Read this from a Vet.

An elderly gentleman once explained that he thought his dog was "going crazy." He said his old setter would sleep by the fireplace. Suddenly it would jump up yelping and begin to run around the room in circles. After several minutes of hysterical commotion, the dog would lie down again and go back to sleep.

After pondering the situation, I examined the dog's ears and found a heavy infestation of ear mites. It appeared that as the heat from the fire warmed the dog's ear canals, the mites would became agitated and began to move around. As the old setter would run around the room, the ears would cool down and the mites would stop their activity. Then the dog would return to the fireside.