Sports Medicine Research: In the Lab & In the Field: Electrophysiological Recovery After Sport-Related Concussion (Sports Med Res)


Wednesday, June 13, 2012

Electrophysiological Recovery After Sport-Related Concussion

Time course of clinical and electrophysiological recovery after sport-related concussion

Prichep LS., McCrea M., Barr W., Powell M., Chabot RJ. Journal of Head Trauma Rehabilitation, 2012; ahead of print

Concussion research has shown that the typical time for cognitive and behavioral signs and symptoms to dissipate is within 7 to 10 days after an injury, however, researchers utilizing functional neuroimaging techniques (e.g., functional magnetic resonance imaging) have reported that neuronal dysfunction may be prolonged for up to several weeks. Therefore, the purpose of this study was to examine the differences in a calculated traumatic brain injury (TBI) index (via EEG patterns) and other clinical outcomes between patients with mild or moderate severity of concussion signs and symptoms as well as among patients with short (< 14 days) or delayed (> 14 days) return-to-play time. Sixty-five athletes who sustained a concussion were included in this study and went through a clinical evaluation (i.e., Concussion Symptom Inventory [CSI], Standardized Assessment of Concussion [SAC], Balance Error Scoring System, [BESS] and Automated Neuropsychological Assessment Metrics [ANAM]), and an electrophysiological evaluation to calculate the TBI index. These tests were conducted within 24 hours of the injury, and then at day 8 and day 45 after the injury. Concussion severity was based on specific concussion signs and symptoms using the CSI and SAC test (e.g., feeling in a fog, slowed down, memory impairment, loss of consciousness). Athletes were placed into either the mild concussion group (n = 51) or the moderate concussion group (n = 14).  At the time of injury, patients with a moderate concussion had more severe signs and symptoms on the CSI and had poorer performances on the SAC and ANAM tests compared to the mild concussed group. However, at days 8 and 45 there were no differences in these outcomes between the two groups. The BESS test was not significantly different between the mild and moderate concussion groups at any of the time points. Despite the clinical outcomes not detecting differences at days 8 and 45 between patients with mild or moderate concussions the TBI index was higher among the moderately-concussed patients compared to the mildly-concussed group at all of the time points (at time of injury, day 8, and day 45). The sensitivity (positively diagnose a patient who has pathology) of the TBI index for moderate concussions at the time of injury was 55% and the specificity (not falsely diagnosing a healthy patient) was about 94%. Seventy-three percent of the patients returned to play within 14 days (mean = 5 days) and 27% took more than 14 days to return to play (mean = 20 days). At the time of injury, the TBI index was lower among patients that returned to play in less than 14 days (TBI index = 5) compared to the group who took 14 days or more to return to play (TBI index = 20).

Brain recovery after a concussion injury may extend beyond clinical recovery. Furthermore, the TBI index may be an objective indicator for concussion severity and predictive of recovery time (based on return-to-play time). This study offers preliminary data to suggest that the TBI index could be used as a prognostic tool however, a study with a larger sample size will be necessary. In this study the TBI index remained significantly elevated in the moderate group compared to mild concussed group up to 45 days after the injury.  Based on these results, the TBI index could help differentiate severity of the concussion. However, we need to keep in mind that it only recognized a moderate concussion compared to a mild concussion 55% of the time. Based on this study the researchers suggest that measuring brain activity at the forehead could be used to calculate the TBI index on the sideline. This may help assess concussion severity and assist in determining return-to-play time. Do you have any experience with EEG? Is this a test you would consider using?
Written by: Jane McDevitt MS, ATC, CSCS
Reviewed by: Jeffrey Driban

Related Posts:
Prichep LS, McCrea M, Barr W, Powell M, & Chabot RJ (2012). Time Course of Clinical and Electrophysiological Recovery After Sport-Related Concussion. The Journal of Head Trauma Rehabilitation PMID: 22588360


Anonymous said...

I have no experience with EEG, but it looks like is is something that may have some real value for us as clinicians. I will be excited to see how this line of study progresses.

It was mentioned that there was a 55% sensitivity vs. a 94% specificity. I don't see this as necessarily a bad thing. From my frame of reference as a clinician, this means that if we get a (+) moderate score, then I know that there's likely to be under 10% chance that it was actually only mild. No, problem: Treat the athlete conservatively and continue to monitor and progress with the set protocols that are in place once symptoms have been relieved. With a (-) moderate score, I know that there's still a chance that it could be worse than it puts on, especially since symptoms can still be brewing and surfacing even 3 or more days later. It doesn't necessarily change the plan to treat conservatively, observe, and progress via established protocol.

What this does do however, is put extra attention onto details that are outside of the typically monitored symptom scale and BESS scoring that most of us use. We are a long way away from predicting the long term outcome of virtually any injury from the sideline, so in my opinion, that possibility is mute as it stands right now. But it would seem that with more research this could begin to emerge as an in-clinic tool to help monitor and show progression.

What are your thoughts on the future of this type of testing in RTP protocols? Do you see this becoming an integral piece?
Also, do you believe that evidence such as this along with data showing delayed brain reaction time and other lasting effects months after a hit may lead us to even more conservative treatment of mTBI's in athletics? Will we ever come to the point where 5 days is far to short to return to full contact, even for relatively mild trauma?

Jane McDevitt said...

I am still a little skeptical about this TBI index based on the EEG. Personally I have no experience using an EEG so I am not sure how I would be able to calculate their TBI Index. However, this article and other research is showing that there does seem to be a delay between relief of s/s and actual brain tissue recovery so more conservative treatment of mTBI does seem to be necessary. I am not sure if the rapid progression of 5 days between injury and return to play will increase or not. This article stated that 75% returned to play within 14 days but how many of the 75% was within 5-7 days? However, 27% took more than 20 days I feel that is higher than what most researchers find. I think every athlete is different, but being on the conservative side may be benifical for the athlete.

Zahida M said...

I have no experience with EEG but I am intrigued after reading this article! I think that using the TBI index could be a good tool to use along with other tests to help determine the severity of the concussion. However, i do not think this would be an important sideline tool. Once we realize an athlete has a concussion on the sideline, we take them out for the rest of the game or practice regardless of the severity of the concussion. I think the TBI index would be helpful during further diagnosis of the concussion and to see when RTP is acceptable, but I do not know if it would be valuable as a sideline assessment tool. There is a lot of concussion research out lately that is leaning towards more and more conservative RTP measures, and I think this is another one that reiterates that matter. I am excited to see where future research in this area leads!

Jane McDevitt said...

You are right I do not believe this is going to be used as a sideline tool. They wanted the TBI index to be used in the follow up measure as well as predict the time for safe return to play. My problem with it is if you are not firmiliar with EEG then you will not be able to calculate the TBI index so I am not sure how easy it will be to use as a follow up measurement. However, it does reiterate the point that concussed athletes do seem to take longer than expected to recover from their injury, and being conservative is the best action you can take as a medical personell.

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