Phil Newton

From Mouse to Man

Youtube helps identify a new tool in the evaluation of brain injury

Using Youtube to identify the Fencing Response

Posted Aug 28, 2009

How YoutubeTM helped researchers identify a new tool for rapid evaluation of head injury.

Boxing, bomb blasts, bar brawls, bike accidents and the Baltimore Ravens.......what do all these things have in common? They're all a cause of Traumatic Brain Injury, or TBI. To many people, that's a "bang on the head", the consequence of which might just be seeing stars.......or something much worse.

In any case of suspected TBI, rapid assessment of the severity of the injury is vital to ensuring a good recovery. Medical staff use a variety of indicators to determine whether a patient has suffered a TBI. Many of these, including amnesia and disorientation are subjective (require a response from the victim) and are not always reflective of the severity of the injury. More objective measures such as convulsions and vomiting do not occur very frequently and may be confounded by other factors such as the presence of alcohol.

Thus there is a need for a bigger panel diagnostic indicators for use in assessing head injury, especially for discerning between mild and moderate TBI where the victim may not show signs of gross damage but may or may not have sustained a serious internal injury.

With this need in mind, Ario Hosseini and Jonathan Lifshitz at the Spinal Cord and Brain Injury Center at the University of Kentucky set out to evaluate cases of TBI for evidence of diagnostic indicators. They used an ingenious approach in keeping with the modern age. Rather than heading out on a Saturday night dressed in white coats looking for bar-room brawls, Hosseini and Lifshitz simply logged into YoutubeTM where there exists a vast database of knockouts and heavy hits, mostly from boxing, mixed martial arts and the NFL.

Existing diagnostic markers of TBI include "tonic posturing preceding convulsion", meaning that the victim exhibits a distinct body pose prior to entering a convulsion. This body pose is very similar to the "en garde" position adopted at the beginning of a fencing bout.

The response is clearly visible in this YouTube TM video of NFL Baltimore Ravens player Willis McGahee getting knocked down by Ryan Clark of the Pittsburg Steelers. Note how the prone player has his right arm raised in the "en garde" position.

What Hosseini and Lifshitz observed was that this so-called "fencing response" is very frequent when an individual is knocked out. They scanned over 2000 Youtube videos and observed ~ three dozen in which the victim did not get back up. The fencing response occurred in two thirds of these "knockout" videos. Importantly most of these knockouts did not result in a convulsion, which I mentioned earlier is a fairly rare event. These observations suggested that, following a head injury, the fencing response and convulsions were separate phenomena with the fencing response being very common. Perhaps the fencing response was a useful marker of moderate head injury?

Back in the lab, Hosseini and Lifshitz probed into the fencing response. They found that it was most commonly associated with a blow to a part of the brain called the brainstem, which is located at the base of the brain on top of the spinal cord. Specifically, Hosseini and Lifshitz found that the fencing response was associated with damage to a part of the brainstem called the lateral vestibular nucleus. The force of the blow ruptures blood vessels, the contents of which appear to activate the lateral vestibular nucleus, producing the characteristic extension and stiffening of the forearm that defines the fencing response.

By conducting a series of detailed laboratory studies, Hosseini and Lifshitz determined that the fencing response only occurs in response to moderate TBI, it did not occur in response to a mild TBI that still might otherwise produce concussion and/or knockout.

The authors conclude that the fencing response is a useful marker of moderate brain injury, suggesting it should be added to the panel of assessments made immediately following a head injury.

This author concludes that research is changing. The availability of huge public databases such as youtube means that a mass of data is now available to everyone. Careful detailed analysis of these data can be a great "hypothesis-generator" for more controlled laboratory studies.

TBI is, unfortunately, a growth area, especially in the military. Improvments in body armor mean that soldiers are now much more likely to survive a blast that would previously have killed them through damage to internal organs. Instead, they are left with intact internal organs but the consequences of a severe blast injury to the head (read about it here).

In fact, TBI is emerging as the signature injury of the ongoing Iraqi and Afghan conflicts due to the prevalence of roadside blasts. Nearly six out of 10 casualties entering the military hospital at the Walter Reed Medical Center in Washington DC have been diagnosed with some degree of traumatic brain injury.

TBI is also a prominent issue in professional sports, especially those such as boxing and NFL where a hefty blow to the head is not uncommon. In sporting cases, the need is often to determine whether the victim is safe to return to the field of play or needs more detailed medical attention.

The fencing response is a useful tool in evaluating these head injuries and ensuring that the victim receives the appropriate level of care.

 ABC News (WTVQ Lexington, Kentucky) report on the fencing response.

Wikipedia entry on the fencing response.

The full Hosseini and Lifshitz paper in the September 2009 edition of "Medicine & Science in Sports & Medicine", official journal of the American College of Sports Medicine (subscription or payment required)

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