VM is a diagnosis, not a pathophysiology. In some peoples opinion it is caused by migraine, whilst in others migraine is just one of the significant symptoms. Please note I was diagnosed with various things including Migraine Associated Vertigo (but never VM). However I think the names for these things changes with fashion.
In any case Amitriptyline has a great track record for reducing symptoms. It really helped me and I only took 20mg nocte at most. You can start at 10mg.
I found almost immediate improvement. But don’t expect complete resolution of symptoms. It did however stop the big basilar migraines dead in their tracks almost immediately. Those things are horrific and I mean HORRIFIC so that was extremely welcome!!
I wrote a bigger post here some while back which might be helpful: Attempting Amitriptyline at Various MAV Stages? - #2 by turnitaround