I am sorry you have had so many concussions. However, that may be a reason to have a brain scan (MRI) that you can get your Doctor to agree to refer you to have the MRI.
If it comes out OK-then no harm in doing, but if it shows any damage it will really help your claim.
My spouse had a scan and lesions showed up now 3 times classic for multiple sclerosis. You never know, but the more tests you have can only help you with your claim. Even if the brain scan comes out normal–it shows you are trying anything to find a way to get better.
Hang in there—its always when you think there is no hope and surrender to the process—the breakthrough happens!