1/12. The role of level of representation in the use of paired associate learning for rehabilitation of alexia.patients with phonological alexia (difficulty reading pseudowords) frequently have concomitant difficulty reading functor words and verbs compared with concrete nouns. The current study compares two techniques for helping two patients with phonological alexia regain the ability to read functors and verbs. One technique follows the approach of reorganization of function, while the other relies on the stimulation approach. Study 1, employing a reorganization approach, resulted in both patients increasing their reading accuracy from approximately 10 to 90% or greater. Study 2, using a stimulation approach, resulted in significant improvement, however neither patient was able to achieve accuracy greater than 59%. Study 3 reverted back to the reorganization approach using the same words from Study 2. Both patients demonstrated significant success, achieving 90% or greater accuracy. Whereas the reorganization approach meets with far greater success than the stimulation approach, both approaches can be seen as instances of paired associate learning. An explanation of the advantage of the reorganization approach is developed which focuses on the nature of the pairings in the paired associate learning paradigm: it is proposed that pairings within the same level of representation are easier to learn than pairings that cut across levels of representation.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
2/12. Morphological units in the Arabic mental lexicon: evidence from an individual with deep dyslexia.An ongoing debate in Arabic morphology concerns the nature of the smallest unit governing lexical organization and representation in this language. A standard model maintains that Arabic words are typically analyzable into a three-consonantal root morpheme carrying the core meaning of words and a prosodic template responsible mostly for grammatical information. This view has been largely supported by research in both theoretical linguistics and psycholinguistics. An alternative theory holds that the meaning of words in Arabic is, rather, encoded in the 'etymon' comprising two unordered consonants of the root only. Results from a recent priming experiment have shown that the etymon induces strong morphological priming effects, supporting its morphological/lexical status. In this paper we present data from a patient with deep dyslexia questioning the role of the etymon as a psychologically real representational unit in Arabic and arguing, instead, for the central role of the root in both morphological and lexical representation in this language.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
3/12. A visual disorder producing highly selective deletion of recurring letters.A case of unusually selective deletion of recurring letters is described. The disorder was primarily visual, spelling being unaffected. There was no evidence of neglect. reading was fluent and rapid (not letter-by-letter), though words often appeared as a series of resolving fragments. Selective deletions were entirely confined to adjacent letters, excluding explanation in terms of repetition blindness (Kaniwisher, 1991). Mixing case and font, or increasing inter-letter distance, did not alter rate of recurring letter deletion, provided the task required some form of perceptual grouping. The final 2 experiments establish the pre-lexical nature of the deficit; they show deletion of recurring symbols, for example, when copying Navon-style global forms constructed from same or different Greek letters. This visual deficit is explained using the neural network model developed by Rolls and Deco (2002).- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
4/12. When phonology fails: orthographic neighbourhood effects in dyslexia.Both cerebral hemispheres contain phonological, orthographic and semantic representations of words, however there are between-hemisphere differences in the relative engagement and specialization of the different representations. Taking orthographic processing for example, previous studies suggest that orthographic neighbourhood size (N) has facilitatory effects in the right but not the left hemispheres. To pursue the nature of this asymmetric N effect, in particular whether there are individual differences in such specialisation, we examined N in a case of developmental dyslexia, FM. We first describe the nature of his difficulties, which are mainly severe phonological deficits. Employing the divided visual field paradigm with FM revealed a greater sensitivity in the right than in the left hemisphere to orthographic variables, with a significant inhibitory N effect in the left, but not right hemisphere. Such inhibition, to a lesser degree, was found among a group of adults with dyslexia but not among age-matched normal readers. We argue that enhanced sensitivity to orthographic cues is developed in some cases of dyslexia when a normal, phonology-based left hemisphere word recognition processing is not achieved. The interpretation presented here is cast in terms of differences between people with dyslexia and typical readers that originate in the atypical way in which orthographic representations are initially set up.- - - - - - - - - - ranking = 2keywords = nature (Clic here for more details about this article) |
5/12. Developmental dyslexia in a regular orthography: a single case study.This study of an adult case examined in detail with eye movement measures the reading speed problem which is characteristic for developmental dyslexia in regular orthographies. A dramatic length effect was found for low frequency words and for pseudowords, but not for high frequency words. However, even for high frequency words it was found that reading times were substantially prolonged although number of fixations did not differ. A neurocognitive assessment revealed no visual deficits (parallel processing, precedence detection, coherent motion detection) but speed impairments for certain verbal and phonological processes. We propose that the reading difficulties are phonological in nature, but these difficulties become manifest as inefficiency and not as inability.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
6/12. The selective impairment of the phonological output buffer: evidence from a Chinese patient.We present a Chinese-speaking patient, SJ, who makes phonological errors across all tasks involving oral production. Detailed analyses of the errors across different tasks reveal that the patterns are very similar for reading, oral picture naming, and repetition tasks, which are also comparable to the error patterns of the phonological buffer deficit cases reported in the literature. The nature of the errors invites us to conclude that the patient's phonological output buffer is selectively impaired. Different from previously reported cases, SJ's deficits in oral production tasks are not accompanied by a similar impairment of writing performance. We argue that this dissociation is evidence that the phonological output buffer is not involved in writing Chinese words. Furthermore, the majority of SJ's errors occur at the onset of a syllable, indicating that the buffer has a structure that makes the onset more prone to impairment.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
7/12. Different patterns of dissociation in unilateral spatial neglect.The aim of this paper is to discuss the issue of dissociations found in unilateral spatial neglect according to the modality of space exploration and the nature of the task. For this purpose we present a reanalysis of the data from a recent paper of Gentilini et al. (1989) comparing visual and blindfolded exploration of a computer keyboard and discuss the performance of a left-brain-damaged patient with right visuospatial neglect and left-sided neglect dyslexia. We conclude that unilateral spatial neglect cannot be interpreted as a disruption of a single attentional mechanism, but rather it reflects impaired attentional mechanisms at several levels of cognitive processing.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
8/12. The psycholinguistic analysis of acquired dyslexias: some illustrations.Three approaches to the neuropsychology of cognitive function are distinguished: the neuroanatomical (where the primary concern is to correlate particular disorders of cognitive function with particular lesion sites), the 'general-cognitive' (in which associations are sought between impairments of performance on specific cognitive tasks and general disorders of broadly defined cognitive processes) and the model-building (in which one attempts to interpret the pattern of impairments and preservations of some cognitive function produced by brain damage in terms of an explicit model of the normal operation of this function). I claim that the model-building approach to the neuropsychology of cognitive function must take precedence over the other two. One reason for this is that any disorder of cognitive function can only be defined with reference to some model of that function. I illustrate this claim with reference to acquired disorders of reading, describing current work of a psycholinguistic nature dealing with two acquired disorders of reading: phonological dyslexia and surface dyslexia. A psycholinguistic account of normal reading is used as a theoretical framework to define and to explain the patterns of deficit and preservation observed in these two dyslexias. The detailed account of surface dyslexia in English provided by this framework is then used to make predictions about the nature of surface dyslexia in other languages: alphabetically written languages where all words are regularly spelled, or where homophones cannot occur, as well as ideographically and syllabically written languages. A case of surface dyslexia in an English-Spanish bilingual, in which such predictions were confirmed, is described.- - - - - - - - - - ranking = 2keywords = nature (Clic here for more details about this article) |
9/12. Developmental deep dyslexia?A detailed analysis was made of the errors of a developmental dyslexic who is now 18 years of age. It was found that her error pattern was very similar to that observed in a particular form of acquired dyslexia, i.e. deep dyslexia. She made semantic, visual, derivational and function word substitution errors, and was almost completely unable to read non-words. Although the possibility of brain damage cannot be completely ruled out, her case remains an unusual one as her reading disorder is a certain extent developmental in nature in that she has never achieved fluent reading.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
10/12. A dissociation between developmental surface and phonological dyslexia in two undergraduate students.This study compares the nature of the reading deficit that was observed in two dyslexic undergraduate students who were severely impaired at reading and spelling compared with normal undergraduates. They both achieved the same (below average) score on the National adult reading Test and on the Schonell spelling test. One of them, however, was good at reading and spelling nonwords, had good phonological awareness skills, was better at reading regular than irregular words, and made phonologically accurate reading and spelling errors (i.e. was a surface dyslexic). The other had poor phonological awareness, produced relatively few phonologically accurate spelling errors, and was poor at reading and spelling nonwords (i.e. was a phonological dyslexic). It is particularly noteworthy that such a clear dissociation between surface and phonological forms of developmental dyslexia occurred in two subjects who were closely matched in terms of their overall reading and spelling ability, and also in terms of their memory span and vocabulary. It is argued that this study strengthens the evidence for the existence of qualitatively different types of developmental dyslexia. The findings are also consistent with the view that phonological awareness skills are more closely related to the operation of the phonological rather than the visual reading route.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
| | Next -> |