Scientists Probe Traumatic Brain Injury at Explosive Technology Research Lab

Obscured beyond installation gates, an understated brown building here houses a state-of-the-art lab where a team of scientific researchers investigates “invisible war wounds” — long- and short-term effects of blast-induced mild traumatic brain injury, which has become increasingly prevalent in recent military conflicts.

Thuvan Piehler, a research chemist with the Army Research Laboratory’s Explosive Technology Branch, said her team’s critical experiments and data collection reveal brain damage thresholds necessary to develop, refine and test protective equipment.

“For mild traumatic brain injury there is currently no treatment available, so we need to assess the mechanism of injury to find out how we can mitigate it,” Piehler said.

Though pinpointing a brain injury mechanism is painstaking, the lab’s team of physicists, engineers and chemists has taken a multiscale approach to leverage unique explosive testing capabilities that closely resemble actual circumstances the warfighter might experience, she explained.

Smaller Experiments, Larger Results

The Army Research Laboratory’s specialized experiments use smaller explosives and offer cost-conscious, repeatable parameters to attain more reliable data and to complement strides made by the Veterans Affairs Department and the medical and academic communities. “When you use a smaller explosive, the duration will be different, but the advantage is that we can see similar impact compared to the big scale,” Piehler said.

For example, she cited the aquarium model used by researchers to depict the brain’s soft tissue, which floats in fluid.

“We designed the aquarium so that we can test in vitro what the brain cells actually experience under a very controlled environment and use it with real explosives,” Piehler said. “We are the only ones in the country to [conduct] these experiments, and that’s how they’ve been done for the last few years.”

Piehler stressed taking a bottom-up approach to assess low-pressure impact as key components of brain cells change through morphology or impact response.

“That may lead to damage [that] will eventually accumulate over time,” she said. Mild cases of TBI are very localized, Piehler said, adding that the basics of how brain cells are injured still need to be figured out.

Delayed Reactions

Piehler said clinical data suggests that many warfighters diagnosed with mild TBI, or MTBI, sometimes did not present symptoms for years after a blast, so understanding, protection and treatment will be long-term goals.

“We know that it’s a very slow process,” she said. “The brain has billions of cells, so we need to figure out which part of the brain is affected.”

Isolating Data

Piehler’s colleague, Nikki Zander, an Army Research Lab chemist, said experimental parameters call for analyzing brain injury within a simplified, short-term model, typically about 24 to 48 hours after a blast.

“We’re looking at individual brains cells, not part of a complex tissue,” she said. “We’re trying to get rid of a lot of confounding factors to understand each cell type’s contribution to potential injury.” This type of data focus can hold the key to treating brain injury symptoms a warfighter may sometimes present years following the trauma, she added.

Zander said scientists assess different outcome measures such as changes in morphology, swelling and edema to correlate experimental data to human data and disseminate those findings to the medical community.

“Ultimately,” she said, “we hope we can use this technology to better test our equipment and understand if it is suitable for the theater environment that the [warfighter] would be exposed to.”

And while the research and focus on treatment by medical and academic communities is relatively nascent, the vulnerability, Zander said, has persisted for decades. Many warfighters were dealing on their own with suicidal thoughts and post-traumatic stress, as well as other types of issues related to sleep, memory, concentration and mood that scientists now associate with a brain injury, she noted.

Zander noted that the condition is far less stigmatized in modern society than it used to be, and warfighters are taking charge to get treatment. “In the past, we didn’t have an understanding that a blast wave, although there was maybe no outward physical damage, could actually cause a lot of long-term mental and cognitive damage,” she said.

PTSD, MTBI Differences

Zander acknowledged the difficulty in distinguishing between post-traumatic stress disorder and MTBI.

“They have very similar symptoms, so we really need this research to understand the physical differences in the brain between the two for better treatment and diagnosis,” she said. “With MTBI, there’s a lot of long-term, neuropsychiatric symptoms, as well as much higher risk for neurodegenerative diseases such as Alzheimer’s [and] Parkinson’s … which obviously may not be the case for PTSD patients.”

In the future, she said, scientists hope to have better knowledge of mechanisms to better understand treatment methods.

“Hopefully, we’ll come up with drugs that we can administer immediately after exposure, and have better blast gauge sensors,” she said. “People may not even know they’re exposed if it’s a very low-level blast exposure.”

As the researchers continue to build the complexity of the models, collaborative efforts will also persist with academic institutions such as Johns Hopkins University in Baltimore to develop from stem cells “mini-brains” that provide three-dimensional human brain tissue aggregates. “We’re hoping to have better data that can be more comparable to the human brain,” Zander said.

Richard Benjamin, the Army Research Laboratory Detonation Science Facility’s lead physical science technician, said the team uses primarily optically or electronically based technology in their experiments.

“We used a technique called an Edgerton Shadowgraph, which allows us to visualize shockwaves in a transparent medium so we can see the shockwaves in the air,” he said.

Upon visualizing the shockwaves, he explained, researchers can measure their locations and use the timing from high-speed video cameras to determine a velocity, which is critical in indicating the shockwave’s pressure. “Once we have all that information, we can tell you what the pressure impacted on our test subject was,” he said.

The researchers will seek enhanced cameras as technology progresses, which he said will greatly improve imaging and data collection. “Ninety percent of our equipment is commercially available,” he added, “but the team has been able to adapt it to research needs.”

Strength in Numbers

Rohan Banton, a mechanical engineer at the lab, then complements his team’s experimental findings through the use of computational models and simulations. In this capacity, he investigates computationally the interactions of pressure waves — generated from laboratory scale live explosive impact — with dissociated brain cells placed in the aquarium experiments.

In his models, Banton provides crucial load impact data on the dissociated brain cells that are otherwise inaccessible from the experiments. Through modeling and simulations, he is able to complement the experimental findings and present useful information that can be shared among academic realms.

“It’s important to be able to use numbers [from simulation and modeling] in a scientific way to achieve your research goals,” Banton said. “That will help you design better helmets, better personal protection equipment and assist the warfighters.”

Brain study is a societal issue, he said, and he’s grateful for warfighters who put their lives on the line each day in defense of the nation.

“I salute them — it’s a tough job,” Banton said. “Working at the ARL gives me an opportunity to expand my horizons and work with world class scientists inside and outside the lab.”

Featured Content: DoD, Amaani Lyle on Twitter: @LyleDoDNews

Featured Image – Hunting for the Cause of TBI, Sensors attached to a translucent model skull are used to measure explosive shock velocity and pressure at the Army Research Laboratory Weapons and Materials Research Directorate at Aberdeen Proving Ground in Aberdeen, Md., March 9, 2016. Data captured by the sensors are used to assist studies in traumatic brain injuries. DoD photo by EJ Hersom