At the time, to someone my age, these numbers were just numbers. As I got older, I came to understand the magnitude of what I had witnessed, and when I became a student of neuroscience, and in particular, brain injury research, I came to realize the lingering costs of the war in human suffering and the lack of attention given to those who served so honorably there.

Most of the brain injuries sustained in Vietnam were visible, primarily caused by bullets and shrapnel. Veterans with injuries to certain areas of the brain were found to have much more severe neurobehavioral problems than those with other types of brain injuries. These neurobehavioral problems, largely ignored by our government, led to high rates of unemployment, divorce and homelessness. We are now facing a new influx of head-injured soldiers from Iraq and Afghanistan. Thanks largely to the protective benefits of body armor, traumatic brain injury has emerged as the "signature wound" of these wars. But unlike brain injuries typical in the Vietnam conflict, much of the damage in the contemporary combat is the result of improvised explosive devices that produce blast-induced traumatic brain injury, often without any visible scars. But inside the brain, it's a different story.

Some soldiers with traumatic brain injury have symptoms that are hard to distinguish from other mental conditions such as depression and post-traumatic stress disorder. Scientific research on soldiers with blast-related traumatic brain injury indicate that many have damage to the same brain areas as Vietnam veterans with neurobehavioral problems. However, the total number of soldiers suffering brain injuries in the current conflicts appears to exceed the numbers from previous wars.

According to Bob Bazell of NBC News: "Brain injuries — thousands of them — could be the legacy of this war just as much as post-traumatic stress and problems from exposure to Agent Orange persisted among many of the troops who served in Vietnam."

At least 18,000 troops have been wounded in Iraq or Afghanistan to date. Some reports suggest that up to 60 percent of those casualties (as many as 10,000) involve some degree of brain injury. These figures do not include civilian contractors or members of the news media who have suffered brain injuries.

There are signs our government is heading down the same road it followed during the Vietnam War — denying the magnitude of the brain injury problem and thereby depriving soldiers the treatment they need.

Until now, the Defense and Veteran Brain Injury Centers program has taken the lead in collecting information on how many soldiers have suffered TBI and how severely have they been injured. The centers have accomplished this on a shoestring budget of $14 million per year spread out over seven centers. This program helps returning soldiers, their families and our government understand the implications of TBIs and their future impact on soldiers' lives, and facilitates the rehabilitation of these casualties.

To deal with the influx of brain-injured soldiers returning from combat, these centers requested that their 2007 fiscal year budget be increased from $14 million to $19 million, a paltry sum compared to the billions a month we are spending on the wars. Instead of granting the requested increase, the budget proposed by President Bush and rubber-stamped by both houses of congress eliminates the program.

Citizens of this country should demand answers to these questions:

• Why does the White House want to kill this program, and why is Congress going along?

• Are Bush administration officials embarrassed by the numbers of brain-injured soldiers returning from Iraq and Afghanistan?

• Do they believe that if data collection is stopped, the problem will vanish?

• What will happen to brain-injured troops when they no longer have access to these services?

Military discipline prohibits our troops from speaking for themselves. We must speak for them.

Call, write or e-mail your U.S. senators and representatives. Tell them you are outraged by the decision to eliminate the Defense and Veteran Brain Injury Centers from the 2007 fiscal year budget. Those who repeatedly admonish us to "support our troops" should be willing to do so themselves.

Stuart Hoffman is an assistant professor of emergency medicine at Emory University and a brain injury researcher. He does not receive funding from the Defense and Veteran Brain Injury Centers program.