Others online have told me the names of certain test they can do (don't ask me the names, I don't remember), but they still aren't solid proof. In my case of dealing with the AF and VA, a simple journal with the date, time, duration, what I was doing at the time, and what I had to do until it passed (lay down, sit down, etc.) was sufficient. Good luck in your claim!
Physical Evaluation Board Forum
joshgo