1/284. Surgical treatment of internal carotid artery anterior wall aneurysm with extravasation during angiography--case report.A 54-year-old female presented subarachnoid hemorrhage from an aneurysm arising from the anterior (dorsal) wall of the internal carotid artery (ICA). During four-vessel angiography, an extravasated saccular pooling of contrast medium emerged in the suprasellar area unrelated to any arterial branch. The saccular pooling was visualized in the arterial phase and cleared in the venophase during every contrast medium injection. We suspected that the extravasated pooling was surrounded by hard clot but communicated with the artery. Direct surgery was performed but major premature bleeding occurred during the microsurgical procedure. After temporary clipping, an opening of the anterior (dorsal) wall of the ICA was found without apparent aneurysm wall. The vessel wall was sutured with nylon thread. The total occlusion time of the ICA was about 50 minutes. Follow-up angiography demonstrated good patency of the ICA. About 2 years after the operation, the patient was able to walk with a stick and to communicate freely through speech, although left hemiparesis and left homonymous hemianopsia persisted. The outcome suggests our treatment strategy was not optimal, but suture of the ICA wall is one of the therapeutic choices when premature rupture occurs in the operation.- - - - - - - - - - ranking = 1keywords = visual, contrast (Clic here for more details about this article) |
2/284. Cerebral metastasis presenting with altitudinal field defect.A 75-year-old man presented with a unilateral inferior altitudinal visual field defect and a history of weight loss and night sweats. The acuity in the affected eye was 20/200, otherwise his ocular examination was normal. neuroimaging demonstrated a post-fixed chiasm, with a frontal metastasis compressing the intracerebral portion of the optic nerve. A chest x-ray showed classical cannon ball lesions, secondary to malignant melanoma. This is the first case report of an intracerebral tumor producing an inferior altitudinal field defect.- - - - - - - - - - ranking = 0.98148580816496keywords = visual (Clic here for more details about this article) |
3/284. 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 = 0.98148580816496keywords = visual (Clic here for more details about this article) |
4/284. On the visual disturbances associated with massive basal aneurysms.When massive basal aneurysms compromise the anterior visual pathways the resulting disturbances of vision are diverse and a firm clinical diagnosis is difficult. Because of the rarity of the condition, a critical analysis of the visual defects was made in five personally studied patients with large anterior basal aneurysms in an effort to clarify the clinical features of the disorder. These observations were related to those reported in larger series of patients by Jefferson and Bull. This study gives support to the opinion that the commonest visual defect seen with massive basal aneurysms is impairment of visual acuity, followed next in frequency by bitemporal hemianopia, and then by junction scotoma.- - - - - - - - - - ranking = 7.8518864653197keywords = visual (Clic here for more details about this article) |
5/284. Bilateral altitudinal anopia caused by infarction of the calcarine cortex.The patient reported here had a bilateral inferior altitudinal hemianopia from lesions of the calcarine (striate) cortex of the occipital lobes. The only significant pathologic findings were bilateral calcarine artery occlusive disease, with infarcts of the striate cortex on both sides. The ages of the infarcts appeared compatible with the clinical development of the respective visual field defects. The rest of the visual system was anatomically intact.- - - - - - - - - - ranking = 1.9629716163299keywords = visual (Clic here for more details about this article) |
6/284. 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 = 3.9259432326598keywords = visual (Clic here for more details about this article) |
7/284. 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 = 0.98148580816496keywords = visual (Clic here for more details about this article) |
8/284. Activation of the remaining hemisphere following stimulation of the blind hemifield in hemispherectomized subjects.We used functional magnetic resonance imaging (fMRI) to investigate the neural substrates mediating residual vision in the "blind" hemifield of hemispherectomized patients. The visual stimuli were semicircular gratings moving in opposite directions on a dynamic random-dot background. They were specifically constructed to eliminate intra- and extraocular light scatter and optimize the activation of extrastriate cortical areas and their subcortical relays. Multislice T2*-weighted gradient echo (GE) echoplanar imaging (EPI) images (TR/TE = 4 s/45 ms, flip angle 90 degrees ) were acquired during activation and baseline visual stimulation. An activation minus baseline subtraction was performed, and the acquired t statistic map transformed into the stereotaxic coordinate space of Talairach and Tournoux. In seven normal control subjects, right hemifield stimulation produced significant activation foci in contralateral V1/V2, V3/V3A, VP, and V5 (MT). Significant activation was also produced in homologous regions of the right occipital lobe with left hemifield stimulation. Stimulation of the intact hemifield in hemispherectomized patients resulted in activation of similar areas exclusively within the contralateral hemisphere. Stimulation of the anopic hemifield produced statistically significant activation in the ipsilateral occipital lobe (putative area V5 or MT) and areas V3/V3A in the only subject with blindsight. We conclude that the remaining hemisphere may contribute to residual visual functions in the blind hemifield of hemispherectomized patients, possibly through the collicular-pulvinar route since the activated areas are known to receive their afferents from these subcortical nuclei.- - - - - - - - - - ranking = 2.9444574244949keywords = visual (Clic here for more details about this article) |
9/284. Traumatic cataract presenting with unilateral nasal hemianopsia.A 56-year-old man developed a nasal field defect in his left eye 3 months after a traumatic accident. An examination showed a posterior subcapsular cataract in the left eye with no neurologic deficits. Humphrey 24-2 visual field testing revealed a nasal hemianopsia in the left eye. After cataract extraction and intraocular lens implantation, the patient's visual field returned to normal. This case shows that a cataract can present with a localized visual field deficit, which may be corrected by cataract extraction.- - - - - - - - - - ranking = 2.9444574244949keywords = visual (Clic here for more details about this article) |
10/284. attention without awareness in blindsight.The act of attending has frequently been equated with visual awareness. We examined this relationship in 'blindsight'--a condition in which the latter is absent or diminished as a result of damage to the primary visual cortex. Spatially selective visual attention is demonstrated when information that stimuli are likely to appear at a specific location enhances the speed or accuracy of detection of stimuli subsequently presented at that location. In a blindsight subject, we showed that attention can confer an advantage in processing stimuli presented at an attended location, without those stimuli entering consciousness. attention could be directed both by symbolic cues in the subject's spared field of vision or cues presented in his blind field. cues in his blind field were even effective in directing his attention to a second location remote from that at which the cue was presented. These indirect cues were effective whether or not they themselves elicited non-visual awareness. We concluded that the spatial selection of information by an attentional mechanism and its entry into conscious experience cannot be one and the same process.- - - - - - - - - - ranking = 3.9259432326598keywords = visual (Clic here for more details about this article) |
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