10th Issue V2

Athlete’s Tough Attitudes, Soft Brains: Analyzing Head Injuries After Sidney Crosby’s Latest Hit

By Caitlin Clancy • February 27, 2011 at 11:59 pm


After sustaining two major head injuries in only four days, 23 year old Pittsburgh Penguin’s captain Sidney Crosby is prohibited from playing for at least the next month, if not the whole season. The team’s performance has already been suffering from his loss, and fans are anxious to see him recover and play again. Many think, “Well, we see pro-athletes in a number of different sports incur what would appear to be a serious injury, jump right back up and play… in the same game! So what’s the big deal?”

Canadian-born Pittsburgh Penguin's captain Sidney Crosby, who has been rapidly ascending to hockey stardom at only 23-years-old | Photo courtsey of flickruser Darthlen, as a creative commons retouch from Vanluven

It’s a huge deal. Let’s quantify just how large of a deal it is, taking Sidney Crosby’s first blow by David Steckel as an example. Blaine Hoshizaki’s research team at the University of Ottawa created brain injury reconstructions after simulating the conditions surrounding the impact, similar to car crash tests, that revealed almost complete “tissue stress” in Crosby’s left brain hemisphere. A surprise? Not really, when you take into account the direct angle of impact and Steckel’s size, (6-feet 5-inches and 217 pounds) and speed (roughly 17 miles per hour). These findings were presented last week at the first-ever hockey safety summit dedicated exclusively to concussions.  Hoshizaki’s research, among others, on the acute and long-term health repercussions of isolated and repeated head trauma only begins to underscore what has been deemed a “concussion epidemic” in professional contact sports.

Extending these results to evaluate the long-term effects of head injury proves even more startling. The rates of sub-concussive and concussive injuries are exceedingly high in several sports. For instance, in hockey, 70% of players suffer multiple concussions in a season, and the league averages 77 concussive events in the season. At Boston University’s Center for the Study of Traumatic Encephalopathy (CSTE), investigations on the post-mortem brain tissue of the donated brains of athletes, including football players, hockey players and boxers, reveal disturbing problems, even for players with limited careers or without a serious documented head injury.

Chronic traumatic encephalopathy (CTE) is a distinct neurogenerative disorder that arises from repeated closed head injuries, often in the context of contact sports. The characteristic neuropathology of concussions includes significant tau immunoreactive neurofibrillary and astrocytic tangles (yes, tau, the same culprit of Alzheimer’s disease). These tau tangles arise in the frontal (planning, attention, long-term memory, drive) and temporal (auditory perception, semantic, short-term memory) cortices in nonuniform distribution, with focal epicenters at sulci (brain folds) and surrounding blood vessels. Moreover, these tau neurofibrillary tangles are found elsewhere, including the limbic and paralimbic regions, basal gangli and brain stem; furthermore, diffuse beta amyloid plaques are also observed throughout the brain. These buildups were found in athletic donors as young as 18 years old! Although the exact role of these protein aggregates in various dementias is uncertain, they are believed in part to be involved in neuronal loss, and are closely associated with other dementias like Alzeheimer’s and Parkinson’s. What’s more, advanced stage CTE is characterized by atrophy of the cerebrum, medial temporal lobe structures (your memory center) and mammillary bodies and enlarged ventricles (Gavett et al, 2010).

Immunoreactive staining shows the presence of tau neurofibrillary tangle build up around blood vessels in the brain of an 18-year-old multi sports athlete donor with a history of concussions | Photo from the BU's Center for the Study of Tramautic Encephalopathy

For many, the dementia caused by frequent head injury is early onset, at around 40 years old (but that’s variable, of course). Families of donors have often reported significant behavioral changes during the later, off-career lives of the donors, including depression, forgetfulness, aggression and confusion. These claims are fortified by the frequently gruesome causes of deaths for these donors (and are representative of many off registry athletes): suicide, drug overdose, reckless car accidents, just to name a few. Reports like these, as well as stories we hear in the media, support that these behavioral changes and actions correlate with brain damage. Although these tragic endings are compounded by other stressful factors of professional athleticism.  For example, the large physical toll exacted on the intense training and playing that may require the use, and later dependency, of and on painkillers. However, it is not clear whether or not these players are inherently inclined towards drug abuse, violence, suicidal tendencies and an overall lower life expectancy.  Yet, the brain areas responsible for controlling impulsiveness, mood regulation and other important functions are literally beaten to a pulp.

For Sidney Crosby and others dealing with head injury, the road to recovery is long. But your health, especially your brain’s health, must always be first priority. It is vital not only for his mental and physical well-being off the ice, but his playing ability as well: during a game at any given moment, he must analyze the situation and make impressively quick, strategic decisions about how he maneuvers and manipulates himself and the puck. As Dr. Michael Cusimano, a neurosurgeon and researcher at St. Michael’s Hospital and a professor at the University of Toronto, put it best: “It’s not that he has bigger muscles, or that he skates faster, or that his slapshot is faster, or that he can hit players better. The difference between him and [others] is his cognitive abilities.” With a growing body of evidence on the brain’s fragility to these destructive events, it is becoming alarmingly obvious that modifications on the rules of the games, player management, safety standards, equipment protection and public/player awareness are absolutely necessary to further minimize the risks of these sports.

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References

Gillis, Cathy, and Charlie Gillis. “Hits to the Head: Scientists Explain Sidney Crosby’s Concussion.” Macleans.ca – Canada News, World News, Politics, Business, Culture, Health, Environment, Education. 17 Feb. 2011. Web. 27 Feb. 2011. <http://www2.macleans.ca/2011/02/17/the-aftershocks/>.

Klein, Jeff Z. “Crosby’s Injury Renews Focus On Hits to Head in the N.H.L.” Online article. New York Times. 20 Jan. 2011. Web. 25 Feb. 2011. <http://www.nytimes.com/2011/01/21/sports/hockey/21concussions.html?pagewanted=all>.

“Sidney Crosby & 2 Concussions…. Head Shots Threaten Hockey.” Web blog post. Brain Injury Blog. 21 Jan. 2011. Web. 25 Feb. 2011. <http://www.braininjuryforum.com/wordpress/?p=1342>.
Gavett, BE; Stern, RA; Cantu, RC, Nowinski, CJ; McKee, AC. 2010. Mild traumatic brain injury: A risk factor for neurodegeneration. Alzheimer’s Research and Therapy 2 (18): 1-3.



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