Diagnosing Concussion

By: Spencer Huntsman


The NFL took another step in the right direction on Thursday when it announced it will place independent neurological consultants on the sidelines during games beginning next season in order to assist with the diagnosis of possible concussions (h/t Curtis Crabtree of NBC Sports). If a concussion is suspected, players will need to be cleared by the sideline consultant before returning to play.

Though the new policy represents a small but important move towards a solution, the controversy surrounding the long-term effects of concussions, the newly described disease chronic traumatic encephalopathy (CTE) and the NFL's past handling of brain injury will remain a topic for years to come.

Some of that controversy is complicated by the fact that the single most important part of a concussion diagnosis is a player's report of symptoms. In the ultra-competitive NFL, if reporting those symptoms could mean losing your job, players hiding their symptoms likely has been commonplace for some time—something I discussed last month.

Greg McElroy reportedly hid his concussion symptoms from his team earlier this season.
Jeff Zelevansky/Getty Images

Unfortunately, neurological consultants have no control over a player truthfully reporting that he doesn't feel well. They will not be able to tell if a player has a headache, feels in a fog or has increased sensitivity to light—only the player can say.

However, concussions can also manifest themselves as objective physical and cognitive signs and limitations. Altered brain physiology is to blame.

Among other changes, a concussion causes an immediate, rapid and unregulated increase in brain neurotransmitter activity—the molecules that carry signals from neuron to neuron. Additionally, blood flow to the brain is decreased, and the ability of the brain to use glucose—its exclusive fuel source—is compromised.

In other words, the brain goes into overdrive while simultaneously using an already-diminished fuel supply less efficiently. If the resulting imbalance is severe enough, it can be detected by a number of signs. Some of those signs are easily observable, while others are much more subtle.

That is where a specially trained neurological consultant comes in.

Physical Deficits

Neurologically speaking, walking and balancing without difficulty is an incredibly complex task. It requires the seamless communication and cooperation of several areas of the brain that control muscle strength, vision andproprioception—the ability of an athlete to know where his or her body is in space. When a concussion causes global dysregulation of brain function, it affects each of those areas.

Among those important areas is the cerebellum, located at the base of the brain above the neck. One of the functions of the cerebellum is to coordinate nerve input from various parts of the body in order to maintain balance. Three ways to test balance include:

  • Standing on two feet approximately shoulder-width apart, with eyes closed and hands on hips
  • Standing on one foot—the non-dominant foot—with eyes closed and hands on hips
  • Standing with one foot in front of the other with eyes closed and hands on hips—the non-dominant foot should be in back
  • Though not everyone can, NFL-caliber athletes should be able to maintain their balance in each of the above three positions for 20 seconds without difficulty. An inability to do so—or being able to but not without trunk-swaying or arm-waving to assist in balance—suggests a concussion.

    Nevertheless, an athlete with an extremely adept sense of balance may be able to hide underlying deficits—an example of how difficult it can be to diagnose a concussion.

    However, much more subtle signs of cerebellar dysfunction—if present—cannot be hidden no matter how much a player may want to. Those signs involve the eyes.

    After a possible concussion, athletes will be asked to follow an examiner's finger with their eyes only while keeping their heads still—called "eye-tracking." If one eye tracks more slowly than the other—something that can also cause blurry or double vision—a concussion can be diagnosed. Additionally, if the eyes shake back and forth upon quickly looking to the left or right—a horizontal type of nystagmus—a concussion is probable.

    That said, a certain degree of horizontalnystagmus is actually normal. There are also many different types of nystagmus. Making the decision between whether or not an observednystagmus is suggestive of concussion requires special training.

    Finally, cerebellar dysfunction can also announce itself as difficulties with coordination.Dysdiadochokinesia—the inability to perform rapid, alternating movements such as flipping one's hands back and forth—and dysmetria—overshooting an examiner's finger when asked to reach out and touch its tip—are two such examples.

    Anyone who has suffered a concussion—I have had three—understands just how bizarre they can feel. You just can't seem to function right, but in many cases you can't put your finger on why.

    Memory problems, difficulties with concentrating and a strange sensation that one's thoughts are moving more slowly than usual are all common complaints. While many of these complaints rely on player report, the cognitive impairments caused by a concussion can sometimes be measured objectively, as well.

    Following a concussion, an athlete can be very disoriented to time and place. To test for such disorientation, an examiner can ask questions such as the following:

    • What day of the week is it?
    • What field are we playing on?
    • What team are you playing?

    Answering these questions correctly can be extremely difficult for a player with a concussed brain. Additionally, even the simplest tests of memory and concentration can be impossible. For instance, an athlete may have problems with tasks such as:

    • What day of the week is it?
    • What field are we playing on?
    • What team are you playing?

    Answering these questions correctly can be extremely difficult for a player with a concussed brain. Additionally, even the simplest tests of memory and concentration can be impossible. For instance, an athlete may have problems with tasks such as:

    • Immediate repetition of a list of three words—testing for anterograde amnesia (forgetting events following the injury)
    • Repeating those same three words a few minutes later—also testing for anterograde amnesia
    • Remembering the score of the game, what half it is or who won last week's game—testing for retrograde amnesia (forgetting events before the injury)
    • Listing the months of the year in reverse order

  • Failing any of the above tests immediately following a blow to the head essentially confirms a concussion, and the athlete should be immediately removed from play.

    Athletes will be athletes. They define themselves by their sport, and if they think they are able to play, they will. However, the addition of independent consultants—implying they are not affiliated with the team in any way—allows for unbiased evaluation and management.

    In an ideal world, evaluations by the athletic trainer and team physician would be unbiased as well. However, I have spoken with current and former Division I NCAA football and NFL team physicians, and the pressure to clear players to return to play can be suffocating, which is the subject of an entirely different discussion.

    For the time being, independent consultants will help alleviate some of that pressure, and though the move is reactionary rather than proactive, the NFL should be applauded for taking such a stance.

    That said, there is still a long, long way to go.

    Dave Siebert is a medical/injury Featured Columnist for Bleacher Report who will graduate from medical school in June. He plans to specialize in both Family Medicine and Primary Care (non-operative) Sports Medicine and has a special interest in concussions

    Siebert, D. (2013 February,1). Diagnosing Concussion. Retrieved from Bleacherreport.com/articles/1511289-diagnosing-concussion-what-will-nfl-sideline-neurological-consutations-look-for




1) What is the main idea of the article?

2) How can you describe the article?


1) Why do you think they put neurological consultants on the sideline?

2) What is the problem with the NFL?


1) What choice would you make if your young child wanted to play football?

2) In your opinion is football a dangerous sport?



1) The main idea of the article is that the NFL is adding things like neurological consultants to the league to make it safer.

2) The article is about how the concussion rate in the NFL is at an all time high and they are trying to make that a lot safer.


1) To try and reduce the rate of players receiving concussions lower and if they do to have a specialist that can treat them.

2) The problem with the NFL is that their concussion rate is at an all time high and they haven't been able to prevent it.


1) I wouldn't allow it, because if it is this dangerous for adults I couldn't imagine how bad it would be for a young child.

2) I think that it maybe a very fun sport but it is very dangerous because, the rate for concussions is at an all time high in the NFL.