Jitesh,
Personally I wrote out 2 pages of brain dump and then during the exam there were only a few "scribbles". For example I quickly jotted down all my in-the-head calculations on paper to verify that my math was right. I don't remember writing down much beyond that.
However, please remember that PMI recently changed the rule on the brain dump and you are now no longer allowed to write anything down before the clock starts ticking. Please review this article here for all the details
www.project-management-prepcast.com/free...-pmp-exam-brain-dump
-- so you can still use a brain dump but are not allowed to write it down before the exam clock starts.
Keeping this change in mind and considering your disability I would DEFINITELY start the process of requesting accommodation. Even if you now think that "it looks like I will be OK", remember that you will be under a ton of stress during the exam. Better be safe.