I would like to add one thing to that article and that is in humans and I dont know about cats, the hairs that they talk about in the ears have little crystals on, its these that transmit the signal to the brain.
I had , they say, a virus which killed the hairs and the crystals became free and got into the wrong part of the ear and caused my balance to go. If I had had treatment with 2 weeks of becoming ill, I should have become instantly better again but because I could not get anyone to believe it was an ear problem I was only seen by neuro 6 months later and had MRI. Nothing showed in the MRI that would cause this, except a minor bleed which they think was caused by a minor stroke at some time but should not have affected my balance.
I desperation I went private and saw an ear consultant and he saw the MRI scan and other test results and told me about the hairs and the crystals that transmit to the brain in which positioin you are etc.
The treatment I should have had very quickly was an Epley Manouvre but as I had it over a year from being ill, I was told that it may not work and if it did, it could take many years because the brain is very to learn that I was unbalanced but it now has to relearn that I am balanced and that is not quick so long after. My age may also be against me. They did a balance test after wards and the treatment had worked!
Its now 5 and half years on since being ill and one year less since having treatment and I can walk straight now and drive, but bending down and back up quickly can make me fall over. If I get knocked unexpectedly , I will fall over. I am so much better than I was but the changes have been slow to happen, so slow I didnt notice. I am not safe among crowds and cant balance at all on a train or a bus and I use a stick outside my garden.
The classic test for a human is to close your eyes and stand with your arms out horizintal to your body and I would fall left.....dont do this unless you have someone to catch you! The other one is the drunk driver test , walking heel to toe on a straight line.......I can do this sometimes now but used to just fall. Another is to be sitting down with eyes closed and try to touch the end of your nose with your index finger alternately with each hand. Obviously you cant test any of this with a cat and because an ear problem is not one that can be visiably seen but by being blind, this would bring on every symptom.
Sorry to hijack this but without an MRI scan, I dont think its possible to rule out an ear problem but I would imagine in a cat one cannot help it either, especially in a blind cat. Please note that my Gp and 3 neuro specialists were not willing to concede it was my ears, only an ear specialist.......professional jealousy or tunnel vision!!