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Asterognosis
The inability to recognize objects by touching them even though the sense of touch and proprioception is intact. Proprioception is the sense of being aware of positions and movements of the body. Astereognosis is caused by damage to the parietal lobe of the brain. The parietal lobe is the middle area of the top part of the brain and is responsible for integrating sensory information to form perceptions. The parietal lobe is located on both sides of the brain.

For people with astereognosis, the damage in the parietal lobe is opposite to the side of the body where they cannot identify objects with touch. Thus, if a person with astereognosis cannot identify objects with his/her left hand, the damage is in the right side of the parietal lobe. If a person with astereognosis cannot identify objects with his/her right hand, the damage is in the left side of the parietal lobe.

Astereognosis is also known as tactile agnosia, stereoagnosis, and stereoanesthesia. Astereognosis comes from the Greek word "a" meaning "without," the Greek word "stereos" meaning "solid," and the Greek word "gnosis" meaning "knowledge." Put the words together and you get "without knowledge of solids," referring to objects.