If the title doesn't ring any bells (it didn't for me):
... He developed a syndrome neurologists call profound amnesia. ... As a participant in hundreds of studies, he helped scientists understand the biology of learning, memory and physical dexterity, as well as the fragile nature of human identity.
In fact Memento is pretty much the only movie that treats amnesia scientifically. In movies, when you get amnesia you forget who you are, but after that you are able to function normally. This almost never happens in the real world, and when it does it is usually psychological rather than a blow to the head. Even less realistic is getting all your memories restored after a second blow to the head.
