From concussions to severe head trauma that can result in permanent disability or death, brain injuries affect millions of Americans every year. And the prevention of brain injuries has received particular attention in recent months, beginning with the March death of actress Natasha Richardson, who suffered an epidural hematoma (or bleeding of the brain) and fell into an irreversible coma after hitting her head during a seemingly minor ski accident.

Now, the effective treatment of brain injuries and the long-term effects of head trauma suffered by children are the focus of new research at UCLA and a nationally-published study.

Some U.S. troops returning from service in Iraq and Afghanistan are being evaluated for potential effects of traumatic brain injury, testing that provides a post-combat bookend for a Department of Defense policy requiring that soldiers undergo similar brain function testing shortly before their deployment. 

The DoD's pre-deployment brain testing of soldiers, a system that has been in place since 2008, includes "basic math, matching numbers and symbols and identifying patterns to measure response time and accuracy," and more than 150,000 service members across all branches of the armed forces have undergone those tests, according to the Associated Press.

Now the 101st Airborne Division is testing its division members as they return to Fort Campbell, Kentucky after service in the Middle East.

The recent death of actress Natasha Richardson, who suffered a fatal head injury after a seemingly minor skiing accident, has drawn attention to serious head injuries and the role that helmet laws might play in their prevention.

While there is no definitive proof that a helmet would have prevented Richardson's death, there is no doubt that use of a safety helmet can go a long way toward protecting you from severe head injuries. And many states and cities now require use of a helmet for activities like bicycling and motorcycle riding. So, what do you need to know about helmet laws?