Sports Medicine Research: In the Lab & In the Field: Balance and Neurocognitive Deficits in Non-Concussed Athletes (Sports Med Res)
Friday, August 31, 2012

Balance and Neurocognitive Deficits in Non-Concussed Athletes

Prevalence of Neurocognitive and Balance Deficits in Collegiate Football Players Without Clinically Diagnosed Concussion

Mulligan, I, Boland, M, Payette,J. J Orthop Sports Phys Ther. 2012;42(7):625-32. Epub 2012 Apr 24.

Post-injury management of sports-related concussion has become increasingly dependent on the results from neurocognitive assessments, which rely on both subjective and objective data, including Balance Error Scoring System (BESS), the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), and the Postconcussion Symptom Scale.  A recent study examining high school athletes 2 days following a concussion found that even in the non-concussion control group, 30% of the athletes had significant changes in symptom scores or neurocognitive testing.  Little research exists examining the prevalence of neurocognitive or balance deficits in athletes who do not report concussion-like symptoms to a healthcare provider.  In this prospective cohort study by Mulligan, et. al., the authors tried to identify the prevalence of neurocognitive and balance deficits in 45 Division IA collegiate football athletes 48 hours following competition.  Athletes between the ages of 18 and 25 years who traveled with the team for the final game of the season were included in the study. Excluded from the study were athletes who sustained a concussion during the season, were not on the traveling team, reported signs and symptoms associated with a concussion and were evaluated at the time of the game or prior to data collection, as well as athletes currently being treated for a lower extremity musculoskeletal injury. The athletes completed ImPACT (Version 2.1), the Postconcussion Symptom Scale, and BESS testing prior to the football season and approximately 48 hours after the last game.  The authors reported the prevalence of scores exceeding reliable change from baseline (“detectable change”), as well as the number of deficits noted for each athlete.  Results showed that 71% of those tested had neurocognitive impairments and/or balance deficits that may be associated with concussion despite no report of concussion-related symptoms.  Of that 71%, 19 of the 32 (59.4%) had detectable change in at least 2 of the 3 screening tools or had at least 2 subcategories with detectable change during ImPACT testing.

The findings of this study suggest that despite having no reported symptoms associated with concussion 48 hours following a game, a significant number of football athletes had deficits on neurocognitive testing. These results also imply that reported symptoms alone may not be sensitive enough to rule out a concussion, and additional assessments may be necessary to evaluate athletes who may have suffered a concussion but do not recognize their deficits or report them to medical professionals. Consequently, further research in the area of improving recognition of an athlete’s potential neurocognitive deficits is needed.  The results of this study should be viewed with caution as the study was conducted on athletes from a single football team and thus may have limited ability to be generalized to all collegiate-level athletes and replication studies with larger samples are needed for validation. Do you include a standardized balance assessment as part of the pre-participation physical examination for baseline purposes?  Is it possible that athletes develop neurocognitive impairments and/or balance deficits over the course of a season as a result of “sub-concussive” hits sustained as part of regular season play?

Written By: Stephen Stache, MD
Reviewed By: Marc Harwood, MD & Jeffrey Driban

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Mulligan I, Boland M, & Payette J (2012). Prevalence of neurocognitive and balance deficits in collegiate aged football players without clinically diagnosed concussion. The Journal of Orthopaedic and Sports Physical Therapy, 42 (7), 625-32 PMID: 22531476

5 comments:

360 Balance said...

This is an interesting article and warrants further investigation. Although we have not performed post-competition testing, we have been part of baseline testing with collegiate athletes for almost 15 years, which includes a symptom checklist as well as computerized cognitive, balance and eye-head coordination testing. We have found a number of athletes (although not as significant as the percentages in this study) who do not test within normal limits for baseline testing even if there is no identified concussion history. These athletes are either followed up with more testing or rehabilitation to normalize their test scores. Thus, baseline testing is not only important for comparative data post-injury but to identify potential at-risk athletes as well as implement athletic enhancement strategies. Baseline testing to identify pre-existing symptoms and/or impairments is also supported in the 2008 Zurich Concussion Consensus Statement.

samwalton said...

I like this study. I feel as though this is certainly an area that could use more attention. I believe that I have seen research (or at least proposals) venturing into the differences in pre- and post-season concussion testing in football players, and that they data showed that there was , in fact, a decline over the course of the season. What I'd like to see in addition to the results in this test would be the comparison to those who did sustain a concussion during the season, and also a study comparing these results to those of other concussion-prone sports like hockey, basketball, soccer and lacrosse.

I have, in the past, assessed balance in my contact athletes upon pre-participation screening, but I feel that even with a baseline there are too many confounding variables to accurately compare a post-injury score to a pre-season measure. What do you think? Do you feel that it's still worthwhile to baseline test balance?

Stephen Stache said...

Thank you for both of your comments.

I agree completely that the finding are quite interesting and highlight the importance of baseline testing. All athletes are not the same and inter-sport differences, in addition to individual athlete differences, are likely common. Pre-season baseline testing could easily highlight these differences, in accordance with consensus guidelines, and be very useful in guiding post-injury management, particularly in athletes with a history of previous concussion.

Additionally, I am eager to see how much baseline testing is mentioned in the new consensus guidelines in the near future.

Kate said...

This study does bring up some very interesting results such as the fact that playing football may be enough to damage the brain without receiving a fully diagnosed concussion and that normal signs and symptoms of a concussion may not be enough to clearly define the parameters of a concussion. That is a scary thought since most return to play decision making is based on if the patient has symptoms or not for a certain period of time. However, the fact that such a high percentage of football players had this reaction should lead to further investigation. It would be interesting if future research would also test non athlete participants that go through the same schedule as the players such as athletic trainers, coaches and equipment managers to see if it is the actual hits that decrease cognitive function or if it is the hectic routine that is a football season. Maybe constant travel, little sleep, and stress can cause the decreased cognitive function that was observed in this study.

Stephen Stache said...

Thank you for your comment, Kate. I think you highlight the importance of using multiple clinical , objective and subjective endpoints when making return to play decisions. Even if an athlete reports clearance of concussion related subjective symptoms, consideration of balance, vestibular and cognitive symptoms, as well as sleep and emotional related symptoms should be part of an evaluation prior to return to play. Athletes need to be fully functional people and students before they and return to competition.

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