Hello and welcome to BYC!
Twitching and loss of balance is definitely something neurological of some sort. Quail often boink their heads on the ceiling if they flush up to hard and fast, bacterial or viral brain swelling from mosquito bites can cause these symptoms your bird exhibits. I had a female Bobwhite that contracted West Nile Virus late fall one year. She twitched pretty badly and slept away much of the days for months, she also showed signs of liver failure. With supportive care of heat and the only food she would eat, (peaches and mealworms) by April of the following year she completely recovered.
I am not sure there is much you can do for your bird other than supportive care and if the bird is not showing signs of improvement or has no quality of life, I would suggest putting the bird down.