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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 70-yr-old man was able to read aloud, without comprehending what he read, following a stroke that caused Wernicke's aphasia with severely impaired comprehension of speech. Tested on admission, and at 3 and 9 months, he could read aloud both orthographically simple and orthographically complex real words, and showed neither semantic errors, preference for nouns, nor difficulty with function words. He could not, however, read aloud orthographically simple nonwords. His disorder thus appears to be the first pure example of 'direct dyslexia', which, in contrast to previously well-documented examples of 'deep' and 'surface' dyslexia, implies the existence in reading of a direct route, independent of phonology or semantics, between visual and oral word representations.
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PMID:Direct dyslexia. Preserved oral reading of real words in Wernicke's aphasia. 273 Oct 22

It has been hypothesized that the residual reading ability in people with deep dyslexia (an acquired dyslexia in which the subjects make semantic paralexias, eg, child read as boy) utilizes right hemispheric structures. A patient who was deep dyslexic following an initial left hemispheric stroke was studied. Following a new left hemispheric stroke, he lost his residual reading ability. In this patient, deep dyslexic reading abilities were dependent on left hemispheric structures.
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PMID:Loss of deep dyslexic reading ability from a second left-hemispheric lesion. 382 89

Seven subjects who were neurologically impaired following encephalitis (n = 2), head injury (n = 3), and stroke (n = 2) were referred several years previously because of acquired dyslexia. Two were almost totally alexic, 2 were surface dyslexic, 2 were deep dyslexic and 1 was a letter-by-letter reader. Following a period of rehabilitation, the 2 with alexia became surface dyslexic and letter-by-letter readers; 1 of the deep dyslexics showed some improvements but remained a deep dyslexic; and the letter-by-letter reader learned to read more quickly. At follow-up, 6 to 10 years later, there had been little significant change. The 2 subjects whose alexia resolved into surface dyslexia with letter-by-letter reading had increased their reading ages but remained surface dyslexic and letter-by-letter readers. The subject who had been a letter-by-letter reader was faster at easier and more frequently used words but slower at harder, less frequently used words. Changes in the other 4 subjects were negligible. Implications for rehabilitation are discussed.
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PMID:Syndromes of acquired dyslexia and patterns of recovery: a 6- to 10-year follow-up study of seven brain-injured people. 792 3

Rehabilitative measures for stroke are not generally based on basic neurobiological principles, despite evidence from animal models that certain anatomical and pharmacological changes correlate with recovery. In this report, we use functional magnetic resonance imaging (fMRI) to study in vivo human brain reorganization in a right handed patient with an acquired reading disorder from stroke. With phonological dyslexia, her whole-word (lexical) reading approach included inability to read nonwords and poor reading of function words. Following therapy, she was able to read nonwords and function words, and preferred a decompositional (sub-lexical) strategy in general. fMRI was performed during a reading task before and after treatment. Prior to therapy, her main focus of brain activation was in the left angular gyrus (area 39). After therapy, it was instead in the left lingual gyrus (area 18). This result suggests first that it is possible to alter brain physiology with therapy for acquired language disorders, and second, that two reading strategies commonly used in normal reading use distinct neural circuits, possibly reconciling several conflicting neuroimaging studies of reading.
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PMID:Different neural circuits subserve reading before and after therapy for acquired dyslexia. 957 25

Several reports of cases of experienced artists showing neglect after a brain lesion can be gleaned from the literature. The analysis of their drawings might provide better insight into the symptoms of neglect than that of non-artists's production. However, most of these reports are anedoctal. We describe in some detail the case of neglect of a distinguished artist, the internationally known Federico Fellini (FF), whom we followed-up for two months after his right parietal stroke. The neuropsychological profile of his neglect syndrome was characterized by left visuo-motor neglect which persisted for two months. At onset, FF also showed indications of neglect dyslexia as well as some evidence of implicit processing of the neglected parts of visual stimuli. However, there was no sign of personal and representational neglect, and FF was well aware of his motor and attentional deficits. FF's neglect was characterised by several dissociations, of which the lack of functional carryover despite intact conceptual and semantic insight is the most relevant.
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PMID:Preserved insight in an artist with extrapersonal spatial neglect. 960 84

This study reports the reading difficulties of five children following unilateral left hemisphere stroke sustained either before or during the early stages of literacy acquisition. Although each of the children experienced a period of disturbed language processing in the initial stages postonset, at the time of testing none of the children were considered to be clinically aphasic. Yet, on a standardized test of oral reading each of the children achieved a reading age that lagged behind chronological age and marked reading impairments were disclosed in four of the five children. A set of standardized and nonstandardized tests, aimed at measuring aspects of cognitive and spoken language processing that are considered to be important for normal reading acquisition, was administered. Where nonstandardized tests were used, performance of each of the stroke children was compared to that of groups of normally developing control children, closely matched for chronological age. A range of residual deficits in cognitive and spoken language processing was disclosed among the five brain-damaged children that appeared to be associated with their reading impairments. Two children had expectedly poor reading due to a selective impairment in verbal IQ; a specific phonological reading disorder was revealed in two children, each of which had a residual impairment to phonological awareness; and delayed reading acquisition was observed in one child with a general language deficit. It is suggested that when a child suffers damage to the left hemisphere in the early stages of reading acquisition, difficulties with learning to read are likely to ensue and may arise as a consequence of an underlying cognitive or linguistic deficit.
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PMID:Spoken language correlates of reading impairments acquired in childhood. 1072 84

Signor Piazza, a patient with a left parieto-occipital haemorrhage and a right thalamic stroke, showed severe right personal neglect (e.g. touching own body parts) and right perceptual neglect in tasks with (e.g. cancelling tasks) or without (e.g. description of a complex picture) motor response. He had also right-sided neglect dyslexia (including single words), without language impairments. However, the patient also presented with a clear left-sided deficit in the representational domain (e.g. imagery tasks). Signor Piazza's pattern of performance suggests dissociation between imagery and perception within the neglect syndrome.
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PMID:Perceiving left and imagining right: dissociation in neglect. 1092 67

There is a substantial body of basic research that has utilized ERPs to investigate the neurological basis of cognition. This research has, in turn, led to the development of practical applications of cognitive ERPs in patient populations. In particular, recent work has focused on the development of ERP-based assessment measures for the neuropsychological assessment of dyslexia and language impairments secondary to stroke. This review describes the innovative assessment methods program (IAMP), an initiative to utilize ERPs for a neuropsychological assessment of patients who cannot be evaluated by traditional methods. The success of this program has demonstrated that ERPs can be used to reliably evaluate an individual's reading and speech comprehension abilities, independent of behavioral and speech production impediments. In contrast to traditional neuropsychological assessment, these ERP methods can discern the cognitive strategies used by an individual to perform a task.
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PMID:The application of cognitive event-related brain potentials (ERPs) in language-impaired individuals: review and case studies. 1102 94

The success of diffusion magnetic resonance imaging (MRI) is deeply rooted in the powerful concept that during their random, diffusion-driven displacements molecules probe tissue structure at a microscopic scale well beyond the usual image resolution. As diffusion is truly a three-dimensional process, molecular mobility in tissues may be anisotropic, as in brain white matter. With diffusion tensor imaging (DTI), diffusion anisotropy effects can be fully extracted, characterized, and exploited, providing even more exquisite details on tissue microstructure. The most advanced application is certainly that of fiber tracking in the brain, which, in combination with functional MRI, might open a window on the important issue of connectivity. DTI has also been used to demonstrate subtle abnormalities in a variety of diseases (including stroke, multiple sclerosis, dyslexia, and schizophrenia) and is currently becoming part of many routine clinical protocols. The aim of this article is to review the concepts behind DTI and to present potential applications.
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PMID:Diffusion tensor imaging: concepts and applications. 1127 97

Neglect dyslexia resulting from damage to word-centred representations is extremely rare. We report on a new case. A left-handed subject, SVE, presented with aphasia and neglect dyslexia/dysgraphia following a right hemisphere stroke. In tachistoscopic reading tasks, some of his errors resulted from retina-centred neglect, as he responded more accurately to words flashed in the left visual field than to words flashed in the right visual field. However, the critical aspects of his reading performance indicated word-centred neglect. SVE incorrectly produced the initial elements of four-letter words, regardless of stimulus location (to the left and to the right of fixation, or at fixation), and orientation (horizontal and vertical presentation). A similar distribution of errors was demonstrated in writing (very inaccurate performance on initial letters). This pattern of performance suggests damage to an abstract letter string representation defined by spatial coordinates, rather than to an ordering mechanism. It is most naturally accommodated by models of word recognition which assume a word-centred level of representation, and cannot be explained by models which do not include such a representational level. Consideration of our subject in the light of other similar reports prompts hypotheses on the neural mechanisms involved in computing word-centred representations.
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PMID:Word-centred neglect dyslexia: evidence from a new case. 1145 18


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