Measurable brain changes were seen in children after a single season of
playing youth football, even without a concussion diagnosis, according to a new
study published online in the journal Radiology.
According to USA Football, there are approximately 3 million young athletes
participating in organized tackle football across the country. Numerous reports
have emerged in recent years about the possible risks of brain injury while
playing youth sports and the effects it may have on developing brains. However,
most of the research has looked at changes in the brain as a result of
‘Young players who experienced more cumulative head impact exposure had more changes in brain white matter, specifically decreased FA, in specific parts of the brain.’
"Most investigators believe that concussions are bad for the brain, but
what about the hundreds of head impacts during a season of football that don't
lead to a clinically diagnosed concussion? We wanted to see if cumulative
sub-concussive head impacts have any effects on the developing brain,"
said the study's lead author, Christopher T. Whitlow, M.D., Ph.D., M.H.A.,
associate professor and chief of neuroradiology at Wake Forest School of
Medicine in Winston-Salem, N.C.
The research team studied 25 male youth football players between the ages of
8 and 13. Head impact data were recorded using the Head Impact Telemetry System
(HITs), which has been used in other studies of high school and collegiate
football to assess the frequency and severity of helmet impacts. In this study,
HITs data were analyzed to determine the risk weighted cumulative exposure
associated with a single season of play.
The study participants underwent pre- and post-season evaluation with
multimodal neuroimaging, including diffusion tensor imaging (DTI) of the brain.
DTI is an advanced MRI technique, which identifies microstructural changes in
the brain's white matter. In addition, all games and practices were video recorded
and reviewed to confirm the accuracy of the impacts.
The brain's white matter is composed of millions of nerve fibers called
axons that act like communication cables connecting various regions of the
brain. Diffusion tensor imaging produces a measurement, called fractional
anisotropy (FA), of the movement of water molecules in the brain and along
In healthy white matter, the direction of water
movement is fairly uniform and measures high in FA. When water movement is more
random, FA values decrease, which has been associated with brain abnormalities
in some studies.
The results showed a significant relationship between head impacts and
decreased FA in specific white matter tracts and tract terminals, where white
and grey matters meet.
"We found that these young players who experienced more cumulative head
impact exposure had more changes in brain white matter, specifically decreased
FA, in specific parts of the brain," Dr. Whitlow said. "These
decreases in FA caught our attention, because similar changes in FA have been
reported in the setting of mild TBI."
It is important to note that none of the players had any signs or symptoms
"We do not know if there are important functional changes related to these
findings, or if these effects will be associated with any negative long-term
outcomes," Dr. Whitlow said.
"Football is a physical sport, and players may have many physical
changes after a season of play that completely resolve. These changes in the brain
may also simply resolve with little consequence. However, more research is
needed to understand the meaning of these changes to the long-term health of
our youngest athletes."