Sorry to hear that news about Ms. Ronstadt’s voice. My Dad died of Parkinsons...he was a big, strong man, always full of life and verve. The disease robbed Dad of all of his muscles to the point he couldn’t sit up, roll over, swallow or talk. But he would always manage a crooked smile and his eyes would gleam. Never once did he complain about his fate, either. He taught me a lot about being a man.
It is a horrible disease and I’m fearful of it.
I saw a video of Annette Funicello (probably here on FR)...same disease. Terrible thing.
I couldn't agree with Rondstat’s politics in any area...but she had a lovely voice.
I know you already know this but don't ignore the little things. Dragging you foot every now and then. Maybe moving a little slower. If you exercise, maybe the muscle recovery time is a little longer. Mild almost indistinguishable tremor. Maybe you drop things a little more often. Maybe your arms don't swing as much as they used to. Depend on you spouse, significant other or family members observations.
It is too easy for a GP to pass it off to aging. Denial is what gets most people in trouble.