1/58. Tactile morphagnosia secondary to spatial deficits.A 73-year old man showed visual and tactile agnosia following bilateral haemorrhagic stroke. Tactile agnosia was present in both hands, as shown by his impaired recognition of objects, geometrical shapes, letters and nonsense shapes. Basic somatosensory functions and the appreciation of substance qualities (hylognosis) were preserved. The patient's inability to identify the stimulus shape (morphagnosia) was associated with a striking impairment in detecting the orientation of a line or a rod in two- and three-dimensional space. This spatial deficit was thought to underlie morphagnosia, since in the tactile modality form recognition is built upon the integration of the successive changes of orientation in space made by the hand as it explores the stimulus. Indirect support for this hypothesis was provided by the location of the lesions, which could not account for the severe impairment of both hands. Only those located in the right hemisphere encroached upon the posterior parietal cortex, which is the region assumed to be specialised in shape recognition. The left hemisphere damage spared the corresponding area and could not, therefore, be held responsible for the right hand tactile agnosia. We submit that tactile agnosia can result from the disruption of two discrete mechanisms and has different features. It may arise from a parietal lesion damaging the high level processing of somatosensory information that culminates in the structured description of the object. In this case, tactile recognition is impaired in the hand contralateral to the side of the lesion. Alternatively, it may be caused by a profound derangement of spatial skills, particularly those involved in detecting the orientation in space of lines, segments and complex patterns. This deficit results in morphagnosia, which affects both hands to the same degree.- - - - - - - - - - ranking = 1keywords = hand (Clic here for more details about this article) |
2/58. Is there a syndrome of tuberothalamic artery infarction? A case report and critical review.Short-term post-acute neuropsychological, neurological, and neuroradiological test results and a 16-month follow-up of a 65-year-old patient with a right hemisphere ischemic lesion in the tuberothalamic area of vascular supply are reported. During a 6-week period of examinations the originally left- but trained right-handed patient exhibited fluctuating neuropsychological disorders including aphasia, visuo-perceptive and visuoconstructive disorders, and memory and attention deficits. In the follow-up examination the patient exhibited no aphasia and significant improvements in most neuropsychological tasks. Based on three-dimensional reconstruction of MRI, lesion topography and involvement of thalamic nuclei were established. We discuss the neuropsychological and neurological symptoms of the present case against the background of the 'syndrome of unilateral tuberothalamic artery territory infarction' proposed by Bogousslavsky and coworkers (1986) and the neuropsychological literature on unilateral ischemic anterior/anterolateral thalamic infarction.- - - - - - - - - - ranking = 0.16666666666667keywords = hand (Clic here for more details about this article) |
3/58. Neglect and constructive disorder.A 61 year-old right handed man, who suffered from right cerebral infarction with evidences of visual-spatial neglect and constructive disorder, was reported. When copying simple geometric designs, he omitted to copy figures on the left side of the page; he tended to bisect the line to the right of the line's real center; after memorizing the familiar pictures he mainly mentioned the pictures on the right side of the page; when copying the "Rey Complex" he also ignored the structures on the left side. The relations of the neglect and construction disorder are discussed.- - - - - - - - - - ranking = 0.16666666666667keywords = hand (Clic here for more details about this article) |
4/58. Weighing the evidence for cross over in neglect.When patients with left-sided neglect are asked to bisect horizontal lines, they tend to place their marks to the right of the line's objective mid-point. However, when asked to bisect short lines they are either more accurate or paradoxically cross over and place their marks to the left of the objective mid-point. Previous explanations of the cross over phenomenon have considered specific aberrations of spatial attention. However, these explanations make no predictions about judgments of non-spatial stimuli. Two patients with right brain damage were asked to judge weights placed on both hands simultaneously. They were biased in reporting weights on the right as being heavier than those on the left. This rightward bias changed with lighter pairs of weights presented in the context of equal reference weights. In one patient the directional bias was eliminated and in the other the bias was reversed so that she was more likely to report the left weight as heavier than the right. These data suggest that a phenomenon analogous to cross over in line bisections also occurs with judgments of non-spatial stimuli. Representations of stimuli appear to be influenced by features of the stimuli encountered on-line and by memory traces of similar stimuli encountered previously. With an attentional deficit, memory traces influence the magnitude of the representation derived on-line disproportionately.- - - - - - - - - - ranking = 0.16666666666667keywords = hand (Clic here for more details about this article) |
5/58. 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.- - - - - - - - - - ranking = 0.16666666666667keywords = hand (Clic here for more details about this article) |
6/58. Loss of left-sided volitional movements caused by a combined lesion of the corpus callosum and right hemisphere:'initiation pseudohemiakinesia'.We report a right-handed patient who showed a marked loss of unilateral volitional movements of the left limbs after the onset of a cerebral infarction in the combined territories of the right anterior and middle cerebral arteries. The same limbs retained their mobility in acts requiring bilateral sides of the body. This left-sided abnormal behavior resembled motor neglect resulting from lateralized brain damage. Behavioral and neuroradiological findings presented by this patient, however, suggested that callosal disconnection was definitely involved in this symptomatology. We postulate that in this patient, the diseased right hemisphere could no longer initiate movements of the left limbs despite its potential ability to realize them, and that the injured callosum prevented the intact left hemisphere from initiating unilateral voluntary movements of the left limbs. We suggest that this so far undescribed symptomatology be called 'initiation pseudohemiakinesia' in order to be distinguished from other rare forms of unilateral voluntary movements like motor neglect, extinction or directional hypokinesia.- - - - - - - - - - ranking = 0.16666666666667keywords = hand (Clic here for more details about this article) |
7/58. Corticobasal ganglionic degeneration with Balint's syndrome.Corticobasal ganglionic degeneration (CBGD) is a neurodegenerative dementia characterized by asymmetric parkinsonism, ideomotor apraxia, myoclonus, dystonia, and the alien hand syndrome. This report describes a patient with CBGD who developed Balint's syndrome with simultanagnosia, oculomotor apraxia, and optic ataxia.- - - - - - - - - - ranking = 468.349761162keywords = alien hand syndrome, hand syndrome, alien hand, alien, hand (Clic here for more details about this article) |
8/58. Detection by action: neuropsychological evidence for action-defined templates in search.How do we detect a target in a cluttered environment? Here we present neuropsychological evidence that detection can be based on the action afforded by a target. A patient showing symptoms of unilateral neglect following damage to the right fronto-temporal-parietal region was slow and sometimes unable to find targets when they were defined by their name or even by a salient visual property (such as their color). In contrast, he was relatively efficient at finding a target defined by the action it afforded. Two other patients with neglect showed an opposite pattern; they were better at finding a target defined by its name. The data suggest that affordances can be effective even when a brain lesion limits the use of other properties in search tasks. The findings give evidence for a direct pragmatic route from vision to action in the brain.- - - - - - - - - - ranking = 25.817313649941keywords = alien (Clic here for more details about this article) |
9/58. Spatial working memory deficit in unilateral neglect.Based on the similarity of brain areas lesioned in neglect and those activated by spatial working memory (WM) tasks in normals, we hypothesized that neglect may involve spatial WM impairments. A left neglect patient with right inferior frontal and basal ganglia damage performed cancellation tasks, making either highly visible marks (to provide a reminder of visited items), or invisible marks (so only spatial WM could represent cancelled items). Invisible marks led to repeated cancellations for targets that differed only in location, but not for targets with memorable unique identities, suggesting a deficit of spatial WM, with non-spatial WM spared. Neglect was greater for cancellation with invisible marks, consistent with a role for deficient spatial WM in cancellation deficits, but contrary to account solely in terms of attention capture by salient visible marks made in ipsilesional space.- - - - - - - - - - ranking = 25.817313649941keywords = alien (Clic here for more details about this article) |
10/58. Unilateral spatial neglect associated with chronic subdural haematoma: a case report.A 69-year-old right-handed man who exhibited unilateral spatial neglect in association with a chronic subdural haematoma, presented with mild left arm and leg weakness first noted 4 weeks prior to admission. neurologic examination on admission revealed a mild left hemiparesis, including the face. Neuropsychologic examination revealed left unilateral spatial neglect, but no language disturbance. Minimal support was necessary to maintain activities of daily living. Computed tomography revealed a large right temporoparietal, extraaxial hypodense fluid collection containing scattered hypodense foci. The haematoma was evacuated via a right parietal burr hole. Following surgery, the patient dramatically improved neurologically and neuropsychologically, as well as in independent performance of daily activities. It is suggested that the improvement in ADL provides a behavioural correlate of improvement in the latter, represented a behavioural correlate of improved cerebral function, and that either direct compression by the chronic subdural haematoma or an interhemispheric pressure difference had caused unilateral spatial neglect. Such neglect is an unusual consequence of chronic subdural haematoma.- - - - - - - - - - ranking = 0.16666666666667keywords = hand (Clic here for more details about this article) |
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