Head impacts from one season of football produce brain cell changes
Repeated impacts to the heads of high school football players caused measurable changes in their brains, even when no concussion occurred, according to new research.
Researchers from UT Southwestern Medical Center's Peter O'Donnell Jr. Brain Institute and the Wake Forest University School of Medicine gathered data from high school varsity players who donned specially outfitted helmets that recorded data on each head impact during practice and regular games. They then used experimental techniques to measure changes in cellular microstructure in the brains of the players before, during and after the season.
"Our findings add to a growing body of literature demonstrating that a single season of contact sports can result in brain changes regardless of clinical findings or concussion diagnosis," said senior author Dr. Joseph Maldjian, Chief of the Neuroradiology Division and Director of the Advanced Neuroscience Imaging Research Lab, part of the Peter O'Donnell Jr. Brain Institute at UT Southwestern.
In the study, appearing in the Journal of Neurotrauma, a team of investigators at UT Southwestern, Wake Forest University Medical Center and Children's National Medical Center evaluated about two dozen players over the course of a single football season.
The group of players was not large enough to draw conclusions about the differences in impacts between positions, researchers said, and additional studies will be needed to determine what the deviations mean clinically for individuals.
"Studies like this are important to understand how and where long-term damage might be occurring, so that we can then take the necessary steps to prevent it," said first author Dr. Elizabeth Davenport, a postdoctoral researcher in the Department of Radiology and the Advanced Imaging Research Center at UT Southwestern.
During the pre-season each player had an MRI scan and participated in cognitive testing, which included memory and reaction time tests.
During the season they wore sensors in their helmets that detected each impact they received. Post-season, each player had another MRI scan and another round of cognitive tests.
Researchers then used diffusional kurtosis imaging (DKI), which measures water diffusion in biological cells, to identify changes in neural tissues. DKI analysis has been used to detect changes in neural tissues to study brain development, as well as brain injury and disease including autism spectrum disorders, attention deficit/hyperactivity disorder (ADHD), Alzheimer's disease, traumatic brain injury (TBI), stroke, schizophrenia and mild cognitive impairment.
DKI also allowed the researchers to measure white matter abnormalities. White matter consists of fibers that connect brain cells and can speed or slow signaling between nerve cells. In order for the brain to reorganize connections, white matter must be intact and the degree of white matter damage may be one factor that limits the ability of the brain to reorganize connections following TBI.
"Work of this type, combining biomechanics, imaging, and cognitive evaluation is critical to improving our understanding of the effects of subconcussive impacts on the developing brain," said Dr. Maldjian, Professor of Radiology and the Advanced Imaging Research Center at UT Southwestern. "Using this information, we hope to help keep millions of youth and adolescents safe when engaged in sports activities."
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