I had never heard of ear twitching until I got Sis. I was told that she had had her ears twitched or it was suspected. She was incredibly head shy, she would rear, jerk, you name it she did it to get away from anything near her ears. Haltering and bridling was a nightmare and she still isn't 100% on either but I can reach up between her ears now and scratch her or touch her ears without her having a meltdown. The lip twitch I've used and it worked well for when the vet needed to tube another mare I owned. I agree training is the key but there are times when you don't have the time to train one before it needs medical/farrier/teeth work done.
Courage is being scared to death but saddling up anyway~~John Wayne