Yes, unfortunately there is no definitive test for chronic traumatic encephalopathy short of a brain autopsy. And tests for the more obvious defects of tbi may miss the more subtle findings of cte,including depression, paranoia, personality changes, disorganization, forgetfulness.
Plus the VA system is geared towards uncovering the severe cases that qualify for military disability/ service-connected status, and probably biased against diagnosing milder, iffy conditions. Although there's nothing mild about it when you're living with it.
