Dr. Jamshid Ghajar: Multiple Definitions of Concussion

Concussions have been around since the beginning of time, but our knowledge and treatment of them are and need to be vastly different. It all starts with the need for one, sound definition.

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Concussion has been around for a very long time, obviously, thousands of years, and ever since anyone had a head injury concussion has been around. And I think people in some ways took it lightly. They thought, well, it's something that's transient. You get a ding, especially in sports. It's something that you shake off, and you go back to the game or you rest a little bit, and everything gets better. And we've found not only from athletes but also returning troops that some of these symptoms and cognitive problems are persistent, and they interfere with a person's quality of life in terms of performing their daily functions, their work, their social interactions, and it can be incredibly disruptive to the point people can't hold down jobs. They have problems in their personal relationships, a lot of depression, suicides and so on. And so this is really--focus people that have originally-- a lot of neurosurgeons that have been looking at severe TBI to now look at concussion or mild TBI as well and from a scientific point of view, what's going on here? These people look like they're awake. A lot of them have CT scans and MRIs that are normal, but obviously, a lot of these folks are suffering from their head injuries, and we have to find out what's going on. That's fine, but you've got to define what it is before you can really target it in terms of diagnostics and therapeutics. And so far, we've had a lot of people put a tremendous amount of work in to come up with an expert-based consensus process definition of concussion, and I'll refer to it as concussion as opposed to mild traumatic brain injury because really concussion is under the umbrella of mild traumatic brain injury. Mild traumatic brain injury means you're awake after a head injury. Really there's other people that have defined it a little further in terms of imaging, but in terms of what we see in the emergency room, Glasgow coma scale, somebody who is awake after a head injury. Concussion has got a little bit more to it, and that's where a lot of consensus groups have focused their efforts on in terms of definition. If we look at that, there are over 30 different definitions, and we're trying to come to some standard definition based upon what the evidence is. Now, what do I mean by the evidence? Now, the evidence in a definition is a little harder to figure out as opposed to what's the evidence for a certain diagnostic or a certain therapeutic. When we do the guidelines for severe traumatic brain injury, we're looking at, say, the effect of Mannitol on intracranial pressure, and outcome in patients with severe traumatic brain injury. Then we can look at the evidence for therapeutics in that area. Now, how do you do a definition? And so we put together a proposal and said we think that looking at the evidence in terms of the signs, the symptoms, the neurology, the cognitive functions of these patients after a presumed head injury, and we look at the prevalence of these signs, symptoms, and neurocognitive deficits after the head injury over, say, a period of 3 months. And let's look at that picture, and let's look at the evidence and weigh the evidence in terms of how good the quality of evidence is. If we create that picture, what can come out of that is really a definition. Here's what we see. Here's the natural history of what happens after somebody has a head injury. That has not been done yet. We don't have a clear picture. We all have our own individual assumptions and biases about what we think a concussion is, but we really need to look at the evidence, and then from the evidence, a definition will come out of that. We put together a proposal. It was funded by the Department of Defense recently. It's a partnership with the CDC, the Centers for Disease Control, and specifically Richard Hunt, head of Injury Prevention. We partnered together to really come up with some kind of definition that's based upon best evidence. And the federal agencies are involved, medical societies, stakeholders in this area are all involved. We want to get the word out. We want people to be involved in this and know what we're doing. And after we go through this process of getting the evidence, the task force, which are representatives of federal agencies, medical societies, and other stakeholders, will be able to look at this evidence in a very clear way and that interaction--from the interaction, a definition will come out of that.
Posted on BrainLine February 2, 2012.

Produced by Noel Gunther and Justin Rhodes, BrainLine.