Inability to recognize people or things despite intact sensory organs, caused by brain damage, cerebral haemorrhage, cerebral infarction, a tumour or an accident. The patient cannot make sense of anything he sees, hears or feels. Usually not all the senses are affected, but perhaps just the sense of touch. If the big toe is affected the patient will know that he is being touched, but not where. If the damage is in the left-hand side of the brain then the agnosia is in the right-hand side of the body, and vice versa. There is no definite treatment for agnosia; the underlying condition must be treated if possible.