Magazine article National Defense

Scientists Hope Bomb Blast Research Can Lead to Better Helmets

Magazine article National Defense

Scientists Hope Bomb Blast Research Can Lead to Better Helmets

Article excerpt

Brain injuries caused by improvised explosive devices are being called the "signature wounds" of the Iraq and Afghanistan wars.

Blasts from roadside bombs are capable of sending shockwaves through the air that penetrate armored vehicles as well as standard headgear.

The effects as the wave ripples through the brain are poorly understood, but the results have a name: mild traumatic brain injury--better known as a concussion.

Scientists are now taking a closer look at exactly what a shockwave does in the milliseconds it takes for it to pass through a helmet, skull and brain.

The University of Nebraska-Lincoln's college of engineering has built a test bed where these waves can be examined in detail and at their simplest forms. It's hoped that this basic research can lead to better helmets for war fighters.

"At the end of the day, the actual damage takes place at the neuron level," Namas Chandra, associate dean of research at the college said in an interview. Neurons are the basic cells that comprise the brain. Shockwaves stretching these cells as they pass through the brain may be the cause of short- and long-term TBI, he said.

The Rand Corp. in a 2008 study estimated the number of war fighters suffering from brain injuries at 360,000. Senior Defense Department medical officials in a March 2009 press conference said that number might be closer to 180,000. However, anywhere from 45,000 to 90,000 of them were categorized as suffering from severe and lasting symptoms.

There is evidence that relatively mild cases of brain trauma may cause problems as well. A January 2008 New England Journal of Medicine report, "Mild Traumatic Brain Injury in U.S. Soldiers Returning from Iraq," found a strong association between mild TBI and post-traumatic stress disorder. Soldiers who temporarily lost consciousness or reported being dazed and confused after a blast were later significantly more likely to report poor general health, missed workdays and medical visits.

"However, the epidemiology of combat-related mild traumatic brain injury is poorly understood," the six researchers who co-wrote the article noted.

UNL researchers hope that by studying shockwaves in a controlled laboratory setting, they can better understand exactly how they interact with brain cells. Working on a $3.2 million Army Research Office grant, the college has designed two enclosed shock tubes where they can perform numerous controlled blasts in a laboratory setting at a much lower cost than open-air tests.

The lab isn't going for realism, Chandra said. The effects of an IED blast in a battle zone are tremendously complex. There are a series of "echo waves" as the energy sent out by the bomb reflects off surfaces such as buildings, vehicles or both. An open-air test will have so many variables, such as the distance from the victim to the bomb, or the shape of a charge, that it is impossible to establish a baseline reading and test equipment such as helmets with consistency, Chandra said.

Fundamental laboratory work is needed to completely understand how the shock-wave propagates through the helmet and skull and how it causes brain damage.

"Then we can clearly see what are the possible effects of a combination of shock-waves a soldier experiences," he said.

Shock tubes have been used to measure blasts since at least World War II, said Aaron Holmberg, an engineering mechanics department graduate student, who helped set up the lab. Most of the previous research focused on the pulmonary effects of explosions on a soldier. …

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