Which disorder features a deficit of awareness of one side of space despite intact sensory input?

• A. Blindsight
• B. Hemisphere neglect
• C. Severed corpus callosum
• D. Thought alienation

Answer: (B)

This describes hemispatial neglect, a deficit in awareness of stimuli on one side of space despite intact sensory input. It usually results from damage to the right parietal cortex, causing patients to ignore or not attend to the left side of their world—even though they can see and feel stimuli there. This isn’t about a failure of the eyes or senses, but an attentional deficit: the brain simply isn’t prioritizing that side of space.

Blindsight involves responding to visual stimuli in a blind field without conscious vision, due to alternative neural pathways and damage to primary visual cortex, not a generalized neglect of space. Severed corpus callosum disrupts interhemispheric communication and can produce split-brain symptoms, but it does not specifically cause unilateral spatial neglect. Thought alienation is a psychiatric symptom involving disturbances in thought or perception of thought, not a neurologic space-awareness deficit.