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At least 811 records · Page 45Linked to original sources
PubMed2005

Post dural puncture headache in a pediatric patient with idiopathic intracranial hypertension.

We describe the occurrence of postdural puncture headache (PPDH) in an adolescent with idiopathic intracranial hypertension (IIH) and its successful management with an epidural blood patch. PPDH is a very rare occurrence in patients with intracranial hypertension and is described as a paradoxical situation in the literature. There are only two previous case reports (in adults) of the possible association. A 15-year-old obese patient with a diagnosis of IIH had an uneventful diagnostic spinal tap using a 22G Quincke needle in the pediatric emergency department but returned 24 h later with PPDH. After a failed trial of conservative management, she had an uneventful but curative epidural blood patch with 15 ml of autologous venous blood and was able to return to school the day after the blood patch. Follow-up review by her neuro-ophthalmologist shows resolution of her headaches, considerable improvement in her visual field defect and resolution of papilledema. This is the first report of PPDH and its successful management with an epidural blood patch in a pediatric patient with IIH.

Adolescent↗
PubMed2001

The cortical deficit in humans with strabismic amblyopia.

To further our understanding of the cortical deficit in strabismic amblyopia, we measured, compared and mapped functional magnetic resonance imaging (fMRI) activation between the fixing and fellow amblyopic eyes of ten strabismic amblyopes. Of specific concern was whether the function of any visual area was spared in strabismic amblyopia, as recently suggested by both positron emission tomography (PET) and fMRI studies, and whether there was a close relationship between the fMRI response and known psychophysical deficits. To answer these questions we measured the psychophysical deficit in each subject and used stimuli whose relationship to the psychophysical deficit was known. We observed that stimuli that were well within the amblyopic passband did produce reduced fMRI activation, even in visual area V1. This suggests that V1 is anomalous in amblyopia. A similar level of reduction was observed in V2. In two subjects, we found that stimuli outside the amblyopic passband produced activation in visual area V3A. We did not find a close relationship between the fMRI response reduction in amblyopia and either of the known psychophysical deficits even though the fMRI response reduction in amblyopia did covary with stimulus spatial frequency.

Adolescent↗
PubMed1991

Hemiplegic cerebral palsy: correlation between CT morphology and clinical findings.

Morphological findings on CT were compared with clinical features of 111 children with hemiplegic cerebral palsy. Periventricular atrophy, interpreted as periventricular leukomalacia, was the most prevalent CT finding, although this type of lesion did not indicate severity of neurological impairment. Maldevelopments were associated with arm-dominated hemiplegia and with a wider range of clinical impairments than previously described. Cortical/subcortical atrophy, less common than presumed, indicated arm-dominated hemiplegia and was associated with more severe impairment than were other CT findings. A normal CT scan indicated leg-dominated hemiplegia and mild impairment. The morphological information obtained by CT was found to be useful for predicting clinical outcome, and was considered an important adjunct to clinical history and findings in these children.

Adolescent↗
PubMed1998

Neuroimaging in children with congenital disorders of the peripheral visual system.

The study investigates the neurological substrate in children with congenital disorders of the peripheral visual system (CDPVS), i.e. disorders of the anterior visual pathways and the globe. The design is retrospective; brain MRI and/or CT scans were traced and reviewed for 79 of 254 children with CDPVS on our database. The neuroradiological findings were considered in the context of degree of visual impairment (profound [PVI] and severe [SVI]), developmental outcome (setback and non-setback), and mode of imaging (MRI and CT). Scans were abnormal in 40 of 79 (51%) children; 23 of 40 (58%) had more than one lesion; and in some children lesions not previously reported were found. The number of abnormalities per child was significantly higher in the PVI than the SVI group (P<0.05); the level of significance varied according to the method of scanning (MRI, P<0.001; CT, ns). Seven children were known to have had developmental setback; significantly more brain abnormalities per child were found in the group with setbacks than in the group without (P<0.001). Eighty-six percent (24 of 28) of MRI compared with 38% (22 of 58) of CT scans were abnormal. MRI detected more lesions per child than CT (P< 0.001). Thus, a significant amount of brain pathology occurs in children with CDPVS. The number of lesions varies directly with degree of visual impairment and both correlate with developmental outcome. As brain pathology will be only one of many factors influencing developmental progress in visually impaired children, prospective multifactorial studies of the CDPVS population, which include MRI studies of the neurological substrate, will be required to clarify the latter.

Brain↗
PubMed1990

Intracranial meningioma: an exercise in differential diagnosis.

A 48-year-old man presented with a unilateral visual disturbance including reduced visual acuity and decreased sensitivity of the temporal visual field. He was initially diagnosed as having optic neuritis. Four months later the condition not only remained unresolved, but showed signs of progression. This presentation was atypical for optic neuritis and further detailed investigation was warranted. The patient's symptoms, along with multi-channel topographic visual evoked potentials and quantitative visual field analysis, were more indicative of a diagnosis of a space occupying lesion. A CT scan confirmed the presence of an intracranial tumour which was surgically excised. Pre- and post-operative visual function are described. The case report highlights the difficulty of differential diagnosis of optic neuritis and the clinical value of the appropriate and judicious use of multi-channel evoked potentials.

Color Perception Tests↗
PubMed1991

Sustained visual aura: a totally new variation of migraine.

An unusual case of an abnormally long-lasting (over 12 months) visual migraine aura is reported. The absence of signs of a structural lesion, as shown by neuro-imaging and clinical investigations, make difficult the differential diagnosis between a new variation and a complication of migraine.

Aged↗
PubMed1995

Late onset globoid cell leukodystrophy (Krabbe's disease)--Swedish case with 15 years of follow-up.

We describe a male patient with late onset globoid cell leukodystrophy (GLD) (Krabbe's disease) still alive at 24 years of age, with a well preserved intellectual and communicative capacity, in contrast to visual failure and severe central pyramidal and extrapyramidal motor disability with spasticity, dystonia, ataxia and peripheral neuropathy. Visual dysfunction began at 4 years of age, limping and balance problems at 8 years and epilepsy at 14 years of age. Neuroimaging at 15 years of age revealed white matter lesions, and nerve conduction velocity examinations showed a slowly developing polyneuropathy. Galactosylceramidase activity was reduced in leukocytes to 0.07 mu kat/kg protein compared with 0.02 (SD 0.01) mu kat/kg protein in infantile GLD.

Adult↗
PubMed1991

Abnormalities of energy metabolism in Alzheimer's disease studied with PET.

Positron emission tomography (PET) is currently the only technology affording three-dimensional measurement of the brain's energy metabolism which is closely coupled to brain function. Studies of glucose metabolism by PET of (18F)-2-fluoro-2-deoxy-D-glucose are therefore widely applied to show the contribution of various brain structures in the performance of a variety of tasks or their participation in functional deficits associated with various diseases. Although glucose metabolism decreases slightly with age to a regionally different degree, most types of dementia show severe changes in glucose metabolism. Alzheimer's disease (AD) is characterized by metabolic disturbances most prominent in the parietotemporal association cortex and later in the frontal lobe, whereas primary cortical areas, basal ganglia, thalamus, brainstem, and cerebellum are not affected. It is this typical pattern that distinguishes AD from other dementia syndromes. A ratio calculated from the metabolic rates of glucose of "affected" and "nonaffected" brain regions was able to separate patients with AD from age-matched controls and permitted the discrimination of patients with cognitive impairment of other origin in 85%. The discriminative power can be further improved by activation studies. A continuous visual recognition task increased the metabolic rate in normal subjects by 21% and in patients with AD by 6% on average, with significant regional differences. During activation the significant relation between severity of disease and temporoparietal metabolic rate became even stronger. In the assessment of effects of treatment on disturbed metabolism, PET studies demonstrated an equalization of metabolic heterogeneities in patients responding to a muscarinergic cholinagonist, whereas general increases in glucose utilization were observed with piracetam, pyritinol, and phosphatidyl-serine. The therapeutic relevance of such metabolic effects, however, must be proved in controlled clinical trials.

Adult↗
PubMed1977

Computerized tomography of the orbits. A report of 196 patients.

The value of orbital CCT scans was studied by grouping the CCT scans of 196 patients into clinical diagnostic categories. In 83% of patients with suspected Graves' ophthalmopathy, CCT confirmed the diagnosis. The CCT scan differentiated patients with Graves' disease from those with orbital pseudotumour or malignancies. The CCT scan was positive in 92% or patients with proven orbital malignancies. In 73% of patients with proptosis of unknown aetiology, and in 56% of patients with ocular motility problems, the CCT scan led to the diagnosis. The CCT scan ruled out orbital mass lesions in cases of optic neuritis, optic atrophy or vascular malformations. The greatest value of the CCT scan was in the localization and determination of the size and shape of various orbital lesions and in the accurate follow-up of those lesions utilizing serial scans.

Adult↗
PubMed1992

Distributed neural network underlying musical sight-reading and keyboard performance.

Music, like other forms of expression, requires specific skills for its production, and the organization and representation of these skills in the human brain are not well understood. With the use of positron emission tomography and magnetic resonance imaging, the functional neuroanatomy of musical sight-reading and keyboard performance was studied in ten professional pianists. Reading musical notations and translating these notations into movement patterns on a keyboard resulted in activation of cortical areas distinct from, but adjacent to, those underlying similar verbal operations. These findings help explain why brain damage in musicians may or may not affect both verbal and musical functions depending on the size and location of the damaged area.

Auditory Perception↗
PubMed1990

Activation of extrastriate and frontal cortical areas by visual words and word-like stimuli.

Visual presentation of words activates extrastriate regions of the occipital lobes of the brain. When analyzed by positron emission tomography (PET), certain areas in the left, medial extrastriate visual cortex were activated by visually presented pseudowords that obey English spelling rules, as well as by actual words. These areas were not activated by nonsense strings of letters or letter-like forms. Thus visual word form computations are based on learned distinctions between words and nonwords. In addition, during passive presentation of words, but not pseudowords, activation occurred in a left frontal area that is related to semantic processing. These findings support distinctions made in cognitive psychology and computational modeling between high-level visual and semantic computations on single words and describe the anatomy that may underlie these distinctions.

Adult↗
PubMed1988

Localization of cognitive operations in the human brain.

The human brain localizes mental operations of the kind posited by cognitive theories. These local computations are integrated in the performance of cognitive tasks such as reading. To support this general hypothesis, new data from neural imaging studies of word reading are related to results of studies on normal subjects and patients with lesions. Further support comes from studies in mental imagery, timing, and memory.

Attention↗
PubMed1995

Visual appearance of matte surfaces.

All visual sensors, biological and artificial, are finite in resolution by necessity. As a result, the effective reflectance of surfaces in a scene varies with magnification. A reflectance model for matte surfaces is described that incorporates the effect of macroscopic surface undulations on image brightness. The model takes into account complex physical phenomena such as masking, shadowing, and interreflections between points on the surface, and it predicts the appearance of a wide range of natural surfaces. The implications of these results for human vision, machine vision, and computer graphics are demonstrated with both real and rendered images of three-dimensional objects. In particular, objects with extremely rough surfaces produce silhouette images devoid of shading, precluding visual perception of the object's shape.

Humans↗
PubMed1986

Morning glory syndrome: clinical and electrofunctional study of three cases.

Three cases of morning glory syndrome are described and some new electrofunctional and tomodensitometric findings are reported. The amplitude of the waves of the electroretinogram is reduced and correlates with the extension of the retinal changes. The visually evoked potentials elicited with bright flashes have normal latencies but generally subnormal amplitudes. The amplitude of the potentials probably depends on the degree of involvement of the optic nerve. The computerised tomography performed in one patient disclosed undescribed changes in the retrobulbar optic nerve.

Adult↗
PubMed1991

Homonymous horizontal sectoranopia: report of four cases.

Four cases of right homonymous horizontal sectoranopia are described. They were investigated with automatic static perimetry matched in three cases with Goldmann perimetry. In two cases--a wound of lateral sinus, a temporal surgically excised oligo-dendroglioma--neuroradiological investigations localised the visual pathways lesion to the optic radiations. In two other cases the lesions of vascular origin were less precise. In both of these there were ischaemic phenomena. In one of them the left anterior superficial sylvian territory was involved and in the other the left anterior choroidal artery territory was in question. This visual field pattern, less rare than was previously supposed, seems in some cases to correspond to retrogeniculate and varied topographic lesions.

Adult↗
PubMed1991

Bilateral homonymous visual field defects as initial manifestation of multiple sclerosis.

Symptomatic suprageniculate lesions in multiple sclerosis expressed as a visual field defect are infrequent. The present case developed a bilateral homonymous defect as the initial and unique symptom of the disease. It was confirmed by nuclear magnetic resonance imaging, which disclosed extensive demyelinating areas in both optic nerve radiations. The mode of onset, perimetric findings, and unusual presentation of this condition are briefly discussed.

Adult↗