A term coined by the neurologist Norman Geschwind (1926–1984) to describe the interruption of information transferred from one brain region to another.
Disturbance of the visual and language functions of the central nervous system due to interruption of the connections between two cerebral hemispheres in the corpus callosum, occlusion of the anterior cerebral artery, or interruption of the connections between different parts of one hemisphere. These disorders also may be produced by tumors or hypoxia. They can manifest in several ways including the inability, when blindfolded, to match an object held in one hand with that in the other; the inability to execute a command with the right hand but not the left; when blindfolded, the ability to correctly name objects held in the right hand but not those in the left; and the inability to understand spoken language while being able to speak normally.