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Sidelined: Sports Concussions

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It’s football season, but this fall there won’t be as many hard-hitting practices in California.

In January, a new state law, signed last year by Gov. Jerry Brown, took effect,  limiting full-contact practice for middle and high-school students to twice per week, and requiring any student who suffered a concussion to wait at least a week before returning to play.

The law is in part a reflection of the increasing concern over concussions, brain injuries caused by a blow to the head or a rapid acceleration and deceleration to the head which could occur during a car accident, collision during a sporting event, or other traumatic event.

Each year, two million people in the U.S. suffer a concussion, according to the Centers for Disease Control.

Concussions are common in contact sports such as soccer and football. Image by Blake McHugh
Concussions are common in contact sports such as soccer and football. Image by Blake McHugh

“The brain hits these bony structures inside of the skull, and that causes damage to occur,” said Eric Freitag, a neuropsychologist based in Walnut Creek who administers cognitive testing to high school students who play contact sports such as football and soccer.


Common symptoms of concussions include fatigue, headache, nausea, blurriness of vision, memory loss and occasionally, loss of consciousness.

Although most people recover from concussions within a week to 10 days, a significant number of patients may have difficulty returning to work or school weeks or months after their head injuries.

Dr. Geoffrey Manley looks at CT and MRI scans at the Brain and Spinal Injury Center in San Francisco.
Dr. Geoffrey Manley looks at CT and MRI scans at the Brain and Spinal Injury Center in San Francisco. Image by Blake McHugh

“There’s a subset of these individuals, at least 15 percent, that go on to have persistent problems,” said Dr. Geoffrey Manley, Chief of Neurosurgery at San Francisco General Hospital. “These aren’t simply having your bell rung, these are life-changing events.”

Doctors often grade traumatic brain injuries according to whether they are considered “mild,” “moderate” or “severe.”  Manley believes more precision is needed to better define, diagnose and treat these injuries, which can vary widely from patient to patient.

In 2010, he received funding from the National Institutes of Health to launch a pilot study that recruited 600 concussion patients from several national trauma centers, and tracked their progress for up to six months following their injuries.

Each of the patients had a CT scan, an imaging technique that Manley calls “the gold standard” of evaluating brain injuries.

Patients also had an MRI scan which detected the presence of micro-bleeds and bruising in the brain for nearly 30 percent of patients who otherwise had normal CT scans.

An MRI scan reveals a micro-bleed in the brain of a concussion patient. Image courtesy of Blake McHugh for KQED Science
An MRI scan with an arrow indicating a micro-bleed in the brain of a patient who suffered a concussion. Image by Blake McHugh 

“These patients with these abnormalities on their MRI scan took much longer to recover and did worse at three months,” Manley said.

In 2013, he received additional NIH funding to expand the study by recruiting 3,000 concussion patients across the United States. In addition to traditional MRI scans, the research team is also using an advanced MRI imaging technique that helps visualize structural damage to white matter fiber tracts that provide long-range communication between different parts of the brain.

Manley and his colleagues at UC San Francisco are looking for genetic differences in dopamine, a critical neurotransmitter in the brain, which may make some people particularly susceptible to longer recovery times following concussions. The research team has also identified a blood-based protein that appears to be released from the brain following a traumatic brain injury. The research may one day yield a blood test that could help diagnose a concussion if imaging techniques aren’t readily available.

“This way, we can develop a more personalized approach to the treatment, because there’s no one-size-fits-all for something as complicated as a brain injury,” Manley said.

A special thanks to Dr. Alexander Leemans for the kind use of his 3D tractography brain imagery and animations. This video story was originally produced and updated by Sheraz Sadiq. 

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