Dr. Farhad Sahebkar, a pediatric neurologist and director of the Pediatric Concussion Clinic at California Pacific Medical Center in San Francisco, often treats kids and teens with sports-related concussions.

Part of his job is to combat misconceptions about concussions - that someone cannot suffer a concussion if he or she does not lose consciousness, for example, or that helmets prevent serious injury. He also often has the task of convincing patients, and their parents, that they need to wait longer to recover fully before returning to playing sports.

Q: Are kids and teenagers more vulnerable to concussions than adults?

A: There is good evidence that the brain of a developing child or a young teen is much more vulnerable to injury than the brain of an adult. It might have to do with the fact that the brain hasn't fully developed and is biomechanically just different.

The theory that is also out there is that the head of a child is disproportionately bigger than the body - they don't have the support of the neck muscle to keep the head stable.

Q: Why is it dangerous for an athlete to return to playing before he or she recovers fully from a concussion?

A: Second-impact syndrome comes into play when there is a second concussion before full recovery has taken place. I cannot emphasize enough the danger of a second injury before the brain has had a chance to fully recover.

When there is a second injury, the brain doesn't have the ability during this already fragile state ... to adequately respond. That can result in long-term brain injury. Even if the second impact is much weaker than the first impact, there is a disproportionate response because the brain isn't fully recovered.

A second injury can cause short-term memory problems, long-term memory problems, learning difficulties, depression, mood disorders, brain swelling and in the worst-case scenario, brain death.

It's very important to have advocates for these kids who understand the consequences of second injury when they have not recovered from a first injury and who are aware of the long-term neurological problems that result from recurrent concussions.

Q: What are some of the long-term risks of minor traumatic brain injury? Can one concussion lead to future problems?

A: There is a cumulative effect of brain injury, leading to a neurodegenerative condition called chronic traumatic encephalopathy (CTE). It's been a really hot topic in neurology since we now have autopsy findings of brains of athletes who have suffered recurrent concussions.

There are definitely changes - macroscopic and microscopic changes that occur to the brain. It can lead to depression, memory issues and learning issues.

There is not enough evidence to suggest that a single minor traumatic brain injury leads to CTE. CTE is a clinical finding that has been seen in patients exposed to recurrent concussions.

Q: How do you treat and manage patients with concussions? What are the challenges?

A: The management of patients with concussions is really centered on symptom control and letting the brain recover. Rest is very important to allow the brain to recover. Cognitive rest and physical rest are both very important components of the healing process.

There are some Alzheimer's drugs that have been used on a trial basis for treatment of post-concussive symptoms, and commonly prescribed medications to treat patients with post-concussive symptoms are painkillers. If the headaches become chronic and there is some depression, we often use antidepressants as well.

One of the challenges we have in managing patients is that we often rely on patient reporting of symptoms. There aren't really any objective ways to determine the severity of a concussion.