A typical case of cerebral achromatopsia was reported. A patient, right handed 65-year-old male, has been complaining “everything looks only black or white” after his second stroke in 1982. Computed tomography demonstrated cerebral infarct in the medio-basal part of the left occipital lobe, having widespread lesion of the old infarction in the inferior part of the right temporal and occipital lobe due to the first stroke in 1977. He had no obvious aphasia, alexia, constructual apraxia. Impairment of color perception, prosopagnosia, topographical disorientation and dressing apraxia were observed. Ophthalmological examinations showed a superior altitudinal visual field defect, normal fundi and VEP.
Detailed tests on color were succeeded. Color naming was severely disturbed except red. Hue tests and coloring showed poor resuits. Ordering according to the brightness was markedly well. On the Ishihara test (14 sheets) he answered 7 sheets correctly but showed minor errors in 2 sheets. Examinations with the Munsell color system revealed that he can discriminate many colored plates correctly (especially red-green system) in spite of his complaints.
Tests on color perception with a red filter among normal controls showed similar results with the patient. These findings suggest that “cerebral achromatopsia” is caused by partial defect of color perception i. e. the patient with cerebral achromatopsia can discriminate colors according to a new “brightness-darkness axis” .
