Washington - To a soldier who has been in Iraq, the sights, sounds and smells are familiar: the pop of an AK-47, the flash of a bomb, the stench of cordite.
The location, however, is not.
Here, in a small, windowless room at the Walter Reed Army Medical Center, researchers are using the latest video game technology - plus a smell machine and a vibration platform - to help patients suffering from post-traumatic stress disorder.
Known as "Virtual Iraq," the treatment may help many soldiers who don't find relief from medication or traditional psychotherapy.
"It really jogs their memory," says Col. Michael Roy, who runs the digital therapy program at Walter Reed. "It puts them back there very powerfully and makes them realize a lot of things they had consciously or subconsciously repressed."
Proponents of the new treatment say that once these memories are available, patients can begin to talk with therapists, eventually rendering the phantoms less terrifying.
Nationwide, only about 50 soldiers have undergone the treatment in the past three years - leading some critics to say the treatment is still unproven.
In Iraq, Lt. Cmdr. Robert McLay, a Navy psychiatrist stationed at Camp Fallujah in Anbar province, has used the treatment on eight soldiers. He says all have gotten better.
"I'm getting very good success," he said. The number of potential patients is enormous. Experts say post-traumatic stress disorder - a debilitating ailment that leaves patients panicky, angry and haunted by battle memories - is or will be a significant problem for many of the 1.7 million soldiers who have served in Iraq and Afghanistan.
A study in the New England Journal of Medicine found that between a quarter and a third of all veterans from these conflicts will suffer from the disorder and other mental health problems.
Last month, the Rand Corp. estimated that up to 300,000 soldiers will experience post-war mental health problems.
Virtual Iraq immerses patients in the harsh world that produced their symptoms.
After putting on virtual-reality goggles and earphones, patients are transported to two scenarios: a Humvee convoy through the desert or a foot patrol through a desolate city.
They use a video game handset to control their movements, and by turning their heads they can change what they see within that environment.
The therapist, who controls all variables in the environment except the patient's movement, slowly ratchets up the stress level by adding sirens, sniper fire and explosions.
This digital world is not only full of threats and stressors - roadside bombs, insurgents firing grenades, a bleeding U.S. soldier slumped in the Humvee's passenger seat - but also the mundane details that evoke everyday life for a soldier in Iraq.
Patients hear the sound of a Muslim prayer call and see Iraqi women walking to market in traditional clothes.
The setup also engages other senses. Under the patient's chair are powerful bass speakers embedded in a platform; when a bomb explodes onscreen, the concussion is palpable. Next to the computer console is a toaster-size odor machine; by inserting pellets, Roy can create a variety of aromas, including sweat, burning trash and Middle Eastern spices. He suspects that the scents and noise might be the most effective elements in evoking Iraq. The brain areas that process odor and sound are closely networked with the regions that play a key role in fear and memory - two key components of post-traumatic stress.
The originator of Virtual Iraq is Albert "Skip" Rizzo, a psychologist and researcher at the University of Southern California. He got interested in the approach 15 years ago, while trying to rehabilitate people who had suffered traumatic brain injuries. One day he was surprised to see a patient completely engrossed in a handheld computer game. Generally, brain injury patients have trouble concentrating on a task for any stretch of time.
Rizzo realized that virtual treatments could increase patients' interest and improve their performance. He was so taken with this idea that he left his job as a clinical psychologist to become a low-level researcher at USC; his salary dropped from more than $80,000 to $30,000. He began working with computer coders, developing virtual software for therapy, and within a few years had created a number of applications, including one for stroke patients and another for children with attention deficit disorder.
In 2003 Rizzo, by now a USC professor, realized that the Iraq war would likely last for years and probably produce large numbers of post-traumatic stress disorder patients. He began work on Virtual Iraq, and linked up with other researchers, such as Roy, who shared his vision.
As concern over soldiers' mental health has grown, virtual therapy has gotten more attention. The Department of Defense is spending about $5 million to fund research at six sites around the country, including Walter Reed and the Weill Cornell Medical College in New York.
The most persuasive study so far involved a group of 14 New Yorkers suffering from PTSD after the Sept. 11 World Trade Center attacks. The subjects, most of whom had tried other treatments without success, improved significantly after virtual therapy.
Roy is conducting the first controlled study, comparing 15 patients who get virtual therapy with another 15 who receive more traditional psychotherapy. Previous research has examined virtual therapy without comparing it directly to other approaches.
Rizzo, Roy and other researchers regularly incorporate ideas from soldiers to make the experience more realistic. Programmers at USC will add the potential for friendly fire and a version that resembles Afghanistan, with more mountains. At the suggestion of patients, the researchers also added a weapon, a training model that has no trigger but is the same weight and size as an M-16 or M-4.
"They like to have a gun in their hand," says Roy. "It makes it more realistic." Many soldiers hold the gun and crouch while on virtual patrol. There's no digital firing: Roy says that would undercut the goal of teaching patients to reduce stress.
Rizzo and others say the digital approach can help the many patients who have trouble accessing the frightening memories that lie at the core of the illness. The most commonly used treatment, known as exposure therapy, asks patients to remember events that trigger panic and stress. Over several sessions, patients go through this process repeatedly, slowly draining the thoughts of their haunting power.
Many people with post-traumatic stress disorder have trouble facing their terrifying memories. A significant percentage - Roy estimates as many as half of all patients - either refuse to enter into traditional therapy or don't finish it.
It is this group that will most benefit from virtual therapy, proponents say. Once immersed in the digital Iraq, patients can more easily recall painful emotions and events. They must still endure the difficult process of imagining and talking about what happened to them, Roy says, but they have help with the crucial first steps.
"Seeing it [on the computer] is definitely not enough," says Roy. "We want them to use it as a stimulus to describe experiences and feelings."
Some researchers are skeptical that the new method improves on traditional therapy.
"We don't have empirical evidence that virtual treatment is needed. And it's quite expensive," says University of Pennsylvania psychologist Edna Foa, an expert on exposure therapy. "I want to see what motivates this, other than a fascination with gadgets."
Foa, who works with PTSD patients - including soldiers - in both the U.S. and Israel, says the images in virtual therapy may be too generic to effectively elicit patients' own memories.
Rizzo says the entire virtual set-up - computers, software and other equipment - costs about $7,000. He argues that each one would pay for itself if it helps even a handful of patients. He and others also say the program provides ample realism.
The military doesn't allow mental health patients to talk with the news media. But others who have seen combat say Virtual Iraq elicits powerful emotional responses.
Navy psychologist Scott L. Johnston spent nine months in Iraq in 2006 and 2007, helping soldiers overwhelmed by acute stress. Because treatment works best when it given soon after combat, Johnston spent most of his tour embedded with Marine infantry units in Ramadi and Fallujah. When he returned to Naval Medical Center in San Diego, he picked up his virtual therapy research.
When he put on the virtual reality goggles, he found that the environment triggered a visceral sense of being in combat.
"It brought me back to what I'd experienced," he says. Although Johnston didn't develop full-blown post-traumatic stress disorder, he did experience some symptoms after returning to the U.S.: He was hyper-aware while driving, easily frustrated, and had trouble focusing. He says the problems have since dissipated.
Johnston now has two virtual therapy studies under way, with 30 subjects. He says early results show that in 80 percent of patients, symptoms decreased significantly; in more than half, the problem disappeared altogether.
Johnston says that from what he has seen, Virtual Iraq produces a response from any soldier who has seen action in Iraq, whether or not he has PTSD. "If they've been in combat, they get very serious while they're playing," he says. "It seems to be provoking memories."
See excerpts of "Virtual Iraq" narrated by The Sun's David Kohn at baltimoresun.com/virtual