The report by the Institute of Medicine said brain injuries "sustained as a result of exposure to the force of an explosion without a direct strike to the head" may be underdiagnosed due to the lack of research on blast injury.

"Explosive devices and other weaponry have become more powerful and devastating throughout the wars in Iraq and Afghanistan, and we are seeing much higher rates of (non-penetrating) traumatic brain injury and blast-induced injury among military personnel who have served in these countries than in earlier wars," lead author George W. Rutherford, professor of epidemiology and preventive medicine at the University of California, San Francisco, said Thursday in a release.

The report said studies link both moderate and severe traumatic brain injury with increased risk for Alzheimer's-like dementia and symptoms similar to Parkinson's disease.

Rutherford's group recommends the U.S. Defense Department conduct pre-deployment neurocognitive tests of all military personnel to establish a baseline for identifying post-injury consequences.