All I can see in every direction is black smoke, with intermittent darts of flame. And all I hear is gunfire, mortar rounds and the rumbling engine of the fortified tank I'm driving to Falluja.
I'm inside a virtual-reality simulation of a war zone in Iraq. High-resolution goggles cover my eyes and headphones cover my ears.
As violent as they are, the computer-generated sights and sounds that fill my senses are intended to heal -- I'm going through a demonstration of a system created to treat soldiers suffering from post-traumatic stress disorder, or PTSD.
Seated next to me, tapping out commands on a controller, is Dr. Albert "Skip" Rizzo, a cognitive psychologist and virtual therapy developer with the Institute for Creative Technologies.
Video
Watch a virtual-reality simulation of a war zone in Iraq.
At this University of Southern California think tank, Hollywood special-effects pros and game developers come together to develop new immersive simulation technologies for the military. Most are used as training tools, but this time, the goal is to help combatants cope with the personal psychological effects of war in places like Iraq and Afghanistan.
Using a handheld control device that looks like a graphics tablet, Rizzo directs each mortar round and IED that explodes along my virtual path.
After a few minutes of increasingly intense activity, my heart speeds up, my breathing becomes more shallow, my palms become warmer -- and I'm really, really ready to stop the sim.
"This is not a self-help tool, and it's not something you download yourself off the internet," said Rizzo, when I'm finally allowed to remove the headgear. "Everything you experienced is a function of us turning knobs and pulling switches. If we noticed your heart rate was too fast, we'd pull back on things."
But in real war, you don't get to take off the goggles.
Developed in 2004 by the Institute for Creative Technologies with the U.S. Office of Naval Research, the VR therapy project has code roots in Full Spectrum Warrior, a first-person shooter originally developed as a tactical training tool for the Army. It was released as a commercial product for Xbox and PC in 2004.
By repurposing images, sounds and other assets from the game, Rizzo and his ICT colleagues crafted an immersive environment that digitally re-creates the causes of combat stress.
Using the control tablet Rizzo calls the "Wizard of Oz" box, a clinician can select any number of environments -- urban war zone, deserted highway, crowded bazaar -- depending on where a patient's initial trauma event occurred.
The control interface can add or silence the sound of gunshots, or flood an area with blasts and smoke. Stress-inducing factors can be increased or decreased, depending on patients' physiological reactions -- and how they say they are doing.
The goal is to gradually reintroduce patients to elements of their traumatic experience, until the memory of that event no longer incapacitates them.
Eventually, Rizzo believes that other sensory stimuli may be added to the therapy, such as vibration and smell.
"We're going to integrate a smell machine, to bring people back to places they've been before," said Rizzo. "We're building a collection. We already have burning rubber, diesel fuel, body odor, garbage and Iraqi spices."
Virtual-reality therapies have been used by some mental health providers since the 1990s to treat phobias. The idea of using it to treat PTSD has a predecessor in Virtual Vietnam, a project conducted by Georgia Tech University researchers in 1997 with a group of Vietnam veterans.
"But never before have we applied it this early," said Cmdr. Russell Shilling, the Office of Naval Research program officer credited with initiating the current project.
"When VR therapy was used with Vietnam veterans, it was applied more than 20 years later," said Shilling. "Here, we're trying to catch people right as they come home, and eventually we'd like to apply it while they're still in the theater."
The potential to re-create all the sensory aspects of a trauma is what makes virtual reality such a promising tool, said Dr. James L. Spira, head of the San Diego Naval Medical Center's Health Psychology Program, who has more than 20 years of clinical experience treating combat-related disorders.
"I've never been as effective a therapist as the last year in which I've been using these VR systems," said Spira. "I can say with confidence that this helps more than anything we've been able to do before."
As part of an ongoing trial, Spira treats Marine and Navy personnel with the system. Some of his PTSD patients are veterans; others remain on active duty.
One of the patients Spira worked with in the VR therapy trial was a Marine sniper, the sole survivor of an attack in which he witnessed at close range the violent deaths of fellow squad members.
"One of them was cut in half, literally, with machine-gun fire. (My patient) ran out on impulse to help him, and was shot in the arm and leg. He picked up the body, scooped up the intestines, brought him back to their vehicle as the guy looked up at him and spoke, dying. His squad truck headed back with them for safety, and was then hit by IED (improvised explosive device), which killed everyone but him."
The Marine was rescued and transported to a hospital, and eventually returned to the United States, where he started VR treatment with Spira.
"Snipers are very tough in general, and during the session, he kept saying, 'I'm fine.' But I had him hooked up with physiological monitors, and when I asked him to tell the story of what happened, his system went through the roof.
"He flew out of his wheelchair in public once, and started pounding on a guy who said we shouldn't be in Iraq," Spira said. "But over time, as the therapy continued, he became calmer and was able to get along with people better."
Another of Spira's patients in the VR program was a Marine machine-gunner who experienced nightmares and other disturbances after suffering a severe shoulder wound in combat.
"The first thing out of his mouth was, 'The pain is pretty intense, but what's more intense is that I hear the voices of my fallen comrades all the time,'" recalled Spira.
"I asked if he meant that he could recall their voices in his imagination, and he said, 'No. I hear them now, calling to me, as if they are right here with us in this room.'"
Spira said the disturbances lessened after weeks of immersive sessions.
About 50 Marine and Navy personnel have participated in the San Diego Naval Center program. Other trials are under way at Tripler Army Medical Center in Hawaii and at California's Camp Pendleton Marine base.
The program may soon be expanded. In July, Congress approved a $1.5 billion increase in funding for veterans' health care after the U.S. Department of Veterans Affairs said it underestimated how many vets would need treatment. Now, supporters of the VR therapy experiments hope that some of this allocation will help fund these new therapeutic tools.
"We spend a lot of money on training people and conducting war," said the Institute for Creative Technologies' Rizzo. "We have to put what's needed into helping these people when they come back."
