re: Elderly dog barking at night, pacing, and seeming restless - any pet owners with advice?

Had a schnauzer that lived to 21. The last year of his life, he was doing the same thing. Was in great physical health (would walk over a mile every day), but mentally he was out of it. Would walk up to a wall, and just keep trying to go through it. Vet said it was def dementia. Finally had to have him put down.