Swiss cheese

A friend of mine, whose mother had Alzheimer's disease, told me that Alzheimer's is like swiss cheese. She explained that sometimes or some days they are on the cheese and seem fine but then other times or days they are in the holes. As the disease progresses, they spend more and more time in the holes, and less time on the cheese. We found this illustration to be true. My mother's disease has progressed to the point that now, she spends most of her time in the holes.