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Testing breakthrough for mild TBI

After months of military officials and medical personnel lamenting the lack of an immediate, unequivocal, physical proof of mild traumatic brain injury, an anesthesiologist thinks he has found a solution.

And it may be as simple as two sensors and a BlackBerry.

Dr. Richard Dutton heads up trauma anesthesiology at the R. Adams Cowley Shock Trauma Center at the University of Maryland and sees about 4,000 people a year who doctors believe have a brain injury. But without a CT scan or an MRI, it’s hard to immediately tell for sure — especially if, as is the case in most trauma situations, doctors are also worried about broken bones, ruptured organs or heavy bleeding. And about 3,000 of those cases are mild TBI, which doesn’t show up on a scan.

So Dutton and a team of engineers decided to see if they could use sonar to “listen” for differences in healthy brains and injured brains. They used a headband with sensors to pick up the sound transmitted through the brain with sonar and then analyzed the data fed back into a computer. The Air Force paid for the research.

“We’d ‘ping’ them with sonar and then listen,” Dutton said Feb. 20 at an American Institute for Medical and Biological Engineering conference.

They hoped to detect differences in brain mass, but they didn’t come up with much. Then, one day, they’d stopped the “pings” but left the sensors on, so the computer was just “listening” to the normal flow of the brain. Somebody looked at the computer and noticed a regular pattern of bandwidths. “We said, ‘Hey, that’s important,’” Dutton said.

The sensors apparently were picking up tiny movements caused by blood coursing through the vessels in the brain. Dutton said this guess — that it is blood causing the movement — is based on previous studies as well as mathematical modeling. “It’s like a digital stethoscope,” he said.

They decided to “listen” to more patients with the “Brain Acoustic Monitor.” Armed with the knowledge that normal brains have even, regulated wavelengths, the researchers listened to the brains of 30 patients, all with severe TBI. The 15 who had normal signals five days after injury got better, while the 15 who were still abnormal did not improve clinically.

“All those patients died or left for rehabilitation in persistently vegetative states,” Dutton said. Those patients, he believes, had turbulent blood flow in the brain, as opposed to the smooth blood flow of a normal brain. Brain injuries typically involve bruising, which causes blood vessels to burst.

The bigger problem, especially for the military, has always been mild TBI. Doctors typically can’t see mild TBI, even with a scan. But they know it’s important not to send a service member back out on patrol with a mild TBI because injuries caused by mild TBI are cumulative; even a slight second head injury can cause death for someone with an already damaged brain, and no one wants to go on patrol with someone whose vision is blurry or who has short-term memory loss.

When Dutton and the engineers tried out their equipment on people they believed to have mild TBIs, they found turbulent blood flow — or irregular bandwidths — on the Brain Acoustic Monitor.

“You hit your head, your BAM becomes abnormal,” Dutton said. “We think we may have an objective marker for brain injury. This is pretty exciting stuff.”

And it’s completely portable, which could be good news for troops in Iraq and Afghanistan. In Iraq, there’s one CT scan — in Balad — and no MRI machine. Medics don’t have access to the heavy, expensive equipment.

But information gained from BAM comes from two sensors placed on the forehead, which is then processed with a laptop or a BlackBerry. They’re working on making it even more medic-friendly by creating a simple “red means no-go, green means go” system to determine whether a person needs to go see a doctor or is good to go back on patrol.

BAM has been tested on more than 400 patients. It’s going through the Food and Drug Administration approval process now, but Dutton said there are some issues. It doesn’t predict the severity of an injury, only that there is one. He said his team hopes to test the use of more sensors placed over more areas of the skull to see if they can detect regional damage. So far, they’ve only tried that on bald patients because hair gets in the way of the signal.

But just determining that there is an injury is huge, especially for mild TBIs. “Mild” is a misnomer because it can mean anything from a soldier who bangs his head but has nothing more than a passing headache to a Marine who bangs his head and has headaches, permanent short-term memory loss and mild seizures.

Some symptoms of mild TBI also are similar to those of post-traumatic stress disorder, so people can be misdiagnosed.

Thousands of troops who have served in Iraq and Afghanistan are believed to have suffered mild TBI from accidents or explosions.

Dutton’s presentation was not the only one to cause excitement at the conference. Marilyn Kraus, associate professor of psychiatry and neurology at the University of Illinois at Chicago, talked about how differences in white brain matter correspond with cognitive and behavioral issues, and therefore looking closely at white matter could help differentiate between PTSD and mild TBI symptoms.

She used Diffusion Sensor Imaging to look at the density of white brain matter and found that scans of people with mild TBI were “significantly different” from normal scans. The differences could also point to future problems, such as epilepsy or dementia.

And David Hovda, professor of surgery at the University of California, said a closer look at brain activity showed that those with brain injuries burn lactate for energy as their metabolic rate declines, which suggests that metabolic therapy through an IV might be important for treating brain injuries. A normal brain uses glucose for energy.

“Fuel is dictated by the needs of the tissue, not by what we think it needs,” Hovda said. “TBI victims tend to come in hyperglycemic, so doctors tend to keep insulin levels low. We may need to look at it differently.”