DiseasesAnalytical, Diagnostic and Therapeutic Techniques and Equipment
HemianopsiaMagnetic Resonance ImagingTomography, X-Ray Computed
Hemianopsia
Partial or complete loss of vision in one half of the visual field(s) of one or both eyes. Subtypes include altitudinal hemianopsia, characterized by a visual defect above or below the horizontal meridian of the visual field. Homonymous hemianopsia refers to a visual defect that affects both eyes equally, and occurs either to the left or right of the midline of the visual field. Binasal hemianopsia consists of loss of vision in the nasal hemifields of both eyes. Bitemporal hemianopsia is the bilateral loss of vision in the temporal fields. Quadrantanopsia refers to loss of vision in one quarter of the visual field in one or both eyes.
Magnetic Resonance Imaging
Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.
Tomography, X-Ray Computed
Tomography using x-ray transmission and a computer algorithm to reconstruct the image.

Surgical treatment of internal carotid artery anterior wall aneurysm with extravasation during angiography--case report. (1/219)

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.  (+info)

Visual perception of motion, luminance and colour in a human hemianope. (2/219)

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.  (+info)

When the left brain is not right the right brain may be left: report of personal experience of occipital hemianopia. (3/219)

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.  (+info)

The association of visual field deficits and visuo-spatial neglect in acute right-hemisphere stroke patients. (4/219)

BACKGROUND: Visuo-spatial neglect (VSN) after stroke is associated with a poor prognosis for rehabilitation. The co-existence of a visual field deficit (VFD) with VSN may be associated with impaired visuo-spatial functioning and thereby poor functional outcome. OBJECTIVE: To determine whether the presence of a VFD (i) exacerbates VSN and (ii) influences recovery of VSN. METHODS: A prospective study of consecutive acute (<7 days), right-hemisphere stroke patients who were able to undergo detailed assessment of visuo-spatial functioning and visual fields. Clinical assessment and a standardized neuropsychological test was administered by one observer, followed by independent assessment of visual fields by a second observer. Patients were followed up for 12 weeks with 4-weekly re-assessments. RESULTS: 44 consecutive patients (23 women) with a first in a lifetime, acute hemisphere stroke were recruited. Twenty had VSN and VFD, seven VSN only, one VFD only and 17 had normal visual fields and no neglect. The finding of a VFD was significantly associated with the presence of VSN (P<0.0001). Patients with both VFD and VSN had a significantly lower score on the behavioural inattention test. One month post-stroke, this difference was no longer significant. Recovery of VSN and VFD was maximal in the first month, however VSN recovery continued for up to 12 weeks. Patients with VSN and a VFD on admission had a greater mortality at 1 and 3 months. CONCLUSION: The presence of a VFD does appear to exacerbate neglect in the acute stroke patient; this effect is no longer seen after 1 month. Recovery of VSN continues independent of a VFD. Patients with neglect and a VFD have an increased mortality, probably because of greater neurological impairment.  (+info)

Attention without awareness in blindsight. (5/219)

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.  (+info)

Parietal and occipital lobe contributions to perception of straight ahead orientation. (6/219)

OBJECTIVES: Several studies have investigated how peripheral stimulation affects the perception of body orientation in healthy subjects. The studies showed that opposing stimulation of two different input modalities can cancel out, leaving perception of body orientation unchanged. It was ascertained whether a comparable phenomenon could be found in brain damaged patients with two distinct disorders which individually lead to opposing shifts of the perceived midline. METHODS: The visual subjective straight ahead was measured in patients with pure neglect, pure hemianopia, or a combination of neglect and hemianopia. RESULTS: As in previous studies, patients with pure neglect displayed an ipsilesional displacement of the perceived straight ahead. Patients with pure hemianopia showed a contralesional shift. By contrast, no significant midline shift occurred in the patients with both neglect and hemianopia. CONCLUSIONS: Neglect and hemianopia interact so that opposing biases in the perception of body orientation neutralise each other. Both parietal and occipital areas seem to contribute to the perception of straight ahead body orientation and seem to have counteracting effects when lesioned in the same hemisphere.  (+info)

Bitemporal pseudohemianopia related to the "tilted disk" syndrome: CT, MR, and fundoscopic findings. (7/219)

We describe a case of the "tilted-disk" syndrome in a patient with a bitemporal field depression (a pseudohemianopia). CT and MR imaging showed thinning and prolapse of the nasal sectors of the posterior walls of the globes and flattening of the temporal portion of the globes.  (+info)

The oculomotor distractor effect in normal and hemianopic vision. (8/219)

The present study investigated the inhibitory effect of visual distractors on the latency of saccades made by hemianopic and normal human subjects. The latency of saccades made by hemianopic subjects to stimuli in their intact visual field was not affected by visual distractors presented within their hemianopic field. In contrast, the latency of saccades made by normal subjects was increased significantly under distractor conditions. The latency increase was larger for temporal than nasal distractors. The results are inconsistent with previous proposals that the crossed retinotectal pathway from the nasal hemiretina to the superior colliculus may mediate a blindsight inhibitory effect when distractors appear within a hemianopic temporal visual field. Instead, the distractor effect appears to reflect the normal processes involved in saccade target selection which may be mediated by a circuit involving both cortical and subcortical structures.  (+info)

Hemianopsia is a visual field defect characterized by the loss of half of the vertical visual field in one or both eyes, which can be either homonymous (same side in both eyes) or heteronymous (different sides in each eye).

Hemianopsia is a medical term that refers to a loss of vision in half of the visual field in one or both eyes. It can be either homonymous (the same side in both eyes) or heteronymous (different sides in each eye). Hemianopsia usually results from damage to the optic radiations or occipital cortex in the brain, often due to stroke, trauma, tumor, or other neurological conditions. It can significantly impact a person's daily functioning and may require visual rehabilitation to help compensate for the vision loss.

Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic medical procedure that uses strong magnetic fields and radio waves to produce detailed cross-sectional or three-dimensional images of the internal structures of the body.

Medical Definition:

Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic imaging technique that uses a strong magnetic field and radio waves to create detailed cross-sectional or three-dimensional images of the internal structures of the body. The patient lies within a large, cylindrical magnet, and the scanner detects changes in the direction of the magnetic field caused by protons in the body. These changes are then converted into detailed images that help medical professionals to diagnose and monitor various medical conditions, such as tumors, injuries, or diseases affecting the brain, spinal cord, heart, blood vessels, joints, and other internal organs. MRI does not use radiation like computed tomography (CT) scans.

X-ray computed tomography (CT) is a medical imaging technique that uses computer-processed combinations of multiple X-ray images taken from different angles to produce cross-sectional or volumetric images of the body, allowing for detailed visualization of internal structures and tissues.

X-ray computed tomography (CT or CAT scan) is a medical imaging method that uses computer-processed combinations of many X-ray images taken from different angles to produce cross-sectional (tomographic) images (virtual "slices") of the body. These cross-sectional images can then be used to display detailed internal views of organs, bones, and soft tissues in the body.

The term "computed tomography" is used instead of "CT scan" or "CAT scan" because the machines take a series of X-ray measurements from different angles around the body and then use a computer to process these data to create detailed images of internal structures within the body.

CT scanning is a noninvasive, painless medical test that helps physicians diagnose and treat medical conditions. CT imaging provides detailed information about many types of tissue including lung, bone, soft tissue and blood vessels. CT examinations can be performed on every part of the body for a variety of reasons including diagnosis, surgical planning, and monitoring of therapeutic responses.

In computed tomography (CT), an X-ray source and detector rotate around the patient, measuring the X-ray attenuation at many different angles. A computer uses this data to construct a cross-sectional image by the process of reconstruction. This technique is called "tomography". The term "computed" refers to the use of a computer to reconstruct the images.

CT has become an important tool in medical imaging and diagnosis, allowing radiologists and other physicians to view detailed internal images of the body. It can help identify many different medical conditions including cancer, heart disease, lung nodules, liver tumors, and internal injuries from trauma. CT is also commonly used for guiding biopsies and other minimally invasive procedures.

In summary, X-ray computed tomography (CT or CAT scan) is a medical imaging technique that uses computer-processed combinations of many X-ray images taken from different angles to produce cross-sectional images of the body. It provides detailed internal views of organs, bones, and soft tissues in the body, allowing physicians to diagnose and treat medical conditions.

HomonymousHemianopiaQuadrantanopsiaBlindnessHemifields of both eyesAltitudinalOptic chiasmBilateralUnilateralMigraineOccurStrokePatientsResultCompleteUpperVisionVisual fielEyesRight sideHalfPersonPublicationsHomonymous hemianopsiaBitemporal hemianopsia and visualBinasalCorticalSymptomsTumorCompressionLoss of visBrainIncludeVisual fieldTerms
Homonymous9
  • A homonymous hemianopsia is the loss of half of the visual field on the same side in both eyes. (wikipedia.org)
  • Homonymous hemianopsia refers to a visual defect that affects both eyes equally, and occurs either to the left or right of the midline of the visual field. (childrensmercy.org)
  • The purpose of this course is to describe homonymous hemianopsia (HH) and visual field cut, discuss diagnoses that can cause a visual field cut, review quick screening tools, and review intervention strategies to maximize occupational performance despite homonymous hemianopsia. (maineot.org)
  • world- right homonymous hemianopsia, and Romberg sign. (cdc.gov)
  • Approximately 40-50% of patients with GCA have ophthalmologic complications, including visual loss secondary to A-AION, central retinal artery occlusion, homonymous hemianopsia or cortical blindness (uni- or bilateral occipital infarction) [ 6 ]. (intechopen.com)
  • Bilateral Homonymous Hemianopsia with Preservation of Central Vision. (ucf.edu)
  • As a residual deficit of the Stroke, he suffered from homonymous hemianopsia (right side visual loss in both eyes). (todaysgeriatricmedicine.com)
  • Having homonymous hemianopsia made it very difficult for Dr. Ramon to read, watch TV, and go to the movies - things that he used to enjoy easily before his stroke. (todaysgeriatricmedicine.com)
  • 8. Homonymous hemianopsia, quadrantopsia, bitemporal hemianopsia, or central scotoma related to cerebral vascular disease by Automated Visual field testing and confrontation visual field testing. (who.int)
Hemianopia2
  • Hemianopsia, or hemianopia, is a loss of vision or blindness (anopsia) in half the visual field, usually on one side of the vertical midline. (wikipedia.org)
  • In individuals in whom it tends to occur, hemianopsia (or hemianopia ) involves the loss of one half of a visual field. (dialecticalsystems.eu)
Quadrantanopsia1
  • Quadrantanopia (quadrantanopsia or quadrantic hemianopsia) is decreased vision or blindness in one quarter of the visual field. (wikipedia.org)
Blindness1
  • A loss of the outer peripheral vision (called a "bitemporal hemianopsia") or complete blindness can occur. (uclahealth.org)
Hemifields of both eyes1
  • Binasal hemianopsia consists of loss of vision in the nasal hemifields of both eyes. (childrensmercy.org)
Altitudinal1
  • Subtypes include altitudinal hemianopsia, characterized by a visual defect above or below the horizontal meridian of the visual field. (childrensmercy.org)
Optic chiasm2
  • Anterior extension to the optic chiasm can result in a classic bitemporal hemianopsia, unilateral temporal hemianopsia, papilledema, or unilateral/bilateral decrease in visual acuity. (medscape.com)
  • The optic chiasm lies in close proximity to the pituitary gland and can be compressed by tumors leading to visual disturbances (bitemporal hemianopsia) [6]. (bvsalud.org)
Bilateral1
  • Bitemporal hemianopsia is the bilateral loss of vision in the temporal fields. (childrensmercy.org)
Unilateral1
  • Visual neglect (also called hemispatial neglect or unilateral spatial neglect) differs from hemianopsia in that it is an attentional deficit rather than a visual one. (wikipedia.org)
Migraine1
  • Temporary hemianopsia can occur in the aura phase of migraine. (wikipedia.org)
Occur1
  • Some patients with neglect also have hemianopsia, however the two often occur independent of one another. (wikipedia.org)
Stroke1
  • Kingston introduced me to a patient whom we'll call Mr. J., whose hemianopsia was a result of a stroke -another form of TBI. (visionaware.org)
Patients6
  • Unlike patients with hemianopsia who actually don't see, those with visual neglect have no trouble seeing but are impaired in attending to and processing the visual information they receive. (wikipedia.org)
  • Whereas hemianopsia can be assuaged by allowing patients to move their eyes around a visual scene (ensuring that the entire scene makes it into their intact visual field), neglect cannot. (wikipedia.org)
  • The authors present six cases of visual loss in patients treated with ethambutol for mycobacterium avium complex, including four patients with bitemporal hemianopsia. (uk.com)
  • In patients being treated with ethambutol, reversible bitemporal hemianopsia was the most commonly noted presentation. (uk.com)
  • Although there is variability in the visual findings of the six reported patients, this case series suggests that bitemporal hemianopsia, reduction of visual acuity and loss of colour vision are the most common presentation of visual toxicity due to ethambutol. (uk.com)
  • What are the symptoms displayed by patients affected by hemianopsia and subsequent loss of usual sensory action of fovea? (dialecticalsystems.eu)
Result1
  • Chiasmal compression may result in bitemporal HEMIANOPSIA. (embl.de)
Complete1
  • A complete right hemianopsia, as David Hubel (1988) pointed out, entails for instance the dimming of the center of gaze, with a decreased efficiency of the foveal region: it is as if, viewing the word far and trying to focus on the a , you could not see the r , but only the f and the left side of the a . (dialecticalsystems.eu)
Upper2
  • Superior hemianopsia - the upper half of the field of vision is affected, possibly because of a tumor beginning to compress the lower part of the chiasma, typically one from the hypophysis. (wikipedia.org)
  • Inferior hemianopsia - the lower half of the field of vision is affected, possibly because of a tumor beginning to compress the upper part of the chiasma, typically a craniopharyngioma. (wikipedia.org)
Vision1
  • I had the opportunity to visit the Western Blind Rehabilitation Center and spoke to John Kingston, Orientation and Mobility Supervisor and Acting Comprehensive Neurological Vision Rehabilitation (CNVR) Coordinator, to learn about an innovative therapy that was helping veterans adapt to hemianopsia. (visionaware.org)
Visual fiel1
  • Therefore, the first step in treating hemianopsia is to demonstrate that there is a visual field loss and to have the person experience what they are missing. (visionaware.org)
Eyes1
  • A heteronymous hemianopsia is the loss of half of the visual field on different sides in both eyes. (wikipedia.org)
Right side1
  • Someone with a left hemianopsia for example, has damaged pathways on the right side of the brain and does not see objects or people on his left side when looking straight ahead. (visionaware.org)
Half1
  • Another very common occurrence is hemianopsia, a condition in which a person loses half of his field of view. (visionaware.org)
Person1
  • A person with hemianopsia is literally not getting the whole picture, and may go for years completely unaware of it. (visionaware.org)
Publications2
  • This graph shows the total number of publications written about "Hemianopsia" by people in this website by year, and whether "Hemianopsia" was a major or minor topic of these publications. (childrensmercy.org)
  • Below are the most recent publications written about "Hemianopsia" by people in Profiles. (childrensmercy.org)
Homonymous hemianopsia5
  • A homonymous hemianopsia is the loss of half of the visual field on the same side in both eyes. (wikipedia.org)
  • world- right homonymous hemianopsia, and Romberg sign. (cdc.gov)
  • However, if a patient with prosopagnosia presents with left-sided homonymous hemianopsia, there should be concern for a right-sided occipital lesion. (aao.org)
  • Homonymous hemianopsia refers to a visual defect that affects both eyes equally, and occurs either to the left or right of the midline of the visual field. (nih.gov)
  • A case of left homonymous hemianopsia, probably hysterical. (nih.gov)
Bitemporal hemianopsia and visual2
  • We report the case of a 54-year-old Chinese man who developed progressive bitemporal hemianopsia and visual loss. (unboundmedicine.com)
  • Here, we report the case of a 67-year-old woman who presented with bitemporal hemianopsia and visual impairment accompanied by mildly elevated prolactin. (uzh.ch)
Binasal1
  • Binasal hemianopsia consists of loss of vision in the nasal hemifields of both eyes. (nih.gov)
Cortical1
  • Introduction: Reversible posterior leukoencephalopathy syndrome - a reversible subacute global encephalopathy clinically presenting with headache, altered mental status, visual symptoms such as hemianopsia or cortical blindness, motor symptoms, and focal or generalized seizures - is characterized by a subcortical vasogenic edema symmetrically affecting posterior brain regions. (uni-wuerzburg.de)
Symptoms1
  • I am sad to report that my dad today presented with symptoms of right hemianopsia. (cancergrace.org)
Tumor2
  • Superior hemianopsia - the upper half of the field of vision is affected, possibly because of a tumor beginning to compress the lower part of the chiasma, typically one from the hypophysis. (wikipedia.org)
  • Inferior hemianopsia - the lower half of the field of vision is affected, possibly because of a tumor beginning to compress the upper part of the chiasma, typically a craniopharyngioma. (wikipedia.org)
Compression1
  • Chiasmal compression may result in bitemporal HEMIANOPSIA. (curehunter.com)
Loss of vis1
  • Bitemporal hemianopsia is the bilateral loss of vision in the temporal fields. (nih.gov)
Brain1
  • The dura is opened, and the meningioma can be seen extending en plaque over the surface of the brain. (medscape.com)
Include1
  • Subtypes include altitudinal hemianopsia, characterized by a visual defect above or below the horizontal meridian of the visual field. (nih.gov)
Visual field3
  • A heteronymous hemianopsia is the loss of half of the visual field on different sides in both eyes. (wikipedia.org)
  • Whereas hemianopsia can be assuaged by allowing patients to move their eyes around a visual scene (ensuring that the entire scene makes it into their intact visual field), neglect cannot. (wikipedia.org)
  • It turned out that Jay suffered from hemianopsia, a loss of half of the visual field. (benetech.org)
Terms1
  • For example, if you use CAD software or work on medical documents, you could enter terms such as DIMSTYLE or hemianopsia to ensure that the words are entered correctly when you use Voice Control. (apple.com)