Knocked Out: Bell Ringing
David Hovda couldn't believe his eyes.
One afternoon, the director of UCLA's Brain Injury Research Center was contacted by the school's football team physician to scan the brain of a concussed middle linebacker from the university squad. "He said his bell was rung, but he was very cognizant," recalls Hovda. "He remembered the name of the president and his girlfriend and the number of classes he was taking."
Hovda went ahead and captured an image of the player's brain using a Positron Emission Tomography (PET) scanner, one of the only noninvasive methods to capture brain-chemistry images. Later that day, Hovda also scanned the brain of a comatose patient who had been in a car accident three days earlier. "The patient was very, very, very severely brain-injured and wasn't moving at all."
The following day, Hovda returned to the office to look at the scans, which showed that each brain was in a state of depression and lacked glucose, the brain's primary fuel. (A healthy brain, according to the scanner's color-coded system, will project an array of reds, while a depressed brain will be predominantly blue.)
What shocked Hovda was that the unmistakably blue images were identical, even though one patient carried on with his normal life while the other lay motionless in a coma.
"We thought it was a fluke, so we did it over and over and over again to make sure," says Hovda. "What we found is it doesn't make a difference how light or hard you were hit. Once your brain reaches a certain bio-energetic state from concussion, then it starts this whole wave of neurochemical and metabolic cascade."
In 2001, Hovda — who adds that a similar discovery was made in the 1930s but was subsequently ignored — published a paper on his findings "that really changed the culture in the NFL and the Department of Defense," he explains. Before that, he says, many thought that concussions were a psychological phenomenon.
"What [Hovda's study] tells us is the brain isn't normal a day or two after a concussion," says Dr. Mark Ashley, founder of the Centre for Neuro Skills. "During that period of vulnerability, we don't want to risk additional injury and insult to the brain. If we were to have this type of vulnerability to the heart, people would instinctively say to take it easy with that muscle until that muscle has recovered. We don't have a similar sensitivity to the brain, however, and we should."
Compounding the metabolic roller coaster, according to Ashley, occurs when concussed athletes are participating in summer and fall sports. "If your core body temp is above normal or if you're dehydrated, we see a rapid acceleration of neurodegeneration within minutes to hours following concussion."
This deterioration, says Ashley, may also include microscopic impairments to a brain's axon function, which helps transmit new impulses and information to different parts of the brain. The only way to detect these types of damages is during autopsy.
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