Sports Medicine Research: In the Lab & In the Field: Does Exercise Influence Reaction Time? (Sports Med Res)
Wednesday, October 16, 2013

Does Exercise Influence Reaction Time?

Effect of Acute Exercise on Clinically Measured Reaction Time in Collegiate Athletes

Reddy S, Eckner JT, & Kutcher JS. Medicine and Science in Sports and Exercise.  Epub ahead of print August 11, 2013; doi:10.1249/MSS.0000000000000140
http://journals.lww.com/acsm-msse/Abstract/publishahead/Effect_of_Acute_Exercise_on_Clinically_Measured.98254.aspx

Take Home Message: Assessing reaction time with a simple sidelines reaction-time task is not influenced by biking exercise.

In efforts to objectively assess concussion symptoms, we measure reaction time via neurocognitive testing or a simple, non-computerized instrument (see related posts below).  However, it is important to determine if exercise has an effect on reaction time to understand how to interpret reaction time changes.  Therefore, the purpose of this study was to examine the effects of varying exercise intensity levels on a simple reaction time task. Among 42 volunteers, the authors randomly selected 28 participants to perform a 4-stage biking task at increasing intensities and 14 control participants who merely sat on the exercise bike. All participants completed the reaction time task and the authors also measured heart rate and rate of perceived exertion among those exercising.  The reaction time task involved holding onto a cylindrical shaft that was dropped at random time increments between 2 to 5 seconds.  The participants completed the reaction time task 8 times after each stage of the exercise protocol (or simulated stages) and the authors calculated the average reaction time at the five testing points. There were no reaction time differences between those that did and did not exercise.  In both groups, participants improved their reaction time as they repeated the reaction time task over the course of 5 tests. 

Clinically, there is no apparent effect of increasing intensity during biking on a simple reaction time task that could be used on sidelines.  This may allow for the use of a simple sideline reaction time task to objectively assess for a possible concussion.  In trying to objectify a concussion evaluation, this may prove to be valuable since neuropsychological testing is not easily and readily available during the course of an event.  It is of note that the exercise bouts studied were simple biking tasks, and none of the athletes studied were cyclists.  It may be interesting to see what the effects of functional exercise bouts may be on this reaction time task.  The authors admitted that there was an apparent learning curve, which led to improved performance over time in both groups.  Also, this task, while simple, may be affected by other various components such as concomitant injury, anxiety, cardiovascular status, etc. Overall, this test continues to be an interesting method to assess reaction time. 

Questions for Discussion: Do you think that you would be interested in utilizing a sideline reaction time task to inform your concussion evaluation?  Are there any other objective measurements that you use?
 
Written by: Nicole Cattano
Reviewed by: Jeffrey Driban

Related Posts:
Consistency of a Clinical Reaction Time Assessment Between Seasons: A Possible Low Cost Concussion Assessment?

Reddy S, Eckner JT, & Kutcher JS (2013). Effect of Acute Exercise on Clinically Measured Reaction Time in Collegiate Athletes. Medicine and Science in Sports and Exercise PMID: 24002343

8 comments:

Greg said...

I really like this method of measuring reaction time. I appreciate the ingenuity and cost effectiveness. I think it has great applicability especially if you are working with a club, small team, etc. that may not have the funds for something like ImPACT but is looking for a little more. It seems much more reasonable to attempt to baseline test a group of 20-30 people vs. a full team of 100+. I really think you can make a pretty strong evaluation from the SCAT3 and this would just add to that. It is clear though that the most important piece of the evaluation is education. If people are being honest about their symptoms there isn't much of a question. Generally by the time they are completely symptom free and have progressed through an RTP protocol (~7-10 days) the other types of testing are normalized.

For this tool specifically I think it would be interesting if they had some normalized values or a value that could be used to rule in/rule out (ie if your time is x you have a 60% risk of being concussed). That would help with the initial incorporation as an adjunct tool. Clearly individualized baselines are best though.

Nicole Cattano said...

Greg-I agree that this type of assessment can only add value towards interpretation/assessment of clinical evaluation for a concussion. Where it is practical, and get that it can be conducted on the sidelines... I do not think it should replace appropriate neuropsychological testing. As clinicians, we do not want to give administrators an option for appropriate management of athlete's health. But in an instance where our hands may be tied-more objective measures may be very beneficial.

Jason Shermer said...

Are there any good variations to this test, that measure different aspects of reaction time, to maybe "Trick" the learning curve?

Nicole Cattano said...

Jason-that's a great question that I do not know the answer to. You're absolutely right that we can't say that it is not the learning curve that caused no differences.

Does anyone have any ideas?

Jeffrey Driban said...

I don't think there are variations to this test yet. It's still fairly new. With that said I love the simplicity of it and that anyone could do it.

Sylvia Thelemaque said...

Incorporating reaction timed task as apart of evaluations for concussion would be great. Do you think it would help determine between the types of concussions such as a epidural hematoma and/or a subdural hematoma. Not that this would be a gold standard and give exact results to specifically determine the type of concussion. But it could help determine the level of severity

Will Bradley said...

Because there was a learing curve in both groups, do you think this testing for reaction time could be an affective tool to use for assessing concusions? If an athlete strugles and reactions worsen, is this something that would be appropriate to document? Or would the use of an IMPACT test results be more appropriate?

Nicole Cattano said...

Jeff-I agree with the simplicity nature of the task. It seems very easy to administer and to have any clinician utilized no matter their experience level.

Sylvia-remember that we are talking about diffuse mild traumatic brain injury with concussions. Not focal injuries such as sub/epi-dural hematomas. You would need to utilize some of your other clinical findings to likely help with your diagnosis of those more severe and potentially life-threateining brain injuries.

Will-you make a great point. I think that if an athlete struggles it is definitely worth using. The value of this tool is that it can be used on the sidelines...perhaps when we cannot utilize an ImPACT test. I would absolutely still have an athlete take an ImPACT, but if they failed or struggles with this task. I would take this as a sign of a concussion.

Remember that ImPACT has a reaction time test built into the software as well. This is just a simple, sideline task that will hopefully help to objectify your concussion evaluation findings.

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