In this episode, we discussed the utility of concussion imaging technology following concussion (e.g., MRI, CT scan), when and how often should someone sleep after a concussion injury, and the stretch shear theory.
Concussion News: Athletes can ‘sandbag’ popular concussion test
To kick off the show, Dr. Marshall talked about a recent news article from the Washington Post titled “Athletes can easily trick popular concussion test, study finds.” The article reports on a Butler University study where many students were able to trick a well-known computerized neurocognitive test (CNT), stating “half of test subjects were able to defeat the flagging mechanisms without being coached.”
What is ‘sandbagging’ and why is this a problem? An athlete purposely exerts less effort so that they would have to match that lower threshold to possibly return to action after a head injury. Basically, they try to trick the test.
As always, baseline testing should include a series of physical and neurocognitive tests. They have shown to have greater test retest reliability when used together, and it may reduce the likelihood that an athlete could successfully ‘sandbag’ a baseline test. More tests. Greater difficulty to trick them all.
Furthermore, we recommend that baseline testing is overseen by a licensed healthcare practitioner with training in concussion management. That way, they can identify whether or not an athlete is actually trying their best.
Furthermore, return to play decisions should not be made on the basis of a single test. In many cases, preseason multimodal baseline testing can help to inform these decisions. But, these decisions should be made by a trained healthcare provider.
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Concussion Imaging: MRI or CT Scan
MRI is normal after a concussion because an MRI is a structural imaging modality. It looks at the structure of the brain.
Concussion is a functional injury. The injury changes how the brain functions, but the structure remains intact. There’s no damage from a structural standpoint.
Therefore, when you look at an MRI or CT scan, it’s going to be normal. The purpose of these scans is to look for something more serious. For example, to pick up skull fractures or brain bleeds. Dr. Marshall suggests that these are only meant to be done when some red flags are present, which may include: low Glasgow-Coma scale two hours after injury, increasing headache, vomiting, significant balance impairments, and other overt neurological signs.
Watch or listen below for the full discussion. Speak to your healthcare provider if you suspect a concussion.
When to sleep after concussion?
Should someone who suffered a concussion be woken up every hour? Dr. Marshall discusses the traditional way of thought in comparison to what the current research shows. Always contact your healthcare provider if you have any questions about the right approach for you.
Stretch Shear Theory
The old theory of a concussion injury was that it was a coup contra coup injury. Research shows that the ‘stretch shear’ theory is the most current thought for concussion mechanism. Concussion is caused by acceleration and/or deceleration leading to a stretching and shearing of neurons. For more information, listen to the full episode or check out this article on the biomechanics of concussion.