Re: Position of arm and hand in parkinson's

[Jeremy Browne <Jeremy@xxxxxxxxxxxxxxxxxxxx>]

In message <960928114647_532117819@xxxxxxxxxxxxxxxxxxxx> writes:
> I was wondering if anyone could answer some question I have  about a sentence
> I read in a posting saying,
> "There is a tendency to hold the arm on the affected side close to the body
> with the elbow bent so that the hand hangs at about waist level."
>
> What does this have to do with Parkinson's and why do PWP do it? Why do
> people bend their elbow? Is it more comfortable that way? Is it
> subconscious? Conscious? Does it keep them more balanced? Does it have
> something to do with the arm muscles? Do they realize that they are doing
> it? Can they teach themselves not to do it if they want to?

I THINK it has to do with the strength of agonist and antagonist muscles
- in a fairly non-technical explanation, let's suppose you want to lift
a coin by about half a metre:
your brain says to your lifting muscles - LIFT! If that's all it did,
you would probably catapult the coin through the ceiling!!! so, you
brain ALSO says to opposing muscles - PREVENT THE LIFT GOING TOO FAR OR
TOO FAST! If it doesn't coordinate those opposing muscles correctly, you
get an oscillation building up.

Normally people's resting arms are under unconscious control in much the
same way. However, since the PWP brain isn't in full control of the
muscles, it stops controlling and the stronger muscles (biceps) tighten
more than the others opposing - hence your bent arm.

Well, that's my theory, anyway!

:-)

--
Jeremy Browne, Hampshire, UK
jeremy@xxxxxxxxxxxxxxxxxxxx
Shaking Hands BBS, Fidonet 2:252/160 (+44 1252 626233, also FAX)