Sports Medicine Research: In the Lab & In the Field: Predicting the Persistence of Concussion-Related Impairments (Sports Med Res)


Tuesday, July 10, 2012

Predicting the Persistence of Concussion-Related Impairments

Identification and validation of prognostic criteria for persistence of mild traumatic brain injury-related impairment in the pediatric patient

Wiebe DJ., Collins MW., Nance Ml. Pediatric Emergency Care, 2012; 28: 498-502.

Athletes returning to play before their concussions fully resolve are more prone to a second concussion, which is usually associated with more severe signs and symptoms (s/s). However, there are no prognostic tests to identify athletes who are going to suffer from a concussion for longer periods of time to ensure a safe return to play. Therefore, the purpose of this study was to develop and validate prognostic criteria to identify children at risk for persistent concussion impairment. This 2-year study recruited patients ages 11 to 17 years that were admitted to the hospital due to an acute concussion (only excluding patients with a penetrating mechanism). All patients were evaluated using neurocognitive testing (ImPACT) at time of hospitalization and again at their clinic follow-up (typically after 2 weeks). The patients were split randomly into 2 groups: 42 participants were placed into a group to develop the predictive criteria and 21 participants were placed into a group to verify the predictive criteria. The authors categorized symptom severity outcomes into “any impairment” or “severe impairment” using previously established definitions. Any impairment (n = 62) was defined as a total ImPACT symptom score higher than 8 (normal is 0 to 8) or scoring less than 25th percentile on at least 1 of the neurocognitive modules at baseline or during the 2-week follow-up. Severe impairment (n = 44) was defined as a total ImPACT symptoms score higher than 12 or scoring less than 25th percentile in at least 2 of the neurocognitive modules. In the development subcohort, 100% of the patients had any impairment and 79% were categorized as severe impairment at baseline and at follow-up 88% had any impairment and 71% had severe impairment. In the validation group at baseline 95% had any impairment and 52% had severe impairment, and at follow-up 95% had any impairment and 81% had severe impairment. Researchers found that using the average of the patients’ 4 neurocognitive modules scores at baseline with a cut point of 26 percentile could correctly predict 62 to 67% of the time whether a patient would have severe impairment at 2 weeks. This corresponded to a 91% chance that when it predicts the person to have a severe impairment at follow-up it will be correct but when it predicts a resolution of severe symptoms it is likely wrong (30% chance of correctly predicting symptom resolution).

There is a tremendous amount of variability in how athletes present and recover from concussions making it difficult for medical personal to safely estimate when athletes may be able to return an athlete to play. This study recognized the need for a prognostic test to help predict how long s/s may linger. These findings demonstrate that neurocognitive testing, like ImPACT testing, may have some potential as prognostic criteria. Using the mean score from the 4 neurocognitive modules at baseline medical personnel can correctly predict about 90% of those who will likely continue to have severe symptoms at 2-weeks (but it may be less accurate at predicting resolution of symptoms). Having objective variables instead of relying on subjective s/s may greatly benefit medical personnel on estimating returning athletes to play. This prognostic tool still needs some additional research especially among a larger more variable population that includes more patients with less severe symptoms. Furthermore, it will be interesting to see if other neurocognitive exams would have these results. It should be noted that this type of predictive rule can only be used as a guide. At the end of the day, the most important thing will be how the patient presents at follow-up. If you do not have a neurocognitive baseline testing do these results prompt you to want to start? Do you think it would be helpful to have a score that could help estimate how long the patient may continue to have s/s or neurocognitive impairment?

Written by: Jane McDevitt MS, ATC, CSCS
Reviewed by: Jeffrey Driban

Related Posts:
Electrophysiological Recovery After Sport-Related Concussion
Wiebe DJ, Collins MW, & Nance ML (2012). Identification and validation of prognostic criteria for persistence of mild traumatic brain injury-related impairment in the pediatric patient. Pediatric Emergency Care, 28 (6), 498-502 PMID: 22653462


Aaron said...

This is a great study and I find the results extremely interesting. While I understand future research is still needed, I believe this can lead to significant clinical implications. Over the last several years concussion management has seen a variety of changes with different suggestions and philosophies always emerging. With the recent media uptake, I foresee this issue remaining at the forefront of research in athletic training.

To answer your first question, I believe it is absolutely imperative for all athletic trainers to use some sort of neurocognitive baseline testing, such as ImPACT, at any level. It is a great tool that helps with the management of concussions and serves as another tool regarding return to play decisions. If future research can further support that neurocognitive testing can quantitatively predict outcome measures, I see little argue against its use.

Secondly I believe it will be helpful to have a score that can better estimate how long an athlete will be out, however as Jane mentioned it still must ultimately come down to the patient and their symptoms. These tests should only serve as an estimate. I believe they can help with patient compliance and managing the return to play process. In my own clinical experience, I find athletes are most frustrated when their most severe symptoms have diminished yet are still not allowed to participate. By giving an athlete an estimate with return to play rather than “when symptoms and scores are back to normal”, I believe they may be more compliant during the RTP process.

Jenna Robinson said...

Agreeing with what Aaron said, I think neurocognitive tests should be required for concussion victims. This will help athletes get a better estimate on when they will return to play. I feel as if a lot of collegiate athletes don't waste anytime in saying that their symptoms are no longer present but in the meantime they still are. This will reduce the risk of severe symptoms if the "OK" to play is given a bit too early. As said, more research needs to be done but I think it will help improve the recovery phase of concussions and let athletes play a safer game.

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