Bitter experience has taught me to not accept the brushoff from a hearing practitioner. Even a repeated brushoff. Do not be a passive consumer of hearing healthcare, and most importantly, do not sit tight and wait for something to go away! Hearing loss has never gone away for me. You are right to want to be sure you are doing everything you can.

Go to another practitioner and politely but assertively advocate for yourself, because hearing health falls into the cracks between different kinds medical practices and the practitioner you land with may actually be somewhat clueless, but won't tell you so. Do not assume anyone will truly have your particular interest at heart unless they have previously proven it. They have to earn your trust. You've got something unusual, so do not settle for anything less than a rigorous multifaceted exam, not just a hearing test! Follow up, follow up, follow up.

I can't vouch personally for the Austin Ear Clinic, but I corresponded privately with someone from this list who went there, and he sent me the tests they did when he went in for sudden hearing loss. The tests he got seemed more comprehensive than the tests I got here in Washington DC when I had a sudden hearing loss. So if I were in that region I would try them.

I wouldn't rule out checking with a neurologist at a university (UT?) or other advanced medical facility where research is being done, maybe in Houston. Hearing has a lot to do with brain function. I know when I'm tired I don't hear well.

Consider connecting with your local Hearing Loss Association of America chapter, and tuning in to their educational programs. Hearing healthcare is highly variable in different parts of the U.S., which unfortunately has a pretty primitive and fragmented healthcare system. So it helps to educate oneself objectively about what services and practices exist elsewhere so you can ask for them wherever you are.

Good luck to you. Keep trying! You are worth it!