My Parkinson's symptoms include (surprise, surprise!) severe difficulty in using a PC.
Specifically, my keyboard skills have deteriorated significantly over time - I used to be a fast touch-typist but now I'm more of a one-fingered typist - the biggest issue being my clobbering the wrong key alongside the key I intended to hit, and creating typo's which required correcting. And mouse control has been as frustrating as hell - as soon as I moved the mouse cursor to the point where I wanted to click it would go haywire and lead a merry dance across a region of screen measuring about 1in square.
I recently started taking Senimet, and my typing skills have definitely improved. I'm still making typing errors, but I feel much less than before. But my mouse control skills have remained stubbornly stuck.
I've tried using Steadymouse from http://www.steadymouse.com/
- and it has helped, but still left me with severe issues. One being that Steadymouse will only work with one monitor - and I have a dual-monitor system.
I bought a trackball mouse (with scroll ring) and it helped a little, but still left me with issues relating to moving and releasing over a specific point.http://www.kensington.com/kensington/us/us/p/1444/K72337US/orbit%E2%84%A2-trackball-with-scroll-ring.aspx
The advantage of a trackball mouse is that you can position the mouse cursor, and take your hand away to click the left/right buttons independently (which you can't do with a regular mouse). So if you manage to position the cursor over the point you want to click, you can leave the cursor in place by removing your hand. This can be handy if you are using page up/page down buttons on a web page - well designed web pages will have these buttons consistently placed.
However, the trackball did NOT fix the primary problem, and trying to control the mouse remains problematical.
So I next took a look at the options for using a computer jobstick. And I could not believe the stratospheric prices of joysticks being sold for disabled users:http://www.disabledonline.com/disabled-online-store/keyboards-and-mice/trackballs-and-joysticks/
You mean hundreds of dollars to buy a disabled joystick? You have to be joking! A joystick with simple X/Y control should be less than £20 in my book.
So as I'm from an electronics background I figured that if I bought a regular game joystick (costs vary - they can be cheap as chips or mega-expensive) then maybe I might be able to persuade that to work in place of a mouse. And so I bought me one of these:http://www.maplin.co.uk/maxfighter-f-17-usb-joystick-512001
At 15 quid that cost is much more palatable. I really didn't need a game joystick with bells and whistles - just something which would provide X/Y control with buttons to emulate left/right buttons on a mouse.
Having got the joystick home and connected (via USB) I had hoped that it would instantly be able to move the cursor around. But it didn't. So the Inspector Clueso in me went looking for a driver which provided the joystick to mouse functionality that I needed. And I came up with this:http://www.tucows.com/preview/292788/Joystick-2-Mouse
This driver should work with any game joystick, so if you've got a games console with a joystick then maybe you won't need to buy a joystick.
Joystick2Mouse is free (donation-ware - pay the author if you find it useful). I downloaded and installed it. And the joystick then managed to move the mouse cursor around on the screen no problem. And using the joystick buttons I was able to click and move stuff around.
That wasn't however the instant solution I was looking for, because I hadn't tuned this driver to work with my joystick, and it was a right pain in the royals trying to move the cursor over the point I wanted to click. Moving the mouse cursor was no problem, but without tuning the driver I'd skid past the point I wanted to click and then be faced with having to try to move back - this wasn't such a great improvement over trying to use a regular mouse/trackball.
I then spent several hours reconfiguring the Joystick2Mouse driver, it wasn't hard to do, but frustratingly slow to go thru the different options like update delay, speed, acceleration, sensitivity and so on. The default values were generally way too high - probably just right for the non-disabled user, so I ended up reducing those parameters to the bare minimum. And as a result, I now have a joystick which is somewhat usable to control the mouse cursor.
This doesn't make me productive in the sense of being able to do a job which would require using a computer mouse, but does give me the means of being able to move the mouse cursor to a specific position on the screen without having the merry dance which I have when trying to use a regular mouse/trackball.
And all for the £15 cost of the joystick.
Because of the way that USB connectivity works, I now have a PC which has a regular mouse, a trackball AND a joystick all plugged in - I can use any of those to move the cursor around - adding a joystick hasn't replaced the other devices.
As an extra I added some double-sided sticky tape to the base of the joystick to keep it positioned on my desk. If you need to get double-sided tape then Halfords is your friend, they sell such tape for fixing number plates etc:http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_750231_langId_-1_categoryId_255230
A joystick might be worth looking at if you have problems using a mouse.