A neurological disorder characterized by a partial or complete lack of awareness of sensory information in (usually) one half of the visual field. It is possible for a person to be totally blind in half the visual field without being aware of this fact, though it is easily demonstrated by the line bisection test. Lesions in either of the cerebral hemispheres in the visual cortex or secondary somatosensory area (see somatosensory cortex) are usually responsible for spatial neglect on the opposite side. Also called unilateral neglect, or unilateral spatial neglect. See homonymous hemianopia.