On most days, a tumor on Zvulun Muola's spinal cord keeps him confined to a wheelchair, but today he is standing on a small, wooden dinghy gliding downstream, navigating between the islands of a tropical paradise.
Muola, whose legs are partially paralyzed, is among a handful of disabled patients in Israel using the Computer Assisted Rehabilitation Environment.
The virtual-reality system puts patients at the helm of a life-size video game, forces them to use atrophied muscles and teaches the basic skills necessary to recover from severe injuries and disorders.
"It gives more confidence," said Muola, standing shakily on a moving platform, sandwiched between a walker and a physical therapist. "It's hard at the beginning but once you get the hang of it ... it improves stability and helps the patient trust himself."
The $650,000 computer system at the Chaim Sheba Rehabilitation Hospital near Tel Aviv is the only one of only a dozen worldwide in clinical use. The others are still in the research phase. But doctors using the system say it can cut rehabilitation times and make the process far easier by helping distract patients from their pain.
More than half of the Tel Aviv hospital's patients — most of them amputees — were maimed by suicide bombs or wounded in last summer's war with Hezbollah guerrillas in Lebanon.
Sgt. Idan Borovski, 23, was wounded in a Lebanese village when shrapnel from a Hezbollah anti-tank missile ripped through a crowd of soldiers, killing nine and injuring 30. The metal shards severed the nerves and muscles in Borovski's foot, leaving him with little feeling and limited use of his leg.
"For one thing it was fun," Borovski said of his two training sessions with the virtual-reality system. "You are actually in a game. You are playing. You don't notice the pain and you can work harder."
The system immerses the patients in a fully reactive virtual and physical environment, using tiny sensors placed on the body, 12 high-speed infrared cameras, a moving platform that reacts to the patients' weight distribution and a life-size 3-D projection screen.
The system simulates daily activities like taking a walk in an urban environment, driving a car, hiking up and down a mountain or — like Muola on the dinghy — steering a boat. The scenarios teach patients to stay balanced and react to situations they will face in the real world.
The dinghy can be steered by leaning in left or right, forward and back, between a slalom of checkpoints and land masses to reach the finish line.
In another scenario that takes a patients down a winding road, the platform lurches with every curve, tilts back and forth over hills and simulates various terrain with vibrations. The patients also can try to "catch" objects floating by — with sensors on their hands — while maintaining balance.
Dr. Itzhak Siev-Ner, head of orthopedic rehabilitation at Sheba, said virtual reality helps his patients retrain their brains and bodies to function and works much faster than traditional rehabilitation methods.
"The system helps to strengthen muscles, to improve your stability, balance, and to translate it to everyday life," he said. "The integration of all these activities — and this is oversimplifying it — enhances the plasticity of the central nervous system."
Siev-Ner said the video game scenarios, which keep scores to allow doctors to monitor progress, distract the patient from pain and involve more complex coordination than normal physical therapy.
"It's like the patient is the joystick of the system ," Siev-Ner said. "Although it can be fun, after 20 minutes they are sweating to hell."
Since Sheba's system came into regular use in 2005, it has logged 600 hours of rehabilitation time with more than 50 patients.
Dr. Michael Yochelson, medical director for brain injury programs at National Rehabilitation Hospital in Washington, D.C., said there is a bright future for virtual reality in medicine.
"It's something that looks very promising and there's a lot of research going on in that area now," he said. "It allows for reproducing different scenarios that we can't necessarily reproduce in the clinic."
It is no accident that the first clinical use of virtual reality is in Israel, where a perpetual state of war has led to a constant flow of casualties.
"Unfortunately there is a quite a good industry here," said Oshri Even-Zohar, the Israeli who first conceived the system in 1990 but said the necessary computer technology wasn't available for seven years. Even-Zohar built the prototype in the Netherlands using a grant from the European Commission.
A new scenario being developed will be set in the aisles of a supermarket, where the patient will have to pick items from the shelves and bring them to the virtual cashier — a decision-oriented game particularly helpful for recovery from brain injuries.
Over the next two years, next-generation models will be installed in Brooke Army Medical Center in Houston and Walter Reed Army Medical Center in Washington D.C., Even-Zohar said.
Yochelson, the American doctor, said it is a sign that the U.S. market for innovative rehabilitation is also growing.
"We always see a lot more advances in amputee care and prosthetics during war time," he said. "Israel has the population to support that. Unfortunately, now our military does too."