For combat vets, the Veterans Administration has a tough message. To get a diagnosis of traumatic brain injury (TBI), it takes more than just having your bell rung by a roadside bomb in Iraq and Afghanistan. For the docs in the VA, the bell has to be still ringing.

That’s a very different standard than employed by the Department of Defense.  Between 2000 and 2012, the DoD diagnosed five times more of its soldiers with TBI than the VA did. And even the DoD figures fall short of what the Rand Report had predicted five years ago.

In 2008, the Rand Corp. did an independent survey of 1,965 service members and veterans. Due primarily to the prevalence of roadside bombs (improvised explosive devices, or IEDs), it estimated that 19 percent of the 1.6 million soldiers serving in Iraq and Afghanistan – about 320,000 soldiers – would come home with possible TBIs.

But the conflict lasted longer than Rand had expected, and more than 2.4 million service members have cycled through Iraq and Afghanistan. According to the Defense and Veterans Brain Injury Center, 266,810 soldiers were diagnosed with TBI from 2000-12.

By comparison, the VA has only diagnosed about 54,000 Iraqi/Afghan vets with TBI.

So what’s been happening here? Did most of the soldiers who had had their bells rung by bombs suddenly get better after they left the service?

Actually, that’s pretty much what the VA says.

According to Dr. David Cifu, national director of the VA’s Physical Medicine and Rehabilitation Services, about 55 percent of the soldiers returning from Iraq and Afghanistan, some 700,000 vets, have sought VA health care, and 7.8 percent of them – about 54,000 vets — have been diagnosed with TBI. By comparison, the VA had diagnosed 834,000 Iraqi/Afghan vets with PTSD as of last year, which is more than the Rand Report projections.

Cifu told me that in 2007, a four-question screening exam was devised to determine the existence of a traumatic brain injury. Administered in person by 108 TBI screening teams, the assessment was also presented to those who had previously complained of possible TBI systems. It found that about 20 percent of the returning vets had a possible injury and about 40 percent of them tested positive, i.e. about 8 percent of the total.

All vets who have suffered an alteration of consciousness in combat remain in a registry, Cifu said, but only those who have experienced 17 to 21 symptoms lasting three months or longer are offered treatment if they wish it. Without symptoms, he said, there’s no need for treatment.

Note that this 8 percent is only of the 55 percent in the VA system; another 45 percent chooses not to participate in the VA system or opts for private care. The Center for Investigative Reporting also said that 900,000 vets have filed claims and are waiting for the VA to process them, a number that could grow to 1 million by the end of this month.

But Cifu told me that his TBI assessment teams have interviewed 99 percent of the vets in the VA system who have claimed head injuries and only this small 7.8 percent continue to experience persistent symptoms.

That begins to make sense, though, after taking a closer look at the DoD’s TBI numbers. More than 82 percent of the TBIs are classified as mild, which is defined as “a confused or disoriented state which lasts less than 24 hours; loss of consciousness for up to 30 minutes; memory loss lasting less than 24 hours; and structural brain imaging (MRI or CT scan) yielding normal results.” And the majority of them were everyday concussions from workplace or home accidents, not the result of battlefield injuries.

In fact, only 28,700 active-duty soldiers were diagnosed with moderate, severe or penetrating TBIs in that period.

On another topic, Cifu is skeptical of preliminary studies at Boston University and the Boston VA Healthcare System that have concluded that brain injuries may result in degenerative brain disorders, known as chronic traumatic encephalopathy (CTE).

“Time-release brain degeneration following minor head trauma is not scientifically proven,” said Cifu, noting that CTE is rare, it may have many cause, and it appears to be associated with multiple injuries, moderate to severe injuries, and concomitant psychological factors – but any association with an isolated, single concussion has not been proven scientifically in longitudinal studies.

“Typically, it only occurs in people who have had multiple injuries and conditions, and particularly those with initial injury that is at least moderately severe,” he added.

Before jumping to conclusions, “I would wait until the real research has been done,” he said. “Telling someone that they had a brain injury five years ago or five minutes ago that may in some way cause their brain to eventually decline isn’t particularly helpful to a patient, other than causing anxiety. Since we don’t have any longitudinal studies that follow patients for anything longer than six months, we don’t really understand this phenomenon.

“We certainly can educate patients that there may be a risk, just as there may be a risk from smoking, drinking, high cholesterol, high blood pressure, but these are all better defined risks and ones we have a specific treatment (or prevention) for. There may also be a genetic risk of trauma related degenerative brain disease and those with an elevated risk should also manage all their other potential risks closely. So while it’s important to be aware of the emerging literature and research from sports and military injury, there are no clear conclusions that have been reached and more importantly, no meaningful advice to offer someone who’s had a brain injury other than to avoid future activities that may cause another one and to optimize their overall health (as you would with any patient).

“This information should be conveyed clearly to patients in a way to encourages them to work hard to enhance their physical and emotional wellness rather than scaring them with some vague fear of inevitable neurodegeneration. I’d rather empower them by saying if you follow your exercise program, eat well, don’t smoke, drink in moderation, see a primary care clinician regularly, utilize relaxation strategies, do things that encourage your productivity and your intellectual stimulation, be part of social groups, have family time, then you are doing everything possible to prevent, lower the risk or reduce the speed of degenerative processes of the brain that may occur. I’d rather give the patient control and give them choices rather than just plant the seed that they’re going to get dementia.

“The key take away point is that there really is no rigorous evidence — zero — in any study that a single concussion can lead to CTE or any cognitive decline,” Cifu said.

“JP brings me peace,” says Bill Austin, a retired warrior whose memories have tended to be less than peaceful.

After three decades of serving as a medic and/or a radio operator in places like Bosnia, Kosovo, Iraq and Afghanistan (twice), this retired master sergeant remembers things like loading a guy who’d been blown up twice in five minutes onto a stretcher and not recognizing one of his best friends until the body on the stretcher suddenly said, “Hey mate.”

“And I said, ‘Mark, is that you?’ Later that day I went back to see him, and the bed was empty; I was afraid he’d died,” says Austin. “Later, I found out they medivacced him out, but I remember going back to see a lot of other guys that I’d helped, only to be told they died of their wounds.”

After retiring from the National Guard with a 100 percent diagnosis of post-traumatic stress disorder (PTSD), Austin found it hard to turn off the mindset that had kept him alive as he dealt with the carnage from the killing fields: the burns, broken bodies, shattered limbs and multiple amputations that regularly confront medics.

“He’s hyper-vigilant,” says his wife, Janet Austin. “He has to sit with his back to the wall, and he doesn’t like to be in crowded spaces. If someone comes up behind him, he turns in a protective posture to see what you’re up to.”

But peace came in the form of a 2-year-old Great Dane named JP, a 150-pound service dog with a harness that says “PTSD – not all disabilities are visible.”

JP pulls Austin out of their house near the Mission Mountains of Montana for regular walks, and people generally stop to talk about the unusual-looking dog.  “He’s a natural ice-breaker,” Janet says. “When someone’s coming toward Bill, he steps between them to provide a safety zone. And when someone’s coming up behind him, he provides advanced warning that someone’s there.”

JP even knows when Austin is having nightmares, says Janet, and he’ll wake Austin out of a troubled sleep by licking his face.

“I’ve had a lot of road rage because there’s too much stimulus and my brain can’t handle it fast enough. It’s sensory overload. But now when I drive, JP puts his head in my lap and I pet him and I hear his gentle breathing and it’s very peaceful,” says Austin.

JP was provided by a breeder in North Carolina, and the Austins trained him themselves as a service dog. They estimate they’ve spent close to $5,000 on him over the first two years. CHAPS (Canines Helping Autism and PTSD Survivors) estimates that a 75-pound service dog will cost at least $4,000 for the first year and more than $2,000 a year thereafter.

Many civic organizations recognize the importance of dogs in stabilizing vets’ mental health. Companions 4 Heroes (C4H) has provided vets with about 150 shelters dogs that would otherwise have been euthanized, says its executive director, Lynne Gartenhaus. “The care and nurturing of an animal brings a veteran to a different place,” she adds. “The animal gives the vet something to think about other than what’s always going through his head.”

But C4H doesn’t train many service dogs. That training can be expensive and difficult, both for the dog and for the vet. “You’re dealing with two very fragile and vulnerable entities,” says Gartenhaus. “It’s really complicated, both for the dog and for the veteran.”

The VA doesn’t provide service dogs either, although it will pay for veterinary care and equipment for some service dogs owned by vets who are blind or who can’t walk. A VA regulation printed last September in the Federal Register does not provide for service dogs to vets suffering from PTSD.

“VA does not cover psychiatric service dogs,” says Janet. “They’ve done studies, but there’s not enough evidence to justify it. They’ll cover seeing-eye dogs and mobility dogs, but not psychiatric service dogs.”

To Janet, however, that evidence was clear on the second day that JP bounded into their lives.  “Janet said, ‘Don’t you get it? This is the first time in two years that you’ve smiled and laughed,’ ” Austin says.

“JP was still a puppy then, and I said, ‘He brings me peace.’ ”