"The Man Who Mistook His Wife for a Hat" e. Dr.Oliver Sacks, page.8

Dr P. was a musician of distinction, well-known for many years as a singer, and then at the local School of Music, as a teacher. It was here, in relation to his students, that certain strange problems were first observed. Sometimes a student would present himself, and Dr.P would not recognise him. Not only did Dr.P. fail to see faces, but he saw faces when there were no faces to see: Magoo-like, when in the street, he might pat the heads of water-hydrants and parking-meters, taking these to be the heads of children. Dr.P. consulted an ophthalmologist, who examined his eyes closely. ´There is nothing the matter with your eyes, but there is trouble with the visual parts of your brain. You must see a neurologist.´And so, as a result of this referral, Dr.P. came to me.

It was while examining his reflexes - that the first bizarre experience occurred, I had taken off his left shoe and scratched the sole of his foot with a key - a frivolous-seeming but essential test of a reflex - and then, excusing myself to screw my ophthalmoscope together, left him to put on the shoe himself. To my surprise, a minute later, he had not done this.

´Can I help?´ I asked.

´Help what? Help whom?´

´Help you put on your shoe.´

´Ách,´ he said, ´I had forgotten the shoe´, adding sotto voce, ´The shoe? The shoe?´ He seemed baffles.

´Your shoe, ´I repeated. ´Perhaps you´d put it on.´

He continued to look downwards, though not at the shoe, with an intense but misplaced concentration. Finally his gaze settled on his foot: ´That is my shoe, yes?´

Did I mis-hear? Did he mis-see?

´My eyes,´he explained, and put a hand to his foot. ´This is my shoe, no?´

´No, it is not. That is your foot. There is your shoe.´

´Ah! I thought that was my foot.´

 He appeared to have decided that the examination was over, and started to look round for his hat. He reached out his hand, and took hold of his wife´s head, tried to lift it off, to put it on. He had apparently mistaken his wife for a hat!