This is a bit overdue but thought I'd post in the hopes it'll help someone. As mentioned earlier, I attended the UVA Vestibular Balance Center and they ran maybe 8-10 different tests on me. Most of them involved me sitting comfortably in a chair, while strapped so that I couldn't move. The chair was much like an upright barber's chair, and it was inside a small room. The lights were turned off, and small images were then flashed in different directions upon the wall as if I were spinning. Later, cold air was run deep into each ear for additional tests. At the same time, I wore something over my head with two small optical wires that could see my eye movements. The doctor (in another room) and her machines/programming could analyze my vestibular processing by studying the eye movements. Very cool. Well, the result of all this is that we found my right ear was 57% weaker than my left ear, with regard to processing balance information. (Note: my hearing is perfectly fine in both ears.) It's interesting that the right ear deficiency couldn't be pinned on the Chiari Malformation, or possibly nerve damage from a virus. When this info was shared with my NS, he believed the issue was not Chiari and was likely an inner ear issue. At the time I thought he was wrong, but am now beginning to believe him because my sympoms have improved since these tests. I still haven't recovered all of my "perfect" balance and still experience nystagmus about once a month, but I'm also staying very active. I often spend 10 hours a day on a weekend doing yardwork, and bicycled for 6+ hours (115 miles) just this last weekend. I do have to be careful (move slowly and take my time) with left and right head movements when vision and balance are especially needed. But, I can live with this. I fortunately have never had headaches or common issues often tied to Chiari. I'm sure in time will know if this is the beginning of something worse, with Chiari... or if I simply sufferred some sort of permanent vestibular loss due to a virus and my current symptoms will stabilize. I believe my body has somewhat compensated for the initial nerve damage, peaking (in Feb) 5 months after it possibly occured, as my balance/vision issues gradually improved since mid-Feb. They also seem to flare up just a little bit after spending hours mowing our property, so possibly the dust is stirring things up just a little bit. Hope this helps and if anyone needs additional info, please just let me know.
Take care, Juan