Abstract
We studied color naming and reading of the unilateral visual field by tachystoscope, and dichotic listening of a case with a tumor lesion in the splenium of the corpus callosum. The patient, a 68-year-old, right-handed female, was admitted to Ushioda General Hospital for acute amnesic syndrome. Magnetic resonance imaging showed a tumorous lesion from the splenium of the corpus callosum to the right forceps major and in the left fornix. Stereotactic biopsy revealed this lesion to be glioblastoma multiforme. Tachystoscopic findings showed color naming disturbance and alexia of the left visual field. Dichotic listening resulted in left ear extinction. The patient exhibited neither apraxia nor agraphia, and she had normal tactile naming of the left hand and no crossed optic ataxia. Since there are few studies on color naming disturbance of the left visual field caused by corpus callosum lesion, its mechanism is unclear. However, this case's lesion extends from the commissural fibers through the splenium of the corpus callosum. Findings suggest that the fibers associated with color naming run through the splenium of the corpus callosum and that these fibers are near the fibers associated with reading and auditory language recognition.
