Dementedly

"She snatched up a stick and hit Cora across the rump with it. The stick was rotten and broke, without having caused Cora to budge an inch. Exasperated at an image of obduracy, the old woman scrabbled up another stick and began whacking at Cora with it, screeching dementedly, "Be off out of it and do as you're bid, ye witch.""