the FAA (and the Air Force, FWIW) may do cognitive testing for neurological, psychological, or psychiatric issues in the special issuance (or waiver) process.
The results of these cog screens can provide lots of data, including an IQ estimate.
It will create a baseline if you have never been tested, which is actually to your benefit.
I'm sure it is frustrating. (an important) Part of the HIMS program is the willingness and ability of the participant to complete the process.