The American Journal of Sports Medicine tracked the concussion rate for athletes in 25 high schools from 1997 to 2008 per 1,000 exposures (games or practices).

Dave Duerson graduated from the University of Notre Dame with a degree in economics. He then became a Pro Bowl safety in the National Football League. After retiring from the NFL, he took several McDonald's franchises and a food business from $24 million to $63 million in revenue in six short years. In 2011, at age 50, he died from a self-inflicted gunshot wound to the chest. He avoided shooting himself in the head so that his brain could be studied for a link between mild TBI and early-onset dementia. That was apparently his reason for taking his life – his brain just wasn’t able to do what it used to do. Boston University researchers subsequently confirmed his suspicions. His brain showed signs of a neurodegenerative disorder linked to concussions. As an NFL player, Duerson was subjected to numerous violent blows to the head. According to a massive study involving older NFL veterans, even a single mild TBI can more than double the risk of early-onset dementia like Alzheimer’s.

The Science

Neurons, or nerve cells, are like long spaghetti strands with a cell body on one end. When a head is struck a violent blow, the skull often rotates, with the brain following suit and rotating inside the skull. This rotation can stretch the axons (the spaghetti strands) of your brain’s nerve cells. This damage opens up molecular channels on the surface of the axon that transport sodium and calcium ions, and those ions flow into the interior of the axons themselves – creating a tidal wave of electrical activity. The brain reacts by pumping ions back out as fast as possible, rapidly depleting its store of energy. Exhaustion sets in and can leave a person lethargic and without energy for days. Like a computer, the brain must almost reboot before it can function normally again. Inside the axons, microtubules can break when stretched. Like a broken train track, molecular cargo can pile up rapidly. This cargo contains proteins that when broken down can form amyloid plaques. Sound familiar? They are commonly found as precursors to Alzheimer’s or other forms of degenerative brain disease.

On a more positive note, a new form of medical imaging makes it possible for doctors and scientists to see these changes where previous technologies did not reveal them. Diffusion Tensor Imaging (DTI) tracks the flow of water molecules down the length of the brain’s axons. If these molecules are seen to be moving laterally, an injury to the microtubules may have occurred. Being able to diagnose or gauge the severity of a mild TBI may aid greatly in establishing the course of treatment for individual patients.

The Skinny

People have been getting hit in the head for thousands of years. With contact sports, motor vehicle travel and life in general, this trend will likely continue. With increased awareness, however, great strides in prevention and treatment can take place. More and more schools are crafting practice techniques to reduce the risk of serious head injuries. Perhaps even more important, protocols are being adopted to deal with athletes who do suffer a mild TBI. Baseline tests can be administered at the beginning of a season to serve as a comparison for post-injury mental function. Players not showing a return to their baseline can be required to sit out until they’ve sufficiently healed.

In 2006, Zackery Lystedt went back out on the football field after suffering a concussion earlier in the game. After being struck in the head again, Zackery collapsed with what proved to be a debilitating brain injury. In 2009, his home state of Washington passed the Lystedt Law. This legislation requires annual mandatory training for athletes, parents and coaches. It also requires the immediate removal from sporting events of any athlete suspected of having suffered a concussion, until such time as a medical professional clears them to return. Since Washington took action, 34 additional states have followed suit.

Awareness is the key. Know the signs (review here) and don’t delay seeking medical attention. And while not everyone plays football, almost twice as many emergency room visits result from bicycling accidents. Automobile crashes account for many times more. The brain is an amazing organ. It is both durable and fragile at the same time. It contains the keys to our functioning, our personality and our identity. Guard yours well, and those of your children.