When I am attacked by the earworm it is usually when I first wake up. As far as I can recollect, it is not the same ditty each time either. One of my brilliant posits is that the human brain, like a computer, needs to go through a checklist each day before it is up to speed. In the case of the earworm some audible memories are leaking through. Perhaps I need to have a cochlear internal earmuff installed?