11/231. Intact verbal description of letters with diminished awareness of their forms.Visual processing and its conscious awareness can be dissociated. To examine the extent of dissociation between ability to read characters or words and to be consciously aware of their forms, reading ability and conscious awareness for characters were examined using a tachistoscope in an alexic patient. A right handed woman with 14 years of education presented with incomplete right hemianopia, alexia with kanji (ideogram) agraphia, anomia, and amnesia. brain MRI disclosed cerebral infarction limited to the left lower bank of the calcarine fissure, lingual and parahippocampal gyri, and an old infarction in the right medial frontal lobe. Tachistoscopic examination disclosed that she could read characters aloud in the right lower hemifield when she was not clearly aware of their forms and only noted their presence vaguely. Although her performance in reading kanji was better in the left than the right field, she could read kana (phonogram) characters and Arabic numerals equally well in both fields. By contrast, she claimed that she saw only a flash of light in 61% of trials and noticed vague forms of stimuli in 36% of trials. She never recognised a form of a letter in the right lower field precisely. She performed judgment tasks better in the left than right lower hemifield where she had to judge whether two kana characters were the same or different. Although dissociation between performance of visual recognition tasks and conscious awareness of the visual experience was found in patients with blindsight or residual vision, reading (verbal identification) of characters without clear awareness of their forms has not been reported in clinical cases. Diminished awareness of forms in our patient may reflect incomplete input to the extrastriate cortex.- - - - - - - - - - ranking = 1keywords = reading, alexia (Clic here for more details about this article) |
12/231. language and calculation within the parietal lobe: a combined cognitive, anatomical and fMRI study.We report the case of a patient (ATH) who suffered from aphasia, deep dyslexia, and acalculia, following a lesion in her left perisylvian area. She showed a severe impairment in all tasks involving numbers in a verbal format, such as reading aloud, writing to dictation, or responding verbally to questions of numerical knowledge. In contrast, her ability to manipulate non-verbal representations of numbers, i.e., Arabic numerals and quantities, was comparatively well preserved, as evidenced for instance in number comparison or number bisection tasks. This dissociated impairment of verbal and non-verbal numerical abilities entailed a differential impairment of the four arithmetic operations. ATH performed much better with subtraction and addition, that can be solved on the basis of quantity manipulation, than with multiplication and division problems, that are commonly solved by retrieving stored verbal sequences. The brain lesion affected the classical language areas, but spared a subset of the left inferior parietal lobule that was active during calculation tasks, as demonstrated with functional MRI. Finally, the relative preservation of subtraction versus multiplication may be related to the fact that subtraction activated the intact right parietal lobe, while multiplication activated predominantly left-sided areas.- - - - - - - - - - ranking = 4.7266389096644keywords = dyslexia, reading (Clic here for more details about this article) |
13/231. When does a deep dyslexic make a semantic error? The roles of age-of-acquisition, concreteness, and frequency.Semantic reading errors are the central and defining feature of deep dyslexia. This study compared the words the deep dyslexic patient LW read correctly with those she omitted and those to which she produced semantic errors in terms of their concreteness, age-of-acquisition, frequency, and length. Semantic errors were made to less concrete, later-acquired, and shorter words than were read correctly; there was no reliable effect of word frequency. More importantly, the actual semantic errors produced were later-acquired than the stimulus words, but they were not more concrete or reliably more frequent. These results implicate age-of-acquisition in the process that produces semantic errors. It is proposed that concreteness determines the specificity of the semantic system to activate a set of candidate responses and that age-of-acquisition biases the ease with which certain words can be selected from this set to be produced as reading responses.- - - - - - - - - - ranking = 5.01048195015keywords = dyslexia, reading (Clic here for more details about this article) |
14/231. brain activation during reading in deep dyslexia: an MEG study.Magnetoencephalographic (MEG) changes in cortical activity were studied in a chronic Finnish-speaking deep dyslexic patient during single-word and sentence reading. It has been hypothesized that in deep dyslexia, written word recognition and its lexical-semantic analysis are subserved by the intact right hemisphere. However, in our patient, as well as in most nonimpaired readers, lexical-semantic processing as measured by sentence-final semantic-incongruency detection was related to the left superior-temporal cortex activation. Activations around this same cortical area could be identified in single-word reading as well. Another factor relevant to deep dyslexic reading, the morphological complexity of the presented words, was also studied. The effect of morphology was observed only during the preparation for oral output. By performing repeated recordings 1 year apart, we were able to document significant variability in both the spontaneous activity and the evoked responses in the lesioned left hemisphere even though at the behavioural level, the patient's performance was stable. The observed variability emphasizes the importance of estimating consistency of brain activity both within and between measurements in brain-damaged individuals.- - - - - - - - - - ranking = 24.200880629293keywords = dyslexia, reading (Clic here for more details about this article) |
15/231. Alexia caused by a fusiform or posterior inferior temporal lesion.We evaluated the alexia and agraphia of three patients with different lesions using Japanese kanji (morphograms) and kana (phonograms) and made a lesion-to-symptom analysis. Patient 1 (pure alexia for both kanji and kana and minor agraphia for kanji after a fusiform lesion) made more paragraphic errors for kanji, whereas patient 2 (alexia with agraphia for kanji after a posterior inferior temporal lesion) showed severe reading and writing disturbances and more agraphic errors for kanji. Brodmann Area 37 was affected in both patients, but in patient 2 the lesion was located lateral to that in patient 1. Patient 3 showed agraphia without alexia after restricted lesion to the angular gyrus. We believe that pure alexia (patient 1) results from a disconnection between the medial fusiform gyrus and posterior inferior temporal area (the lateral fusiform and inferior temporal gyri), whereas alexia with agraphia for kanji (patient 2), corresponding to lexical agraphia in Western countries, results from damage to the posterior inferior temporal area, in which whole-word images of words are thought to be stored. Furthermore, restricted lesion in the angular gyrus (patient 3) does not produce alexia; the alexic symptom of "angular" alexia with agraphia may be the result of damage to the adjacent lateral occipital gyri.- - - - - - - - - - ranking = 1.47161006883keywords = reading, alexia (Clic here for more details about this article) |
16/231. Cerebral localization of the center for reading and writing music.The mechanisms that underlie the ability to read and write music remain largely unclear compared to those involved in reading and writing language. We had the extremely rare opportunity to study the cerebral localization of the center for reading and writing music in the case of a professional trombonist. During rehearsal immediately before a concert, he suffered a hemorrhage that was localized to the left angular gyrus, the area that has long been known as the center for the ability to read and write. Detailed tests revealed that he showed symptoms of alexia with agraphia for both musical scores and language.- - - - - - - - - - ranking = 1.851529121457keywords = reading, alexia (Clic here for more details about this article) |
17/231. The simultaneous activation hypothesis: explaining recovery from deep to phonological dyslexia.Deep dyslexia evolved into phonological dyslexia in one patient. Semantic errors resolved while phonological and derivational errors persisted in reading. Nonword reading improved but remained inferior to word reading. Despite a residual semantic deficit naming improved. The Simultaneous Activation Hypothesis explains recovery from deep to phonological dyslexia and the continued dissociation between reading and naming errors. Partial recovery to all three reading routes increased constraints for word selection at the phonological output lexicon (POL) improving word reading. With recovery, the POL receives additional supportive information from the partially recovered direct oral reading route and grapheme-to-phoneme conversion (GPC) eliminating semantic errors in oral reading. Nonword reading also improved because of partial recovery to all three routes. Semantic errors in naming persisted because additional constraints were unavailable at the POL to activate a phonological entry. Phonological and derivational errors were more frequent in reading than in naming the result of incomplete GPC recovery. Residual nonword reading deficits resulted from incomplete GPC recovery, indicated by the persistence of neologisms in nonwords. The Simultaneous Activation Hypothesis readily accounts for the evolution from deep to phonological dyslexia.- - - - - - - - - - ranking = 38.664640398772keywords = dyslexia, reading (Clic here for more details about this article) |
18/231. Neuropsychological evidence for case-specific reading: multi-letter units in visual word recognition.We describe a patient (GK) who shows symptoms associated with Balint's syndrome and attentional dyslexia. GK was able to read words, but not nonwords. He also made many misidentification and mislocation errors when reporting letters in words, suggesting that his word-naming ability did not depend upon preserved position-coded, letter identification. We show that GK was able to read lower-case words better than upper-case words, but upper-case abbreviations better than lower-case abbreviations. Spacing the letters in abbreviations disrupted identification, as did mixing the case of letters within words. These data cannot be explained in terms of letter-based reading or preserved holistic word recognition. We propose that GK was sensitive to the visual familiarity of adjacent letter forms.- - - - - - - - - - ranking = 5.862011071607keywords = dyslexia, reading (Clic here for more details about this article) |
19/231. Category specificity in reading and writing: the case of number words.In standard models, word meanings contribute to reading words aloud and writing them to dictation. It is known that categories of knowledge and the associated word meanings can be spared or impaired selectively, but it has not been possible to demonstrate that category-specific effects apply to reading and writing. Here we report the case of a neurodegenerative patient with selectively spared numerical abilities whose brain damage left him able to read and write only number words.- - - - - - - - - - ranking = 1.7030582429139keywords = reading (Clic here for more details about this article) |
20/231. Intensive training of phonological skills in progressive aphasia: a model of brain plasticity in neurodegenerative disease.Three patients with a typical syndrome of nonfluent primary progressive aphasia (Mesulam's syndrome) were trained daily with a remediation protocol including auditory exercises specifically designed to involve several aspects of phonological processing, a domain known to be specifically affected in the condition. The speech content of the exercises was based on the temporal theory of phonological processes according to which increasing the duration of formant transition should facilitate phoneme discrimination and phoneomic awareness. Significantly improved performance on the trained tasks was demonstrated in the three patients. Improvement further generalized to other tasks such as nonword repetition and reading. We conclude that such results (1) argue for using intensive focused therapy of language impairment in neurodegenerative disorders, (2) may constitute a good model of brain plasticity in neurodegenerative disorders in general, and (3) support theories of phonological processing emphasizing temporal features of the auditory signal.- - - - - - - - - - ranking = 0.28384304048565keywords = reading (Clic here for more details about this article) |
| <- Previous || Next -> |