Dennis wrote:
>>> Dennis Greene <[log in to unmask]> 02/15/98
04:47am >>>
>>>Brian Collins wrote: >As you probably know, you are
down to the last 20% of your Dopamine-producing cells
when the symptoms show<<<
>This is a statistic that those of us who have been around
the traps for a while take as a given. . . I don't know exactly
what is meant by it. . . .Does it mean we are down to 20% at
the time we are diagnosed (surely the earliest opportunity for
anyone to start measuring) or as actually stated does the
20% relate to our earliest symptoms which in many
anecdotal cases seem to predate diagnosis by between 6 to
10 years?
>>This implies, to me at least, the following.
1. If the 20% relates to true onset of symptoms. . . then
By the time a diagnosis is made the substantia nigra will
have been reduced even more than 80%. The exact figure
will vary from individual to individual depending on how late in
the process they are diagnosed. This discrepancy alone
would go some way to explaining why PWP experience such
varied periods of time before encountering some of the
complications of dopamine replacement meds.
2. If the 20% relates to the time of diagnosis. . . then
This would imply that the substantia nigra is reduced by 80%
before the symptoms are sufficiently established for a
diagnosis to be made. If this is the case it means that
symptoms start to appear after the loss of a smaller (yet to
be established) % of the substantia nigra?<<<
Dennis:
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%.
Several clinical studies support the theory that patients
who will develop the PD symptoms exhibit "abnormalities" 4
to 6 years before dx. "Does a long preclinical period occur in
PD?" Neurology 1991; 41(Supp. 2) 8-13. PD patients
(pre-dx) were reported to have more frequent signs of anxiety,
dizziness, depression, fainting, stiffness and memory
problems. Also, reported were muscle pains and joint pains,
increased blood pressure and angina.
I do not know how the scientists theorized the 20%
number. There is a minority theory that a long latency period
is the exception. Rather, researchers should concentrate on
the reason for the variable rates of progression of PD. This
theory states that nerve cell loss occurs within 1 to 2 years
of dx and more effort should be paid to events occurring
close to the start of the disease to establish cause (virus,
drug induced, trauma, toxins).
By the bye, this all changes West of Perth.
Now, do you feel smarter? I don't!
Stephan 53/7
