Sport-related concussions once again have hit the headlines. It is estimated that at least 300,000 of them occur every year. Martial artists who do full-contact sparring are certainly at some risk for these injuries.

But are concussions such a big deal?

Medically, a concussion is considered to be a mild traumatic brain injury. It is caused either by some type of blunt trauma – such as a punch or kick- or by forces accelerating or decelerating the brain within the skull. Typically, there is no discernible damage to the structure of the brain, but concussions do temporarily disrupt brain functions. As a result, concussions are diagnosed and graded based on their symptoms rather than by neuroimaging. The severity of concussive injury depends on the nature, duration and extent of disrupted brain functions, not on the shape, size or color of what shows up on a brain scan.

Just because there are no signs of physical damage, doesn’t mean that no harm was done or that the injury isn’t serious. Medical researchers don’t know for sure what happens to the brain during a concussion and what causes the brain functions to be impaired, but it seems to be linked to damage that occurs at a cellular level. When abrupt rotational forces cause the concussion, the risk increases for damaging areas of axons within the brain. This is known as “diffuse axonal injury.” Axons are the pathways that allow neurons to communicate with each other. Disrupt the pathways, and you disrupt the function.

The cumulative effect of repeated concussions is a subject of ongoing medical inquiry.

For many years, the medical literature has reported cases of “pugilistic dementia”, sometimes called “punch drunk syndrome” due to its effect impairing speech, coordination, and cognitive functions. These cases have mostly been reported among professional boxers after about 15 years of competing. The more contemporary term used to describe the phenomenon is “chronic traumatic encephalopathy” (CTE).

CTE has recently been in the news because of claims that it is linked to the deaths of several retired professional athletes, primarily football players. Researchers at Boston University’s School of Medicine have established the Center for the Study of Traumatic Encephalopathy to better understand the problem by examining the brains of affected individuals after their death. By studying the brains directly after death, neurologists can see damage that does not appear on traditional scans. The youngest case they have studied is that of an 18-year-old high school football player who had suffered multiple concussions.

In these brain studies, researchers have found deep structural abnormalities called neurofibrillary tangles caused by the build-up of “tau”, an abnormal and toxic protein. Interestingly, neurofibrillary tangles have also been implicated in Alzheimer’s dementia. Signs of CTE may start with memory problems or disturbances in mood or behavior, such as depression, mood swings, or erratic/impulsive actions. Incidentally, in a survey I conducted of more than 400 combat sports athletes, those who had a history of multiple concussions were much more likely to be seriously depressed than those with no concussive history.

Researchers believe that problems associated with CTE get worse over time. As the protein accumulates, the effects get progressively worse, eventually killing brain cells and; in some cases, ultimately leading to full-blown dementia. Once the build-up occurs, the cell damage may progress and the brain functions may continue to deteriorate even years after the repeated concussions have stopped.

Of course, most people who get concussions – even more than one – do not seem to develop this severe and progressively worsening condition. There seems to be no reliable way right now, though, to distinguish in advance those who will from those who won’t. The risk of concussions is not unique to martial arts and combative sports – there is a larger number that occurs from football-related injuries. But those who train or compete in full-contact martial arts should be aware that sustaining repeated concussions – at least in some cases – can have serious consequences. Any single impact may seem like an insignificant “ding”, but the cumulative effects, particularly over the years, can be troubling.

If you train or compete in full-contact sports, there are a few things you can do to educate yourself and mitigate your risk.

First, learn to recognize the signs of concussive injury. Sometimes people think if there’s no loss of consciousness or memory, there’s no problem. That’s not necessarily true. While loss of consciousness and amnesia (memory loss) are often related to the severity of the injury, neither is a necessary condition to diagnose concussion, and neither is a good isolated marker of its effects. Experts suggest that symptoms – and possibly cognitive and postural testing – be assessed and monitored at the time of the event and afterward. Common signs at the time include confusion, feeling “foggy”, clumsy or uncoordinated movement, dizziness, balance problems, headache, nausea, and vision problems. If you are with someone who may have had a concussive injury, you can ask a couple of simple questions. Check whether they know where they are and what day it is, whether they remember the hit and what preceded it, whether they can remember new words you give to them and repeat a series of two or three numbers backward. These questions don’t provide a diagnosis. That’s not what you’re trying to accomplish. But failing these basic tasks could suggest the person has sustained some injury – however minor – and at least should sit out the day and perhaps consult his or her healthcare professional.

Second, after sustaining a concussion, give your brain plenty of time to recover. It is tempting for some fighters to try to tough it out and go immediately back to trading blows, but getting a second concussion while the brain is still recovering from the first can seriously compound the severity and damage. Studies have shown that, on average, it takes approximately seven days for athletes to fully recover from symptoms of a concussion. At a minimum, the National Athletic Trainers’ Association recommends that athletes who experience a head injury resulting in loss of consciousness or amnesia should refrain from participating on the day of the injury and that management should be more conservative for athletes who have a history of prior concussions.

You can find additional information about sport-related concussions from the Centers for Disease Control and Prevention (www.cdc.gov/ncipc/tbi/) or the University of Pittsburgh Medical Center (sportsmedicine.upmc.com/ConcussionProgram.html).