Traumatic brain injury (TBI) is an impact to the head that causes a disruption of brain function. The severity of symptoms can range from a temporary change in alertness to loss of consciousness.

The Centers for Disease Control and Prevention estimates each year 1.4 million Americans experience a TBI. Of those, 1.1 million are treated in a hospital emergency room, 235,000 are hospitalized and 50,000 die. Males are 1.5 times more likely than females to experience a TBI. The highest rates of incidence are among young children (four and under) and those 15 to 19.

The most common cause of TBI is falls (accounting for about 28 percent of all cases). Other leading causes include motor vehicle accidents (20 percent of cases), being struck by or against an object (19 percent) and assaults (11 percent).

A TBI can have a wide range of consequences. It can affect thinking and memory, speech and understanding, sensation and emotion. About 5.3 million Americans have some degree of disability from a TBI and need help performing daily activities.

Protecting the Brain

Head trauma can cause swelling in the brain. As brain cells die, they release toxic chemicals that can further damage the brain. Doctors have been looking at ways to protect the brain after a serious head injury and prevent the serious cascade of continued damage. One of the treatments under study is use of the hormone, progesterone.

In laboratory studies, researchers found female animals tended to recover better than male animals from traumatic brain injury. However, the degree of recovery in females appeared to be dependent upon the phase of the animal's equivalent to a menstrual cycle. Outcomes were much better when the female animals had higher levels of progesterone. So, investigators gave a trial of progesterone to animals after a brain injury to measure response. The preliminary research found those animals who received progesterone have better behavioral and functional outcomes.

Doctors at Emory School of Medicine have recently completed a trial of progesterone for human patients with a new TBI. The subjects were randomized to receive either intravenous progesterone or a placebo, and then observed for outcome and signs of recovery. Participants also received a neurological exam 30 days after the injury.

Researchers found patients who got the progesterone had a much lower 30-day mortality rate compared to those who received a placebo. As for functional outcome - there was little difference between the two groups for patients with severe TBI. However, the drug did make a difference in those with moderate TBI, who had a better functional outcome than those who received placebo.

Donald Stein, Ph.D., Neurobiologist says progesterone appears to help by reducing swelling in the brain. It also stops the cascade of toxic build-up and helps stimulate the growth and repair of proteins needed to rebuild vital circuitry in the brain that enables nerve cells to communicate.

For general information about traumatic brain injury:

Brain Injury Association of America

Centers for Disease Control and Prevention

National Institute of Neurological Disorders and Stroke