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At least 1,081 records · Page 60Linked to original sources
PubMed1998

[Brain lesions of perinatal and late prenatal origin in a neuropediatric context].

INTRODUCTION: The obstetric and neonatal technological advances have changed the frequency and syndromic classification of perinatal brain lesions. OBJECTIVE: To study all prevalent patients during 1996, with perinatal or late intrauterine brain lesions, in the outpatient neuropediatric clinic at our hospital. METHODS: Selection of patients according to neuroimaging findings, and/or neurological sequela with documented perinatal antecedent. EXCLUSION CRITERIA: a normal MRI, brain lesions of doubtful origin, or uncertain sequela with normal CT or echography studies. Descriptive study, and also analytical, using logistic regression to study the relationship between antecedents and sequela. RESULTS: A total of 111 patients with: brain lesions due to hypoxic-ischemic encephalopathy (22 cases), lesions due to prematurity (29), late intrauterine infection or neonatal meningitis as the only cause of fixed neurological impairment (12), unexpected vascular brain lesions during the neonatal period (11), late intrauterine brain lesions (37). The neurological sequela observed were: cerebral palsy (68%), epilepsy (47%), mental retardation (45%), learning disorders in (34%) of those of school age and free from mental retardation, strabism (26%), microcephaly (19%), visual impairment (14%), hyperkinesis (10%). The neuroimaging findings were: focal lesions (45%), hydrocephaly (28%), intraventricular haemorrhage (22%), white matter lesions (24%), venous thrombosis (2%). The multivariable analysis showed, as the most noticeable finding, the relationship between the antecedent of mechanical ventilation and late development of hyperkinesis (OR: 10), in this sample of patients with severe sequela. Three patients should be noted: a case of late-onset dystonia secondary to a late intrauterine brain lesion, a child with exclusively cerebellar symptoms due to a destructive cerebellar lesion of prenatal onset, and a patient with an acquired perinatal biopercular lesion and pseudobulbar palsy as the only long-term sequelae.

Abnormalities, Multiple↗
PubMed1998

[Arteriography using helicoidal computerized tomography in the study of complex aneurysms of the circle of Willis].

INTRODUCTION: Computed tomography angiography (CTA) can add information to digital subtraction angiography (DSA) in selected cases of aneurysms of the circle of Willis. CLINICAL CASES: 1. Patient with progressive visual loss and headache. CT and DSA showed an image of partially thrombosed suprasellar aneurysm. CTA better defined the relationship between the lesion and regional vessels. 2. Woman with subarachnoid hemorrhage (SAH). CTA defined the aneurysmal neck and its relationship to the clinoid process. 3. Man with SAH, CT and DSA showed an arteriovenous malformation and three arterial aneurysms one of which was in a tortuous vessel. CTA confirmed digital angiographic data. CONCLUSION: CTA is a new image technique that can either add or confirm DSA findings in complex aneurysms of the circle of Willis.

Adult↗
PubMed1998

Pre- and peroperative misdiagnosed sellar tumour.

We describe the case of a 76-year old woman complaining of headaches and progressive sight loss. Cerebral CT scan and MRI disclosed a large sellar tumour. Endocrine evaluation showed no evidence of pituitary hypersecretion, but a slight hyperprolactinemia related to stalk compression. A non-functioning pituitary adenoma was suspected. The pathological diagnosis was however a meningioma. In the literature, about 5% of sellar tumours are not pituitary adenomas and this is an alternate diagnosis to consider in the presence of non-secreting macroadenomas.

Adenoma↗
PubMed1998

Intracranial Ewing's sarcoma.

Three patients with intracranial Ewing's sarcoma had neuro-ophthalmologic manifestations. In one patient, the primary tumor was in the skull and in two, it involved the long bones. Two patients complained of intermittent headache associated with bilateral, transient visual symptoms suggestive of migraine, which prompted imaging that showed occipital metastases. The third patient had an orbital syndrome.

Adolescent↗
PubMedDate not supplied

[Impairment of visual pathway function in right hemisphere in patients with arteriovenous malformation of the parietooccipital area of left hemisphere].

Marked arteriovenous malformation in the left parietooccipital area manifested only by symptoms of associative migraine involving changes of visual fields indicative of impaired functions of symmetrical compartments of the other brain hemisphere. Visual evoked potentials were changed in this patient because of dysfunction of both hemispheres and largely because of disorders in brain structures symmetrical to the site of arteriovenous malformation. This can be regarded as a manifestation of the so-called stealing phenomenon, when blood supply to one brain compartment is decreased because of excessive blood delivery to other regions of the brain. The results permit us to hypothesize regulation of blood supply to symmetrical compartments of brain hemispheres.

Cerebral Angiography↗
PubMed1999

Imaging of the pediatric orbit and visual pathways: computed tomography and magnetic resonance imaging.

Techniques for pediatric MR imaging and computed tomography and anatomy of the orbit and intracranial visual pathways are presented and reviewed in this article. Imaging findings are presented for the following categories of abnormality: a) orbital anomalies related to congenital disorders of the brain, b) disorders of the orbit (ocular, nonocular, or multicompartmental), c) disorders of the intracranial visual pathways (suprasellar cistern, optic radiations, or occipital cortex), and d) disorders of gaze (extraocular muscles, cranial nerves, and brainstem). Careful assessment of the clinical findings, anatomic location of the visual impairment, and familiarity with disorders that often affect pediatric patients are helpful in guiding neuroimaging evaluation of the child with ocular, orbital, or central patterns of visual disturbance.

Brain Diseases↗
PubMed2003

Value of electrodiagnostic assessment in nonsyndromic microcephaly.

PURPOSE: To evaluate the value of electroretinogram (ERG) and visual evoked potentials (VEP) in children with nonsyndromic microcephaly. METHODS: In this observational case series, six children with nonsyndromic microcephaly aged 8.5 to 158 months were examined. Main outcome measures included the amplitude of the flash ERG (photopic, flickering, scotopic, and dark-adapted responses), the amplitude and latency of the VEP (flash or pattern-reversal stimulus), visual acuity, slit-lamp biomicroscopy, and indirect ophthalmoscopy. RESULTS: Three children demonstrated normal fundus appearances, ERG, and VEP responses: two in this group demonstrated poor vision and brain computed tomography in the third showed schizencephaly. The remaining three children demonstrated abnormal ERG with predominant reduction in photopic amplitudes. Retinal pigmentary granularities were detected in two children in this group, one of whom has poor vision, generalized brain atrophy, and 40% reduction in VEP amplitudes. CONCLUSIONS: Abnormal ERG is not uncommon among children with nonsyndromic microcephaly. Although cone photoreceptors are affected more than rods, this does not anticipate poor vision. It appears that defects in posterior visual pathway or developmental malformations of the brain should be responsible for poor visual function in nonsyndromic microcephaly.

Atrophy↗
PubMed2001

Identification of cervical neoplasia using a simulation of human vision.

OBJECTIVE: To determine whether a computer simulation of human vision could detect and discriminate cervical cancer precursors and cancer from normal epithelium. METHODS: The Georgia Tech Vision (GTV) system was trained to recognize normal and abnormal cervical features. GTV then assessed a new series of images to determine whether it could detect and diagnose cervical neoplasia without any a priori information about the images. RESULTS: After training on one set and testing on another set of images, GTV demonstrated 100% sensitivity and 98% specificity to detect cervical intraepithelial neoplasia 3 (CIN3). GTV also had 88% sensitivity and 93% specificity to detect cervical cancer following training on one set and testing on another set of digitized cervical colposcopic images. CONCLUSION: This study demonstrated that GTV can detect CIN3 and cancer from digitized cervical colposcopic images. Furthermore, GTV could discriminate cervical cancer precursors and cancer from normal cervical epithelium, including immature metaplasia.

Journal Article↗
PubMed1995

Impairments of reaching movements in patients without proprioception. II. Effects of visual information on accuracy.

1. The aim of this study was to determine how vision of a cursor indicating hand position on a computer screen or vision of the limb itself improves the accuracy of reaching movements in patients deprived of limb proprioception due to large-fiber sensory neuropathy. In particular, we wished to ascertain the contribution of such information to improved planning rather than to feedback corrections. We analyzed spatial errors and hand trajectories of reaching movements made by subjects moving a hand-held cursor on a digitizing tablet while viewing targets displayed on a computer screen. The errors made when movements were performed without vision of their arm or of a screen cursor were compared with errors made when this information was available concurrently or prior to movement. 2. Both monitoring the screen cursor and seeing their limb in peripheral vision during movement improved the accuracy of the patients' movements. Improvements produced by seeing the cursor during movement are attributable simply to feedback corrections. However, because the target was not present in the actual workspace, improvements associated with vision of the limb must involve more complex corrective mechanisms. 3. Significant improvements in performance also occurred in trials without vision that were performed after viewing the limb at rest or during movements. In particular, prior vision of the limb in motion improved the ability of patients to vary the duration of movements in different directions so as to compensate for the inertial anisotropy of the limb. In addition, there were significant reductions in directional errors, path curvature, and late secondary movements. Comparable improvements in extent, direction, and curvature were produced when subjects could see the screen cursor during alternate movements to targets in different directions. 4. The effects of viewing the limb were transient and decayed during a period of minutes once vision of the limb was no longer available. 5. It is proposed that the improvements in performance produced after vision of the limb were mediated by the visual updating of internal models of the limb. Vision of the limb at rest may provide configuration information while vision of the limb in motion provides additional dynamic information. Vision of the cursor and the resulting ability to correct ongoing movements, however, is considered primarily to provide information about the dynamic properties of the limb and its response to neural commands.

Adult↗
PubMed2003

Hydrocephalus with visual deficits in a cat.

A 22-month-old male Japanese mongrel cat with a history of dysuria and recurrent generalised tonic-clonic seizure was examined by neuro-opthalmological testing and computed tomography (CT). Vision testing revealed narrowing of the visual field in the right eye, and complete visual deficits in the left eye. Pupillary reactions, and motor and sensory function in the eyelids and the eyes were normal. The cat was diagnosed as hydrocephalus by CT examination, because dilation of the right lateral ventricle, and compression of the right temporal and occipital cortices was shown. The etiology of the hydrocephalus was unclear. Although a unilateral lesion of the upper visual pathway was suspected, a complete homonymous hemianopsia was not shown.

Animals↗
PubMed2000

The vision for the Department of Defense's computer-based patient record.

To meet the Department of Defense's clinical information management mission for the next century, a vision for the computer-based patient record (CPR) was needed. This article describes the generation of that vision as well as the resulting definition, characteristics, and essential functions of the Department's CPR.

Forecasting↗
PubMed1996

A computer model of processes of binocular vision in the cerebral cortex.

Fundamentals and options of modeling cortical processes of binocular vision are dealt with in this paper. Physiologically characterized cell types of the visual cortex are modelled and used as basis of a network implementing a simulation of the binocular vision. An attempt is made to establish correlations between typical activity patterns of visual cortical cells and the network incorporating them.

Animals↗
PubMed2001

Using a web-based prototype and human-computer interaction concepts to develop a vision for a next generation patient care management system.

This paper describes the novel use of two tools to develop requirements for a new generation patient care system: a web-based prototype and a human-computer interaction framework. These tools allowed a development team to crystallize new requirements for a patient care system, illustrate to clinicians a radical change in care process models, and begin the change management process in a large enterprise.

Hospital Information Systems↗
PubMed2001

[Technical realization of an LCD-based vision test device].

We describe a computer-aided self-test vision screener for testing near and far visual acuity. The device generates images separately for each eye on a LCD. Acuity can be measured in the range between 0.1 and 1.6 for any distance between 0.34 m and 6 m. In addition, it also enables testing for colour deficiency, phoria, stereopsis and contrast sensitivity. The device is fully automatic and enables self-testing of the above mentioned functions. Initial practical application in an industrial environment has demonstrated the practicability of the device.

Diagnosis, Computer-Assisted↗
PubMed1999

Role of feedback in mammalian vision: a new hypothesis and a computational model.

This paper presents a novel hypothesis on the function of massive feedback pathways in mammalian visual systems. We propose that the cortical feature detectors compete not for the right to represent the output at a point, but for exclusive rights to abstract and represent part of the underlying input. Feedback can do this very naturally. A computational model that implements the above idea for the problem of detection is presented and based on that we suggest a functional role for the thalamo-cortical loop during perception of lines. We show that the model successfully tackles the so called Cross problem. Based on some recent experimental results, we discuss the biological plausibility of our model. We also comment on the relevance of our hypothesis (on the role of feedback) to general sensory information processing and recognition.

Algorithms↗
PubMed2004

Speed-accuracy tradeoff during performance of a tracking task without visual feedback.

To help people with visual impairment, especially people with severely impaired vision, access graphic information on a computer screen, we have carried out fundamental research on the effect of increasing the number of detection fields. In general, application of the parallelism concept enables information to be accessed more precisely and easily when the number of sensors is high. We have developed a "Braille Box" by modifying Braille cells to form a tactile stimulator array which is compatible with the fingertip. Each pin can be controlled independently so that we can change the size and type of array in order to study the tactile perception of both simple and complex graphical forms. Our results show that by applying the parallelism concept to the detection field, people with visual impairment can increase the speed of exploration of geometric forms without decreasing the level of accuracy: thus, avoiding a speed-accuracy tradeoff. Further experiments need to be done with this Braille Box in order to improve the device and help people with visual impairment access graphic information.

Adult↗
PubMed2003

[Asthenopic complaints and ocular convergence at the computer workstation: new test procedures for practice and research].

BACKGROUND: The present paper summarizes a series of ergonomic studies on the relation between asthenopic complaints and binocular vision at the computer workstation. In particular, the paper reports on measurements of the accuracy of ocular convergence during fixation of central fusion stimuli (i. e. fixation disparity) as a function of viewing distance. METHODS: Different versions of subjective tests for fixation disparity (using dichoptic nonius lines) are presented, including a computer-controlled procedure (the eye-test PC). RESULTS: These new tests suggest that non-presbyopic subjects with normal binocular vision may suffer from asthenopic complaints if they have - in near vision - an exo fixation disparity larger than average. CONCLUSION: In these cases, the stress exercised on the convergence system can be reduced by using a longer viewing distance at the workplace.

Accommodation, Ocular↗