1/74. Palinopsia with bacterial brain abscess and noonan syndrome.Though positive visual symptoms can be psychological in nature, or can result from a perceptive or anxious patients recognizing optical principals in the eye itself, this case illustrates how a thorough history is required to delineate those rarer signs which accompany serious macular or neuro-ophthalmic pathology.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
2/74. visual perception of motion, luminance and colour in a human hemianope.Human patients rendered cortically blind by lesions to V1 can nevertheless discriminate between visual stimuli presented to their blind fields. Experimental evidence suggests that two response modes are involved. patients are either unaware or aware of the visual stimuli, which they are able to discriminate. However, under both conditions patients insist that they do not see. We investigate the fundamental difference between percepts derived for the normal and affected hemifield in a human hemianope with visual stimuli of which he was aware. The psychophysical experiments we employed required the patient, GY, to make comparisons between stimuli presented in his affected and normal hemifields. The subject discriminated between, and was allowed to match, the stimuli. Our study reveals that the stimulus parameters of colour and motion can be discriminated and matched between the normal and blind hemifields, whereas brightness cannot. We provide evidence for associations between the percepts of colour and motion, but a dissociation between the percepts of brightness, derived from the normal and hemianopic fields. Our results are consistent with the proposal that the perception of different stimulus attributes is expressed in activity of functionally segregated visual areas of the brain. We also believe our results explain the patient's insistence that he does not see stimuli, but can discriminate between them with awareness.- - - - - - - - - - ranking = 0.25keywords = brain (Clic here for more details about this article) |
3/74. When the left brain is not right the right brain may be left: report of personal experience of occipital hemianopia.OBJECTIVES: To make a personal report of a hemianopia due to an occipital infarct, sustained by a professor of neurology. methods: Verbatim observation of neurological phenomena recorded during the acute illness. RESULTS: Hemianopia, visual hallucinations, and non-occipital deficits without extraoccipital lesions on MRI, are described and discussed. CONCLUSIONS: Hemianopia, due to an occipital infarct, without alexia, is not a disability which precludes a normal professional career. Neurorehabilitation has not been necessary.- - - - - - - - - - ranking = 2keywords = brain (Clic here for more details about this article) |
4/74. Variability not ability: another basis for performance decrements in neglect.OBJECTIVE: To determine reaction time (RT) and its variability, as a function of horizontal spatial position, in subjects with neglect. Background: In neglect, performance is frequently reported a as mean and a decreased ability to perform the task inferred by comparison to control groups. Few studies have examined how consistency and optimal performance relate to spatial neglect. methods: Ten subjects with brain damage, five with and five without spatial neglect, were assessed on a RT task. Subjects responded by pushing a computer key to the onset of a white square appearing on a black screen. The locations of stimuli were randomly varied along the horizontal meridian. RESULTS: For three of five neglect subjects, optimal RT showed no or little relation to horizontal location. Four of five neglect subjects demonstrated an increased variability in RT that correlated with spatial position and which was not present in our brain damaged subjects without neglect. The relationship was not an artifact of left sided stimuli, in general, being processed differently. For the two neglect subjects with the most trials, a significant correlation between RT variability and spatial position existed for left-sided trials alone. Increased variability was not a consequence of simply looking left proportionately less often, nor could a model of multiple compensatory systems operating in parallel explain the enhanced variability. Neither hemianopsia alone nor brain damage per se could account for the spatial modulation of RT variability. CONCLUSIONS: That neglect subjects perform the RT task normally on some trials, even in their 'neglected field', challenges the notion that neglect must reflect an irreparably damaged cognitive system. Performance decrements in neglect can reflect an inability to consistently detect and respond. Evaluating optimal performance and variability of performance can indicate if a capacity has been lost absolutely or merely degraded such that normal performance cannot be sustained.- - - - - - - - - - ranking = 0.75keywords = brain (Clic here for more details about this article) |
5/74. Subarachnoid haemorrhage as initial symptom of multiple brain abscesses.The case of evolving multiple brain abscesses which became symptomatic with a sudden hemianopsia and the clinical and radiological signs of a subarachnoid haemorrhage, is reported. A common pathomechanism which could explain both the sudden focal neurological deficit and the subarachnoid bleeding is discussed.- - - - - - - - - - ranking = 1.25keywords = brain (Clic here for more details about this article) |
6/74. multiple sclerosis simulating a mass lesion.The cases of two young women with a homonymous hemianopia are described. Both women had a progressively enlarging mass lesion that was seen with neuroimaging studies. One patient had neurologic deterioration despite intravenous corticosteroid treatment. In each case, results of a stereotactic biopsy showed demyelination that was consistent with multiple sclerosis. multiple sclerosis infrequently presents as a mass lesion. The atypical clinical and radiographic features of large demyelinating plaques may lead to an erroneous diagnosis of a brain tumor, infection, or demyelination from other causes.- - - - - - - - - - ranking = 0.25keywords = brain (Clic here for more details about this article) |
7/74. The Heidenhain variant of Creutzfeldt-Jakob disease: clinical, pathologic, and neuroimaging findings.We report two patients who developed isolated visual symptoms and signs as initial manifestations of Creutzfeldt-Jakob disease (CJD). Both patients had normal conventional T1- and T2-weighted brain magnetic resonance (MR) images; in one patient, early cortical abnormalities were detected by diffusion-weighted and fluid attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI). Results from the cerebrospinal fluid assay for the 14-3-3 brain protein were also negative in one patient, despite pathologic confirmation of CJD at autopsy. The Heidenhain variant of CJD should be considered in all patients who present with isolated visual manifestations, including homonymous hemianopsia and normal conventional brain MRI. diffusion-weighted and FLAIR MRI may demonstrate early cortical abnormalities in patients with CJD. The CSF assay for the 14-3-3 protein may be normal, even in pathologically confirmed cases.- - - - - - - - - - ranking = 0.75keywords = brain (Clic here for more details about this article) |
8/74. Bitemporal visual field defects in presumed multiple sclerosis.Three patients with presumed multiple sclerosis had bitemporal hemianopia mimicking that caused by parasellar tumors; the visual loss was probably due to a plaque within the chiasm. The diagnosis of multiple sclerosis was made on the basis of a history of relapse and remission, signs and symptoms indicating involvement of different levels of the central nervous system, and normal neuroradiological studies. Extensive neuroradiological studies may be delayed or omitted in patients with established multiple sclerosis and nonprogressive bitemporal visual field defects if central visual acuity is not greatly reduced.- - - - - - - - - - ranking = 0.08685341992306keywords = central nervous system, nervous system (Clic here for more details about this article) |
9/74. tuberous sclerosis presenting in late adult life.A 59 year old woman presented with a three year history of left sided weakness. magnetic resonance imaging of the brain showed a large high signal lesion occupying most of the right temporal lobe with mass effect. A probable diagnosis of low grade glioma led to temporal lobectomy. histology revealed dysplastic cortical morphology typical of tuberous sclerosis. There were no clinical signs or family history of the disease. Ultrasound showed multiple bilateral renal angiomyolipomas, confirming the diagnosis of tuberous sclerosis. Molecular genetic analysis of peripheral white blood cells identified a novel mis-sense mutation R1409W in exon 33 of the TSC2 gene.- - - - - - - - - - ranking = 0.25keywords = brain (Clic here for more details about this article) |
10/74. Retinotopic modulation of space misrepresentation in unilateral neglect: evidence from quadrantanopia.A patient with right sided brain damage suffered contralesional neglect, inferior quadrantanopia (with 0 degrees sparing in the left eye and 13 degrees sparing in the right), and a visual field restriction (to 15 degrees ) in the upper contralesional quadrant of the left eye. In binocular vision, the patient showed underestimation of the horizontal size of contralesional line segments unless cued to localise their end points. When asked to reproduce, in monocular vision, 10 degrees and 20 degrees distances between two attentionally cued end points lying on the frontal vertical plane, the patient showed relative contralesional overextension and ipselesional underextension along the directions falling within the blind sectors of the neglected space. No asymmetry was present along the directions falling within the seeing sectors of the same space. These findings suggest precise retinotopic modulation of space misrepresentation in unilateral neglect.- - - - - - - - - - ranking = 0.25keywords = brain (Clic here for more details about this article) |
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