Hi Minh,
This is just a theory of mine but it might be worth testing.
It is known that taking steroids brings your hearing back...
If you suffer from Sudden Hearing Loss, from causes other than AN, Steroid treatment, Hyperbaric treatment are known to save hearing.
What isnt clearly understood yet is the mechanism involved in hearing preservation for AN's. Why it works for some and not for others, and why it seems to work so well so quickly, and why things get worse so quickly for some when you stop taking them.
One mechanism that maybe at play here, is one of the side effects of steroids which is increased blood pressure.
As your blood pressure increases more blood flows to the nerves and cochlear, may improve hearing.
Quite often the blood vessel to the cochlear is squashed by the AN in the Internal Auditory Canal.
If your blood pressure is higher it maybe enough to push past the restriction in the IAC and supply the cochlear and nerves with blood again.
Then when your blood pressure drops, blood supply to the cochlear and nerves drop and you hearing gets worse.
So my theory is, that when you take steroids, one of the mechanisms at play is that the increased blood pressure helps blood flow to the cochlear. When you stop taking steroids your blood pressure falls and your hearing diminishes again.
So How can we test this theory safely?
Maybe worth getting a blood pressure monitor...
Blood pressure is naturally low first thing in the morning and while you are asleep..
If the theory has merit, you hearing would be poor first thing in the morning and improve when your blood pressure reaches the point where it pushes past the restriction.
The best way to safely raise your blood pressure, to test the theory, is through excercise.
If you excercise for 30+ Minutes, does your hearing improve temporarily?
If yes then maybe there are safer options to slightly raising your blood pressure, other than taking steroids.
My thoughts are with you.