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There are a number of factors which contribute to the variability of PD symptoms and progression of the disease.. One is that neurologist don't have a diagnostic test for PD. They are forced into a process of elimination of other ailments which could be causing the symptoms. The second is that PD is normally associated with the death of dopaminergic cells in the Substantia Nigra. However, I once saw a statistic that as high as 25% of the people who exhibit PD symptoms don't have degeneration in the Substantia Nigra. If you look at the interconnection of the Substantia Nigra with parts of the Basil Ganglia you can speculate that a failure of the dopamine receptors in these areas could cause similar symptoms. Third, the Substantia Nigra has axons that terminate in the Pallidus, Thalamus and STN of the Basil Ganglia. Each of these areas has a different effect on motor control. This is the reason a Pallidotomy is done for dystonia and a Thalladotomy is done for tremor. Fourth, PD symptoms do not appear until approximately 60%-70% of Substantia Nigra cell loss has been realized. Since we can't tell when the cell loss began, it is difficult to predict at what rate the disease is progressing. Fifth, the origin of this cell loss is unknown. In some people, it may be genetic. In some it may be environmental. In some it may be genetic sensitivity to the environment. Since we don't know the origin, it is possible that a common degeneration mechanism is at work that attacks the weakest area in the brain. In our PD brain, the weak link may be the Substantia Nigra. Sixth, the risks for developing dementia are 10% for young onset and 30% for diagnosis at 70, per statistics presented at a symposium I attended last year. Is this caused by the same mechanism as Alzheimers? Only time will tell. These are some cold hard facts and some speculation, but we should use this data to plan for the future. We can get depressed and spend every day wringing our hands or we can get out there and live each day to it's fullest. I came to the same conclusion that Micheal J. Fox did. I can use my intellect and abilities now to do my part in finding a cure or treatments to improve my quality of life in the future. MJ, myself and a large portion of this list are in a very productive phase of our lives. We don't know how quickly things will deteriorate, but we know they won't get better. The time is now to make it happen! Phil Gesotti 50/46+