexia, aged 9 years, were compared to both age-matched children and younger spelling-ability matched children. Participants completed an alphabet-writing task and a composition task on the surface of a digital writing tablet. Children with dyslexia wrote the same amount of letters per minute in the alphabet task but wrote fewer words per minute when composing their texts than children of the same age. Crucially, no differences were found between children with dyslexia and their same age peers for speed of handwriting execution, measured by the tablet, when writing the alphabet or composing their texts. However, children with dyslexia were found to pause within their compositions as often as the spelling ability matched group. Thus handwriting execution is not impaired in children with dyslexia. The slow writing that is typical of children with dyslexia is due to pausing more often when composing and is related to spelling ability. This may reflect processing problems in response to high cognitive load through having to contend with spelling and composing concurrently.     

Do dyslexic individuals present a reduced visual attention span? Evidence from visual recognition tasks of non-verbal multi-character arrays

A controversy has recently developed regarding the hypothesis that developmental dyslexia may be caused, in some cases, by a reduced visual attention span (VAS). To examine this hypothesis, independent of phonological abilities, researchers tested the ability of dyslexic participants to recognize arrays of unfamiliar visual characters. Employing this test, findings were rather equivocal: dyslexic participants exhibited poor performance in some studies but normal performance in others. The present study explored four methodological differences revealed between the two sets of studies that might underlie their conflicting results. Specifically, in two experiments we examined whether a VAS deficit is (a) specific to recognition of multi-character arrays as wholes rather than of individual characters within arrays, (b) specific to characters’ position within arrays rather than to characters’ identity, or revealed only under a higher attention load due to (c) low-discriminable characters, and/or (d) characters’ short exposure. Furthermore, in this study we examined whether pure dyslexic participants who do not have attention disorder exhibit a reduced VAS. Although comorbidity of dyslexia and attention disorder is common and the ability to sustain attention for a long time plays a major rule in the visual recognition task, the presence of attention disorder was neither evaluated nor ruled out in previous studies. Findings did not reveal any differences between the performance of dyslexic and control participants on eight versions of the visual recognition task. These findings suggest that pure dyslexic individuals do not present a reduced visual attention span.     

Spatial ability and achievement in introductory physics

This research was undertaken to clarify the nature of the relationship between visual-spatial abilities and achievement in science courses. A related purpose was to determine what influence visual-spatial abilities have on the high attribution rate characteristic of many introductory college-level science courses. Three sections of introductory college level physics (S = 136) and one nonscience liberal arts section (S = 52) received pre- and postmeasures of visual-spatial ability in the areas of perception, orientation, and visualization. Increases in visual-spatial abilities were greatest with an experimental section that received a spatial intervention. These gains were related to test items that utilized graphical form and to laboratory work. Substantial gains in visual-spatial ability were also registered by a placebo and by control sections. These increases suggest that taking introductory physics improves visual-spatial abilities. Although students who withdrew from the course demonstrated mathematics skills comparable to those of students who completed the course, their scores on perception tests were appreciably lower. Visual-spatial scores of the liberal arts group were lower than those of the physics sections, suggesting that visual-spatial ability influences course selection.     

阅读障碍者的视空间能力:补偿还是缺陷?

阅读障碍者的视空间能力近些年来广受研究者的关注和争论,其争论的焦点在于阅读障碍者的视空间能力存在补偿还是缺陷,不管在英语阅读还是汉语阅读领域都发现了不同的研究结论.迥异甚至相互矛盾的研究结果存在多方面的原因,在未来的研究中,需要更明确的界定阅读障碍的操作性定义、选取更具代表性的被试样本、设计更科学的实验材料、采用更先进的技术手段对阅读障碍者的视空间能力做更精细化、综合性的研究,同时未来也需要更加重视汉语阅读障碍的研究.     

Visual spatial representation in mathematical problem solving by deaf and hearing students

This research examined the use of visual-spatial representation by deaf and hearing students while solving mathematical problems. The connection between spatial skills and success in mathematics performance has long been established in the literature. This study examined the distinction between visual-spatial "schematic" representations that encode the spatial relations described in a problem versus visual-spatial "pictorial" representations that encode only the visual appearance of the objects described in a problem. A total of 305 hearing (n = 156) and deaf (n = 149) participants from middle school, high school, and college participated in this study. At all educational levels, the hearing students performed significantly better in solving the mathematical problems compared to their deaf peers. Although the deaf baccalaureate students exhibited the highest performance of all the deaf participants, they only performed as well as the hearing middle school students who were the lowest scoring hearing group. Deaf students remained flat in their performance on the mathematical problem-solving task from middle school through the college associate degree level. The analysis of the students' problem representations showed that the hearing participants utilized visual-spatial schematic representation to a greater extent than did the deaf participants. However, the use of visual-spatial schematic representations was a stronger positive predictor of mathematical problem-solving performance for the deaf students. When deaf students' problem representation focused simply on the visual-spatial pictorial or iconic aspects of the mathematical problems, there was a negative predictive relationship with their problem-solving performance. On two measures of visual-spatial abilities, the hearing students in high school and college performed significantly better than their deaf peers.     

Cerebellar tests differentiate between groups of poor readers with and without IQ discrepancy

A comprehensive test battery, including phonological, speed, motor and cerebellar tasks, was administered to the entire cohort of two schools for children with learning disabilities. Testing was undertaken blind without accessing the psychometric data on the children. Children were then allocated to a discrepancy group on the basis of their IQ, with the majority (n = 29) classified as nondiscrepant (IQ < 90) and a smaller set (n = 7), with IQ of at least 90, classified as discrepant (with dyslexia). Both groups showed significant deficits relative to age-matched controls on almost all the tests. On phonological, speed, and motor tasks, the nondiscrepant group were at least as severely impaired as the discrepant group. By contrast, on the cerebellar tests of postural stability and muscle tone, the nondiscrepant group performed significantly better than the children with dyslexia and close to the level of the controls. The findings indicate that cerebellar tests may prove a valuable method of differentiating between poor readers with and without IQ discrepancy. The findings are interpreted in terms of the cerebellar deficit hypothesis for dyslexia.     

Assessing visual–spatial talents: the use of the Impossible Figures Task with Chinese students in Hong Kong

Ninety university undergraduate students were tested on a number of tasks assessing their recognition of possible and impossible figures, mental rotation, ideational fluency, and self‐report artistic and creative characteristics. Scores on the Impossible Figures Task (IFT‐14) and the Mental Rotation Test, and self‐ratings on the Artistic Characteristics Rating Scale were found to differentiate among Fine Arts students, Architecture students, and students from Arts Faculty disciplines less related to visual–spatial abilities, suggesting that the IFT‐14 could be used to assess visual–spatial or visual arts talents. The application of the IFT‐14 with the same related measures to a sample of 103 primary and secondary gifted students provided further supporting evidence. Implications of the findings on the development of more sensitive measures for identifying students with visual–spatial or visual arts talents are discussed.     

What is not working in working memory of children with literacy disorders? Evidence from a three-year-longitudinal study

The goals of this study were to explore the deficits in working memory associated with literacy disorders (i.e. developmental disorders of reading and/or spelling) and the developmental trajectories of these working memory deficits. The performance of 28 children with literacy disorders was compared to a non-disabled control group with the same group size at five bi-annual times of measurement in a three-year-longitudinal study beginning at the end of primary school (9.5 years of age). Storage capacity and central-executive working memory were assessed in phonological and visual-spatial modalities, the latter under static and dynamic conditions. Overall, children with literacy disorders were outperformed by their typical developing peers in all phonological and in dynamic visual-spatial storage and central-executive tasks except for the static visual-spatial storage task. Results at single times of measurement revealed that the most consistent deficit was found in the storage capacity of the phonological loop. An additional central-executive impairment is supported by low backward spans. The causes for output deficits in dynamic visual-spatial tasks and good performance under static visual-spatial condition are discussed.     

Impaired visual attention in children with dyslexia

Reading involves the correct and rapid identification of visual stimuli with letters and words. The processing of visual stimuli depends not only on the integrity of the peripheral and central visual system but also on the attentional systems involved. In the present study, a cue-target visual attention task was administered to a population-based sample of 25 children with dyslexia from 10 to 12 years of age. A control group matched for group size, age, and gender was obtained from the same general population. A two-stage screening process involved a spelling task of regular words followed by a battery of five single-word reading tasks. The cue-target task involved both a computer-controlled stimulus presentation and a computer-controlled measurement of reaction time. The data were analyzed by visual field, cue condition (valid, invalid, and no cue), and cue-target interval (CTI). The results showed a general pattern of slower responses in the dyslexia group compared to the control group. The dyslexia group also had longer reaction times in the short CTI condition (covert shift of attention) and in the long CTI condition (overt shift of attention). The findings may reflect a general attentional deficit to visual stimuli in dyslexia, possibly related to problems with the recruitment of necessary cognitive resources for the performance of complex reaction time tasks and for fluent reading.     

Neuropsychological intervention in kindergarten children with subtyped risks of reading retardation

Kindergarten children at risk of developing language problems were administered the Florida Kindergarten Screening Battery. A principal components analysis revealed a verbal and a visual-spatial component and subsequent discriminant function analyses a high verbal/low visual-spatial group (LAL: Latent L) and a high visual-spatial/low verbal group (LAP: Latent P). LAL- and LAP-children were considered at risk for developing an L- or P-type of dyslexia, respectively. As is common practice with children suffering from manifest L- or P- dyslexia, the LAL- and LAP-kindergartners received right and left hemisphere stimulation, respectively. The outcomes were compared with those of bilateral hemispheric stimulation and no intervention. Reading tests were administered in primary school Grades 1 and 5/6; teachers’ evaluation of reading took place in Grade 5/6. Overall, the LAL- and LAP- groups showed significant backwardness in word and text reading, both at early and late primary school. Types of intervention made a difference though: not significantly backward in early word, late word, and late text reading were the LAL-children who had received right hemisphere stimulation. Nonintervened LAP-children did not show significant backwardness in early word reading and late text reading, nor did LAP-children who had received left hemisphere or bilateral stimulation. Early text reading was not affected by any treatment. Teacher’s evaluations were in support of these findings.     

Development of lexical tone awareness in Chinese children with and without dyslexia

This paper describes two studies that examined the lexical tone awareness of Chinese children both with and without dyslexia at different primary school ages.Study 1 examined the contributions of lexical tone awareness to distinguish children with and without dyslexia with respect to their Chinese character reading skills. Two hundred and seventy Chinese children participated in Study 1. Ninety of these were children with dyslexia (equally recruited from second, fourth, and sixth grades). Moreover, ninety children functioned as a chronological-age control group, and an additional ninety children functioned as a reading-level control group. The participants were tested for nonverbal intelligence, Chinese character reading, and cognitive-linguistic skills and lexical tone awareness. Our results revealed a later developmental ceiling in Chinese children with dyslexia than in those without dyslexia. Furthermore, children’s lexical tone awareness could serve to distinguish children with dyslexia from typically developing children in all primary school years.Study 2 compared the lexical tone awareness and Chinese character reading skills of Chinese children with dyslexia both before and after introducing the Perceptual Training Method. The participants in this study consisted of all the participants with dyslexia from Study 1, and the measurements were the Chinese character reading test and the lexical tone awareness task from Study 1. Our results revealed that only second-grade children with dyslexia gained substantially from the training on both lexical tone awareness and character naming, whereas those in the fourth grade obtained a significant improvement only on lexical tone awareness.     

Working memory deficits in children with specific learning disorders

This article examines working memory functioning in children with specific developmental disorders of scholastic skills as defined by ICD-10. Ninety-seven second to fourth graders with a minimum IQ of 80 are compared using a 2 x 2 factorial (dyscalculia vs. no dyscalculia; dyslexia vs. no dyslexia) design. An extensive test battery assesses the three subcomponents of working memory described by Baddeley (1986): phonological loop, visual-spatial sketchpad, and central executive. Children with dyscalculia show deficits in visual-spatial memory; children with dyslexia show deficits in phonological and central executive functioning. When controlling for the influence of the phonological loop on the performance of the central executive, however, the effect is no longer significant. Although children with both reading and arithmetic disorders are consistently outperformed by all other groups, there is no significant interaction between the factors dyscalculia and dyslexia.     

Implicit sequence learning is preserved in dyslexic children

This study investigates the implicit sequence learning abilities of dyslexic children using an artificial grammar learning task with an extended exposure period. Twenty children with developmental dyslexia participated in the study and were matched with two control groups—one matched for age and other for reading skills. During 3 days, all participants performed an acquisition task, where they were exposed to colored geometrical forms sequences with an underlying grammatical structure. On the last day, after the acquisition task, participants were tested in a grammaticality classification task. Implicit sequence learning was present in dyslexic children, as well as in both control groups, and no differences between groups were observed. These results suggest that implicit learning deficits per se cannot explain the characteristic reading difficulties of the dyslexics.     

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.     

Imitation and performance in confrontations between competent peers: The role of the representation of the task

This study (N=75) examined the influence dynamics that take place between two competent individuals presenting divergent solutions for a cognitive task. The hypothesis was that such settings (i.e., conflict of competencies) are unlikely to have a positive effect on intellectual performance because of the representation of the task, and that an increase in performance may be found if such a representation is modified. Three conditions were examined: a control condition in which participants completed the task by themselves, a conflict of competencies condition in which participants declared to be highly competent where confronted with a equally highly competent (bogus) partner who offered diverging solutions (standard conflict of competencies condition), and a conflict of competencies condition in which a decentring procedure was induced to modify the representation of the task. The results showed that participants in the decentring condition solved the task better compared to the standard conflict of competencies condition and the control condition. However, the results unexpectedly revealed imitation in the two conflict of competencies conditions compared to the control condition. Complementary analyses suggest that in the standard conflict of competencies condition imitation corresponds to a defensive motivation.