WASHINGTON  Pentagon officials estimated for the first time Wednesday that up to 360,000 Iraq and Afghanistan veterans may have suffered brain injuries. Among them are 45,000 to 90,000 veterans whose symptoms persist and warrant specialized care.

Army Brig. Gen. Loree Sutton provided the estimate during a news conference about March as Brain Injury Awareness Month. She heads the Pentagon's Centers of Excellence for Psychological Health and Traumatic Brain Injury.

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Pentagon officials have been reluctant to estimate the number of potential brain-injury casualties among the 1.8 million troops who have served in Iraq and Afghanistan.

Sutton based her estimate upon military health-screening programs showing that 10% to 20% of returning troops have suffered at least a mild concussion. Among them are 3% to 5% with persistent symptoms that require specialists such as an ophthalmologist to deal with vision problems.

Sutton's estimate is similar to a RAND Corp. study last year that said 320,000 may have suffered a brain injury. Following direction from Congress, the U.S. military began to screen all troops returning from the war zones for brain injury last year.

Persistent symptoms can range from headaches and sleep disorders to memory, balance and vision difficulties, said Lt. Col. Lynne Lowe, the Army's program manager for traumatic brain injury.

Research suggests the vast majority of these troops recover, said James Kelly, director of the National Intrepid Center of Excellence, a Pentagon treatment center for traumatic brain injury and psychological health.

Kelly said scientists are trying to understand the severity and extent of brain injury caused by exposure to a blast. Many of the wounded in Iraq and Afghanistan were hurt by roadside bombs.

The science is so new that it remains unclear whether symptoms attributed to brain injury are actually the result of post-traumatic stress disorder caused by the same combat incident — a roadside bomb blast, for example — that caused the brain injury, Lowe said.

The Pentagon's official figure for U.S. military war casualties of all kinds in Iraq and Afghanistan is about 33,000.

Sutton said at least 9,100 troops have been diagnosed with brain injuries since the war began.

The Department of Veterans Affairs reports that it has treated about 8,000 former servicemembers for brain injury after their return from Iraq and Afghanistan.

The rest of those who may require care have problems that can be treated by a family physician — issues such as headaches and sleep disorders, Kelly said. "It's not unusually complicated care."

Hotline phone numbers available for troops concerned about symptoms that might be related to a brain injury are, at the Centers of Excellence, 866-966-1020; and at the Defense and Veterans Brain Injury Center, 800-870-9244.