[Low visual acuity, disorders of the visual field: how to adapt the imaging of optical pathways to clinical practice?].
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Pheochromocytoma is very rare in children. We report a case of bilateral pheochromocytoma in a 12-year-old boy who had blurred vision due to hypertensive retinopathy. Abdominal ultrasound and computed tomography revealed bilateral suprarenal tumors. Resection of the bilateral tumors along with right total and left subtotal adrenalectomy were performed. Blood pressure and visual acuity returned to normal after surgery.
INTRODUCTION: Recently the clinical and genetic investigation of cerebellar diseases has experienced an extraordinary advance due to localization of the disorders in different chromosomal loci. This type of investigation has been done in Peru in the last decade, studying a Peruvian family from the Huarochiri province. PATIENTS AND METHODS: A Peruvian family of 65 individuals in five generations, affected by several neurological disturbances associated with ataxia, were studied by clinical, neurological, ophthalmological, neuroradiological and genetic methods. The genetic study was done in the neurogenetics laboratory of the University of Utah (Salt Lake City, United States). RESULTS: The patients showed equilibrium disturbances, gait difficulties, ophthalmoplegia, corticospinal signs, cognitive deficiencies, visual weakness, maculopathy, retinal degeneration, optic nerve atrophy and atrophy of the cerebellum, brain stem and cerebral hemispheres. The DNA in 30 individuals showed, in the neurologically affected, repeated expansion of CAG triplets in the short arm of chromosome 3p. CONCLUSIONS: The findings in this family suggests that they suffer from spinocerebellar ataxia type 7. This could be the first description of the disease in Latin-America.
Rotational and translational vestibulo-ocular reflexes (RVOR and TrVOR) function to maintain stable binocular fixation during head movements. Despite similar functional roles, differences in behavioral, neuroanatomical, and sensory afferent properties suggest that the sensorimotor processing may be partially distinct for the RVOR and TrVOR. To investigate the currently poorly understood neural correlates for the TrVOR, the activities of eye movement-sensitive neurons in the rostral vestibular nuclei were examined during pure translation and rotation under both stable gaze and suppression conditions. Two main conclusions were made. First, the 0.5 Hz firing rates of cells that carry both sensory head movement and motor-like signals during rotation were more strongly related to the oculomotor output than to the vestibular sensory signal during translation. Second, neurons the firing rates of which increased for ipsilaterally versus contralaterally directed eye movements (eye-ipsi and eye-contra cells, respectively) exhibited distinct dynamic properties during TrVOR suppression. Eye-ipsi neurons demonstrated relatively flat dynamics that was similar to that of the majority of vestibular-only neurons. In contrast, eye-contra cells were characterized by low-pass filter dynamics relative to linear acceleration and lower sensitivities than eye-ipsi cells. In fact, the main secondary eye-contra neuron in the disynaptic RVOR pathways (position-vestibular-pause cell) that exhibits a robust modulation during RVOR suppression did not modulate during TrVOR suppression. To explain these results, a simple model is proposed that is consistent with the known neuroanatomy and postulates differential projections of sensory canal and otolith signals onto eye-contra and eye-ipsi cells, respectively, within a shared premotor circuitry that generates the VORs.
30 patients with megadolichobasilar artery, explored by angiography, are reported; 23 among them were first studied by computerized tomography and 4 by magnetic resonance. From the clinical point of view, 9 had transient ischemic attacks or definitive ischemia, 7 had subarachnoid or intracerebral hemorrhage, and 7 had deficits of the cranial nerves; in the other 7 cases the condition was incidentally discovered as isolated asymptomatic anomaly or with other unrelated lesions. Among the patients with ischemic symptoms, vertebrobasilar insufficiency and pontine infarction were the most common clinico-radiological findings. Among the patients with intracranial hemorrhage, four had associated aneurysm or arteriovenous malformations. CT and MR allow a correct diagnosis of this anomaly. MR seems to be superior to CT in delineating the relationship of the anomalous artery with the nervous structures, and the coexisting pathology.
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Two patients with migraine and repetitive visual field defects of homonymous hemianopic type are reported. The visual field defects were confirmed by Goldmann perimetry and automated static perimetry. Neither computed tomography nor magnetic resonance imaging showed abnormal findings. Decreased cerebral blood flow at the left basal ganglion area was the only abnormal finding detected in one patient by 123I-IMP (iodoamphetamine)-SPECT (single photon emission computed tomography), which is applicable to right homonymous hemianopia. A visual field test that includes the current automated static perimetry is important to the diagnosis and the subsequent treatment of patients with migraine, particularly those who have experienced visual negative phenomena.
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We report a case with a sequential appearance and disappearance of homonymous hemianopsia, palinopsia and metamorphopsia in the defective visual field within two days. She had a stroke nine months ago and recovered completely. During that episode, dizziness and unsteadiness happened suddenly and was followed by above-mentioned visual symptoms. Brain image and blood perfusion studies showed an old right occipital lesion with hemodynamic changes. Electroencephalograms performed immediately just after the disappearance of all the above-mentioned symptoms subsided and four months later showed similar findings, some isolated independent sharp waves over bilateral temporal areas, with right posterior extension. These were independent of her visual symptoms. The pathophysiologies of our case could be a sequential hemodynamic change in the right occipital area, from hypoperfusion to transient hyperperfusion and finally to normal perfusion. Potential mechanisms are discussed with literature review.
An application of digital signal processor (DSP) in the visual electrophysiology record system is presented in this paper. The system's design and implementation are described in detail. Results of its simulation and the clinical experiments are acceptable.
The characteristics of visual display terminal (VDT) and related eye symptoms were analyzed. Research of the effect of VDT on visual function, visual development and characteristics of ocular surface was presented. Currently research still stays in the initial stage. Intensive research of VDT related eye problem will provide effective prevention and treatment methods for clinic work.
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The value of endoscopic ultrasonography in the diagnosis of subepithelial tumors and extrinsic compression of the esophagus and the stomach was evaluated in 34 patients with 21 subepithelial tumors and 13 extrinsic compressions. Endoscopic ultrasonography was always performed after axial-vision fiberscopy anal routine biopsy specimens were obtained. Computed tomography was also done in all cases of extrinsic compression. Distinction between subepithelial tumor and extrinsic compression was made in all patients by endoscopic ultrasonography and in 5 cases by fiberscopic examination with biopsy specimens. Localization and intramural spread of subepithelial tumors were correctly determined in 12 of 13 cases by endoscopic ultrasonography (diagnostic accuracy: 92 percent). The echoendoscopic semiology of 21 subepithelial tumors was retrospectively established. The histologic nature of some of these tumors can be suggested by these signs. Endoscopic ultrasonography is superior to computed tomography in the evaluation of esogastric extrinsic compressions, particularly in the diagnosis of posterior mediastinal carcinomatosis and of tumoral invasion of the deep parietal layers. We conclude that endoscopic ultrasonography is currently the best procedure in the assessment of subepithelial tumors and extrinsic compressions of the esophagus and the stomach.
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Stereopsis testing has received renewed interest because of its relationship to strabismus and amblyopia. This paper discusses clinical implications of stereo responses on traditional line stereograms and on newly developed random dot stereograms in normals, strabismics and amblyopes. Random dot stereograms are computer generated which when binocularly fused give rise to stereoscopic depth.
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