The Japanese journal of neuropsychology

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ArticleTitle	A case of metamorphopsia caused by a small infarction adjacent to the posterior corpus callosum of the left side
Language	J
AuthorList	Yumiko Uchiyama, Makoto Iwata, Shinichiro Uchiyama
Affiliation	Department of Neurology, Tokyo Women's Medical University
Publication	Japanese Journal of Neuropsychology: 28 (3), 229-235, 2012
Received	Jul 19, 2011
Accepted	Sep 13, 2011
Abstract	We reported on a 57-year-old right-handed Japanese man with a small infarction adjacent to the posterior corpus callosum of the left side. This patient had never experienced a migrainous attack. Metamorphopsia appeared after the stroke in the right side of the visual field persistently and continued over one year, although diminished in increments. The features of his metamorphopsia were the inflation of seen objects to the right side. At first the objects which cased metamorphopsia were not only face and hands, but also simple geometrical figures and some things like a bowl. After one year, metamorphopsia occurred only in human faces. The visual field defect, color agnosia and prosopagnosia were not detected. The result of a visual perception test was negative except for the deterioration in cognitive ability for distortion of objects. SPECT showed a slight hypoperfusion in the left temporal lobe. Lesions of the posterior corpus callosum affected commissural fibers; those connecting the right and left visual fields for the interhemispheric integration of visual informations. We speculated considered that metamorphopsia is caused by a dysfunction of interhemispheric synchronizations, which may help the fusion of both visual hemifields into the percept of a single visual scene.
Keywords	metamorphopsia, cerebral infarction, corpus callosum, interhemispheric integration of visual informations, object recognition