It’s hard to respond without access to specific data, but here’s and example of how one of the first reports in JAMA was based on shitty science :

https://www.discovermagazine.com/mind/bad-science-of-the-havana-embassy-sonic-attack

if you check a bunch of different categories and define impaired as below 40th percentile, then a bunch of people suddenly have a “syndrome”.

I cant find the link at the moment (so this could be made up) but there are other problems with methodology. If you ask a doctor “Does this look like brain damage?” without proper blinding, (mixing in normal scans as controls), there is a tendency to over-diagnose, especially if you tell them they are looking for ray gun damage beforehand.

Some more info here. https://sciencebasedmedicine.org/did-microwaves-harm-us-employees-at-its-embassy-in-havana/