My 12 1/2 year old Goldie has begun to act oddly. He has started coming upstairs in the night when previously he never did as stairs frighten him. He also snaps at the air in his sleep and occasionally sleeps so deeply that it takes a gentle shake to wake him up. He's had the odd accident in the night and looks really upset about it.In all other ways he is very fit for his age. Not visibly arthritic(vet thinks he's in great shape for his age and breed), happy to go on gentle walks or play (followed by a long kip) and not showing any aggression. He has begun to forget his manners and has taken food off the table and filched and chewed a few small items. I know that this sounds like normal doggy stuff but, he never ever did this stuff before. His hearing has become a little 'selective' - can hear food cupboard, can't hear 'come back'. Do dogs go loopy as they age? Anybody with an old Goldie out there?