There does seem to be a fair amount of research into MAV - this is the latest finding I could find on google scholar:
http://en.cnki.com.cn/Article_en/CJFDTOTAL-HLYX201106009.htm
Most of the most conclusive research over the years seems to indicate that stress is perhaps the most important factor in MAV. However I feel until researchers distinguish types of stress (possibly: anxiety, excitement, pressure, physical, short term panic, long term depression) there will be muddled results. Even with the existing puzzles, i do feel that dizziness leading to anxiety is a red herring - it is a common experience but must not be confused with the most important hypothesis that stress causes migraines and therefore dizziness.
The mystery remains - why do most people who suffer great stress not get dizzy, whereas MAV sufferers do?
On a positive note - often in nature a combination of one or two factors can create complex and seemingly random outcomes - hopefully we can isolate these factors and then make sense of the variety of different symptoms that cause us much trouble and anguish.
Mark