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Biomedical subjects

D C Bienfang

Publications and source records attributed to D C Bienfang.

At least 19 recordsLinked to original sources
PubMed2002

Visual deficits in a patient with 'kaleidoscopic disintegration of the visual world'.

We describe psychophysical, neuropsychological and neuro-ophthalmological studies of visual abilities in a patient who, following a right hemisphere stroke, had difficulty in combining parts of objects into a whole and in reading. Strikingly, her perceptual problems were accentuated when the objects moved or when she moved. Formal testing showed that her main deficits were in depth perception, various tasks of motion and object recognition of degraded stimuli. But low-level detection and discrimination of form and color were normal. Despite her deficits in visual motion and degraded static-object recognition, her visual recognition of 'biological motion' stimuli was normal. Structural magnetic resonance imaging revealed an infarct in the ventro-medial occipito-temporal region, extending ventro-laterally and leading to a 'kaleidoscopic disintegration of visible objects'.

Adrenalectomy↗
PubMed2000

A lesion of cortical area V2 selectively impairs the perception of the direction of first-order visual motion.

Lesions of area MT/V5 in monkeys and its presumed homologue, the motion area, in humans impair motion perception, including the discrimination of the direction of global motion in random dot kinematograms. Here we report the results of similar tests on patient TF, who has a discrete and very small, unilateral infarct in the medial superior part of the right occipital cortex. Structural MRI, co-registered in software with a standardized human brain atlas, reveals that the lesion involves area V2. The patient was impaired in his retinotopically corresponding left lower quadrant on several motion tasks including discrimination in random dot kinematograms of direction, speed and motion-defined discontinuity. He was also impaired on tasks selectively involving first-order motion based on luminance contrast but not on second-order motion based on texture contrast. The results show that even though area MT/V5 is intact, motion perception is abnormal and, in particular, his perception of first-order motion is impaired.

Cerebral Infarction↗
PubMed1998

Management of functional vision loss.

BACKGROUND: Functional vision loss is a general term used to describe vision loss not associated with organic disease. Such cases are major challenges to the practitioner and demand a special workup. METHODS: Patients may manifest symptoms in typical ways that should alert the examiner to the possibility of functional vision loss. In addition, a variety of techniques help distinguish functional from organic causes of vision loss. These techniques include standard tests that yield characteristic findings in functional vision loss, as well as problem-specific procedures that have the specific aim of detecting functional vision loss. Techniques are described according to whether they are useful in monocular or binocular vision loss and in cases of moderate or severe vision loss. RESULTS: Three cases that illustrate the use of standard and select techniques to detect functional vision loss are presented. Differential diagnosis of functional from organic vision loss and special considerations in the management of patients with functional vision loss are also discussed. CONCLUSIONS: Although it is necessary to rule out underlying pathology in all cases of vision loss, a variety of techniques can provide positive evidence of functional vision loss.

Adult↗
PubMed1996

Mesencephalic clefts with associated eye movement disorders.

OBJECTIVE: To describe two patients with mesencephalic midline clefts and associated eye movement disorders. DESIGN: Case reports. RESULTS: The first patient developed bilateral internuclear ophthalmoplegia with exotropia, reduced convergence, right ptosis, right fourth-nerve palsy, and right elevator palsy several years after meningitis with hydrocephalus. The second patient had bilateral internuclear ophthalmoplegia with exotropia, reduced convergence, bilateral ptosis, limited upward gaze, and right hypertropia since childhood. In both patients, magnetic resonance imaging showed a midline cleft extending from the cerebral aqueduct into the midbrain. CONCLUSION: It is likely that the clefts affected the oculomotor nuclei and medial longitudinal fasciculi, accounting for the eye movement disorders.

Adult↗
PubMed1994

Pseudotumor cerebri associated with corticosteroid withdrawal in inflammatory bowel disease.

We treated two patients with Crohn's disease and one patient with ulcerative colitis who developed headache, papilledema, and intracranial hypertension (pseudotumor cerebri) during corticosteroid withdrawal. One had four separate episodes with corticosteroid withdrawal, which suggested a causal relationship. This association between pseudotumor cerebri and corticosteroid withdrawal has been documented in children, but is rare in adults with inflammatory bowel disease.

Adolescent↗
PubMed1992

Horner's syndrome caused by intra-oral trauma.

A 7-year-old boy developed a Horner's syndrome after falling on a stick that penetrated his peritonsillar soft palate. He did not suffer from any major vascular injury, and pharmacologic testing indicated a preganglionic lesion. We review previously reported cases of oculosympathetic paresis caused by surgical and nonsurgical intra-oral trauma. Because of the proximity between sympathetic and vascular structures in the lateral and parapharyngeal space, Horner's syndrome in the setting of intra-oral trauma should prompt evaluation of the internal carotid artery. Magnetic resonance imaging may be a reasonable noninvasive method for this investigation.

Anisocoria↗
PubMed1990

Ophthalmology.

Explore the source record for details and available documents.

Cataract↗
PubMed1990

Intact "biological motion" and "structure from motion" perception in a patient with impaired motion mechanisms: a case study.

A series of psychophysical tests examining early and later aspects of image-motion processing were conducted in a patient with bilateral lesions involving the posterior visual pathways, affecting the lateral parietal-temporal-occipital cortex and the underlying white matter (as shown by magnetic resonance imaging studies and confirmed by neuro-ophthalmological and neuropsychological examinations). Visual acuity, form discrimination, color, and contrast-sensitivity discrimination were normal whereas spatial localization, line bisection, depth, and binocular stereopsis were severely impaired. Performance on early motion tasks was very poor. These include seeing coherent motion in random noise (Newsome & Paré, 1988), speed discrimination, and seeing two-dimensional form from relative speed of motion. However, on higher-order motion tasks the patient was able to identify actions from the evolving pattern of dots placed at the joints of a human actor (Johansson, 1973) as well as discriminating three-dimensional structure of a cylinder from motion in a dynamic random-dot field. The pattern of these results is at odds with the hypothesis that precise metrical comparison of early motion measurements is necessary for higher-order "structure from motion" tasks.

Cerebral Cortex↗
PubMed1990

Oculographic analysis of acute esotropia secondary to a thalamic hemorrhage.

We used electrooculography to study the saccadic velocities, smooth pursuit, and vestibular ocular reflex in a patient with an acute thalamic hemorrhage. Our findings confirmed what others have shown in that there were hypometric saccades contralateral to the lesion, impaired smooth pursuit ipsilaterally, and a preserved vestibular ocular reflex. In addition, we demonstrated an asymmetry with the contralateral eye being more affected. It is also shown that the "convergence" movements seen on attempted upgaze are typical of saccades and not vergence movements. A discussion of possible pathophysiologic mechanisms with review of other studies is presented.

Aged↗
PubMed1990

Penicillamine-induced ocular myasthenia gravis in rheumatoid arthritis.

We report a case of a 47-year-old woman with rheumatoid arthritis who developed ocular myasthenia gravis during penicillamine treatment. Her serum contained elevated titers of acetylcholine receptor antibodies, and her symptoms resolved 8 weeks after discontinuation of penicillamine. We review the clinical and laboratory features of this syndrome of penicillamine-induced myasthenia gravis and discuss its pathophysiology and treatment.

Arthritis, Rheumatoid↗
PubMed1989

Loss of the ocular pulse in the acute phase of temporal arteritis.

Severe cases of temporal arteritis often have infarctions of the optic nervehead. Such cases frequently have a decrease in the amplitude of the ocular pulse. This is in contrast to cases of anterior ischemic optic neuropathy not due to temporal arteritis. In addition to aiding in the diagnosis of temporal arteritis, monitoring of the ocular pulse may help in following the course of this disease.

Biopsy↗
PubMed1984

Aberrant regeneration involving the oculomotor and abducens nerves.

An unusual case of severe head trauma is reported with postoperative 'total' ophthalmoplegia of the right eye. Subsequent recovery led to an apparent transposition of right medial and right lateral rectus function. Optokinetic stimulation induced convergence nystagmus when the target was moved to the patient's left, and a divergence nystagmus when the target was moved to the patient's right. In addition, attempted lateral gaze induced ipsilateral pupillary constriction. Aberrant regeneration involving the right abducens and right oculomotor nerves is proposed as the underlying mechanism.

Abducens Nerve↗
PubMed1983

Complete bilateral internal carotid artery occlusion in a young man.

Partial or complete occlusion of the internal carotid artery is a familiar consequence of severe atherosclerosis seen in the elderly. Complete obstruction of both internal carotids is rare, particularly in the young or middle-aged. The rapid onset of bilateral internal carotid occlusion would be expected to produce devastating neurological sequelae and probably not be compatible with survival. We present a case of a young man with complete obstruction of both internal carotid arteries whose presenting symptoms were those of a visual field cut. The history suggests that the carotid occlusion occurred as a result of blunt trauma. The patient had no known predisposition to vascular abnormalities (no history of hypertension, hyperlipidemia, signs of systematic arteriosclerosis or vasculitis, and an unremarkable family history for vascular abnormalities). Computerized tomography revealed an infarct in his right parietal lobe. Angiography demonstrated complete occlusion of both internal carotid arteries and the right posterior communicating artery and failed to disclose the development of extensive collatorals, adding further evidence to the acuteness of the occlusion. The patient was followed by noninvasive studies and in the subsequent year showed marked neurological and ophthalmological improvement.

Adult↗
PubMed1982

Bromocriptine reduces pituitary tumor size and hypersection. Requiem for pituitary surgery?

Twelve patients with pituitary tumor whose prior treatment included surgery and radiotherapy in four, surgery alone in four, radiotherapy alone in one, and none in three were studied. Nine had hyperprolactinemia, two had elevated serum growth hormones, and one had no pituitary hormone excess. Visual field defects were present in six. All had pituitary-gonadal insufficiency manifested as impotence or amenorrhea. All were tested with bromocriptine, 7.5 to 25 mg daily, and followed up for eight to 27 (mean 15) months. Serum prolactin levels decreased to normal in seven of nine patients. Serum growth hormone values were normalized in both acromegalics. When hormone levels were reduced to normal, pituitary tumor size decreased. Vision was restored to normal in five of six patients, including one patient with pituitary tumor but no pituitary hormone excess. Bromocriptine corrects the physiological defects associated with pituitary tumors that have been incompletely treated with surgery, radiotherapy, or both and may be a useful primary treatment for patients with pituitary tumors.

Adult↗