Traumatic Brain Injury

THE AIR FORCE AND THE DEFENSE VETERANS BRAIN INJURY CENTER SEEK NEUROREHABILITATION THERAPY FOR TRAUMATIC BRAIN INJURIES.

It is an unintended and disturbing consequence of modern warfare triggered by improvements to military protective equipment, most notably life-saving helmets that can deflect bullets and shrapnel. Thanks to such new helmet materials and technology, many warfighters in the global war on terror are surviving head injuries that in previous wars would have been fatal, however, they subsequently are plagued by traumatic brain injury (TBI), which can be a chronic and debilitating condition without proper diagnosis and treatment.

The impact and ballistic protection provided by contemporary military combat helmets has reduced the number of penetrating head wounds, but increased the number of survivable concussive injuries. The challenge now facing military medical specialists and researchers is to ensure that warfighters who suffer from head impact or concussive blasts injuries are properly examined to determine if  they are also suffering from TBI. Then, caregivers need to provide victims the best possible medical care and rehabilitation therapy.

Dr. Catherine Harrison, a research psychologist with the Air Force Research Laboratory’s Human Effectiveness Directorate (AFRL/HE) at Wright-Patterson Air Force Base, Ohio, wants to implement a novel and comprehensive approach to therapy for TBI victims. She has established an agreement with the Defense and Veterans Brain Injury Center (DVBIC) in Washington, D.C., that teams Air Force researchers with the nation’s premier brain injury treatment center.

When Harrison pitched her alternative TBI treatment methods to DVBIC officials late in 2006, she had mentally prepared herself to face a frustrating bureaucratic shuffle. Instead, the welcome response from DVBIC medical director Dr. Warren Lux launched AFRL/HE and DVBIC on a collaborative research project that could dramatically alter TBI rehabilitation therapy.

In blessing Harrison’s proposal for enhanced neurorehabilitation methods, Lux said a successful project could “revolutionize health care reimbursement for brain injury” by scientifically establishing the benefits of nontraditional therapies, according to Harrison. While traditional speech and physical therapies and vocational rehabilitation can retrain a patient to perform specific tasks, Harrison’s approach instead stimulates the brain to reclaim broader capabilities that flexibly support the ability to learn many functions.

“What we’re trying to do is provide experiences that will stimulate an injured person’s brain to recover all of its capabilities, rather than training them to perform a particular task,” Harrison said, whose doctorate degree is in cognitive psychology. “A traditional approach might involve training them to be good workers by rote learning of a job, but we need to discover the experiences that are necessary to make them learners again. Then they can not only learn a job but they can also learn to function in their church, in their community, in all of the other aspects of their life. It’s an all-encompassing approach to develop the capacity to recover.”

Traumatic brain injuries in the military typically result from the concussive effects of improvised explosive devices (IEDs), the roadside bombs widely used against American troops in Iraq. A recent National Geographic magazine article indicated that more than 20 percent of the 20,000-plus American military casualties from Iraq also suffer from TBI. About 60 percent of all injured solders entering Walter Reed Army Medical Center from Iraq and Afghanistan suffer from TBI as a primary or secondary injury, according to DVBIC statistics.

“Traumatic brain injury is the signature injury of the Iraq war,” said Harrison. “We have much better Kevlar armor and helmets so soldiers are surviving head injuries that once would have been fatal.” When there is no open head wound, many TBI cases can go undiagnosed. In some instances, the symptoms do not show up immediately, compounding the difficulty in diagnosing TBI. Symptoms of TBI include loss of attentiveness, headaches, dizziness, confusion, balance problems, loss of memory and in extreme cases, severely irritable or violent behavior.

The effects of TBI can drastically transform a victim’s personality and behavior, turning everyday tasks into difficult and frustrating challenges. Victims may have lost their normal social skills and mental capacity, hampering their ability to interact with other people. Some victims initially require 24-hour care and supervision.

Basic research has shown that environmental enrichment promotes recovery from brain injury. Armed with that data and her own ideas for demonstrating the effectiveness of neuroscience-based rehabilitation, Harrison impressed upon

DVBIC officials the merits of evaluating this concept in clinical trials, enabling the partners to simultaneously achieve the DVBIC rehabilitation mission while collecting the data needed to test her theories.

DVBIC works to identify all soldiers suffering from a closed head injury during combat operations and give them the best care available. For example, at Walter Reed Army Medical Center, DVBIC reviews all incoming casualty reports and screens all patients who may have sustained a brain injury including those injured in blasts, motor vehicle crashes, falls, and gunshot wounds to the head.

DVBIC is responsible for rehabilitating all the brain-injured soldiers returning to the United States from Iraq and Afghanistan. They operate a number of facilities throughout the country, each with a treatment mission and a research mission. Under the collaboration agreement with DVBIC, Harrison’s neurorehabilitation ideas will be tested at DVBIC’s new facility in Johnstown, Pa., and overseen by Dr. George Zitnay, a prominent TBI rehabilitation advocate and researcher.

Her proposed alternative methods include Tai Chi—the ancient Chinese mind-body exercise of relaxed, flowing movements—and immersing patients in a three-dimensional virtual reality world for a multi-sensory experience. Adjusting a patient’s schedule and environment to stimulate their senses and minimize stress is also a critical aspect of her therapy method.

Harrison believes that a sciencebased methodology can complement and improve upon the common-sense approach of traditional practice-based brain injury rehabilitation. For Harrison’s project, researchers plan to compile scientific evidence showing that “enriched environment” methods are effective for rehabilitating victims of TBI.

“Traditional rehab is based on the successful practices of generations of physicians, so it’s good but it’s not optimized. The 1990s were the decade of the brain, a time when there were really profound discoveries of how the brain works, and that has been applied in many different ways,” Harrison said. “But that data is yet to fully make its way into the area of rehabilitation.”

Traumatic brain injury is not limited to military situations. In the civilian world, TBI can result from a sports injury, automobile accident or blow to the head. But civilian or military, the results of a brain injury are the same. Brain injuries sever the neural connectors or pathways a person needs to function normally. Harrison proposes therapy to induce the brain to reconnect vital brain regions using different, previously unused paths, ultimately leading to recovery of physical and mental capabilities.

“Parts of the brain never recover from injury, so to recover the functions that you had you have to rewire the brain,” Harrison said. “We call that forming alternative pathways. You’re recruiting parts of the brain to do functions they did not have to do before.”

Traditional TBI therapy teaches patients how to do tasks, but Harrison wants patients to learn how to learn again through an “enriched environment,” a term that includes enhanced social opportunities, more physically and psychologically stimulating surroundings, and most importantly, stimulation of the hippocampus— the section of the brain that controls learning and memory formation.

Located in the temporal lobe, the hippocampus also is responsible for forming connections throughout the brain. To understand how the hippocampus works, consider the memory of a childhood event or activity. The human brain saves the visual, olfactory, audio and emotional pieces of that memory in discrete locations. When a person forms a memory of the event, the hippocampus links together these separate pieces to recreate the experience as an integrated, whole entity.

Because the hippocampus is a spatial tool that functions in three dimensions rather than linearly, it can be stimulated using rehabilitative tools such as 3-dimensional exploration and acrobatic learning (using complex motor skills), two techniques that make Harrison’s project unique among traumatic brain injury rehabilitation methods.

Dr. Harrison envisions a 3-dimensional virtual reality world with embedded memory tasks so patients can actively explore new environments and perform tasks that physical injuries might prevent them from doing in the real world. She believes such activity stimulates experience- based learning and new memory formation that occurs in the hippocampus.

“Maybe they can fly, climb up into buildings, go into the woods and climb trees in this virtual world,” Harrison said. “We reduce the stress and adjust the difficulty so it’s challenging but not discouraging.”

“What makes this approach different is that we are deliberately trying to form alternative pathways in the brain to make learning easier,” Harrison said. “We want to recover the fundamental ability to learn instead of giving rote training for a specific task.”

Colonel Rick Riddle, chief of AFRL/ HE’s Biosciences and Protection Division, believes the knowledge gained from this work not only will benefit TBI patients, but will help researchers’ understanding of the brain’s inner workings and will potentially apply to the areas of enhanced cognition that are key components of the Air Force’s research portfolio.

“Dr. Harrison’s unique perspectives in cognitive psychology research will lead to both innovative therapies for TBI patients and, more broadly, to enhancing the warfighters’ ability to think, assess, and make decisions in the increasingly complex combat situations they face,” Riddle said.
 
While practitioners at the DVBIC center are working hands-on with TBI patients, Harrison will be helping to analyze the data they have gathered, determining the effectiveness of the therapy and making adjustments as necessary. In addition to incorporating neuropsychological and physiological measures she will be tracking stress hormone levels, which are disturbed by traumatic brain injury.

“We need to see when their stress hormone levels return to a normal function, when their stress system becomes more normal. That’s important,” Harrison explained. “And then we look at brain imaging to see when their brain becomes more normal in appearance and activity.”

Using magnetic resonance imaging (MRI) while a subject is performing a task, researchers can determine if a subject’s brain looks more like a normal or non-TBI brain during this activity. This gives researchers the ability to connect improvements back to basic neuroscience principles, rather than relying solely on observed outcomes. Building a base of empirical data will not only confirm the validity of traditional outcome-based rehabilitation, but more importantly, will provide a means of objectively proving that Harrison’s neurorehabilitation methods are achieving the anticipated results.

Harrison hopes to see preliminary results in the form of lower stress hormone levels, improved patient behavior and increased activity levels perhaps a year to 18 months after the project begins. But it takes longer and is more difficult to look at outcome measures such as successfully integrating TBI victims into society and seeing them obtain and keep post-injury employment.

“Outcomes are still the bottom line because none of this matters if the patients aren’t better equipped to be employed, to keep their marriages intact, to be good parents,” Harrison said. “But we can test these neuropsychological and physiological measures, the stress system, brain function and body chemistry, and keep tweaking this to reach an optimized rehabilitation.” ♦

Back_To_Top