Senior Cat Head Twitch

My mom's cat, Whiskers, is 16 years old. She has been relatively healthy with a few issues here and there. Within the last few months, she has started a very odd head twitch. It isn't consistent and I can't seem to find anything that triggers it. She is eating normally, litterboxing normally, affectionate, etc. Every time we go to get it on camera, it stops by the time we get the phone out.

She has a checkup next month, so we will talk to the vet them. I think she may have ear mites- could they cause twitching?

Could be mites but usually that's visible if you look into the ear and is accompanied by scratching. Could it be ear polyps?

She has brown waxy buidlup in there. I don't see anything that looks like polyps

Maybe she just has too much wax then? I'm not sure if polyps are always visible, but I really don't know that much about them.

We will find out!