It looks very complicated; has to be through your school or can be done by your parents instead with "documentation" that is rather obnoxious looking (looks like would require psychological testing, that's a special type of psychologist, not a therapist), etc. Types of Psychological Testing | Psych Central

http://www.collegeboard.com/prod_dow...structions.pdf

But just because your school gives you accommodations, doesn't mean you will get them for the test as they have their own criteria.