The cognitive profile and multiple-deficit hypothesis in Chinese developmental dyslexia.

The present study was conducted to examine the cognitive profile and multiple-deficit hypothesis in Chinese developmental dyslexia. Thirty Chinese dyslexic children in Hong Kong were compared with 30 average readers of the same chronological age (CA controls) and 30 average readers of the same reading level (RL controls) in a number of rapid naming, visual, phonological, and orthographic tasks. Chinese dyslexic children performed significantly worse than the CA controls but similarly to the RL controls on most of the cognitive tasks. The rapid naming deficit was found to be the most dominant type of cognitive deficit in Chinese dyslexic children. Over half of the dyslexic children exhibited deficits in 3 or more cognitive areas, and there was a significant association between the number of cognitive deficits and the degree of reading and spelling impairment. The present findings support the multiple-deficit hypothesis in Chinese developmental dyslexia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Understanding chinese developmental dyslexia: Morphological awareness as a core cognitive construct.

Tasks representing 9 cognitive constructs of potential importance to understanding Chinese reading development and impairment were administered to 75 children with dyslexia and 77 age-matched children without reading difficulties in 5th and 6th grade. Logistic regression analyses revealed that dyslexic readers were best distinguished from age-matched controls with tasks of morphological awareness, speeded number naming, and vocabulary skill; performance on tasks of visual skills or phonological awareness failed to distinguish the groups. Path analyses further revealed that a construct of morphological awareness was the strongest consistent predictor of a variety of literacy-related skills across both groups. Findings suggest that morphological awareness may be a core theoretical construct necessary for explaining variability in reading Chinese. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Double dissociation of functions in developmental dyslexia and dyscalculia.

This work examines the association between symbols and their representation in adult developmental dyscalculia and dyslexia. Experiment 1 used comparative judgment of numerals, and it was found that in physical comparisons (e.g., 3-5 vs. 3-5) the dyscalculia group showed a significantly smaller congruity effect than did the dyslexia and the control groups. Experiment 2 used Navon figures (D. Navon, 1977) in Hebrew, and participants were asked to name the large or the small letters. Phoneme similarity modulated performance of the control and the dyscalculia groups and showed a very small effect in the dyslexia group. This suggests that the dyscalculia population has difficulties in automatically associating numerals with magnitudes but no problems in associating letters with phonemes, whereas the dyslexia population shows the opposite pattern. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implications of visual search deficits for cognitive theory.

Neuropsychological evidence was presented and found to be consistent with Treisman's Feature Integration Theory (FIT). Several studies were reported using groups of patients with unilateral visual neglect, stable patients with known lesion loci, and a single patient with bilateral parietal-occipital lesions. Collectively, the data support a distinction between feature and conjunction search. They also support arguments for the primary role of spatial representation in forming correct conjunctions between features and for individuating objects. Nevertheless, the data do call for some refinements in FIT. The spatial maps involved in feature integration for serial visual search and for the experience of an accurately conjoined object appear to be relatively late. Features are likely to be integrated in the nervous system at sub-threshold levels in early vision (e.g., vl or v2), but it requires supra-threshold spatial knowledge to successfully conjoin features in visual experience (Wojciulik, Robertson & Kanwisher, 1994). The evidence as a whole, however, is consistent with FIT in that spatial information is necessary for controlled visual search and for the accurate conjunction of features in multi-item arrays. In addition, it suggests that explicit access to relatively late spatial information is necessary to correctly conjoin features in the experiences percept. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention-based visual processes.

Attention is often compared to a spotlight or locus of enhanced processing. We have found that this gain comes with certain unexpected costs. Specifically, judgments of positions of stimuli surrounding an attended event are distorted, repelled away from the additional focus. But there is more to attention than just selection. Our work shows that it is better characterized as an image which keeps track of attended objects. We find that the resolution or grain of attention--the finest packing of targets which still allows an individual item to be identified and tracked--is much coarser than the smallest visual feature which can be resolved. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Less efficient elementary visuomotor processes in 7- to 10-year-old preterm-born children without cerebral palsy: An indication of impaired dorsal stream processes.

Follow-up studies of preterm children without serious neurological complications have consistently found deficits in visuomotor skills. To determine whether these deficits may be related to impaired elementary visuomotor processes, we investigated movement programming and execution of simple pointing movements in 7- to 10-year-old preterm (     

Functional MRI activation in children with and without dyslexia during pseudoword aural repeat and visual decode: Before and after treatment.

Children without dyslexia (n=10) received nonphonological treatment, and those with dyslexia received phonological (n=11) or nonphonological (n=9) treatment. Before and after treatment they performed aural repeat, visual decode, and aural match pseudoword tasks during functional MRI scanning that separated stimulus input from response production. Group map analysis indicated that children with dyslexia overactivated compared with good readers during the aural-repeat/aural-match contrast in bilateral frontal (Brodmann's area [BA] 3, 4, 5, 6, 9), left parietal (BA 2, 3), left temporal (BA 38), and right temporal (BA 20, 21, 37) regions (stimulus input) and underactivated in right frontal (BA 24, 32) and right insula (BA 48) regions (response production); they underactivated in BA 19/V5 during the visual-decode/aural-match contrast (response production). Individual brain analysis for children with dyslexia revealed that during the aural-repeat/aural-match contrast (stimulus input), phonological treatment decreased and normalized activation in left supramarginal gyrus and postcentral gyrus. Nonphonological treatment increased and normalized activation during the visual-decode/aural-match contrast (response production) in BA19/V5 and changed activation in the same direction as good readers during aural-repeat/aural-match contrast (stimulus input) in left postcentral gyrus. The significance of the findings for competing theories of dyslexia is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prolonged reading tasks in visual research.

Two experiments are reported on the relationship of speed of perception in reading varying type faces to the length of the reading period. "Reading periods of 10 minutes or more produced a significant retardation in reading italic in comparison with roman print… . Retardation in speed of reading all-capital material in comparison with roman print was large and approximately the same irrespective of the length of the reading period within the limits of 4 to 16 minutes… . Measuring speed of perception in reading is a relatively sensitive technique for use in typographical studies when prolonged periods of reading are employed." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Art students who cannot draw: Exploring the relations between drawing ability, visual memory, accuracy of copying, and dyslexia.

Some art students, despite being at art school, cannot draw very well, and would like to be able to draw well. It has been suggested that poor drawing may be a particular problem for students with dyslexia (and a high proportion of art school students is dyslexic). In Study 1 we studied 277 art students, using a questionnaire to assess self-perceived drawing ability and a range of background measures, including demography, education, a history of dyslexia, a self-administered spelling test, and personality and educational variables. In Study 2 we gave detailed drawing tests to a sample of 38 of the art students, stratified by self-rated drawing ability and spelling ability, and to 30 control participants. Students perceiving themselves as good at drawing did indeed draw better than self-perceived poor drawers, although the latter were still better than non-art student controls. In neither Study 1 nor Study 2 did skill at drawing relate to dyslexia or spelling ability, and neither did drawing ability relate to any of our wide range of background measures. However Study 2 did show that drawing ability was related both to ability at copying simple angles and proportions (using the “house” task of Cain, 1943), and also to visual memory (as suggested by Jones, 1922), poor drawers being less good at both immediate and delayed recall of the Rey-Osterrieth complex figure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-related deficits in component processes of working memory.

Working memory deficits in normal aging have been well documented, and studies suggest that high memory load plus the presence of distraction negatively impacts successful memory performance to a greater degree in older individuals. However, characterization of the component processes that are impaired by these task manipulations is not clear. In this behavioral study, younger and older subjects were tested with a delayed-recognition and recall task in which the encoding and delay period were both manipulated. During the encoding period, the subjects were presented with either a single letter or multiple letters at their predetermined forward letter span, and the delay period was either uninterrupted or interrupted with a visual distraction. There was an age-related impairment of working memory recognition accuracy only in the combination of high memory load and distraction. These results suggest that when working memory maintenance systems are taxed, faulty recognition processes may underlie cognitive aging deficits in healthy older individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and visual marking: Selective deficits for moving stimuli.

The selective processing of new visual information can be facilitated by the top-down inhibition of old stimuli already in the visual field, a capacity-limited process termed visual marking (D. G. Watson & G. W. Humphreys, 1997). Three experiments assessed the effects of aging on visual marking using stationary (Experiment 1) and moving (Experiments 2 and 3) items. For young participants, visual marking was observed in all experiments. For older participants, visual marking was observed only with stationary items. The results are not consistent with any simple account of general age-related decrements and provide further support for the deployment of different methods of visual marking depending on the properties of the old items and the current task demands. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of two visual display presentations.

The applicability of the results of dial legibility studies based on slide presentations to legibility of actual dials was tested experimentally by comparison of time and error measures for reading actual dials, and reading slide projections of the dials. There was a slight but insignificant advantage in favor of panelmounted slides over projection of pictures of the slides. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Order or disorder? Impaired Hebb learning in dyslexia.

The present study offers an integrative account proposing that dyslexia and its various associated cognitive impairments reflect an underlying deficit in the long-term learning of serial-order information, here operationalized as Hebb repetition learning. In nondyslexic individuals, improved immediate serial recall is typically observed when one particular sequence of items is repeated across an experimental session, a phenomenon known as the Hebb repetition effect. Starting from the critical observation that individuals with dyslexia seem to be selectively impaired in cognitive tasks that involve processing of serial order, the present study is the first to test and confirm the hypothesis that the Hebb repetition effect is affected in dyslexia, even for nonverbal modalities. We present a theoretical framework in which the Hebb repetition effect is assumed to be a laboratory analogue of naturalistic word learning, on the basis of which we argue that dyslexia is characterized by an impairment of serial-order learning that affects language learning and processing. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Age-related deficits in guided search using cues.

The ability of young and older adults to engage in guided conjunction search was tested in 2 experiments. In the cued condition, a picture of the target was presented before the search. In the noncued condition, there was no picture of the target. In Experiment 1, the cue was presented for 200 ms; the magnitude of the cuing effect (noncued response time - cued response time) was greater for the young than for the older observers. In Experiment 2 (older observers only), the cue duration was doubled, and older observers had a larger magnitude of cuing effect than found in Experiment 1 but not as large as what would be expected under generalized slowing. The results indicated that older observers had difficulty with interpreting the cue and setting search parameters when the target varied across trials. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relevance of audio-visual feedback mechanisms in the acquisition of reading skills.

There has been much confusion in the past on the topic of reading disabilities. The distinction is made between acquired cases of dyslexia where a previously acquired language skill is lost as the result of injury, disease or trauma to the central nervous system and cases of a more congenital nature where children seem to find it very difficult to acquire the normal reading skills. The study of acquired dyslexia has thrown much light on the various brain centra involved in all the complex language skills of which reading and writing is but one aspect. The cases of congenital dyslexia which are encountered frequently in all schools more than likely have little evidence of brain damage. Rather, a development lag or neurological disorganization seems to be at the root of such troubles. The importance of cerebral laterality for speech and language skills is being realized. In particular it appears that auditory dominance, an aspect of laterality that is still being investigated, is extremely important in the acquisition and execution of language skills. When a subject's voice is picked up by a microphone, delayed for .2" and then fed back to the subject via earphones the subject begins to stutter. Under certain conditions it is possible to demonstrate that the subject's speech will be more impaired when this delayed feedback is on his dominant ear than when it is on his non-dominant ear suggesting an assymetry of the monitoring functions of the two ears. This finding, if further investigated and validated, may have far reaching consequences in the remediation of language disorders. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Supramodality effects in visual and haptic spatial processes.

In this article, the authors investigated unimodal and cross-modal processes in spatial working memory. A number of locations had to be memorized within visual or haptic matrices according to different experimental conditions known to be critical in accounting for the effects of perception on imagery. Results reveal that some characteristics of the generated mental image remained strictly inherent to the modality in which information was acquired; in general, accuracy was higher when configurations were visually rather than haptically explored (Experiments 1 and 3). Interestingly, the same pattern emerged when the effects of simultaneous versus sequential processing of the stimuli inherent to vision and haptics were isolated from perceptual modality (Experiment 2). Supramodal elements were also identified (Experiment 3) that were specifically associated to the nature of the cognitive processes, regardless of the original characteristics of the sensory information. These data indicate that both unimodal modality-specific and higher order supramodal mechanisms are simultaneously used in spatial processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dual-task attention deficits in dysphoric mood.

The attentional functioning of nondysphoric, mildly dysphoric, and moderately to severely dysphoric college students was tested using the attentional blink (AB) paradigm. These groups performed equally well at reporting a single target appearing in a rapidly presented stream of stimuli. All groups showed an AB, with report sensitivity for a 2nd target being reduced when the 2 targets were presented less than 0.5 s apart. Nondysphoric and mildly dysphoric participants showed the same size ABs, but the ABs for moderately to severely dysphoric participants were larger and longer. As predicted, the results showed that moderately to severely dysphoric individuals have attentional impairments. These impairments, however, were evident only in the more demanding dual-task condition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predicting delayed letter knowledge development and its relation to Grade 1 reading achievement among children with and without familial risk for dyslexia.

The authors examined the developmental trajectories of children's early letter knowledge in relation to measures spanning and encompassing their prior language-related and cognitive measures and environmental factors and their subsequent Grade 1 reading achievement. Letter knowledge was assessed longitudinally at ages 4.5, 5.0, 5.5, and 6.5 years; earlier language skills and environmental factors were assessed at ages 3.5 and 4.5 years; and reading achievement was assessed at the beginning and end of Grade 1. The analyses were conducted on a longitudinal data set involving children with and without familial risk for dyslexia. Emerging from the trajectory analysis of letter knowledge were 3 separate clusters: delayed (n = 63), linearly growing (n = 73), and precocious (n = 51). The members of the delayed cluster were predominantly children with familial risk for dyslexia, and the members of the precocious cluster were predominantly control group children. Phonological sensitivity, phonological memory, and rapid naming skills predicted delayed letter knowledge. Environmental predictors included level of maternal education and the amount of letter name teaching. Familial risk for dyslexia made a significant contribution to the predictive relations. Membership in the delayed cluster predicted poor reading performance at Grade 1. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A comparison of the cognitive deficits in reading disability and attention-deficit/hyperactivity disorder.

This study used a nonreferred sample of twins to contrast the performance of individuals with reading disability (RD; n?=?93), attention-deficit/hyperactivity disorder (ADHD; n?=?52), RD and ADHD (n?=?48), and neither RD nor ADHD (n?=?121) on measures of phoneme awareness (PA) and executive functioning (EF). Exploratory factor analysis of the EF measures yielded underlying factors of working memory, inhibition, and set shifting. Results revealed that ADHD was associated with inhibition deficits whereas RD was associated with significant deficits on measures of PA and verbal working memory. The RD?+?ADHD group was most impaired on virtually all measures, providing evidence against the phenocopy hypothesis as an explanation for comorbidity between RD and ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Commentary on two articles concerning generalized and specific cognitive deficits.

This is a commentary on essays in this journal issue by M. E. Strauss (see record 2001-17627-002) and R. A. Knight and S. A Silverstein (see record 2001-17627-003) on research methodology for studying cognitive deficits. Concentrating mostly on Knight and Silverstein's article, the authors review the psychometric issues in the matched-task design, analyze Knight and Silverstein's "process-oriented" objections to that design, and scrutinize their methods for studying cognitive deficits, examining 2 of their empirical studies as examples of those methods. (PsycINFO Database Record (c) 2010 APA, all rights reserved)