Don't know whether the phrase has been coined yet, but I'd call this phenomenon "sensory consonance", meaning that multiple senses are stimulated in a consistent way to generate a realistic feeling. Sensory consonance is what we experience all the time every day. The experimenters took advantage of sensory consonance to induce a real feeling of an unreal situation.

"Sensory dissonance" happens if different senses give you conflicting information. This happened when the hammer was swung in the experiment. Your eyes say you've been hit, but your nose says otherwise.

This conflict can induce an uneasy, even sickening feeling. If you've ever been to an IMAX movie, you've probably experienced it. The movie screen fills your whole field of vision, and it tells you that you're swooping through the Grand Canyon, or something equally engaging. But the seat of your pants tells you you're sitting still. Depending on your constitution, you can get serious motion sickness during those swooping scenes.

I work in Iowa City, home of the National Advanced Driving Simulator. The "advanced" simulator has a 360-degree screen and a sophisticated motion base. The video and motion respond very realistically to your driving inputs, accelerating and turning through a virtual landscape. An earlier, "pre-advanced" simulator had the video, but not the motion base. The video responded realistically to your inputs, but the "car" did not move. I drove this old simulator once. During gentle maneuvers, it felt OK. But during the more evasive maneuvers I felt some serious motion sickness.

And heaven help you if the software isn't working right on the advanced simulator, because the steering wheel/gas pedal, the video, and the seat of your pants can be telling you three different things.

It happened to me over a month ago for the first time: positional vertigo. I awoke screaming in terror at 5 a.m. with an awful feeling in my head and opened my eyes to see the room being wrenched violently back and forth, which was followed awhile later by a violent wretching of my stomach.

Since then I've had dizzy spells everyday and often have the sense that I'm falling... even now as I sit in front of this computer screen, typing these words.

I had BPV for about 18 months. It's awful, eh? Here's what you can do to put yourself back in alignment with the world:

<link>

Scroll down to the "Home Epley Maneuver" -- just make sure you know which ear was damaged. When you do it, you're going to feel like the room is wrenching itself apart around you, and all the air is being sucked out of the room, so it might help to have someone with you the first time, to remind you that you're ok.

Whatever you do, please see an otolaryngologist (Ear nose and throat guy), because if this isn't simply loose otoconia, you may have something more serious.

Dear Iso

My doc gave me a pamphlet with the maneuver... and it's done jack squat for me. Some it helps... others not. My doc suspects its due to a virus, which means it just has to run its course. He says I have no obvious signs of either a brain tumor or stroke.

If it's the former, well, if it's benign it will manifest itself in other ways and if it's malignant, well, I'll just update my will. I've seen enough of treatments and medical 'hope' over the years to say, "no thanks."

But thanks for caring. That means a lot.