Cases reported "Dyslexia"

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1/164. 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. ( info)

2/164. Simultaneous activation of reading mechanisms: evidence from a case of deep dyslexia.

    We report the performance of LC, a deep dyslexic. We investigated extensively her errors according to serial cognitive neuropsychological models of oral reading. Initial evaluation of her reading suggested impaired access to the phonological output lexicon (POL). Impaired grapheme-to-phoneme conversion (GPC) and semantic errors in reading suggested that LC read via an impoverished semantic route. However, a serial model of oral reading could not explain error differences in reading, picture naming, spontaneous speech, and repetition. Neologisms occurred in oral reading but not in spontaneous speech and repetition. Semantic errors in naming exceeded those in oral reading. To account for these different error patterns we propose that the semantic route, the direct route from the orthographic input lexicon to the POL, and GPC activate simultaneously during reading, converging at the POL to constrain phonological selection. These routes are modular but not functionally encapsulated. For LC, the POL receives ambiguous information due to degradation of all routes, causing reading errors. ( info)

3/164. Unidirectional dyslexia in a polyglot.

    Alexia is usually seen after ischaemic insults to the dominant parietal lobe. A patient is described with a particular alexia to reading Hebrew (right to left), whereas no alexia was noted when reading in English. This deficit evolved after a hypertensive right occipitoparietal intracerebral haemorrhage, and resolved gradually over the ensuing year as the haematoma was resorbed. The deficit suggests the existence of a separate, language associated, neuronal network within the right hemisphere important to different language reading modes. ( info)

4/164. A modality-specific mapping impairment: spoken versus written production.

    A 29 year-old dysphasic woman (AF) presented with superior ability in written over spoken sentences. In contrast, her comprehension showed the reverse trend. Cognitive neuropsychological investigations revealed that her double dissociation was more apparent than real. AF's superior auditory comprehension was attributed to suspected dyslexic factors impeding written comprehension. However, an account of a strong dissociation between her written and spoken production was less obvious. The evidence suggested AF suffered from a procedural mapping deficit which had a disproportionate effect on spoken production. AF's performance challenge current models of lexical access which consider syntactic knowledge to be amodal. An alternative account is considered within Caramazza's (1997) Independent Network model of lexical access. ( info)

5/164. A case study of an English-Japanese bilingual with monolingual dyslexia.

    We report the case of AS, a 16 year-old English/Japanese bilingual boy, whose reading/writing difficulties are confined to English only. AS was born in japan to a highly literate Australian father and English mother, and goes to a Japanese selective senior high school in japan. His spoken language at home is English. AS's reading in logographic Japanese Kanji and syllabic Kana is equivalent to that of Japanese undergraduates or graduates. In contrast, his performance in various reading and writing tests in English as well as tasks involving phonological processing was very poor, even when compared to his Japanese contemporaries. Yet he has no problem with letter names or letter sounds, and his phoneme categorisation is well within the normal range of English native speakers. In order to account for our data that show a clear dissociation between AS's ability to read English and Japanese, we put forward the 'hypothesis of granularity and transparency'. It is postulated that any language where orthography-to-phonology mapping is transparent, or even opaque, or any language whose orthographic unit representing sound is coarse (i.e. at a whole character or word level) should not produce a high incidence of developmental phonological dyslexia. ( info)

6/164. 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?" ( info)

7/164. A case study of transient dyslexia.

    This paper presents a case study of a seizure-induced transient dyslexic episode experienced by a radio presenter while reading a script live on air. An analysis of the recording of the episode in conjunction with the script being read yields a number of interesting observations. There is, for example, a distinct temporal pattern of breakdown from what can be characterized as orthographic errors through to semantic confusions. Many of the orthographic errors can be explained as a form of repetition blindness. Furthermore, the pattern of lexical error lends support to a two-stage model lexicalization. ( info)

8/164. The impact of semantic memory impairment on spelling: evidence from semantic dementia.

    We assessed spelling and reading abilities in 14 patients with semantic dementia (with varying degrees of semantic impairment) and 24 matched controls, using spelling-to-dictation and single-word reading tests which manipulated regularity of the correspondences between spelling and sound, and word frequency. All of the patients exhibited spelling and reading deficits, except at the very earliest stages of disease. Longitudinal study of seven of the patients revealed further deterioration in spelling, reading, and semantic memory. The performance of both subject groups on both spelling and reading was affected by regularity and word frequency, but these effects were substantially larger for the patients. Spelling of words with exceptional (or more precisely, unpredictable) sound-to-spelling correspondences was most impaired, and the majority of errors were phonologically plausible renderings of the target words. reading of low frequency words with exceptional spelling-to-sound correspondences was also significantly impaired. The spelling and reading deficits were correlated with, and in our interpretation are attributed to, the semantic impairment. ( info)

9/164. 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. ( info)

10/164. 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. ( info)
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