1/19. Acute onset of blindness during labor: report of a case of transient cortical blindness in association with hellp syndrome.The coincidence of hellp syndrome and cortical blindness is an uncommon but very dramatic event, for the patient as well as the obstetrician. This report describes the first case of HELLP-syndrome-associated cortical blindness occuring suddenly in the third stage of labour. There were only modest correlates of cortical blindness in cerebral CT, MRI and angiography findings, but no signs of a posterior leucoencephalopathy syndrome. Mother and baby were discharged from hospital to outpatient care in good health on the 12th day.- - - - - - - - - - ranking = 1keywords = posterior (Clic here for more details about this article) |
2/19. antiphospholipid syndrome with cortical blindness resulting from infarction around the posterior cerebral artery in an elderly woman.An 87-year-old woman with antiphospholipid syndrome accompanied by cortical blindness and thalamic syndrome resulting from infarction of the posterior cerebral artery is reported. She was hospitalized because of laceration of the head. Two months later, she complained of loss of visual acuity, sharp pain and numbness involving the left half of the body except her face. New right posterior lobe infarction and the existence of old left infarctions were confirmed by serial CT scans. Helical CT scan revealed embolization of the posterior cerebral artery with atherosclerotic stenosis. Serological examination showed biologically false-positive and positive findings for lupus anticoagulant. She was treated with warfarin potassium and clonazepam.- - - - - - - - - - ranking = 7keywords = posterior (Clic here for more details about this article) |
3/19. Direction-specific motion blindness induced by focal stimulation of human extrastriate cortex.Motion blindness (MB) or akinetopsia is the selective disturbance of visual motion perception while other features of the visual scene such as colour and shape are normally perceived. Chronic and transient forms of MB are characterized by a global deficit of direction discrimination (pandirectional), which is generally assumed to result from damage to, or interference with, the motion complex MT /V5. However, the most characteristic feature of primate MT-neurons is not their motion specificity, but their preference for one direction of motion (direction specificity). Here, we report that focal electrical stimulation in the human posterior temporal lobe selectively impaired the perception of motion in one direction while the perception of motion in other directions was completely normal (unidirectional MB). In addition, the direction of MB was found to depend on the brain area stimulated. It is argued that direction specificity for visual motion is not only represented at the single neuron level, but also in much larger cortical units.- - - - - - - - - - ranking = 1keywords = posterior (Clic here for more details about this article) |
4/19. MRI findings in a case of transient cortical blindness after cardiac catheterization.The magnetic resonance imaging findings in a case of transient cortical blindness (TCB) after cardiac catheterization are described for the first time. In addition, a literature review of TCB, comparison with reversible posterior leukoencephalopathy, and a hypothesis regarding the pathophysiology of TCB are presented.- - - - - - - - - - ranking = 1003.3854113846keywords = posterior leukoencephalopathy, leukoencephalopathy, posterior (Clic here for more details about this article) |
5/19. Posterior reversible encephalopathy syndrome due to severe hypercalcemia.Posterior reversible encephalopathy syndrome (PRES) is a leukoencephalopathy clinically characterized by headache, altered mental status, visual loss and seizures. neuroimaging demonstrates symmetrical posterior cortical and subcortical lesions. The exact pathophysiology is unknown but there is a strong association with immunosuppressants and hypertension. We report two cases of PRES in normotensive patients with severe hypercalcemia as the only identifiable cause. Possible pathophysiological mechanisms are discussed.- - - - - - - - - - ranking = 48.491728507991keywords = leukoencephalopathy, posterior (Clic here for more details about this article) |
6/19. Distinct neuropsychological characteristics in Creutzfeldt-Jakob disease.OBJECTIVES: To characterise the nature of cognitive change in Creutzfeldt-Jakob disease (CJD). methods: Case histories are reported of four patients with sporadic (sCJD) and two with familial CJD (fCJD), with postmortem pathological findings in four cases. The data derived from cognitive examination are examined with respect to the presence or absence of a variety of characteristics to elicit performance profiles across cognitive domains. RESULTS: Three patients with sCJD exhibited clear focal cortical deficits. One patient had visual impairment leading to cortical blindness, associated with posterior hemisphere abnormalities on single photon emission computed tomography (SPECT) imaging; two others had impairments in language, mirrored by left hemisphere SPECT abnormalities. The remaining three patients showed no specific cortical symptomatology. Despite these differences all six patients shared common qualitative characteristics: episodic unresponsiveness, interference effects, and profound verbal and motor perseveration. These common features are interpreted in terms of impaired activation and regulation of neocortex from subcortical structures. Findings from postmortem pathological examination and from the published literature provide converging evidence to implicate a critical role of the thalamus. CONCLUSION: These preliminary findings suggest that sCJD and fCJD may be associated with distinct neuropsychological characteristics.- - - - - - - - - - ranking = 1keywords = posterior (Clic here for more details about this article) |
7/19. Affective blindsight: intact fear conditioning to a visual cue in a cortically blind patient.Blindsight refers to remarkable residual visual abilities of patients with damage to the primary visual cortex (V1). Recent studies revealed that such residual abilities do not apply only to relatively simple object discriminations, but that these patients can also differentially categorize and respond to emotionally salient stimuli. The current study reports on a case of intact fear conditioning to a visual cue in a male patient with complete bilateral cortical blindness. The patient was admitted to the stroke unit of the neurological department because of complete loss of vision. Both CT and structural MRI scans confirmed lesions in both territories of the posterior cerebral artery. No visual evoked potentials could be detected confirming complete cortical blindness. During fear conditioning, a visual cue predicted the occurrence of an aversive electric shock. Acoustic startle probes were presented during and between the conditioned stimuli. Relative to the control condition, startle reflexes were substantially potentiated when elicited in the presence of the conditioned stimuli. No such potentiation was observed prior to conditioning. These data suggest that fear learning to visual cues does not require a cortical representation of the conditioned stimulus in the primary sensory cortex and that subcortical pathways are sufficient to activate the fear module in humans.- - - - - - - - - - ranking = 1keywords = posterior (Clic here for more details about this article) |
8/19. Postpartum blindness: two cases.We present 2 cases, one eclamptic patient and one noneclamptic patient, of headache, cortical blindness, and seizures. Both patients demonstrated findings consistent with posterior leukoencephalopathy syndrome. posterior leukoencephalopathy syndrome is a rapidly evolving neurologic condition that is characterized by headache, nausea and vomiting, seizures, visual disturbances, altered sensorium, and occasionally focal neurologic deficits. posterior leukoencephalopathy syndrome can be triggered by numerous conditions, including preeclampsia-eclampsia, and can be seen in the postpartum period. It is characterized predominately by white matter vasogenic edema of the occipital and posterior parietal lobes. This condition can be difficult to differentiate clinically from cerebral ischemia, and magnetic resonance imaging with diffusion-weighted imaging and apparent diffusion coefficient are needed to do so. In most cases of posterior leukoencephalopathy syndrome, the prognosis is excellent, with full resolution of symptoms.- - - - - - - - - - ranking = 17458.151254672keywords = leukoencephalopathy syndrome, posterior leukoencephalopathy syndrome, posterior leukoencephalopathy, leukoencephalopathy, posterior (Clic here for more details about this article) |
9/19. MR findings of cortical blindness following cerebral angiography: is this entity related to posterior reversible leukoencephalopathy?We describe MR findings in three patients who experienced transient cortical blindness following cerebral angiograms. All angiograms were performed by using the same nonionic contrast medium. On the basis of similar clinical and radiologic findings, we believe that this entity is closely related to and probably has the same pathophysiology as posterior reversible leukoencephalopathy.- - - - - - - - - - ranking = 242.45864253996keywords = leukoencephalopathy, posterior (Clic here for more details about this article) |
10/19. subacute sclerosing panencephalitis: a cause of acute vision loss.A 4-year-old male presented with only acute vision loss. His neurologic examination, funduscopic examination, and pupils were normal. Cranial magnetic resonance imaging revealed abnormal hyperintense, bilaterally symmetric lesions (on T(2)-weighted and fluid-attenuated inversion recovery, images) in bilateral optic radiations, pulvinar region in the thalami, crus posterior of internal capsules, periventricular white matter, and unilaterally left anterior pons. Elevated measles antibody titers in the cerebrospinal fluid confirmed the diagnosis of subacute sclerosing panencephalitis. Vision loss improved and cranial magnetic resonance imaging findings regressed,but myoclonic jerks and deterioration began 7 months later. The diagnosis of subacute sclerosing panencephalitis should be considered in cases with acute vision loss resulting from cortical blindness even when classical findings of the central nervous system do not exist.- - - - - - - - - - ranking = 1keywords = posterior (Clic here for more details about this article) |
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