I have had issues as well, all of which I point to medication as a cause. I will read over my writing and discover missing and jumbled up words (like thing instead of think, diningroom instead of light switch) and other unbelievably silly mistakes. In addition the 'form' my writing takes fluctuates from big loopy letters to weenie little letters printed at the time of incredibly tremmoring hands.

There have been a few times I've had to ask someone to fill out forms for me as I just couldn't do so myself.

The problem though has been behind me these last several months - since I have resumed journalling. I write for 15 min to an hour a day and the exercise of doing so seems to have improved the results. The writing seems more consistant and fluid.

I really like the above suggestion of strengthening the muscles in the wrist and hand. I add to that the suggestion of daily practise.