Parkinson's, I think a particularly insidious disease...the mind is willing the brain is not. We have known several folks with Parkinson's. One, vital, vigorous man suffered for 12 - 14 years that we knew him. At first it was tremors, and then almost total disability. A new medication or treatment would give relief, almost normalcy, for a few months and then cease working, and over the years the cycle repeated. I would think when he was in remission, he must have felt like a mouse cowering in the corner of a herpatarium waiting for the snake to get hungry, but he cherished every able moment. My heart goes out to Linda Ronstadt. It goes out to all Parkinson's sufferers.

As to Joni Mitchell and some others of that generation, perhaps they have nothing new to say musically, and have gracefully retired from the public rather than repeat old material the no longer find relevant. Most R&B oldies acts could take a clue.