What Are The Tests To Confirm Parkinson S Disease?

I believe I have had Parkinson s for quite some time now but have never been tested. I have thumb hand and arm tremors on the left side, I drool much more than ever before. I am experiencing extreme tiredness as well periods of very restless sleep. I have sore muscles and joint pain. I also have a problem with memory especially short term memory. There appears to be no history of Parkinson s in my family. I am a 51 year old male. I have however suffered pretty severe head trauma through two car accidents at age 15 and 22. Do you think I have Parkinson s disease? Or what tests would confirm it?