[bpsdb] Let me say from the start that Sir Terry Pratchett is a legend, a genius, the closest thing I, cynic that I am, have to a genuine hero. He is a master of satire, cleverly disguised in rich fantasy, and I was genuinely upset to hear that he had been diagnosed with Alzheimer's. The Daily Mail today reports that Sir Terry is undergoing treatment using a special light helmet that "promises to slow Alzheimer's", developed by a certain Dr Gordon Dougal. I take no pleasure in picking apart this story, but the fact is that this claim and the doctors behind it have some history, as we'll see.