Brain Health at Risk
By University of Rochester Medical Center
.webp)
But what about all the other impacts to the head—like
hitting the ground during a tackle, colliding with another helmet during a
block, a foul tip off a baseball bat hitting a player’s mask during a game or
practice, or a soccer player heading the ball toward the goal? Players can
often stay in the game in the short term, but what do these repeated blows to
the head mean for their long-term brain health?
Concussion research has introduced protocols that are
changing the landscape of contact sports. These range from professional
athletes following multistep return-to-play protocols to youth soccer players
being prohibited from heading the ball until they are 11 years old. It’s widely
understood that a concussion requires treatment and care, much like a bad
sprain or a broken bone. But what happens when someone hits their head once,
twice—or multiple times—without any obvious signs of injury?
Jeff Bazarian, MD, professor of Emergency Medicine and Neurology at the University of Rochester Medical Center, whose research has transformed what we know about concussions, believes these repeated hits to the head are a silent danger. Each blow can compound the one before, sometimes without symptoms to warn of a growing injury.
When a person’s occupation or activity exposes them to
repeated head hits–like members of the military or athletes–they can experience
subtle declines in neurologic function, such as balance, eye movements, and
rapid decision-making. These declines in neurologic function are not currently
detectable by a doctor but can impair athletic or military performance and
increase the risk of sustaining other injuries. In the long term, these
repeated head hits may contribute to developing serious neurodegenerative diseases
or disorders. However, unlike concussions, there is no current standard of care
to track, prevent, or treat these hits because there is still much to learn
about them.
“We’re trying to determine if we can detect and mitigate the
acute effects of exposure to repetitive head hits on the brain. Do these hits
alter neurologic function in a way we can pick up using objective measures
suitable for use in low-resource environments like battlefields and athletic
fields? If so, what can be done to return neurologic function back to baseline
as quickly as possible? In a sense, we are borrowing from the field of
occupational medicine by applying a brain health monitoring approach to
individuals exposed to an environmental factor (repetitive head hits) that
increases their risk for neurologic injury. Our hope is that one day this
approach may lower the longer-term risk of neurodegeneration in those exposed,”
said Bazarian, who recently received a $6.3-million grant from the Army Medical
Research Acquisition Activity (ARMY MRAA) to lead a four-year, multi-pronged,
and multi-site study to better understand these repetitive hits to the head,
with goals to find ways to detect, prevent injury, and treat them.
Building the team
Four institutions will recruit and track college athletes
for this study. In the fall, researchers will recruit male football players and
female soccer players from teams at the University of Rochester, University of
Buffalo, Indiana University, and The Citadel, a military college in South
Carolina. Participants will wear mouthguards with special sensors during every
practice and game to keep track of the number of head hits and magnitude,
including direction and force, and brain proteins in the blood will be tracked
before and after games. Previous
research has shown that the brain protein GFAP is elevated after a single
football game and that elevation is related to head hits. Last year, the
FDA approved a blood test to detect GFAP and the brain protein UCHL1 to be used
to determine if a person with a concussion needs a CT scan.
Participants will also complete several tests before and
after a handful of games during the season.
Before & after game tracking tests:
- Quantitative
EEG – five minutes of brainwave activity.
- Blink
reflex to test eye lid closure reaction time.
- Hand-eye
reaction time.
- Near-point
convergence – measuring the point of focus of a single pen point moving
toward the eyes. The range can vary by 2-6 centimeters before and after a
game.
Researchers anticipate finding subtle abnormalities in
athletes’ performance on these tests, but none can currently be used as a
diagnosable tool in the clinic. “A soccer or football player can go through a
whole season of repeated head hits and have no symptoms and a normal physical
exam. But we hypothesize that one of these tests, or a combination of them,
will be a little bit abnormal,” said Bazarian, “and that these abnormalities
will correlate with head hit exposure and with neurologic injury in our reference
standard, changes in structure of the retina of the eye.”
Seeing into the brain
Researchers aim to see this change in the brain using
optical coherence tomography (OCT). This non-invasive imaging technique uses
light to create pictures of the back of the eye, including the retina and
nerves coming from the brain. This tool is widely available at ophthalmologist
offices and provides consistent outputs between machines. Bazarian and retina
expert Steven Silverstein, PhD, professor of Psychiatry, Center for Visual
Science, Neuroscience, and Ophthalmology, have already used this technique to
correlate the number of head hits some University of Rochester football players
have had during a season to changes to their retinas.
Could time or exercise be treatment approaches?
At the end of the football and soccer seasons, researchers will split the athletes with evidence of clinically silent neurologic abnormalities from repetitive head hits into two groups. One group will rest for two weeks. The other group will be treated with a daily aerobic exercise for 20-30 minutes. The latter is the current standard of care for a concussion. Researchers anticipate that more subjects in the aerobic exercise group will have improvements in neurologic function than in the rest group.
But what about during the season? Is there a threshold of
head hits that a player can sustain and stay healthy? Or is it less about the
number of hits and more about the interval of time between the hits? Using a
soccer ball heading machine, researchers will closely monitor participants who
head the ball in sessions every day and compare those who have days off between
heading sessions. “The question is, if we put some time between these sessions
of head hits, does that reduce the impact of these head hits on these subtle
neurologic changes,” said Bazarian. “We think it probably will.”
How many hits are too many?
Researchers will also investigate if there is a threshold
for how many head hits the brain can sustain before abnormalities present.
Using an animal model, study co-investigators at Boston Children’s Hospital
will try to understand if there is a threshold number of hits below which there
is no demonstrable brain injury, or if all hits are harmful.
The research was funded by the U.S. Army Medical Research
Acquisition Activity.
