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Special Report: Brain Injury

War on the Brain

CARROLL, LINDA

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Linda Carroll is a medical and science writer whose work has appeared in The New York Times and Health magazine as well as on msnbc.com.

Margaret Benoit sits quietly watching her son learn to walk for a second time. The improvised bomb that blew through the bottom of Sgt. James Benoit's Humvee over a year ago left him missing much of the muscle on his lower left side and with unseen injuries to his brain that, for a time, made him seem like a stranger to those who knew him best. “Each day he becomes more and more his old self,” says his mother. “But it's taken a year to get there.”

Benoit had always been an easygoing guy back home in Wharton, N.J. But after the blast in Iraq, he became very particular. Little things jangled his nerves. And it wasn't just the 24-year-old soldier's personality that had changed. His thinking had slowed and his memory dulled. He now had trouble keeping track of the simplest details of daily life.

The changes were all signs that Benoit had sustained a brain injury in the blast-even though he had no external wound to his head. Although doctors don't fully understand what happens to the brain in an explosion, they suspect much of the damage occurs when soft, delicate tissue slams up against the solid inside wall of the skull.

This kind of brain damage is so common among soldiers coming home from Iraq that many experts are calling traumatic brain injury (TBI) the signature wound of the war. While TBI was not unheard-of in previous conflicts, a far greater proportion of the soldiers returning from Iraq and Afghanistan have suffered significant injuries to their brains.

The rise in the incidence of traumatic brain injuries results partly from the widespread use of improvised explosive devices, or IEDs, by insurgents. And ironically it results partly from innovations in protective gear and emergency medicine. Soldiers who might have died in earlier conflicts are surviving because high-tech helmets and body armor protect the head and torso from penetrating wounds. Advances in first aid and quicker trips to sophisticated medical centers are saving soldiers who might have died on the battlefield. But many are surviving with badly wounded brains.

And those survivors with the worst brain injuries must learn to live with lifelong disabilities. “TBI looms large in terms of chronic consequences,” says neurologist Warren Lux, M.D., acting director of the Defense and Veterans Brain Injury Center. “Brain injuries, like amputations, are for life.”

More than 20,000 U.S. military personnel have been wounded in the war through mid- September, according to the Defense Department. But nobody knows exactly how many of them have suffered traumatic brain injuries. That's because it's possible to have a TBI without any external wounds. And no one checks each and every soldier for signs of a brain injury after a blast.

Figure. REFLECTING B...
Figure. REFLECTING B...
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The impact of a missing leg or arm is clear to anyone meeting an amputee. But changes in the brain that result from a soldier being thrown around in a bomb blast aren't always immediately obvious, even to the soldier. When the wound is invisible, it can be easy to dismiss. “And a lot of guys don't want to leave their buddies after they've been injured,” Dr. Lux says. “They try to tough it out.”

At Walter Reed Army Medical Center in Washington, D.C., where many of the most severely injured soldiers are treated upon returning to the U.S., everyone gets checked for TBI. Doctors there found that about 60 percent of the soldiers screened have suffered TBI, with more than half of those injuries diagnosed as moderate or severe.

Figure. BASIC TRAINI...
Figure. BASIC TRAINI...
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Figure. Defining TBI...
Figure. Defining TBI...
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“Soldiers aren't being routinely screened for brain injury, and they should be,” says Wayne A. Gordon, Ph.D., associate director of the department of rehabilitation medicine at the Mount Sinai School of Medicine in New York City. “Without routine screening, soldiers with traumatic brain injury may be slipping through the cracks.”

James Benoit may have trouble recalling aspects of day-to-day life, but he remembers every detail of the day he drove down a road in Baghdad and a bomb ripped through the bottom of his heavily armored vehicle.

“I was the driver,” Benoit says impassively as he takes a break from his physical therapy, propping himself up against the rail of the parallel bars he's been using to practice walking. “I just heard this sound and looked around at the guys to ask what had happened and, suddenly, I had this numb feeling in my backside. And then my vision went black.”

Though temporarily blinded, Benoit was conscious as his comrades pulled him from the damaged Humvee. He remembers the long, slow ride back to the base and being loaded up onto a helicopter. After that, there is nothing until the moment he woke up at Walter Reed with a multitude of doctors milling around and his mother standing by his side.

She'd flown down to Washington while he was still being stabilized in Germany. The doctors initially weren't optimistic. “They thought I'd be fl ying to Germany next,” she recalls. “At that point, they put his chances of living at 5 percent.”

The injuries to Benoit's left side were serious - and easy to see. The wounds to his brain couldn't be detected-even with the help of a brain scan.

That's because much of the damage in a TBI is to individual cells, experts say. And such fine structure doesn't show up on any type of scanning device currently available.

While experts don't fully understand what happens to the brain when a soldier like Benoit gets hurled around in a bomb blast or gets hit by its shockwave, they suspect that the damage is comparable to that suffered by people in a car wreck or infants with shaken-baby syndrome.

Delicate brain structures smash up against the corrugated inside walls of the skull. There's bruising and sometimes outright death of brain cells, explains Douglas H. Smith, M.D., director of the Center for Brain Injury and Repair at the University of Pennsylvania. Beyond this, nerve fibers can be torn by the sudden stretching. “The brain is like Silly Putty,” Dr. Smith says. “It can stretch under normal conditions. But there is damage when the brain undergoes rapid accelerations and decelerations.”

Small rips in nerve fibers can eventually lead to cell death days after the originalinjury, experts say. The cells that don't die may permanently be impaired.

Nerve cell fibers, which act like phone wires to carry information from the body's extremities to the brain and also between various brain structures, have an outer covering called myelin which keeps the signaling quick and crisp. When the nerve fibers are twisted and stretched in a blast, “the protective covering gets stripped away,” explains Keith Cicerone, Ph.D., director of neuropsychology at the JFK-Johnson Rehabilitation Institute in Edison, N.J.

Just as words become unintelligible when a phone line with chewed-up insulation starts to crackle and buzz, the information carried by nerve fibers with damaged myelin can be slowed, disrupted, or distorted.

“If the information isn't being transmitted as quickly,” Dr. Cicerone says, “mental connections are not made and processing speed becomes very slow. There are tremendous repercussions, including memory problems.”

“Think of it in terms of a kitchen sink that's partially clogged. If there's only a little water flowing into the sink, it works fine. But if you turn up the flow of water-or add more information, in the case of the injured brain-then it starts to back up. If there's a lot of water flowing into the sink, it doesn't work at all.”

People with TBI can get overwhelmed and completely shut down if there's too much happening at the same time. Often, when there are multiple conversations going on, it may be impossible to focus on any one. Patients become fatigued by routine mental activities. They can't get as much done during the day as they did before the injury.

And, because the specific parts of the brain damaged in a TBI-the frontal lobes-are needed for higher-level thought processes, just about everything, from behavior to problem solving, is affected. “The frontal lobes are involved in what is called executive function: the ability to reason, to initiate, to plan, and to organize,” says Mel Glenn, M.D, director of outpatient and community brain injury rehabilitation at Spaulding Rehabilitation Hospitalin Boston. “This part of the brain also is what allows you to look at yourself from an outsider's point of view, and to monitor yourself.”

In the vast physical therapy room at Walter Reed, James Benoit moves from the parallel bars to a stationary bike while a fellow soldier tosses a ball back to his therapist and another soldier is having his ankle fl exed on a bed. Later, Benoit will go for a different kind of therapy, one designed to help rewire brain connections that were shorted out by the blast-and to develop strategies for coping with damage that can't be repaired.

Brain connections formed over a lifetime are severed when neurons die after a TBI, experts say. Some of these circuits can be rewired with the right kinds of therapy; some cannot. And even when new connections are made, the substitute circuitry rarely works as well as the original wiring did. That's because the brain has to wire around the damage, using cells that weren't necessarily designed to do the job.

“It's a teaching process,” Dr. Glenn says. “Just as an amputee might learn to walk in a different way using a prosthesis, you can teach people to do things again by force of habit. Sometimes they end up doing it in a different way and sometimes it's in a similar way.”

Figure. Causes of TB...
Figure. Causes of TB...
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Some of this mental rewiring is accomplished through repetition, Dr. Cicerone says. This allows you to recruit neurons that aren't damaged. For friends and family, the hardest adjustment can be to changes in personality and behavior. When the frontal lobes are damaged, social skills learned over a lifetime are lost. TBI patients often don't see subtle facial cues or pick up on body language. They sometimes will blurt out any thought that comes to mind.

The process of getting these mental abilities back is almost like growing up all over again, experts say. “I often tell families it's sort of like having an adolescent,” says Carla Alexis, a therapist who works with brain-injured patients at Walter Reed. “We're trying to get them to understand their mortality mortality again so they do things a little safer. We're getting them to pay attention, to listen and not get distracted. We're getting them to respect other people.”

Often the therapy involves getting patients to stop and to think out loud about things that were once almost refl ex. “We try to get them to say things in their own words-why something might not be safe, for example,” Alexis says. “We try to get them to self-censor. The difference here, of course, is that they have to learn not only society's norms, but also military standards. Yes, in society we can do X, Y, and Z, but that's not permissible in the military.”

Figure. TRAUMATIC ST...
Figure. TRAUMATIC ST...
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And, while it might at first seem that having to learn yet another set of social rules would complicate a soldier's rehabilitation, it probably makes the journey a bit easier, Alexis says. That's because the Army provides much-needed structure and because therapists can use soldiers' ranks to help them reconnect with the identity they had before the injury.

“Think about how structured the military is,” Alexis says. “It's repetitive, controlled. Everything is based on your rank. I had a soldier who said to me one day, ‘Don't call me sir. I'm a Specialist, not a sir.’ As profoundly injured as he was, he said, ‘I am a Specialist.’ Because of that, I could say, ‘specialist, stand up straight,’ and he would. As much of a fog as they can be in, I can say ‘specialist’ or ‘Corporal’ or ‘sergeant’ and then tell them what I need them to do. And those ingrained patterns will pull them along.”

Ultimately, both the family and the TBI patient need to recognize that there might be some permanent changes.

Therapy can only bring people back so far, Dr. Cicerone says. “We're not looking to make you who you were-but who you are now, the person you've already become.”

For some soldiers, that may be enough.

As a result of the bomb blast, James Benoit's life has changed in ways nobody could have predicted. When his mother learned he was injured, she contacted all of his hometown friends, including a woman who started visiting Benoit regularly at Walter Reed. The two grew close. In the fall, the couple will be getting married. “It's kind of odd,” Benoit says. “In the end, a lot of good came out of it.”

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ON THE HOME FRONT

5.3 MILLION Americans are currently disabled by traumatic brain injury

1.5 MILLION Americans suffer a traumatic brain injury each year

80,000 Americans sustain long-term disability from TBI each year

EVERY 21 SECONDS, someone in the U.S. suffers a traumatic brain injury

©2006 American Academy of Neurology

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