The bomb, two large artillery shells buried at the side of the road, exploded just a few feet from the left front of the Stryker.
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The blast along a highway in central Iraq didn't so much as puncture the tires. But it hit the soldiers inside so hard that some couldn't think straight for days. At least two of the men still feel the effects more than two months later.
"The first few days were miserable. I was wearing sunglasses inside my room. My head was just pounding," said Sgt. Brian Kerrigan, who was inside the Stryker at the gunner's station.
His boss, Command Sgt. Maj. Jeffrey Du, was standing in a hatch in the same vehicle, his head and shoulders exposed.
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He wasn't hit by any of the football-sized chunks of asphalt that the bomb sent flying. But the pressure wave rocked him hard enough to inflict a severe concussion.
Later he lost his appetite and had trouble sleeping — problems that persist.
Du and Kerrigan survived that and another explosion in a span of 10 days late last summer. In addition to their concussions, Kerrigan suffered damage to his right arm and other wounds.
They're among hundreds of soldiers from the 3rd Brigade, 2nd Infantry Division — back from 15 months in Iraq — who are dealing with the signature injury of the Iraq War. It's referred to as mild traumatic brain injury, to distinguish it from more-severe cases in which patients must relearn how to walk or talk, or worse.
But there's nothing mild about the way these injuries are inflicted. And the symptoms can profoundly change the lives of soldiers.
They can have persistent headaches, feel restless and tired, be easily frustrated and irritable, and have trouble remembering things or doing more than one task at a time.
All can lead to trouble at work and home, especially when symptoms are compounded by the anxiety, depression and other mental health issues that many soldiers bring home from combat.
Post-traumatic stress disorder and mild traumatic brain injury share some symptoms, but there are differences. Patients with brain injuries alone do not typically suffer nightmares and flashbacks, for example.
"When the brain is injured, the behavior is going to change. Emotions don't appear out of the air," said Kenneth Zych, a Madigan Army Medical Center neuropsychologist who treats returning soldiers.
"The brain is the organ of behavior, and when that organ is injured, you will have results."
New screenings for returning Stryker troops and creation of a traumatic brain injury center at Madigan are among the ways the Army is confronting the challenge of brain injuries.
But Army medical officials acknowledge that their service was slow to recognize and respond to the growing numbers of soldiers at risk for mild traumatic brain injury as insurgent bombs struck with greater power and frequency across Iraq.
Kerrigan, 29, said he's conscious of changes in him. At his home in Frederickson, he's caught himself staring blankly at the TV during a Seahawks game or getting unusually aggravated when his kids — Cian, 6, and Abbey Rose, 5 — leave their toys around or make a racket.
He said he's uncertain how it will work out.
"I can see my arm and know that it's healing. But I can't see my brain," he said. "I think that there's a lot of soldiers who are going to have issues with this later, and it's going to be one of those things where a lot of people are going to push it off: 'He's just faking it, it's not that bad.'
"I really pray and hope people aren't like that, but some of these guys, maybe myself included, are going to come into some of these roadblocks in life."
Blast concussions have been a fact of life for soldiers in Iraq since late 2003, the first year of the war. Because of protective gear and advances in battlefield medicine, soldiers are surviving wounds that in past wars would have killed them.
But only this year did the Army launch specific programs to identify potential mild traumatic brain injury victims and to teach soldiers, leaders and family members to recognize signs of the injury.
Frederick Flynn, a longtime neurologist at Madigan and medical director of the new traumatic brain injury center, noted that the Army has been dealing with soldiers with the injury for a long time — primarily those who suffer moderate to severe cases.
"Anyone would say in hindsight that we could have done better" to respond to the growing numbers, Flynn said. "But we are screening every single soldier who comes back for this specific problem."
The new programs are part of the Army's Medical Action Plan, which arose after reports of problems at Walter Reed Army Medical Center in Washington, D.C. Medics early this year received new guidance for how to assess and treat soldiers who might have concussions.
At Fort Lewis, soldiers returning from Iraq and Afghanistan are required to complete an online questionnaire designed to find those at risk for mild traumatic brain injury. The 3rd Brigade is the first major unit at the post to go through it. Through mid- October, 2,325 of the brigade's 3,800 soldiers had done so. Of those, 1,000 were found to likely have suffered a mild traumatic brain injury and were recommended for secondary screening at Madigan, which consists of more tests of their cognitive abilities and an appointment to talk with a senior physician or psychologist.
Of the 1,000, 205 soldiers have been referred to further treatment.
Flynn said each soldier in the brigade — and especially the hundreds who screened positive for mild traumatic brain injury — will be screened again in three to six months.
Madigan and Fort Lewis have received $1.3 million from the most recent Iraq War supplemental spending bill to create a traumatic brain injury center, and are hiring a staff of about two-dozen neurologists, psychologists, therapists and others. Congress also provided money for similar centers at most major Army posts.
The Government Accountability Office in September said the Pentagon and the VA still face hurdles to improve care, in particular finding professional staff to work on the new initiatives.
At Madigan, officials acknowledge the prospect of being overwhelmed with new patients.
Their guiding principle, they say, is to protect soldiers and families from the effects of unrecognized brain injury and to reassure them. They also teach coping skills — including learning new habits to cover for haphazard memory or taking on a new job that doesn't require tracking many tasks at once.
"We want to leave them with the natural sense that they are going to get better ... we have follow-up," Flynn said. "We're not going to abandon them."
'I need to be out there'
One rule in dealing with concussions is to make sure a person doesn't get another one before the first has had time to heal. It's why high school athletic associations have restrictions against players coming back too soon after head injuries.
On the streets of Iraq, there were plenty of opportunities for 3rd Brigade soldiers to get attacked more than once.
And they generally were reluctant to stand down for long after they'd been hit.
"You had to order guys," said Lt. Col. Barry Huggins, who commanded the brigade's 2nd Battalion, 3rd Infantry Regiment.
In action from Mosul to Baghdad to Najaf, he estimated his battalion of about 770 soldiers and 317 Stryker vehicles got hit at least a dozen times a month with roadside bombs.
"For the most part, guys had to be told 'You will stand down. You will not go off the FOB (forward operating base),' " he said. "They did not want to be seen as shirking."
The brigade's surgeon, Lt. Col. Michael Oshiki, estimates doctors wrote hundreds of one-day to three-day "profiles" for 3rd Brigade soldiers — orders preventing them from going back on patrol. By early 2007, about halfway through their deployment, new procedures required soldiers to be evaluated by medics on their return to the operating base, he said.
Du didn't think he could sit still for long after he was bombed in late August. Du, the top enlisted leader in the brigade, is responsible for the welfare of about 3,800 soldiers.
"The doctor was kind of wary if I should go out or not," said Du, 50. "But they retested me, and I told him — I forced him — I said, 'Hey, I really don't want them to go out without me.'
" 'I need to be out there with the boys,' that's what I told him. He said I was well enough to go out as far as he could see, but he was kind of worried that we'd get hit again, and I'd get a concussion."
Oshiki recalled his advice to Du: "He'll tell you that he should have listened to me when I said, 'Don't go back out.' He took a hit. His brain was still inflamed after the hit he took coming back from Baqouba. He'll tell you straight up. He's told me half-a-dozen times since coming back, 'Doc, I should have listened to you.' "
Du said he hasn't done his post-deployment mild traumatic brain injury screening or visited the Madigan neuropsychologists, but said he will.
'A pretty big hit'
Maj. Brett Clemmer, who was a company commander for the first half of the deployment, figures he "ate" at least three enemy bombs.
"The adrenaline gets pumping. You're a leader, and you're going, 'Are you OK? Am I OK? Are all my people OK? Yes? Then let's find this guy who just tried to kill us and kill him.' "
A veteran of three tours, Clemmer managed to avoid serious injury during the deployment that just ended. And he wouldn't let a head injury keep him down until he fell to the ground.
One day in Mosul, a suicide car bomber hit the Stryker behind him in their three-vehicle convoy. The explosion was devastating.
"It threw me forward and down into the hatch," Clemmer said.
His driver kept moving, but by the time Clemmer picked himself up and looked back, they could see no one was following. So they turned around and went back, where the Stryker that had been bombed was on fire.
As Clemmer's men were pulling out the injured, insurgents opened up with rocket- propelled grenades and small-arms fire. The soldiers loaded the wounded onto the two other Strykers and raced them to the hospital.
That's when Clemmer's adrenaline ran out. Oshiki was a witness.
"I saw these guys when they got back to the (hospital) and this commander had been pushing, pushing, pushing," Oshiki recalled. "He'd taken a pretty big hit.
"He got his guys back all right, then literally dropped to the floor. We ended up hospitalizing him. He got a significant TBI from that but slogged through it."
Clemmer said he had an MRI and spent the night in the hospital, but he was back to his company by 7 the next morning. He went on patrol later that day.
"If it were one of his guys that had experienced that in the field," Oshiki said, "he probably would have made that guy get medevac'd. But because he was the commander, he felt he had to stay there."
Clemmer was called on for further assessment at Madigan shortly after his return home in September. It included some further cognitive tests, and then a chance to talk one on one, behind closed doors, about his experiences in Iraq.
"Fifteen months is a long time, and I got blown up a lot," Clemmer said.
In the weeks before their return, Clemmer said, brigade leaders stressed that everyone should answer the questionnaires candidly — and that there would be no stigma attached to anyone who sought help.
"You never read about the guy who comes home, and he's just fine. You read about the guy who comes home and has problems with his wife, and you don't want to be that guy," Clemmer said.
"There's a lot of stuff I worry about. You hear of guys who can't remember their bank PIN or their family members' names, or you forget to do what you told your wife, pay a bill, pick up something on the way home," Clemmer said. "It spirals into frustration, and you think, 'Something's wrong with me.'
"That's what I worry about. It hasn't happened to me, but that's probably a big concern for a lot of people."
Clemmer, 34, said he was impressed by the program at Madigan.
"It was reassuring to me that we are doing something different this time," he said.
It's too early to tell the extent to which 3rd Brigade soldiers will suffer from mild traumatic brain injury. Many are in that phase where they see any problem at home as minor compared with the life-and-death experiences of Iraq.
But Fort Lewis officials say they know the "honeymoon" feeling can wear off. That's why they have another extensive mental health screening and assessment program required for soldiers after they're home three to six months. At the Kerrigans' home, they're focused on his recovery from wounds to his arm, legs and abdomen.
He's doing physical and occupational therapy at Madigan, and recently returned to work at the brigade headquarters.
He keeps two pieces of shrapnel that surgeons removed from him in a plastic container on the mantel.
Kerrigan is beginning to talk to doctors about his head injury. He said he won't try to tough that out; if he thinks he needs help, he'll ask. Worry about the possible long-term effects of his head injury will wait, but Andrea Kerrigan said she wants to be optimistic.
"There's physical wounds, and there's mental wounds," she said.
"He struggles going to sleep, he struggles being alone. That's difficult because you try to be strong and understand, but it's hard.
"I think we can do this, and we can move forward."
Kerrigan plans to finish his enlistment next spring and then leave the Army for school.
He had planned to pursue a job with a police department but that hinges on whether he regains full arm strength.
He expects he'll become active in veterans affairs. He has mixed feelings about going through the system to seek benefits.
"I don't want to take money from the VA if I'm OK, but then I think, 'Wait a minute, that's what the money is for,' " he said.
"What if 20 years from now I start having headaches again, or start losing my memory, or what if my arm hurts? You want to be sure to cover yourself for you and your family. But at the same time there is a mentality of a soldier: Tough up, heal up and handle it and get back out there, drive on."
He said he's taken the initiative to learn about the potential effects of mild traumatic brain injury.
He counseled a friend who was exposed to blasts just like him but was never diagnosed with a concussion.
"It really is up to the soldier to go out and say, 'I need help,' because the Army is not going to ask you if you need help," Kerrigan said.
"You have to look out for yourself and ask."