Cases reported "Dyslexia"

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1/65. Cross-modal priming evidence for phonology-to-orthography activation in visual word recognition.

    Subjects were asked to indicate which item of a word/nonword pair was a word. On critical trials the nonword was a pseudohomophone of the word. RTs of dyslexics were shorter in blocks of trials in which a congruent auditory prime was simultaneously presented with the visual stimuli. RTs of normal readers were longer for high frequency words when there was auditory priming. This provides evidence that phonology can activate orthographic representations; the size and direction of the effect of auditory priming on visual lexical decision appear to be a function of the relative speeds with which sight and hearing activate orthography.
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keywords = visual
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2/65. A school-aged child with delayed reading skills.

    During a health supervision visit, the father of a 7.5-year-old African American second-grader asked about his son's progress in reading. He was concerned when, at a recent teacher-parent conference to review Darren's progress, the teacher remarked that Darren was not keeping up with reading skills compared with others in his class. She said that he had difficulty sounding out some words correctly. In addition, he could not recall words he had read the day before. The teacher commented that Darren was a gregarious, friendly child with better-than-average verbal communication skills. His achievement at math was age-appropriate; spelling, however, was difficult for Darren, with many deleted letters and reversals of written letters. A focused history did not reveal any risk factors for a learning problem in the prenatal or perinatal periods. Early motor, language, and social milestones were achieved on time. Darren had not experienced any head injury, loss of consciousness, or chronic medical illness. He had several friends, and his father denied any behavioral problems at home or at school. His teacher completed a DSM-IV-specific behavioral survey for attention-deficit/hyperactivity disorder (ADHD). It did not show any evidence of ADHD. Darren's father completed 1 year of college and is currently the manager of a neighborhood convenience store. His mother had a high school education; she recalled that she found it difficult to complete assignments that required reading or writing. She is employed as a waitress. Darren does not have any siblings. The pediatrician performed a complete physical examination, the results of which were normal, including visual acuity, audiometry, and a neurological examination. It was noted that Darren seemed to pause several times in response to questions or commands. On two occasions, during finger-nose testing and a request to assess tandem gait, directions required repetition. overall, he was pleasant and seemed to enjoy the visit. His pediatrician concluded that he had a learning problem but she was uncertain about the next step. She asked herself, "Is there anything else I can do in the office to evaluate Darren's problem with learning? Should I quickly refer him for educational testing or encourage a reading tutor? What questions can I ask his teacher that would be helpful? Am I missing a medical disorder?"
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ranking = 0.16666666666667
keywords = visual
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3/65. Converging evidence for the role of occipital regions in orthographic processing: a case of developmental surface dyslexia.

    Recently, there have been several reports focusing on the neural basis for word recognition. Two different views have emerged: one emphasizing the role of the left angular gyrus in recognizing printed words, and the second view suggesting that visual word processing activates the left extrastriate cortex. This paper describes the case of EBON, a 14-year-old girl with an extensive early (most likely congenital) brain lesion in the left occipital lobe. She demonstrates a clear pattern of developmental surface dyslexia in that she is more successful at reading and spelling regular words than irregular words and makes frequent regularization errors. Thus, EBON is the first case reported with the potential to establish converging evidence for the role of extrastriate regions in the left hemisphere in the acquisition of orthographic representations.
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ranking = 0.23845454503709
keywords = visual, cortex
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4/65. Selective uppercase dysgraphia with loss of visual imagery of letter forms: a window on the organization of graphomotor patterns.

    We report a patient who, after a left parieto-occipital lesion, showed alexia and selective dysgraphia for uppercase letters. He showed preserved oral spelling, associated with handwriting impairment in all written production; spontaneous writing, writing to dictation, real words, pseudowords, and single letters were affected. The great majority of errors were well-formed letter substitutions: most of them were located on the first position of each word, which the patient always wrote in uppercase (as he used to do before his illness). The patient also showed a complete inability to access the visual representation of letters. As demonstrated by a stroke segmentation analysis, letter substitutions followed a rule of graphomotor similarity. We propose that the patient's impairment was at the stage where selection of the specific graphomotor pattern for each letter is made and that the apparent selective disruption of capital case was due to a greater stroke similarity among letters belonging to the same case. We conclude that a visual format is necessary neither for spelling nor for handwriting.
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keywords = visual
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5/65. Rapid word identification in pure alexia is lexical but not semantic.

    Following the notion that patients with pure alexia have access to two distinct reading strategies-letter-by-letter reading and semantic reading-a training program was devised to facilitate reading via semantics in a patient with pure alexia. Training utilized brief stimulus presentations and required category judgments rather than explicit word identification. The training was successful for trained words, but generalized poorly to untrained words. Additional studies involving oral reading of nouns and of functors also resulted in improved reading of trained words. Pseudowords could not be trained to criterion. The results suggest that improved reading can be achieved in pure alexia by pairing rapidly presented words with feedback. Focusing on semantic processing is not essential to this process. It is proposed that the training strengthens connections between the output of visual processing and preexisting orthographic representations.
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ranking = 0.16666666666667
keywords = visual
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6/65. Atypical cognitive disorders in a man with developmental surface dyslexia.

    The neuropsychological profile of a man with a developmental surface dyslexia is presented here. This case study is of interest because J.C. exhibited a pattern of cognitive disorders rarely documented in previous data. Results showed that JC's difficulties in reading comprehension were closely related to complex memory disorders and were also associated with cognitive slowness. The present observations do not support the visual memory failure hypothesis. The data rather suggest that the core difficulty primarily lies with the nonautomatization of grapheme-phoneme correspondence rules, which in turn dramatically contributed to lexicon weaknesses. The hypothesis of a timing mechanism in reading disorders is discussed.
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ranking = 0.16666666666667
keywords = visual
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7/65. Visual implicit memory deficit and developmental surface dyslexia: a case of early occipital damage.

    This study reports the case of EBON, a fifteen-year-old right-handed female Swedish student, who suffered an early medial/dorsal occipital brain lesion and showed a clearly defined pattern of developmental surface dyslexia. EBON and 17 controls were examined with within and cross-modality (visual and auditory) word stem completion tasks together with tasks requiring free-recall and recognition for visually and auditory presented words. Compared to age-matched controls, EBON was found to show a significant deficit of visual priming following visual presentation, and a deficit approaching significance following auditory presentation. Explicit memory and visual and spatial abilities were not significantly different from controls. Therefore, EBON represents the first childhood case establishing the role of occipital regions in visual priming, as well as illustrating a profile of surface reading difficulty as a developmental consequence of this locus of lesion.
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ranking = 1
keywords = visual
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8/65. Number processing and calculation in a case of visual agnosia.

    We describe the performance of a brain-damaged subject who suffered from visual agnosia leading to major difficulties in generating and exploiting visual representations from long-term memory. His performance in a physical judgement task in which he was required to answer questions about the visual shapes of Arabic numerals reflected his agnosic problems. However, he showed no impairment in usual number processing and calculation tasks. This case shows that, despite some commonalities in number and object processing, actual numerical processes are not affected by visual agnosia and can be preserved even when fine visual processes are impaired.
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ranking = 1.5
keywords = visual
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9/65. Visuographemic alexia: a new form of a peripheral acquired dyslexia.

    We report a single-case study of peripherally acquired dyslexia that meets the clinical criteria of "alexia without agraphia." The patient, AA, has a large infarct involving the left posterior cerebral artery. The most striking feature is a severe impairment in recognizing single visually presented letters that precludes explicit or implicit access to reading, even in a letter-by-letter fashion. AA can, however, differentiate letters from similar nonsense characters and digits, and he is also able to identify alphanumeric signs when the visual channel is bypassed (through somesthesic or kinesthesic presentation). Spelling tasks are also well performed. Since there is a breakdown in mapping a visually presented letter to its abstract graphemic representation, we propose the term "visuographemic alexia" for this kind of reading disorder. The pattern of deficits is interpreted following theoretical models previously developed in cognitive neuropsychology. An alexia for arabic numerals with preserved comprehension lends additional support for the crucial processing of different notational systems (e.g., phonographic vs logographic). More general perceptive disorders do not seem to account for these patterns; they are material-specific. Finally, we attempt to specify functional correlations with the implied neural networks.
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ranking = 0.5
keywords = visual
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10/65. Word-centred neglect dyslexia: evidence from a new case.

    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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ranking = 0.33333333333333
keywords = visual
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