Our brains are extremely vulnerable. This is the message Linda Carroll and David Rosner want to get across in their book, “The Concussion Crisis: Anatomy of a Silent Epidemic.”

In recent years, stories started to surface about football players suffering lasting brain damage from multiple concussions, Carroll says.

Dr. Bill Meehan, Director of the Sports Concussion Clinic and Director of Brain Injury Research at Children’s Hospital Boston, defines a concussion as a “trauma-induced brain dysfunction.” When a person suffers a concussion, there is no structural damage to the brain and no bruising, bleeding or swelling. The problem is the functionality of the brain.

“You can’t see a concussion,” he explains. “You diagnose it by history and physical examination.”

According to the book, children’s brains are far more vulnerable than those of adults because their brains have not yet finished developing. Young athletes are also more susceptible to second-impact syndrome, which is when they sustain a jolt after they’ve suffered a concussion that was not treated properly. While rare, this could lead to a lifelong disability and even death.

If concussion symptoms are noticeable (see sidebar), Dr. Meehan says the athlete should be pulled from a game immediately — even if he or she is used to playing through pain and injury. If proper treatment is administered, a full recovery is expected; but in the worst-case scenario, he says, an untreated concussion can lead to catastrophic brain injury. Other long-term problems include issues with memory, reaction time, depression and anxiety.

When a concussion occurs, activities that require concentration, like schoolwork and video games, should come to a halt. Dr. Meehan also recommends discontinuing working out and lifting weights.

Though Dr. Meehan says there’s been an increase in diagnoses, thankfully this is a problem that “in a large part, people are more aware [of].”

Adds Carroll: “We’d like people to take concussions much more seriously and to make sports as safe as possible.”