Have you ever had a concussion? How many concussions have you had in your lifetime?
Many people underestimate the answer to these questions, not because they are trying to hide the real answer, but because they don’t know what qualifies as a concussion. It is a common misconception that, to have a concussion, you have to lose consciousness or have significant symptoms that last for a long time. As a result, many go undiagnosed because the person doesn’t know that the symptoms they are experiencing are enough to be considered a concussion.
There is one easy way to solve this problem. It doesn’t require intensive concussion education or hours of training. In fact, it can be done in under 30 seconds on the sideline, in the athletic training room, in the doctors office, in an emergency department, or any other setting. The solution: provide a clear and thorough concussion definition.
Several studies have shown that the number of reported previous concussions increases after participants are given a detailed concussion definition. In our research at the Boston University CTE Center, we asked participants how many concussions they had in their lifetime. Then we gave them this definition:
“Some people have the misconception that concussions only happen when you black out after a hit to the head or when the symptoms last for a while. But, in reality, a concussion has occurred anytime you have had a blow to the head that caused you to have symptoms for any amount of time. These include: blurred or double vision, seeing stars, sensitivity to light or noise, headache, dizziness or balance problems, nausea, vomiting, trouble sleeping, fatigue, confusion, difficulty remembering, difficulty concentrating, or loss of consciousness. Whenever anyone gets a ding or their bell rung, that too is a concussion.”
In a 2014 CTE Center study of 466 current and former athletes from a variety of sports (48% football, 88% male), 73 percent of the athletes increased their estimate of their lifetime concussions after hearing the definition. The athletes reported, on average, double the number of concussions after hearing the definition. The pre-concussion average was seven, while the post-definition average was 15 reported concussions. These results were similar regardless of the level of play the athlete reached or whether they played a contact or non-contact sport.
Another CTE Center study found even more striking results in former NFL players, who reported an average of five times more concussions after hearing the definition. These athletes may have been basing their original number off of what was considered a concussion in their playing days decades earlier.
Other recent research has had similar findings. A quarter of Icelandic elite female athletes changed their answer from having sustained no sport-related concussions to having had one ore more after being given the definition, with 16 percent of those changing from zero to four or more concussions post-definition. Thirty percent of youth and high school athletes in another study reported more previous concussions after being provided the concussion definition. Both of these studies used the definition above, but the former added “Whenever anyone gets dazed after a blow, that too is a concussion. Note that a direct blow anywhere on the head and body with an impulsive force may cause a concussion.”
This research shows that providing a clear and comprehensive concussion definition is critical to getting a more accurate answer, both when asking about the number of concussions a person has sustained, or if they have ever sustained a concussion at all. I can tell you from my personal experience, after giving the concussion definition, I have had former athletes tell me they sustained hundreds or thousands of concussions. Some said it happened almost every time the played their sport.
When taking a concussion history, whether as part of a preparticipation exam or during a patient’s concussion evaluation, whether in a sport-related setting, a clinic, or a hospital, it is essential that all clinicians provide a concussion definition like the one above. This will clarify for the patient what a concussion is and increase the likelihood that they will provide an accurate concussion history.
Concussion research should include a similar concussion definition. It is likely that studies using self-reported concussion histories have historically underestimated the actual number of previous concussion sustained by athletes. Some studies only ask about diagnosed concussions, despite the fact that many concussions go undiagnosed. In other studies, it is likely that many participants underreported their previous concussions because they didn’t know that what they had was a concussion.
A thorough concussion definition should also be incorporated in concussion education so that athletes are aware, in the moment, that what they are experiencing qualifies as a concussion. It may increase the likelihood that they seek care for their injury.
I have had athletes that were surprised after hearing that definition, unsure how many concussions to tell me they had experienced in part because they couldn’t believe the number was so high. I think many athletes likely feel the same way, but because research has historically presented a lower average number, they feel that their estimate couldn’t be accurate, even if it is. They aren’t exaggerating. They are sharing what they have actually experienced. And in some cases it was so common it was impossible to accurately estimate. Yet they never sought care in the majority of those cases.
We shouldn’t assume that people know what a concussion is, even if they have had concussion training or they play a contact sport in which concussions have been a greater part of the conversation in recent years. It isn’t enough to simply ask, “Have you ever had a concussion?” or “How many concussions have you had?” Providing a detailed concussion definition is a quick and simple way to give athletes and other patients necessary information to know what qualifies as a concussion.