HALIFAX - Canadian military scientists are trying to develop a technology to detect possible brain injuries as more soldiers are being exposed to powerful blasts that can leave them with dangerous yet hidden wounds.
Researchers are looking at several methods that could be used on the battlefield to help determine what happens to soldiers who are near improvised explosive devices, or IEDs, when they detonate, or when they suffer other forms of head trauma.
The problem now is that there is no way to know whether troops who are exposed to blasts but bear no visible injuries have suffered a mild form of brain trauma even if they are a distance from the explosion.
"This tool would be very useful because you'd be able to diagnose a non-visible injury, because right now if you don't have any penetrating wound we presume that you're OK," Dr. Bob Cheung, a scientist with Defence Research and Development, said in a recent interview from his office in Downsville, Ont.
"The statistics from the United States really suggested that (brain injuries) are undiagnosed and under-diagnosed."
Medical experts and both the U.S. and Canadian militaries have started examining the issue of traumatic brain injury more closely as the number of troops coming in contact with blasts rises steadily.
The U.S. recently dedicated $450 million for research into treatment of brain injuries in the wake of studies that show roughly 40 per cent of combat soldiers in Iraq have suffered some form of head injury.
While physicians know what to do with soldiers who have a penetrating wound from an IED or are knocked unconscious, they have no way of knowing what kind of impact the over-pressure from a blast has on the brain.
Dr. Homer Tien, a trauma surgeon at Sunnybrook Hospital in Toronto, said soldiers that are even one kilometre away from a blast site may suffer damage, even if they're not knocked out or visibly wounded.
A bomb's acceleration force can stretch the brain's nerve fibres, but that stretching may not manifest itself until days or weeks later in the form of confusion, anxiety, behavioural changes and hearing loss.
"Our current ability to screen for these people will show nothing," he said, referring to CAT scans and other conventional methods that won't detect subtle injuries.
"Brain injury is the leading cause of death and disability in civilian and military traumas. What's new is this idea of mild traumatic brain injury that is really subclinical, but only manifests itself months or years."
Tien, who is in the reserves, plans to take his research to Afghanistan later this year when he begins a two-month rotation in Kandahar.
That could include using Cheung's device or a battery of validated tests to measure a soldier's cognitive abilities following a blast
Brain injuries can be defined as severe, moderate or mild. Severe and moderate can result from a penetrating injury, such as a bullet or shrapnel wound, or a blunt trauma injury that could be caused by a knock on the head inside a military vehicle, for example.
A severe injury can leave someone in a coma, while a moderate brain trauma might cause confusion, blurred vision, vomiting and numbness after a bleed in the brain.
The difficulty for physicians is diagnosing troops who have a mild brain injury and might black out momentarily, but, like hockey players who get hit, say they're OK and want to carry on without knowing that can cause further damage.
"Treatment for mild ones is just watching them so they don't progress because some of these mild brain injuries will progress to severe," said Tien. "This is a very new phenomenon so we don't really know anything about it."
Data that Tien gathered between February 2006 and February 2007 showed 76 Canadian Forces members in Afghanistan were injured and had to be flown out of Kandahar.
Of those, seven had moderate or severe brain injuries, while six had what are considered mild brain injuries. In a three-month period last year, seven of 12 deaths were from traumatic brain injury.
The issue for physicians and military leaders is knowing who needs to be scanned for possible injury. If someone was one kilometre from a blast site, for example, could they have suffered damage?
"Who do we define as those who are at risk? Some may not have been knocked down and are still subject to this over-pressure of air from the explosion," Tien said. "At what point do you send them for further screening? No one really knows."
"We don't have a sense of how big this problem is. I don't know what sorts of problems these people could have in a year, so we need to do long-term follow-up studies."
Cheung, whose contract for the device is worth C$296,000, is looking at several real-time technologies, including ones that measure brain wave activity and cerebral blood flow. He is exchanging information with colleagues in the U.S. and is hoping the portable device they hope to develop will be applied to the civilian population.
American researchers recently developed a small device that resembles an oversized iPod and has an electrode strip that can indicate whether a patient's brain functions deviate from normal.
