Impaired visual perception in patients with visual agnosia.

DOI 13 References
  • Torii Hosaku
    Sakuragaoka Hospital Department of Neuropsychiatry, Kanazawa Medical University

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  • 高次視知覚障害研究　　視覚失認を中心として

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    Most of visual agnosic patients have several impaired visual perception, since their occipital lobe or lobes were damaged. In 13patients whom we had reported as visual agnosic visual perceptual functions were investigated. Several disorders of visual perception might be related to a visual agnosic symptom and relationship of perceptual disorders to visual agnosia was discussed.<br>    1) Many patients with right occipital lesions showed impaired discrimination or learning of unfamiliar faces, whether they had prosopagnosia or not. In our patient prosopagnosic symptom was mild and relatively transient, although disturbed perception of unfamiliar faces was profound and persistent. Some authors supposed a double dissociation between the recognition of familiar and unfamiliar faces.<br>    2) Our patients with visual object agnosia had several disturbances of perception or copying of simple and overlapping figures. Such disturbances, however, could be observed in almost all patients with medial occipital lesion in either cerebral hemisphere.<br>    3) In patients with color anomia a kind of visual perceptual distortion was observed. Despite their normal hue perception they committed some errors in nonverbal color tasks, since they were more sensitive to color brightness rather than hue. But such a distortion of color perception was revealed in patients with medial occipital damage on either side.<br>    Only few findings were known about relationship of visual perceptual impairments to agnosic symptoms. Further studies are expected concerning this problem.

Journal

  • Higher Brain Function Research

    Higher Brain Function Research 18 (4), 265-270, 1998

    Japanese Society of Aphasiology (Renamed as Japan Society for Higher Brain Function)

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