Alzheimer's disease has been described as "the great unlearning," a "disease of memory," a "demise of consciousness." But what does it reveal about the nature of human identity? What remains when memory unravels? And how might such insights help Alzheimer's sufferers themselves?
Could the brains of 670 nuns from Mankato, Minnesota be the key to understanding Alzheimer's?
British fantasy writer Sir Terry Pratchett advocates a right to "early death." Video of his Richard Dimbleby Lecture.