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On Wed 18 Feb, Dennis Greene wrote: > > > I have heard at seminars and read in reports that the > > symptoms of Parkinson's disease BECOME NOTICEABLE > > when the levels of dopamine in the striatum are decreased by > > 70% to 80%. > > which is not the same as saying that we have lost 70% to 80% of the > substantia nigra, though it does imply it. It also answers my > original question in favour of the "when symptoms are first noticed > by the PWP" option. > > I suppose what really worries me is that we as a community use > variations of the following statements as if they were > interchangeable: > > 1. "The symptoms of Parkinson's become apparent when the level of > dopamine in the brain drops by 80%." > 2. "The symptoms of Parkinson's become apparent when we lose 80% of > our substantia nigra" > 3. "By the time we are diagnosed we have lost 80% of our substantia > nigra". > 4. "By the time we are diagnosed dopamine levels in the brain have > dropped by 80% ". > Based on your information I shall henceforth use version 1 in my own > presentations. > > Thanks > > Dennis. > > OK Dennis, you have had 4 shots at the target, and I am still not 100% happpy with your choice! Let's agree first that this is not an overnight thing: We can all think back to a time when the early symptoms were noticeable, although at the time we barely noticed anything, and it may have been several years (6 in my case) before the neuro announced that you were definitely Parkie. Also, you should be in no doubt that the Dopamine-producing cells DO die off. They cannot be revived; they have ceased to be; they are, in short, dead. You have probably seen those slides showing the Substantia Nigra (the neuro's way of saying 'Black Stuff')which is where the dopamine is produced, and then you see a PWP's brain, and almost all of the pigmented cells have disappeared. So what is my version? The symptoms of PD become apparent when about 80% of the dopamine- producing cells which we were born with have died, for reasons as yet unknown. -- Brian Collins <[log in to unmask]>