Cases reported "Ataxia"

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1/67. A case of the subacute brainstem encephalitis.

    A case of brainstem encephalitis of undetermined etiology is reported in 66-year-old woman who had a sudden onset of illness with left abducens palsy, nystagmus and ataxia. The symptoms progressed to complete paralysis of eye movements, dysphagia and left hemiparesis with generalized hyperreflexia. Examination of CSF, CT scan and MRI of the brain were normal. The patient died 4 months after onset of disease. Neuropathologic study disclosed in the brainstem numerous perivascular and nodular inflammatory cell infiltrations composed predominantly of lymphocytes T and B. Most intensive inflammation concerned midbrain and pontine tegmentum and to a lesser degree medulla oblongata, pontine nuclei and cerebellar nuclei. basal ganglia, cerebral and cerebellar cortex were unaffected. Neuropathological finding was reminiscent of brainstem encephalitides related to viral infection or to paraneoplastic syndrome. However, HSV-1, EBV, and CMV antigens were not detected by immunohistochemistry, as well as evidences of malignancy were not present in this case.
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ranking = 1
keywords = cortex
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2/67. Deletion including the oligophrenin-1 gene associated with enlarged cerebral ventricles, cerebellar hypoplasia, seizures and ataxia.

    Non-specific X-linked mental retardation is a heterogeneous group of disorders with an incidence of approximately 1 in 500 males. A recently identified gene in Xq12, encoding a Rho-GTPase-activating protein, was found to be mutated in individuals with mental retardation. We describe here two sisters with a 46,XY karyotype and a microdeletion of the oligophrenin-1 gene and 1.1 Mb of flanking dna. We have characterised the molecular interval defining this microdeletion syndrome with the fibre-FISH technique. A visual physical map of 1.2 Mb was constructed which spans the oligophrenin-1 gene and the androgen receptor gene. The analysis of the patients revealed a deletion which extended from the 5' end of the AR gene to a region approximately 80 kb proximal to the EPLG2 gene. The clinical manifestations of the two sisters include psychomotor retardation, seizures, ataxia, hypotonia and complete androgen insensitivity. Cranial MRI scans show enlargement of the cerebral ventricles and cerebellar hypoplasia. Our findings give further support for the involvement of the oligophrenin-1 gene in specific morphological abnormalities of the brain which is of importance in the investigation of male patients presenting with mental retardation. In combination with our results from physical mapping we suggest that a region around the oligophrenin-1 locus is relatively bereft of vital genes.
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ranking = 0.14459723320695
keywords = visual
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3/67. A paradoxical improvement of misreaching in optic ataxia: new evidence for two separate neural systems for visual localization.

    We tested a patient (A. T.) with bilateral brain damage to the parietal lobes, whose resulting 'optic ataxia' causes her to make large pointing errors when asked to locate single light emitting diodes presented in her visual field. We report here that, unlike normal individuals, A. T.'s pointing accuracy improved when she was required to wait for 5 s before responding. This counter-intuitive result is interpreted as reflecting the very brief time-scale on which visuomotor control systems in the superior parietal lobe operate. When an immediate response was required, A. T.'s damaged visuomotor system caused her to make large errors; but when a delay was required, a different, more flexible, visuospatial coding system--presumably relatively intact in her brain--came into play, resulting in much more accurate responses. The data are consistent with a dual processing theory whereby motor responses made directly to visual stimuli are guided by a dedicated system in the superior parietal and premotor cortices, while responses to remembered stimuli depend on perceptual processing and may thus crucially involve processing within the temporal neocortex.
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ranking = 1.8675833992417
keywords = cortex, visual
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4/67. An 'automatic pilot' for the hand in human posterior parietal cortex: toward reinterpreting optic ataxia.

    We designed a protocol distinguishing between automatic and intentional motor reactions to changes in target location triggered at movement onset. In response to target jumps, but not to a similar change cued by a color switch, normal subjects often could not avoid automatically correcting fast aiming movements. This suggests that an 'automatic pilot' relying on spatial vision drives fast corrective arm movements that can escape intentional control. In a patient with a bilateral posterior parietal cortex (PPC) lesion, motor corrections could only be slow and deliberate. We propose that 'on-line' control is the most specific function of the PPC and that optic ataxia could result from a disruption of automatic hand guidance.
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ranking = 5
keywords = cortex
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5/67. Visually misguided reaching in Balint's syndrome.

    A patient with bilateral parietal damage leading to Balint's syndrome was tested on his ability to reach to, and to describe the locations of visual targets. RM was better at reaching to targets than he was at describing the locations of the same targets. Moreover, he was better at reaching to targets when he could not see them, compared to when he was reaching with visual guidance. In a final experiment, we found that RM showed strong inhibition of responses to non-target items, even though he had a poor representation of their location in depth. As a result of intact inhibition and impaired depth representation, he ignored both target and non-target items in a given direction. These results suggest that in RM a disturbed visual representation of space disrupts an otherwise relatively intact reaching control system.
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ranking = 0.43379169962086
keywords = visual
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6/67. Optic ataxia: clinical-radiological correlations with the EMIscan.

    After coronary by-pass surgery, a 47 year old, right-handed man developed Gerstmann's syndrome, a visual-spatial perceptual deficit, and a gross impairment of movememt under visual guidance ("optic ataxia"). visual fields and extraocular movements were intact; he had a left hemiparesis. The EMIscan showed three lesions: a left parietal-occipital lesion; a posterior callosal lesion, and a right frontal lesion. It is hypothesized that optic ataxia in both visual fields requires bilateral lesions which, in the present case, were strategically placed so as to effectively disconnect motor cortex from visual input.
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ranking = 1.5783889328278
keywords = cortex, visual
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7/67. Broadening the clinical spectrum: unusual presentation of spontaneous cerebrospinal fluid hypovolemia. Case report.

    The syndrome of spontaneous intracranial hypotension is characterized by orthostatic headaches in conjunction with reduced cerebrospinal fluid (CSF) pressure or CSF volume, and characteristic magnetic resonance (MR) imaging findings. A 50-year-old man presented with a 1-year history of paroxysmal ataxia of gait and short attacks of blurred vision when he stood up from a recumbent position and began to walk. Orthostatic headache was not a feature of his clinical presentation. Magnetic resonance images of the brain revealed diffuse enhancement of the dura mater and hygromas over both cerebral convexities. Magnetic resonance images of the spine demonstrated dilated cervical epidural veins and dilation of the perimedullary veins. Radionuclide cisternography identified a CSF leakage that was localized to the T12-L1 level on subsequent myelograms and on computerized tomography scans obtained after the myelograms. An epidural blood patch was administered and visualized with tungsten powder. The patient's clinical symptoms and sites of disease on imaging completely resolved. The unusual clinical presentation in this case--paroxysmal ataxia of gait, lack of orthostatic headaches, and dilated epidural and perimedullary venous plexus--supports a recently noted broadening of both the clinical and imaging characteristics of spontaneous intracranial hypovolemia.
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ranking = 0.14459723320695
keywords = visual
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8/67. Balint's syndrome in a 10-year-old male.

    A 10-year-old male was referred with difficulties at school. He had particular difficulty with reading long words, following the sequence of text down a page, writing words in the correct order, writing words in line, and copying from the blackboard. He had a history of infective endocarditis complicated by intracerebral haemorrhage at the age of three years. Detailed history taking revealed symptoms typical of 'dorsal stream' pathology, namely a deficit of 'vision for action'. This included a spatial disorder of attention (simultanagnosia), defective hand and foot movements under visual control (optic ataxia), and acquired oculomotor apraxia which are consistent with Balint's syndrome. Strategies were suggested for coping with the symptoms and one year later a distinct improvement in adapting to the disability was found.
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ranking = 0.14459723320695
keywords = visual
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9/67. Pointing errors in immediate and delayed conditions in unilateral optic ataxia.

    The present paper provides an analysis of the pointing errors of a patient with unilateral optic ataxia (O.K.) following right hemispheric damage, revealing the type of errors related tothe use of the contralesional hand and/or to the reaching of targets located in the contralesional visual field. In addition, comparison between immediate and delayed pantomime pointing allow testing of whether pointing deficits of this patient are specific to real-time visuo-motor control and, subsequently, whether delay could improve his pointing performance. The results show different patterns in the four hand-field combinations. The following conclusion can be drawn from the results of the delayed condition. In the case of patient O. K., the delay reduced the pointing variability for both hands in the left visual field but not in the right visual field. However, the pointing biases did not improve accordingly. As in healthy subjects, target locations tended to be coded in memory with a bias directed toward the fixation point. These results are discussed and contrasted with respect to those previously obtained in the literature in patients with bilateral optic ataxia.
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ranking = 0.43379169962086
keywords = visual
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10/67. Troubled reaching after right occipito-temporal damage.

    We encountered a man with an unusual reaching disturbance due to a stroke in the right occipito-temporal cortex and subjacent white matter. We studied his behavior in detail including vision and hand control. He had a left homonymous hemianopia. In his remaining fields static visual acuity and stereoacuity were normal, but he could not detect a coherent motion signal or follow moving targets with smooth pursuit. Transduction of limb movements using an optoelectronic technique showed abnormal morphology, increased variability and markedly prolonged latencies for transport to external visual targets, yet he achieved these targets with precision. Reaching to self-bound targets, and to the remembered locations of external targets with vision blocked was 5 x faster. The findings may be explained by: (1) damage in regions homologous to areas TF and TH in the monkey, which provide visual inputs to hand and forelimb representations in the cortex; (2) injury in human regions homologous to the monkey's MT complex, with inability to use visual information on the movement of the limb due to a visual motion processing defect; and (3) disruption of visual cortical-subcortical connections mediating crucial transformations among limb and target representations.
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ranking = 2.8675833992417
keywords = cortex, visual
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