A brilliant businesswoman who taught at Harvard, consulted on the Gemini and Apollo space programs, and was employed at a think tank in Palo Alto, she refused to believe what was happening to her. She scoured the country trying to find a neurologist who would tell her it wasn't Parkinson's Disease. Two years later another sister, Mary Anne, with five children of her own and maybe the smartest of us all, started dragging her left foot. Both are dead now. Parkinson's Disease is a movement disorder that results from a depletion of the neurotransmitter dopamine in the brain.
Brain cells die off, and as a result muscles no longer get the message to move.
Everything slowly grinds to a halt. You walk less, blink less, swallow less, until you breathe less and die. Often an infection or pneumonia sets in earlier and kills you. That's what happened to my father. Medication can lessen the symptoms.