I first learned about entrainment last month from my audiologist. I mentioned to him that at work, when the security gates sound, the sound continues in my ear for a second or two after the actual sound is gone. He explained that the term for that is entrainment, when the sound is on the same frequency as feedback and the hearing aid kind of gets stuck in a loop. Unfortunately it doesn't seem to have stopped just at the security gates.
It took me awhile to figure out, but music in the car seems to be doing the same thing. I noticed with a few songs (of course, I can't remember any titles off the top of my head) that I'd start to feel kind of irritated during the song as though it were louder than it needed to be, no matter how the volume was set. Then after the song ended I'd hear a bit of ringing in my ears. I don't know why I didn't put two and two together, that it's entrainment and my hearing aid is probably giving me feedback throughout the entire song, just drowned out by the music. If it's really something that can't be fixed this is going to be annoying! I have to keep the volume of music very low in the car to avoid the problem, which means I may as well just not listen to anything. And once the hearing aid starts giving me feedback it doesn't seem to want to stop.
I'm definitely going to mention this at my next appointment with the audiologist. I hope it can be fixed!