11/53. writing, calculating, and finger recognition in the region of the angular gyrus: a cortical stimulation study of gerstmann syndrome.OBJECT: In an attempt to gain a better understanding of the cerebral functions represented in the angular gyrus and to spare them during surgery, the authors studied patients with brain tumors located close to the angular gyrus and mapped cortical sites by using electrostimulation. methods: Before undergoing tumor removal, six right-handed patients (five with left and one with right hemisphere tumors) were studied using cortical mapping with the aid of calculating, writing, finger-recognition, and color-naming tasks in addition to standard reading and object-naming tasks (for a total of 36 brain mapping studies). Strict conditions of functional site validation were applied to include only those cortical sites that produced repetitive interferences in the function tested. Preoperatively, four of the patients exhibited discrete symptoms related to gerstmann syndrome while performing very specific tasks, whereas the other two patients presented with no symptoms of the syndrome. No patient had significant language or apraxic deficits. Distinct or shared cortical sites producing interferences in calculating, finger recognition, and writing were repeatedly found in the angular gyrus. Object- or color-naming sites and reading-interference sites were also found in or close to the angular gyrus; although frequently demonstrated, these latter results were variable and unpredictable in the group of patients studied. Finger agnosia and acalculia sites were also found elsewhere, such as in the supramarginal gyrus or close to the intraparietal sulcus. Mechanisms involved in acalculia, agraphia, or finger agnosia (either complete interferences or hesitations) during stimulation were various, from an aphasia-like form (for instance, the patient did not understand the numbers or words given for calculating or writing tasks) to an apparently pure interference in the function tested (patients understood the numbers, but were unable to perform a simple addition). CONCLUSIONS: Symptoms of gerstmann syndrome can be found during direct brain mapping in the angular gyrus region. In this series of patients, sites producing interferences in writing, calculating, and finger recognition were demonstrated in the angular gyrus, which may or may not have been associated with object-naming, color-naming, or reading sites.- - - - - - - - - - ranking = 1keywords = reading (Clic here for more details about this article) |
12/53. Visual object agnosia and pure word alexia: correlation of functional magnetic resonance imaging and lesion localization.We present a case of a 64-year-old, right-handed female with a metastatic breast cancer lesion involving the left posterior inferior temporal lobe causing complete loss of the ability to recognize visually common objects and words. After her symptoms resolved on corticosteroid therapy, functional magnetic resonance imaging (fMRI) mapping demonstrated strong left-hemispheric dominance for word recognition and right-hemispheric dominance for object recognition. The case illustrates the relationships among ventral occipito-temporal cortical activation, lesion localization, and lesion-induced deficits of higher visual function. The relationship between hemispheric dominance determined by fMRI and risk of postoperative deficit depends on the specific visual function of interest.- - - - - - - - - - ranking = 0.84120037680986keywords = alexia (Clic here for more details about this article) |
13/53. Negative emotions and anosognosia.patients with anosognosia fail to acknowledge, or feel distressed by, their disability. Given the recent suggestion that right (frontal) systems are selectively involved in negative emotions, it might be claimed that anosognosia results from a disruption in negative emotions. This is not consistent with the finding that some anosognosic patients exhibit substantial fluctuations in emotion, including the experience of negative emotions such as sadness. The present study investigates a patient (IW) with a right convexity lesion and anosognosia. He reported being frequently overcome by powerful emotions, especially sadness. IW was assessed on a self-report emotion questionnaire, where his reports were typically of higher levels of emotion than the control group. He was also assessed on the more indirect measure of Affective Story Recall. Here his pattern of emotional experience was similar to that of two control groups, one of which consisted of non-anosognosic patients with hemiparesis. His performance on Story Recall was notable in that he directed his emotions to a different 'object' to that of controls (other vs. self, respectively). These findings are not consistent with any claim that anosognosia results from an absence of negative emotions.- - - - - - - - - - ranking = 0.00025025896061124keywords = disability (Clic here for more details about this article) |
14/53. reading aloud in jargonaphasia: an unusual dissociation in speech output.A patient is described who showed several dissociations between oral and written language processing after bilateral retrorolandic vascular lesion. Dissociation was firstly between abolished auditory comprehension and preserved written comprehension and then involved confrontation naming, clearly superior in the written modality. The third striking dissociation involved oral output; spontaneous speech, although fluent and well articulated, consisted of neologistic jargon, while reading aloud was clearly superior though not perfect. Data are discussed with reference to a cognitive model of word processing. The pattern of dissociation in word production may be due to a failure in retrieving the phonological word form from the semantic system.- - - - - - - - - - ranking = 0.33333333333333keywords = reading (Clic here for more details about this article) |
15/53. Are specific reading and writing difficulties causally connected with developmental spatial inability? Evidence from two cases of developmental agnosia and apraxia.Two cases studies of subjects suffering from severe developmental constructional apraxia are presented. These two subjects demonstrated normal to high ability in reading, writing and arithmetical tests. The analysis of cognitive tests performed by them indicates that extreme developmental, perceptual, spatial and motor deficits may be dissociated from the acquisition of efficient reading ability.- - - - - - - - - - ranking = 2keywords = reading (Clic here for more details about this article) |
16/53. Balint's syndrome in subacute hiv encephalitis.A 45 year old patient with AIDS is described in whom Balint's syndrome developed over several days without other higher cognitive defects. Radiological findings were typical of subacute hiv encephalitis involving mainly the white matter of the occipital lobes with extension into the parietal and temporal lobe on the left side and into the temporal lobe on the right side. While the patient could usually recognise only one single component within her visual field, her performance in reading much improved if she was allowed to observe the examiner writing. This finding is attributed to well preserved movement perception in our patient, which may have helped her in directing her visual attention. The preservation of movement perception despite damage to the lateral temporo-occipital area may be due to the distinct pathology of subacute hiv encephalitis, which leaves the cortex and adjacent subcortical white matter virtually intact and therefore allows information transfer between primary visual areas in the occipital lobe and movement specific areas in the lateral temporo-occipital area through U-fibres.- - - - - - - - - - ranking = 0.33333333333333keywords = reading (Clic here for more details about this article) |
17/53. speech discrimination and lip reading in patients with word deafness or auditory agnosia.The purpose of this study was to assess the ability of four patients with word deafness or auditory agnosia to discriminate speech by reading lips. The patients were studied using nonsense monosyllables to test for speech discrimination, a lip reading test, the Token Test for auditory comprehension, and the aphasia test. Our results show that patients with word deafness or auditory agnosia without aphasia can improve speech comprehension by reading lips in combination with listening, as compared with lip reading or listening alone. In conclusion, lip reading was shown to be useful for speech comprehension among these patients.- - - - - - - - - - ranking = 3keywords = reading (Clic here for more details about this article) |
18/53. Word deafness in head injury: implications for coma assessment and rehabilitation.Pure word deafness, usually involving left hemisphere focal lesions that destroy Heschl's gyrus and/or isolate auditory association cortex, may be rare, but cases with additional perceptual or cognitive symptoms may not be. Word deafness can be transient or evolving, and has been seen in various conditions without identifiable focal lesions. Only two closed head injury cases with focal contusions have been reported; we report two more, with diffuse damage and no focal signs. One patient's symptoms evolved soon after they were recognized. The other patient's unresponsiveness to spoken verbal stimuli persisted despite relatively preserved reading and speech, in a context of poor initiation and moderately severe cognitive impairment. Unrecognized, word deafness following head injury could lead to overestimation of coma duration if transient, and impede rehabilitation if chronic.- - - - - - - - - - ranking = 0.33333333333333keywords = reading (Clic here for more details about this article) |
19/53. A historic case of visual agnosia revisited after 40 years.In one of the seminal works on visual agnosia, Adler (1944, 1950) presented the case of a 22-yr-old woman who sustained carbon monoxide cerebral toxicity in the Cocoanut Grove nightclub diaster of 1942. We located this patient 40 yrs after injury and performed a detailed reevaluation. The patient demonstrated persistent deficits in visual recognition, characterized most prominently by defective recognition of elemental shape and form, associated with alexia, prosopagnosia, visuospatial disorientation and impaired visual imagery. visual acuity, colour recognition, writing ability and verbal intelligence were relatively preserved. Isolated bilateral occipital injury was demonstrated by CT and MRI scanning. On comparison with previously reported cases, our results support the hypothesis that carbon monoxide toxicity can induce a visual agnosia of the apperceptive type with well defined characteristics, seldom seen with other types of cerebral injury. prognosis for long-term recovery is poor.- - - - - - - - - - ranking = 0.21030009420247keywords = alexia (Clic here for more details about this article) |
20/53. occipital lobe infarction and positron emission tomography.Even though the PET study revealed a total infarct in the territory of the left PCA in our 3 cases of pure alexia, it is still obscure which part of the left occipital lobe is most closely associated with the occurrence of the pure alexia. In order to elucidate the intralobar localization of the pure alexia, it is needed to have an ideal case who shows an pure alexia due to the localized lesion within the left occipital lobe. Furthermore, high-resolution PET scanner will circumvent the problem in detecting the metabolism and blood flow in the corpus callosum which plays an important role in the pathogenesis. We have shown that the occlusion of the right PCA also produced a left unilateral agnosia which is one of the common neurological signs in the right MCA infarction. To tell whether the responsible lesion for the unilateral spatial agnosia differs between the PCA occlusion and the MCA occlusion, the correlation study should be carried out in a greater number of the subjects. Two distinctive neuropsychological manifestations, cerebral color blindness and prosopagnosia, have been considered to be produced by the bilateral occipital lesion. The PET studies disclosed reduction of blood flow and oxygen metabolism in both occipital lobes in our particular patient who exhibited cerebral color blindness and prosopagnosia.- - - - - - - - - - ranking = 0.84120037680986keywords = alexia (Clic here for more details about this article) |
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