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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Visual illusions and hallucinations may accompany a wide variety of disorders with many different aetiologies; therefore, they are non-specific phenomena. Lesions in the visual pathway may be associated with visual misperceptions. In these cases more exact information about the misperceptions--whether they are monocular or binocular, present in the whole visual field or a hemifield--may contribute to diagnostic accuracy and to a more comprehensive understanding of the patient and his state of mind. Illusions such as perseveration, monocular diplopia and polyopia, and dysmorphopsia may also occur in healthy individuals, but they are found most often in patients with epilepsy, migraine and stroke. These phenomena do not permit exact localization and definition of an aetiology, but lesions in the occipital and occipitotemporal regions near the visual pathway are involved in most cases. Hallucinations always represent a pathological form of perception. They are classified as unformed (photopsias) or formed (complex). Photopsias may be described in terms of colour, shape and brightness. Their wide variety makes it difficult, if not impossible, to arrive at an exact description of their aetiology, but it is possible to define their anatomical origin in some cases. Complex hallucinations suggest an occipitotemporal locus. Whether they appear in the whole visual field or in the hemifield may prove decisive in determining pathogenesis. A number of characteristics permit a rough classification of these phenomena. Complex hallucinations accompany physical illness and are susceptible to psychodynamic interpretation.
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PMID:Visual illusions and hallucinations. 813 1

Visual perceptual abnormalities may be caused by diverse etiologies which span the fields of psychiatry and neurology. This article reviews the differential diagnosis of visual perceptual abnormalities from both a neurological and a psychiatric perspective. Psychiatric etiologies include mania, depression, substance dependence, and schizophrenia. Common neurological causes include migraine, epilepsy, delirium, dementia, tumor, and stroke. The phenomena of palinopsia, oscillopsia, dysmetropsia, and polyopia among others are also reviewed. A systematic approach to the many causes of illusions and hallucinations may help to achieve an accurate diagnosis, and a more focused evaluation and treatment plan for patients who develop visual perceptual abnormalities. This article provides the practicing neurologist with a practical understanding and approach to patients with these clinical symptoms.
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PMID:Visual perceptual abnormalities: hallucinations and illusions. 1087 81