General, research

A cautionary tale for collision athletes

Colleges and universities revolve around athletics. Sporting events create unity and camaraderie among students, alumni, and parents. Sporting events provide entertainment. Sporting events produce money. Yet, we now understand that certain sports come with a price.

Only recently have we come to face the realities of the NFL and the devastating consequences repeated head injuries. Recently popularized by major motion pictures, such as “Concussion,” the lay public is, at the very least, confronted with the reality that football, and other collision sports, may not be as safe as once believed.

Football, hockey, and rugby all have a high incidence of concussion. A concussion is a head injury caused by biomechanical forces. These forces lead to a pathophysiological process that affects the brain. The word concussion actually comes from its Latin origin, concutere, which means “agitation or shaking” of the brain (Maroon et al., 2000). Concussions often (but not always as we’ll come to see) come with signs such as altered consciousness, blurred vision, dizziness, headache, balance disturbance, confusion, and short-term amnesia.

To fully understand the potential damage that is done, it is necessary to review general neuroanatomy of gross brain structures. To start, several protective layers encase the brain, starting with three meningeal layers. The pia mater firmly adheres to the brain’s surface. The arachnoid mater is a spidery substance that attaches to the inside of the thicker, third meninge: the dura mater. Between the pia mater and the arachnoid mater lies the subarachnoid space. Here, cerebrospinal fluid (CSF) surrounds the brain. CSF plays many roles in brain health and function. The CSF helps maintain homeostasis, intracranial pressure, and clears waste.

The CSF also acts as a cushion for the brain. The brain is suspended in this fluid, which protects it from the hard encasing skull – the skull, of course, protecting the brain from direct and destructive trauma. However, when blunt trauma occurs, the brain swishes forward in the CSF, colliding with the skull at the trauma location, and then swiftly bounces back, striking the opposing side of the skull. This back and forth movement and hitting of the skull is known as coup contrecoup. Not only does the brain become contused at the collision sites, but the suspension of the brain in the CSF also allows for the stretching of the brain, often tearing white matter tracts during is propulsion backward.

Consider that a professional boxer throws a punch at approximately 20 mph, a football player makes a tackle at approximately 25 mph, and a soccer ball can make contact with a players head at 70 mph. These are hits that occur repetitively, even at the high school and collegiate level. Then consider that fewer than 10% of concussions involve a loss of consciousness and approximately 47% of athletes do not even report any symptoms after a concussive blow.

Often concussions are considered minor, or even go unnoticed. However, the accrual of concussions and mild head injuries over time can lead to long-term damage and symptoms. Although most research is retrospective and correlative in nature, mild head injuries and concussions are associated with poorer performance in several cognitive (e.g., memory and decision-making) and functional domains (e.g., headaches).

More on this and potential avenues for research later.

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