Well I would be more concerned about the short term memory function and the verbal memory function, since both have been impaired by MDMA use. As more as you take as more you are impaired that is a fact (doesn't necceseraly mean brain damage). So just take it few times if you don't want to risk long lasting effects.
MDMA is NOT the reason for Parkinson's desease. There might be some risk, but I would say that the main reason for Parkinson's desease would be rather more the folllowing drugs: speed (dopamin antagonist), meth (high dopamin antagonist) amphetamine, cocaine (high dopamin antagonist) and alcohol (destroys everything it "touches"). MDMA is also a dopamin releaser, but it is far less than the listed drugs.