kajack

I know this has been discussed more than once, but I wanted to start a topic specifically for folks who have, or may have, experienced this or have knowledge of it.
Some of you may know, I had a dehydration event in 2012, which led to a fall and resulting concussion. ( No fun )
Since that time, I have experienced occasional episodes of "seeing spots", felt lightheaded, etc, after getting up from a seated position or laying down. Fewer occurances the farther away from my concussion it becomes.
Two weeks ago, I had the most significant bout with this I've ever had. Actually, passing out and falling down three times within appx 10 minutes. Luckily, I was at home and there were no injuries. There were NO symptoms leading up to this. 5 minutes after it was over, I felt like nothing had happened.
I called my PCP and got in to see him at the first available time. We discussed EVERYTHING, history, eating habits, drinking habits, exercise, weightloss....everything. He did an EKG at the office = perfect. He did blood work = came back perfect. Today I went for a brain MRI. And he's gonna have me do a stress test if the MRI doesn't show anything abnormal. He said lots of times they won't come to any definate conclusions of what cause it.
I've done a lot of reading, researching on the web, and find lots of information. Some suggest that these type symptoms COULD be caused by stimulation of the Vagus Nerve. So thats got me thinking....isn't the band is supposed to stimulate the vagus nerve?
Thoughts?