Concussion, a primer pt 2

The contact and the big hits of football and other contact sports are a big part of the game day action.  Our understanding of that action has changed as the word “concussion” has entered into our everyday language.  In this second installment of our series on concussions, we will examine the anatomy and the assessment of concussions.

Injury on Impact
Source -

The anatomy of concussion offers a crash course in physics, anatomy, physiology, and neurology.  In a split second, the hit we see can change an athlete’s next play, next season, and even their entire career.

When a concussion occurs, here’s what happens in actual time:

  • A blow to the body occurs.  It does not need to be directly to the head, but the force is transmitted to the head (or a shock wave is directed toward the person, such as in a military scenario).
  • The brain sits in fluid (called cerebrospinal fluid) and this fluid is there to withstand normal everyday movement and protect the brain.
  • When the shock or force to the body is so great that the fluid cannot fully absorb the force and maintain the brain’s stability, the brain is decelerated by the rigid bones of the skull.
  • This impact of the brain on the skull can cause irritation or interrupt brain function.

These are theoretical ideas and based upon post-concussion analysis of what happens.  We do not have real-time data of a concussion as it occurs, since it is not something you can run experiments on.  I hope you would not sign up for that experiment!

The brain and the central nervous system are incredibly plastic and adaptable, but very delicate at the same time. These contradicting aspects of the brain and its sub-systems both assist us in the assessment of a concussion but add to the difficulty of assessing it as well.

The science of the examination of a concussion is still emerging and may be very different in just a short few years.  However, current state of the art requires several symptoms that are essential to evaluate, including the following:

  • Self-reported symptoms of distress
  • Cognitive changes
    • Memory
    • Reaction
    • Inhibition
  • Balance changes
  • Personality changes

Protecting athletes requires us to gather and use as much data as possible to make the all important return-to-play decision.  Nowhere in sport or medicine should decisions of importance be made with only one piece of data.  In the case of concussions this is vital, the more information the better!  Some information is gathered with subjective means and measures (for instance, just by asking the athlete) while others are more objective and are able to assess information directly from the body.

Subjective/Computer-Based measures:

Subjective means are those tests where the assessor depends on gathering information from the person.  These include tests that many of us have heard of and have become familiar with to some degree.  The ImPact computerized neurocognitive assessment ( allows assessors to gather baseline information before an incident and then compare the results after an impact.  The Sport Concussion Assessment Tool (SCAT) is also widely used as a means to test healthy functioning and then compare that with a post-concussion assessment.

Balance and Coordination

Post concussion balance changes can be due to conflicting or insufficient information being sent to the injured brain.  Balance is assessed to determine the presence of any changes or deficiencies.  The Balance Error Scoring System (BESS) was developed to assess these changes, and is comprised of six different balance conditions, each of which lasts for 20 seconds.  The BESS system can be seen at:

The National Athletic Trainers’ Association (NATA) highly supports the use of the BESS as a brief concussion assessment tool.

Neuropsychological Testing

Neuropsychological testing has been found to be a significant tool in evaluating cognitive functioning, recovery, and assisting in answering return-to-play questions.  Cognitive impairments that follow a sport-related concussion typically include deficits in memory, attention, concentration, processing speed and decision making.  Often these difficulties can be detected for up to 5-7 days post-concussion.

Subjective tests have their place, as it is very important to engage with the athlete to assist with their understanding, emotional changes, and sense of hope about return-to-play and quality of life.

However, only gathering self-reported information can be a disadvantage.  First, such information is not always the most accurate for a whole host of reasons, including the limitations of the person’s ability to describe symptoms, dishonesty of reporting symptoms (athletes learn to look better than they are for competitive advantage and to maximize playing time), and lack of effort attended to the task of assessing an athlete’s baseline.  Effort at baseline testing is not always the same, but when your playing time and livelihood are at risk, effort can go up yielding very confusing results.  For instance, a concussed athlete may perform better on these tests after the concussion than before due to their heightened attention on the testing process.  This being said, subjective information is essential as a part of the whole picture of a concussion report and treatment.  But again – the more information, the better!

Objective measures here now, and on the horizon:

Neuroimaging, or computed tomography (CT) and magnetic resonance imaging (MRI), are often used when a more serious brain injury is suspected, and most often will not show a concussion or its impact.  For more serious brain injury, this objective test works wonders.  However, the leading researchers on sport-related concussion have suggested that CT and MRI provide very little help because the images often reveal normal structures.  In the future, these types of images may provide excellent information but currently practitioners are looking elsewhere.  Also remember that concussions are functional in nature, not structural.  If a head injury is structural, then the athlete has incurred a more serious brain injury.

CT scan of concussion
Images from

The U.S. Army is working on a blood test to diagnose mild traumatic brain damage or concussions.  This form of information is very promising and would assist care providers and athletes alike in learning more about detection, prognosis, and timelines for treatment.  However, again this would not be a “gold standard” but a piece of information that would fill in the blanks of a complete report about an athlete.

Blood Test to Flag Concussions? Army Says Yes

Researchers Say the Procedure Identifies Key Proteins From the Brain

Rochester Investigating Blood Test for Concussions

NIH Funding Expands Brain Research from Scans to Biomarkers

This is an exciting arena for scientific growth, assisting in the detection and treatment of concussions.  More objective data will be a game changer in the evaluation, treatment and decision-making regarding return-to-play.   However, nothing will replace gathering information from multiple sources and using the detective/scientific process to solve the mystery.  More data will yield better decisions, which are critical because player’s lives are at stake when they walk onto the field less than fully functional.  Reviewing less data results in less definitive answers, and greater risk for the athletes!

The human brainMiscellaneous but cool links:

Here is a cool app from the Apple store: the 3D Brain ( by Cold Spring Harbor Laboratory (Genes to Cognition (G2C) (

The 3D Brain is described this way from the Apple store “Use your touch screen to rotate and zoom around 29 interactive structures. Discover how each brain region functions, what happens when it is injured, and how it is involved in mental illness.  Each detailed structure comes with information on functions, disorders, brain damage, case studies, and links to modern research. . . “Modern neuroscience can and will continue more about concussions and performance in sport this app is a great way to become familiar with the brain.

For those of us who don’t have or use a iphone or ipad this is just as cool a 3D model of the brain right on your computer brought to you by the The Skull Base Institute (SBI), a center devoted entirely to the art of skull base surgery.  Find the 3D model at


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