Aug. 17, 2010 -- Repetitive head traumas and concussions, including the type sustained by many professional football players, may increase risk for developing a motor neuron disease that looks and acts a lot like amyotrophic lateral sclerosis (ALS) or Lou Gehrig’s disease. The disease is calledchronic traumatic encephalopathy.
The new findings appear in the September issue of the Journal of Neuropathology and Experimental Neurology.
"We are not suggesting that this is the same disease as ALS," says study researcher Robert Cantu, MD, clinical professor of neurosurgery at Boston University School of Medicine and co-director of The Center for the Study of Traumatic Encephalopathy there. "We think this is a disease that mimics ALS in terms of the spinal cord."
ALS attacks nerve cells in the brain and spinal cord resulting in progressive muscle weakness and wasting, according to the ALS Association. When chronic traumatic encephalopathy affects the brain and spinal cord, the symptoms are similar to what is seen in ALS.
Testing Tissue of Pro Athletes
In the new National Football League-funded study,researchers looked at tissue samples taken from the brain and spinal cords of 12 deceased athletes. Three of the 12 athletes -- pro football players Wally Hilgenberg and Eric Scoggins and one professional boxer/veteran -- had developed a motor neuron disease; two died after being diagnosed with ALS.
But the new research suggests that the three athletes may have actually had chronic traumatic encephalopathy. There was an abnormal form of tau protein in the brain and spinal cords of all 12 athletes. This abnormal protein is a hallmark of chronic traumatic encephalopathy.
What's more, 10 of the 12 also showed a second abnormal protein called TDP-43 in their brains. Only three of those 10 also had evidence of this protein in their spinal cord, and these were the same three athletes who were diagnosed with motor neuron disease, the researchers report.
This may have resulted in some of the ALS-like symptoms that led to the erroneous ALS diagnosis, Cantu explains. TDP-43 is found in brains of people who are diagnosed with ALS, but the amount was more extensive in the athletes than in their counterparts with true ALS.
Did Lou Gehrig Have Lou Gehrig's Disease?
The new findings suggest that professional baseball player Lou Gehrig may not have died from Lou Gehrig’s disease.
"Maybe Lou Gehrig had chronic traumatic encephalopathy," Cantu says. He sustained at least five documented concussions during his career. In addition, there are reports that he was knocked unconscious for five minutes after being struck in the head with a ball. He also played football at Columbia University before joining the New York Yankees.
Gehrig's brain and spinal cord tissue cannot be analyzed, so the truth may never come to light.
Going forward, "we need to get a better grasp of the incidence of this," says Cantu, who was recently appointed senior advisor to the National Football League Head, Neck and Spine committee.
"From this research hopefully will come animal research to get an animal model of the disease and then, we can work on medications and other therapies that could modify the disease in animals and then if successful, go on to humans," Cantu says, adding that the new study is very preliminary.
Brain Injuries of Combat Veterans
Time is of the essence. Traumatic brain injury has become the signature injury of the Afghanistan and Iraq war, suggesting that some veterans may be prone to this ALS-like disease.
"I suspect we see it in individuals with injuries such as blast injury," he says. Given the numbers of soldiers who develop these injuries, "this is very worrisome," Cantu says.
"The study just provides new information on the possibility that some motor neuron diseases are due to multiple concussion and head trauma from collision sports injuries," says Raymond A. Sobel, MD, a professor of pathology at Stanford University Medical Center and the editor of the Journal of Neuropathology and Experimental Neurology. Earlier studies have suggested that there was a link between head trauma and these diseases, but the new work is the first time that there has been evidence seen in the brain and spinal cord.
More study is needed before any sweeping conclusions can be drawn, he tells WebMD.
"This research may lead to a better understanding of what is happening in people with these diseases at a molecular level, which could lead to therapies or help preventing also in people who are at risk," he says.
"It is premature to say we may have misdiagnosed patients who were thought to have ALS," says Erik Pioro, MD, PhD, director of the section for ALS and related disorders at the Cleveland Clinic in Ohio.
"I think that it suggests a connection between trauma and motor neuron degeneration," he says.
Perhaps ALS is not a single disease, he adds. "ALS, as we know it, may not be a single disease, but a syndrome," he says. "This research provides a piece in the puzzle of our understanding of what ALS is and is teaching us that it is more of a complex condition."