Hello,
I'm new to this group, not sure if I'm doing this posting right, anyway here it goes.
"Brain Gym" I've been practicing it for about 4 years now. I don't do it every day, and it only takes about 15 minutes, but their's lots of different exercises so you can, so do as many as you like and do different ones each time.
When I lived in Calgary, I belonged to the young onset pd group. Once of the facilitators put together a course on "Brain Gym". She told us that pd'ers practicing this have shown improvements. I don't remember where she got the following info, but it really sounded interesting: "By practicing Brain Gym, you will stimulate new areas of the brain to create dopamine" Sounds good enough for me, so I signed up for the course.

So what is "Brain Gym"
Info taken from: brainworksnaturally.com
Brain Gym® consists of various combinations of 26 targeted movements. It grew out of clinical studies started in 1969 by Paul Dennison. In the more than thirty years since, research has shown that application of Brain Gym® provides significant improvement in concentration, memory, reading, organization skills, language and number skills, writing, speaking, athletic performance and more. It is used worldwide in more than 90 countries, in 40 different languages. In 1989, in response to "The Nation At Risk" study, The National Learning Foundation selected Brain Gym® as a recommended learning strategy, and continued to rate it highly throughout the 1990’s.

Who Benefits ?
Students with special needs, ADD, ADHD, autism, dyslexia, patients with Alzheimer's or Parkinson's disease, and people with learning disorders have all shown improvement using brain gym. Change may be remarkably immediate or take place in a period of days or weeks, according to the extent of the problem, but profound differences are usually noticed by the clients themselves. Check into research studies for more information.
Anyone who wants to think better, clearer and faster can benefit. Academic, physical and personal goals are met using Brain Gym®. No matter what your age, it is never too late to activate! Learn simple ways to energize, meet challenges and optimize learning potential.

The best book I found on "Brain Gym" is called:
Brain Gym for Business by Gail & Paul Dennison
cost around $18.00 at Amazon.com
I couldn't find a book that specificallly for pd'ers

These exercises are fun and easy to do.
They are mostly cross-overs. Like an infant learning how to crawl, this is a cross over. You will be working both sides of the brain, creating new or strengthing the links between them.
These exercises will improve your balance, concentration, problem solving, handwriting, reading, speaking, memory, writing skills, focus, improves posture, releases stress, etc.

Here is an example of one of these exercises.
Called: "The Cross Crawl"
Taken from: Brain Gym for Business by Gail & Paul Dennison
You will need to be standing. Start by marching in place, alternate touching each hand to the opposite knee. Continue during the course of 4 to 8 complete, relaxed breaths. A variation of this movement can be done sitting down.
The Cross Crawl activates both brain hemispheres simultaneously. It engages the brain for coordinating visual, auditory, and kinesthetic abilities, thus improving such skills as lisitening, reading writing and memory.

I've had pd for 7 years now, and something I'm doing has dramatically slowed down the progression. As the months go by, I've been getting better, maybe "Brain Gym" has something to do with it. Who knows. It couldn't hurt. I'm also taking mucuna. Been taking it for over a year now with excellent results.

Sincerely.
Max