Nun Study -- yielding valuable research into aging. And it's okay with the Pope!

Interesting study and clip.

Maybe the plaque that causes alzheimers disease has trouble settling in on live wires. There is also a possibility, that if alzheimers disease affects a thought string, keeping the brain active, allows and encourages dendrites to form detours to bridge gaps.
Another thing I've thought of is the acceleration of the disease, because, something like the death of a partner can induce depression, and sap the 'will to live' so the brain while focusing on the loss, and counting the days until death. 'resigns' from thinking, and memories past are the primary content, with day to day living and details seen to have little importance.