On July 4, which commemorates the birth of this nation, it is essential to help those who have been wounded in the service for this country. Today we take a look at traumatic brain injury, which has devastated many soldiers returning from Iraq and Afghanistan, as well as their families. Click here to find out how you can help.

John, a 23-year-old Marine corporal, recently returned from duty in Iraq shaken but intact--he did not lose any body parts. He did, however, live through a few explosions from improvised explosive devices (IEDs). Regardless, his wife is happy to have John home and in one piece. 

John, however, is not the same person he was before his service in Iraq. He sometimes forgets simple tasks, such as how to make a sandwich. He's more irritable and has been quick to fight with friends who annoy him. He also has a short temper with his wife. He is not violent, but he is angry and withdrawn.

For the purpose of this article, John is not an actual person. The stories, however, are real, and they are common among veterans of the wars in Iraq and Afghanistan. Many suffer from traumatic brain injury (TBI) but don't know it.

TBI sounds severe, but the toughest cases to diagnose are those that are mild. Whether or not IED explosions cause visible signs of bodily harm, they send waves of energy through the air. TBI happens when the energy from an IED explosion is absorbed by the body, enters the brain and causes cellular damage that is often undetectable.

The wars in Iraq and Afghanistan are unique in that the enemy uses IEDs more than it ever has before. IEDs account for almost 80 percent of all wounds to U.S. troops, and the Department of Veterans Affairs (VA) says troops have been exposed to anywhere from six to 25 bomb blasts during their time in combat, reports USA Today.

"Some people are calling TBI the agent orange of Operations Enduring Freedom [Afghanistan] and Iraqi Freedom [Iraq]," says Lisa Jaycox, senior behavioral scientist with RAND Corporation, a nonpartisan public-research institution.

RAND conducted a study, "Invisible Wounds of War," of TBI, post-traumatic stress disorder (PTSD) and the frequency of soldiers seeking treatment. According to the study, nearly 20 percent, or 300,000 soldiers, who have returned from Iraq and Afghanistan report symptoms of PTSD or major depression, and 19 percent report being exposed to a blast that could have caused a TBI. Of the returning troops who met the criteria for TBI, 57 percent had not been evaluated by a physician for a brain injury.

"It's very easy for a service member to relate in some visceral way to a lost leg--that's a real problem you can see," says Commander Martin Holland of the U.S. Navy medical corps. "But there's mystery and misunderstanding and reticence to accept a brain injury as a real issue. The classic approach is to shake it off and say, 'You just got your bell rung.'" Holland is a staff neurosurgeon and director of the TBI program at the Naval Medical Center in San Diego.

It appears that TBI will only get worse as the Iraq war--which has resulted in the deaths of more than 4,000 troops--rages on. Compounding the problem of diagnosis is the fact that many soldiers fear that revealing a psychological issue will cause them to lose their jobs. Beyond that, too often, people who volunteer for military service are people from the nation's poorer communities, who are not accustomed to regular doctor visits, or in the case of underrepresented ethnic groups, may harbor negative perceptions of the medical profession due to historical mistreatment.

"The military is drawing from an all-volunteer [population] and it is largely comprised of minorities and impoverished people ... it's a vulnerable group to begin with," says Jaycox. "TBI can have so many different symptoms, and they overlap with PTSD, such as concentration problems, memory problems, sleep problems--those can go along with [diagnoses of] TBI, PTSD or depression."

Furthermore diagnosing minor TBI remains a problem because there is "no one definition of what it is," says Holland.

So letting military families know the symptoms and that there is treatment is very important. Of the more than 1 million military personnel who have been deployed in Iraq and Afghanistan since 2001, only 300,000 have sought treatment from the VA for any injury, says Jaycox.

And it is not expected that most of the returning soldiers will seek treatment for injuries. After the war in Vietnam, only one-third of returning soldiers sought treatment from the VA.

Early on in the wars in Afghanistan and Iraq, soldiers who sought treatment for injuries were not evaluated for TBI automatically. But that has changed.

"Now there's much more evaluation of people returning from deployment," says Jaycox. "The [Department of Defense] is doing more screening now of anyone documented to have gone through [a blast], and the VA is screening anyone for head injury if they were deployed, no matter what reason they come into VA."

Also, in 2007, Congress authorized $150 million for brain-injury research in an emergency spending bill passed for the Iraq and Afghanistan wars, reports USA Today.

Holland says the media attention has helped. Military family members, who see their returning soldiers struggle to remember tasks such as driving or making a sandwich, or who witness mood swings, are beginning to report to doctors that their veteran is not the same person and needs help.

"Treatment for TBI … is not a pill to make your brain work better," says Holland. Treatment teaches veterans strategies of how to remember simple tasks or calm their nerves.

"Treatment is teaching compensatory strategies … you have difficulty making a sandwich because you can't remember the order. That may seem stupid, but people are having real problems with it. We teach them how to organize their world in such a way so they remember," says Holland.

He adds that for veterans who wear prosthetic limbs, TBI is most disturbing because it could prevent them from remembering how to wear their prosthesis.

"We may not have a good short-term answer, but we're learning a lot of treatment strategies," Holland says.