You are leaving Medscape Education
Cancel Continue
Log in to save activities Your saved activities will show here so that you can easily access them whenever you're ready. Log in here CME & Education Log in to keep track of your credits.



Acute Brain Changes Linked to Head Trauma in Sports

  • Authors: News Author: Deborah Brauser
    CME Author: Charles P. Vega, MD
  • CME / ABIM MOC / CE Released: 12/14/2016
  • Valid for credit through: 12/14/2017, 11:59 PM EST
Start Activity

Target Audience and Goal Statement

This article is intended for primary care clinicians, neurologists, sports medicine specialists, nurses, and other clinicians who care for athletes.

The goal of this activity is to provide medical news to primary care clinicians and other healthcare professionals in order to enhance patient care.

Upon completion of this activity, participants will be able to:

  1. Evaluate the effects of a season of football on the brain architecture of children
  2. Analyze acute and subacute neurologic outcomes after a session of heading soccer balls


As an organization accredited by the ACCME, Medscape, LLC, requires everyone who is in a position to control the content of an education activity to disclose all relevant financial relationships with any commercial interest. The ACCME defines "relevant financial relationships" as financial relationships in any amount, occurring within the past 12 months, including financial relationships of a spouse or life partner, that could create a conflict of interest.

Medscape, LLC, encourages Authors to identify investigational products or off-label uses of products regulated by the US Food and Drug Administration, at first mention and where appropriate in the content.


  • Deborah Brauser

    Journalist, | Medscape Cardiology


    Disclosure: Deborah Brauser has disclosed no relevant financial relationships.


  • Robert Morris, PharmD

    Associate CME Clinical Director, Medscape, LLC


    Disclosure: Robert Morris, PharmD, has disclosed no relevant financial relationships.

CME Author(s)

  • Charles P. Vega, MD

    Health Sciences Clinical Professor of Family Medicine, University of California, Irvine, School of Medicine, Irvine, California


    Disclosure: Charles P. Vega, MD, has disclosed the following relevant financial relationships:
    Served as an advisor or consultant for: Allergan, Inc.; McNeil Consumer Healthcare
    Served as a speaker or a member of a speakers bureau for: Shire 

CME Reviewer/Nurse Planner

  • Amy Bernard, MS, BSN, RN-BC

    Lead Nurse Planner, Medscape, LLC


    Disclosure: Amy Bernard, MS, BSN, RN-BC, has disclosed no relevant financial relationships.

Accreditation Statements

Medscape, LLC is accredited by the American Nurses Credentialing Center (ANCC), the Accreditation Council for Pharmacy Education (ACPE), and the Accreditation Council for Continuing Medical Education (ACCME), to provide continuing education for the healthcare team.

    For Physicians

  • Medscape, LLC designates this enduring material for a maximum of 0.25 AMA PRA Category 1 Credit(s)™ . Physicians should claim only the credit commensurate with the extent of their participation in the activity.

    Successful completion of this CME activity, which includes participation in the evaluation component, enables the participant to earn up to 0.25 MOC points in the American Board of Internal Medicine's (ABIM) Maintenance of Certification (MOC) program. Participants will earn MOC points equivalent to the amount of CME credits claimed for the activity. It is the CME activity provider's responsibility to submit participant completion information to ACCME for the purpose of granting ABIM MOC credit.

    This Enduring Material activity, Medscape Education Clinical Briefs, has been reviewed and is acceptable for credit by the American Academy of Family Physicians. Term of approval begins 9/1/2016. Term of approval is for one year from this date. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Approved for 0.25 AAFP Prescribed credits.

    Medscape, LLC staff have disclosed that they have no relevant financial relationships.

    AAFP Accreditation Questions

    Contact This Provider

    For Nurses

  • Awarded 0.25 contact hour(s) of continuing nursing education for RNs and APNs; none of these credits is in the area of pharmacology.

    Contact This Provider

For questions regarding the content of this activity, contact the accredited provider for this CME/CE activity noted above. For technical assistance, contact [email protected]

Instructions for Participation and Credit

There are no fees for participating in or receiving credit for this online educational activity. For information on applicability and acceptance of continuing education credit for this activity, please consult your professional licensing board.

This activity is designed to be completed within the time designated on the title page; physicians should claim only those credits that reflect the time actually spent in the activity. To successfully earn credit, participants must complete the activity online during the valid credit period that is noted on the title page. To receive AMA PRA Category 1 Credit™, you must receive a minimum score of 75% on the post-test.

Follow these steps to earn CME/CE credit*:

  1. Read the target audience, learning objectives, and author disclosures.
  2. Study the educational content online or printed out.
  3. Online, choose the best answer to each test question. To receive a certificate, you must receive a passing score as designated at the top of the test. We encourage you to complete the Activity Evaluation to provide feedback for future programming.

You may now view or print the certificate from your CME/CE Tracker. You may print the certificate but you cannot alter it. Credits will be tallied in your CME/CE Tracker and archived for 6 years; at any point within this time period you can print out the tally as well as the certificates from the CME/CE Tracker.

*The credit that you receive is based on your user profile.


Acute Brain Changes Linked to Head Trauma in Sports

Authors: News Author: Deborah Brauser CME Author: Charles P. Vega, MDFaculty and Disclosures

CME / ABIM MOC / CE Released: 12/14/2016

Valid for credit through: 12/14/2017, 11:59 PM EST


Clinical Context

The issue of subacute head injury in sports has caught the attention of the larger public, particularly in cases of damage to children and adolescents. There is increasing evidence that even subacute head trauma, not associated with concussion, can produce deleterious functional and even anatomic effects on the central nervous system.

Two studies address this issue. The first, by Whitlow and colleagues,[1] observed 25 male youth football players between 8 and 13 years old for the 2012-2013 season, with magnetic resonance imaging (MRI) performed before the season and at the end of the season. Children with a history of concussion during the season were excluded from study participation.

The results of this study have been published online October 24, 2016, in Radiology. The researchers found that there were changes in functional anisotropy, which is used to measure axonal diameter and myelination, in comparing preparticipation MRI with postseason MRI. These changes were most prominent in the inferior fronto-occipital fasciculus.

The second study, by Stewart and colleagues, evaluates the objective effects on brain function after a heading exercise among soccer players.[2] The results of this study are summarized in "Study Highlights."

Study Synopsis and Perspective

Head impact exposures during youth and young adult sports are associated with acute changes in brain function, and with cognitive impairment -- even in those who do not receive concussions, suggests 2 new studies.

The first included 25 boys 8 to 13 years old. During just 1 single season of football, there was a significant association between subconcussive head impact and fractional anisotropy changes in white matter tracts, as shown with diffusion-tensor imaging.

"There's expert consensus that concussions are bad for the brain. But we wondered about all the other head impacts that can occur that don't lead to a concussion and questioned: should we be worried about them?" coinvestigator Christopher T. Whitlow, MD, PhD, associate professor and chief of neuroradiology at Wake Forest School of Medicine in Winston-Salem, North Carolina, told Medscape Medical News.

"We were able to detect a very subtle change in the white matter of the brain. But we don't yet know whether this persists over a long period of time," said Dr Whitlow. The findings were published online October 24 in Radiology.[1]

The second study, which was published online October 22 in EBioMedicine and examined 19 adult amateur soccer players,[2] showed a significant increase in corticomotor inhibition immediately after routine head-butting of a ball, which was the primary outcome measure.

Reductions in memory were also found, but this result, as well as the primary finding, normalized 24 hours after the "heading" event.

Although the changes in brain function were transient, "these effects may signal direct consequences of routine soccer heading on (long-term) brain health which requires further study," write the researchers.

Coinvestigator William Stewart, MD, Department of Neuropathology at Queen Elizabeth University Hospital at the University of Glasgow, Glasgow, United Kingdom, noted that both studies should be treated with caution because of the low numbers of participants.

"So 'take-home messages' are hard to extrapolate," Dr Stewart said to Medscape Medical News.

However, "taking all we currently know, I think we can say there is enough in the data to date to suggest we should be limiting 'voluntary' exposure to head impact as much as possible, whenever at all possible."

Football Affects White Matter Integrity

The first study included 25 participants in a youth football league (mean age, 11.7 years) who played the sport during the 2012-2013 season. None had a clinically diagnosed concussion.

The Head Impact Telemetry system recorded head impact data, which was then "quantified as the combined-probability risk-weighted cumulative exposure (RWECP)," report the investigators.

The system is placed on the sidelines of a field during play and is fed real-time data from sensors embedded into padding gaps in the players' helmets. All participants also underwent MRI.

Seasonal fractional anisotropy changes were assessed in the following white matter tracts: inferior fronto-occipital fasciculus, superior longitudinal fasciculus, and inferior longitudinal fasciculus.

Results showed a significant association between RWECP and decreased fractional anisotropy in the left inferior fronto-occipital fasciculus (P =.003), as well as in that tract's core (P =.007) and terminals (P <.001) and in the right superior longitudinal fasciculus fiber terminals "where white matter and gray matter intersect" (P =.03).

Associations between impact exposure and decreased fractional anisotropy in the whole right superior longitudinal fasciculus missed significance (P =.08). There were also no significant associations with changes in the inferior longitudinal fasciculus.

Overall, the results suggest that "an increase in subconcussive head impact exposure may have an effect on WM [white matter] integrity in youth athletes," write the investigators.

"This study adds to the growing body of evidence that a season of play in a contact sport can result in brain changes at MR imaging, even in the absence of concussion."

Dr Whitlow noted that the fractional anisotropy decreases were especially interesting because similar changes have been reported in cases of mild traumatic brain injury. However, there are still many questions, including whether the changes go away or whether more changes occur with more seasons of play.

"I think this has made us more aware that we need to do more research to figure out what all of this means," he said.

Soccer Heading Impact

Of the 19 young adults (mean age, 22 years) in the second study, 5 were women. All headed 20 soccer balls that were launched by using a machine at standardized speeds during 10-minute sessions.

Measures of transcranial magnetic stimulation (TMS) were taken before the heading and immediately afterward, as well as 24 hours, 48 hours, and 2 weeks afterward, to assess corticomotor inhibition.

This outcome is "expressed by a longer period of electromyographic silence (cortical silent period -- cSP), after a motor evoked delivered to the primary motor cortex during contraction," the authors write. Cognitive function and cortical excitability were among the secondary outcomes measured.

Results showed that 14 participants (74%) had a measurable increase in corticomotor inhibition immediately after the heading sessions, with a mean increase in cortical silent period duration from 117.8 to 123.1 milliseconds (P <.05).

Error scores were also significantly higher on the Spatial Working Memory subtask of the Cambridge Neuropsychological Test Automated Battery (CANTAB) cognitive assessment tool (P =.03), which signified short-term memory impairment.

In addition, there a significant increase (by 67%) in error scores on the CANTAB's Paired Associated Learning task (P =.007).

All of these increases, however, went back to near-baseline readings at all subsequent follow-ups. In addition, TMS did not show significant changes in corticospinal excitability at any time point.

Electrophysiologic, Cognitive Impairments

"Sub-concussive head impacts routine in soccer heading are associated with immediate, measurable electrophysiological and cognitive impairment," write the researchers.

"[A]lthough the magnitude of the acute changes observed was small, it is the presence of the effect that is of interest," they add.

Dr Stewart noted via email that this was essentially a pilot study to establish protocols, and the investigators did not expect so few participants to yield strong data. "I'd be the first to admit that, given these (relatively) small numbers and (relatively) low exposures, I expected that we'd find nothing."

He added that they are now planning "many, many follow-up studies" to assess the effects from a larger study population, age, brain changes during a season, and a greater number of repeated exposures.

He also noted that even with the small numbers, as a parent he would interpret the current study to suggest, at the very least, "that heading should be avoided if you want your brain to be firing on all cylinders at any time in the following 24 hours. Exam on Wednesday? No heading on Tuesday."

When asked about the study from Dr Whitlow and colleagues, Dr Stewart said "it is far from the first of its kind and, I suspect, won't be the last."

"We've seen similar studies showing white matter changes across a season in sport. What it means is the question."

The study by Whitlow and colleagues was supported by grants from the National Institutes of Health. The study by Stewart and colleagues was supported by the National Institute for Health Research Brain Injury Healthcare Technology Cooperative and by existing funding awarded as part of the Framework 7 programme of the European Union. Dr Whitlow has disclosed no relevant financial relationships. Disclosures for the coauthors are available in the original study. Dr Stewart and his coauthors have disclosed no relevant financial relationships.

Radiology. Published online October 24, 2016.

EBioMedicine. Published online October 22, 2016.

Study Highlights

  • In the study by Stewart and colleagues, researchers enrolled 23 amateur soccer players, and outcomes were available for 19 participants. Their average age was 22 years, and 5 participants were girls.
  • All participants were asked to refrain from vigorous activity and alcohol and caffeine consumption for 24 hours before the study. They completed baseline measurements of cognitive function and postural stability.
  • They also completed TMS to measure corticomotor inhibition as well as electromyography.
  • The intervention consisted of heading a standard soccer ball 20 times during a 10-minute period, which mimics heading practice that many players perform. The ball was launched from a machine set to deliver it at 38.7 kph. Participants wore accelerometers to measure the gravitational force of heading.
  • Testing was repeated immediately after the heading session, 24 hours later, 48 hours later, and 2 weeks later.
  • The main study outcome was the effect of heading the ball on corticomotor inhibition. Cognitive function and cortical excitability were secondary outcomes.
  • Corticomotor inhibition increased in 74% of the participants immediately after the ball heading. The mean duration in the cortical silent period across the entire cohort increased from 117.8 milliseconds at baseline to 123.1 milliseconds after the intervention.
  • The cortical silent period regressed to baseline levels at all subsequent testing points.
  • There was a moderate, but not significant, association between increased corticomotor inhibition and a higher gravitational force associated with the delivered ball.
  • There was no change in corticospinal excitability from baseline after the ball heading.
  • There were significant deficits in the domains of short-term memory and long-term memory on neuropsychological testing immediately after heading the ball. These deficits resolved by 24 hours.
  • Attention and processing speed were unaffected by the heading exercise. In a similar manner, heading did not affect a test of rapid visual processing.

Clinical Implications

  • A study by Whitlow and colleagues found changes in fractional anisotropy in comparing brain MRI studies before vs after a season of youth football. These changes were most prominent in the inferior fronto-occipital fasciculus.
  • Repetitive heading of a soccer ball was associated with increases in corticomotor inhibition and memory deficits immediately after the exercise in the current study by Stewart and colleagues, but any effect from the heading exercise resolved by 24 hours. Heading did not affect corticospinal excitability, attention, or processing speed.
  • Implications for the Healthcare Team: Many players and their caregivers have questions regarding potential cortical damage in contact sports. The current studies serve as reminders that concussion may not be the only risk for athletes, and the healthcare team should provide appropriate perspective on this issue.

CME Test

  • Print