The government is more than quadrupling monthly payments to some veterans suffering brain injuries, as the number of such war wounds mounts in Iraq and Afghanistan.

The new compensation is based on the assessment that even some troops who have the mildest form of traumatic brain injury could end up with chronic headaches, memory loss, anxiety or other symptoms that will hurt their chances of getting a job or job advancement -- thus reducing their lifetime earnings by 40 percent.

In a regulation announced Tuesday by the Department of Veterans Affairs, officials changed how they evaluate injuries. They now judge a person to be 40 percent disabled in such cases rather than 10 percent. The lower rating was set by a 1961 regulation. The change means that an unmarried veteran who now receives $117 in monthly compensation could receive up to $512. Troops with spouses and children would also get more money.

Mild traumatic brain injury is basically a form of concussion that results from severe shaking of the brain after a blast. It can cause blurred vision, irritability and other problems.

The change takes effect in 30 days, and those receiving compensation under the old system can have their cases reviewed.

Roughly 1.7 million American troops have served in Iraq and Afghanistan, and a RAND Corp. study estimated early this year that up to 320,000 may have suffered a traumatic brain injury.