Evidence for damage found in the vestibular system found by independent clinicians?

That would require such evidence to not be classified. Which it presumably is, as one possibility for the cause is "some other military surreptitiously pointing directed-energy weapons at us while we're out-and-about"; and — regardless of the likelihood of that explanation — just in case it is the explanation, they wouldn't want to do anything that could provide a public-channel feedback loop for said other military to learn exactly how effective their new weapon is.

Also, if you look for statistical anomalies in a random group of people, you just have to pre-screen for 30 variables that you don't mention in your report to get one with p<0.05