Sports Medicine Research: In the Lab & In the Field: Differences Among Sports and Teams on Baseline Concussion Performance (Sports Med Res)
Tuesday, November 26, 2013

Differences Among Sports and Teams on Baseline Concussion Performance

Sport and Team Differences on Baseline Measures of Sport-Related Concussion

Zimmer A, Piecora K, Schuster D, Webbe F. Journal of Athletic Training. 2013;48(5):659-667. http://natajournals.org/doi/pdf/10.4085/1062-6050-48.5.06

Take Home Message: Sport and height may affect performance on baseline concussion assessments. Therefore, when athletic trainers evaluate a patient who lacks a baseline concussion assessment they should be cautious using normative data because it may not be optimal.

Pre-season baseline concussion testing of athletes is not always possible. When baseline measurements are unavailable it is recommended that athletic trainers compare testing performance to normative results. However, it is unknown if there are factors that affect normative results for performance on baseline concussion assessments. Therefore, the purpose of this study was to determine if various sports and teams perform differently on baseline concussion testing and to determine if athlete characteristics – such as, sex and height – play a role. 437 student-athletes who competed across 10 varsity sports and 18 athletic teams of a NCAA Division II university performed baseline concussion testing. The student-athletes completed the Concussion Resolution Index (CRI), Balance Error Scoring System (BESS), and the Standardized Assessment of Concussion (SAC). The authors found no consistent differences between sexes across all three baseline concussion tests. Also, they found no differences in SAC scores among the athletic teams. In contrast, teams differed in BESS testing and CRI performance. Women’s soccer performed the best in BESS testing on a hard surface while men’s basketball performed the worst. For the CRI, baseball and soccer players, regardless of sex, had faster processing speeds than male basketball athletes. Furthermore, men’s cross-country athletes had slower reaction times compared with softball and women’s rowing. They also found that height was a key factor in BESS performance. Taller individuals performed worse on BESS testing than shorter individuals.

This study suggests that sports/teams may perform differently on baseline concussion assessments and that individual factors, like height, may influence balance scores. Therefore, using normative comparisons in concussion evaluations may not be optimal. This ultimately suggests that baseline comparisons should be utilized over normative comparisons if possible. If a baseline comparison is unavailable to a clinician, then the clinician should consider the differences that may exist between sports (such as reaction time and BESS performance on a hard surface) to make the safest return-to-play decisions. When it is necessary to rely on normative data it would be beneficial if we could compare our patient’s test results to age, sex, and sport-specific normative values. Fortunately, although differences were noted at baseline between teams, it is unclear if these differences are enough to change the overall results of a concussion evaluation. Overall, clinicians should use a variety of different measures in posttraumatic concussion evaluations, including the SAC, to minimize the influence of sport and other individual characteristics (e.g., height) on test outcomes.

Questions for Discussion: Have you ever conducted concussion testing on an athlete without baseline scores? What normative values did you use to compare?

Written by: Tiffany Kobordo
Reviewed by: Lisa Chinn and Jeffrey Driban

Related Posts:
Zimmer A, Piecora K, Schuster D, & Webbe F (2013). Sport and team differences on baseline measures of sport-related concussion. Journal of Athletic Training, 48 (5), 659-67 PMID: 23952044

13 comments:

Jake Meyer said...

This is an interesting idea. I have seen it many times where an athlete will be diagnosed with a concussion and will have no baseline data to compare to. This mostly happens in a high school setting, however I have seen this in the collegiate setting where normative data has to be used. I have always wondered what kind of data is used as normal. Do they simply pick average college aged individuals and have them do these computerized cognitive tests to compare athletes to? How can we compare athletes to average collegiate students?
I find it interesting that there are even differences between athletes based on different factors such as height and sport. Very useful to know and I think this information should be in the back of every clinician's mind when dealing with a concussed athlete. Always use clinical judgement along with these great tools and knowledge that is developing. It is very difficult to rely solely on a normative value that may not be completely applicable

Morgan Hooven said...

Why do you think soccer players performed the Bess test better then basketball players? Also soccer and baseball players had faster speeds in the CRI compared to basketball players. Do you think basketball players are lacking something other sports teams are being taught considering they were deficient in both tests.

Tim Gribbin said...

I agree with Jake about it being very useful to know that different demographics show differences in concussion assessments. For example, it is good to know that taller athletes may perform worse during the balance testing portion of the exam. This is something to keep in mind when either ruling out concussion, as the athlete may just have poor balance, or when making return to play decisions, as the athlete may never return to what is deemed a "good" BESS score.
Personally, I have had experience when evaluating a highschool athlete with no baseline data, or if he did have baseline data I was unaware of it. He was from a visiting school at a wrestling tournament that I was covering. In a situation like that, I think that even with the athlete having baseline data, or normative data to compare to, it comes down to the clinician's judgement. In the limited time that we have due to rule restrictions in wrestling, a decision needs to be made based on the immediate presentation, without reference to baseline scores or normative data. This makes it difficult initially, but after the match is over if he is cleared to wrestle, I do see the need to have access to a baseline score or, at minimum, normative data to reference.

Tkobordo said...

Jake, I have also observed clinicians working in a high school setting having to compare to normative data. I feel that this may be due to the inability to conduct baseline testing in most high schools due to either time issues, financial concerns, or possibly not having a full-time ATC. I also believe it would be best to compare the athletes to normative data for college or high school athletes rather than just college-aged or high-school aged students.

Morgan, although I am not certain of all the factors that played into female soccer players performing better on the BESS test than male basketball players, I believe that height may have played a large role. The study did find that taller individuals performed worse on the BESS test on a stable surface, and I can image that male basketball players on average would be significantly taller than female soccer players. I am not certain as to why male basketball players also had slower processing speeds, that may be something to explore further to see if it just occurred within the team observed or if it would be a consistent trend.

And Tim, I agree that during certain sports where quick return to play decisions are to be made, comparing to baseline data is much more difficult. I do feel though, that at that time, having normative data values in mind may contribute to the return to play decision.


Lauren Rao said...

I agree with Tkobordo that height probably plays a role in BESS performance. I am surprised to learn that they found no significant differences between genders overall, though. If height plays a key and girls are the generally shorter sex, why didn't women have better BESS scores? I'm intrigued by this fact.

With that being said, this has always been an issue in the back of my mind for concussions as well as other tasks such as injury screening. How can you say a person is definitely concussed or at a huge risk for injury when you have nothing to compare it to? There are several red flags in that question that this study provides a bench to additional research in sport by sport baselines.

Bethany Rohl said...

I agree with Lauren. I also wondered how there were no differences between sex, but BESS scores seemed to differ based on height. I would be interested to see if this trend is evident through other balance tests as well. While base line data is ideal, it is not always possible. Like Tim stated, with visiting teams, there is not always access to this data. At the high school level, the traveling team does not bring an athletic trainer, so it is up to the host athletic trainer to make decisions during the game. Normative data is helpful in order to have some comparison. It is evident that more research needs to be done.

Tkobordo said...

Lauren and Bethany, I think you both have strong points regarding the fact that concussion diagnosis is difficult when you do not have normative data to compare to. And additionally, that much more research needs to be done to see if there could possibly be any established normative baseline data as far as sport and sex are concerned to help facilitate return to play decisions.

In addressing the question of why if girls are generally the shorter sex, there was not an overall sex difference, I believe this is due to sport specific height characteristics of college athletes. Although females are typically shorter than males in the general population, female volleyball players can sometimes be much taller than male wrestlers or male soccer players. This study looked at BESS performance of different athletic teams and compared performance based on gender. With height differences varying by sport, perhaps overall male college athletes were not significantly taller than the female athletes in this study (therefore not seeing a main effect of sex).

Kaitlyn Kelly said...

When testing for return to play athletes who do not have a baseline testing score do you recommend the Athletic Trainers take into consideration what type of conditioning that sports team does? Could that be why Basketball players are lacking in both set of test?
- Kaitlyn Kelly

Jenna Robinson said...

I'm assuming that men's basketball received the worst ratings in the BESS testing because of their height. It was mentioned that taller individuals scored less than those of smaller build. I think soccer players received higher results because of their increased muscle stability in the legs considering what sport they play. Soccer focuses on mainly the lower extremes which help with things such as balance. But I'm curious as to what height has an impact on?

Alex Ruxton said...

I think the basketball players may score lower on the balance tests because their center of gravity is higher than most other athletes. Since there are difference among different sport's normal scores, I think it would be beneficial a specific-sport norm. I think that would give more of an appropriate idea to compare what the athlete should score if there was no baseline measure.

Sylvia Thelemaque said...

Based off the BESS test results of taller individuals performing worse than shorter people is most likely because the shorter individuals have a lower center of gravity causing them to have a larger base of support; making them more stable.

Will Bradley said...

Why might you think taller individuals performed worse compared to shorter individuals with the BESS test? posibly because of different center of gravaties? or maybe even different vestibular, visual, or somatosensory imput abilites?

Jeffrey Driban said...

Will - There have been hypotheses that taller individuals may have slower reaction times b/c they length of the axons are longer. Thus their balance may be slightly worse. A higher center of gravity could be another issue.

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