After a decade of war, America is well schooled on post-traumatic stress, lost limbs and traumatic brain injury, but the most common injury sustained by U.S. troops is literally a silent wound: hearing loss.

Mark Brogan, a retired Army captain, can speak quite personally about almost all of those examples of combat carnage – he suffered a brain injury, a spinal injury and a nearly severed right arm when a suicide bomber on foot detonated his weapon near Brogan six year ago in Iraq.

Mark Brogan sustained a spinal injury, a brain injury, a nearly severed arm – and severe hearing loss – when a suicide bomber blew himself up not far from Brogan in Iraq six years ago.

What does Brogan, 32, consider the worst of the physical trauma? “Hearing loss and the brain injury,” he said from his home in Knoxville, Tenn. He has “profound unusable hearing” in his right ear and severe hearing loss in his left, he said, along with constant ringing, or tinnitus, in his ears.

After the insurgent’s bomb killed a soldier just behind Brogan – along with the person who was wearing the device – other U.S. troops quickly rushed Brogan’s side and saw blood streaming from both ears, he said.

“You’ve been to a concert – you know how your ears are ringing afterward? It’s just like that my entire life,” Brogan said. “A lot of guys get home and they probably don’t even think about getting their hearing checked.

According the Department of Veterans Affairs, the most prevalent service-connected disabilities for veterans receiving federal compensation in 2011 were tinnitus and hearing loss, respectively, followed by PTSD.

“I suspect today’s generation of veterans – those who have been in a combat environment – probably have a higher severity of hearing loss (than past generations), especially with the explosions and the IEDs and the ruptured ear drums they’ve sustained,” said Brett Buchanan, a VA-accredited claims agent with Allsup, a national provider of services with disabilities.

Allsup recently organized a one-day Web expo where younger veterans had a chance to log in and seek advice on how and where to get treatment — including a primer on how to successfully access and steer through the monolithic VA system.

While chatting online with dozens of veterans, Buchanan repeatedly was told about their hearing loss, he said.

To Buchanan, a former Army artillery officer who was among the first wave of U.S. troops to invade Iraq in 2003, the massive scope of the disability is simple to grasp.

“The military, in general, is just a high noise-producing environment,” Buchanan said. In the Navy, where most sailors work only below deck, there is ” the constant drumming of the engines and metal-on-metal noise.”

And in the Army and Marines, many personnel, he added, spend hours inside “military vehicles that are not quiet,” including tanks and personnel carriers.

In addition, service members typically devote time to practicing at firing ranges.

“In those cases, hearing protection negates the loud noise to a large degree. But when you’re in these environments for years upon years, that negation you do with hearing protection may not be enough to prevent injury long term,” Buchanan said.

“Then you get into the combat environment where weapons are going off, explosions are going off. In combat, you can’t call time out and say, ‘Hey, I need to put in my earplugs.’ ”

Service-related injuries in veterans are assessed and rated by VA doctors to determine how much monthly compensation those veterans will be paid for their physical sacrifices. Those ratings span scores of 0 to 100 depending on the severity of the wounds. (Brogan, who due to the partial spinal injury has weakness on his right side and a lack of sensation on his left side – but no paralysis – is classified as 100 percent disabled by the VA, he said).

Through earphone-tone exams and other diagnostic means, the VA also rates hearing loss and tinnitus in veterans who come in for checkups.

“For hearing loss, the ratings I usually deal with for my clients are 0 percent, meaning they’ve had some hearing loss but it doesn’t quite meet the criteria to get the minimum VA disability rating, which is 10 percent,” Buchanan said. “Tinnitus is a simple 10 percent rating. There’s nothing above that. My tinnitus might be worse than yours but there’s no test for that.

For Brogan, post-military life has included mastering subtle tricks and new technology to adapt to his muffled hearing. For example, his phone transcribes conversations as they take place. “And in a loud restaurant with background noise, I pretty much can’t understand anybody’s voice,” Brogan said. “I have to tell somebody, ‘Hey, can you repeat that? Can you speak slower so that I can understand you?’ There are techniques, over time, that you learn.”

But his world is not devoid of pretty sounds. At age 5, he learned the piano. Six years after a bomb bloodied the insides of his ears, someone donated a new piano to the veteran. Brogan tickles those black-and-white keys as physical therapy for his brain and for the weakness in his right hand. He’s mastering covers of popular tunes. And he’s even composed his own melody, captured on video.

Finally, he’s making music again.