BY THOMAS R. COLLINS
CHICAGO—The cumulative head impact in youth playing football over two seasons at the primary school and high school levels did not predict performance on neurocognitive assessments, according to the findings of a prospective study presented here at the Child Neurology Society annual meeting.
Sean C. Rose, MD, assistant professor of pediatric neurology at Ohio State University and co-director of the Complex Concussion Clinic at Nationwide Children's Hospital, said the study, which is ongoing, is a forward look at a topic that for the most part has been studied only retrospectively.
"We wanted to do a prospective study that looks at the kids at the time that they're getting hit," Dr. Rose said.
Researchers recruited fifth- and sixth-grade players and a group of high school players. Thirty-five of the primary school players and 20 high schoolers performed a wide-ranging battery of cognitive assessments before the first football season and after the second, including subtests from the Wechsler Intelligence Scale for Children, the Child and Adolescent Memory Profile, the Wechsler Abbreviated Scale of Intelligence, among others.
The tests, which took a total of 3.5 hours to administer, assessed attention control, verbal memory, processing speed, self-reported mood and behavior traits, balance, and other characteristics.
An impact sensor was placed in a sleeve between the player's head and the padding of the helmet. Using the Ridell InSight Impact Response System, the impacts were converted into G-forces. The impacts were also grouped into five intensity "bins," based on the G-forces measured.
Researchers found no predictive value for cumulative impact or the intensity of the impact the players experienced — whether a player had experienced prior concussions, anxiety, depression, headaches or migraines.
"Based on other studies that have been published in the last five years or so, we hypothesized that cumulative impact and the impact intensity would predict worse outcomes," Dr. Rose said. "We were surprised by the lack of significant correlations here."
He acknowledged that the follow-up time is short, and investigators are continuing to follow the players. They are now tracking them through season three and hope to track them for a fourth season.
"We looked at two seasons," Dr. Rose said. "We tested them before and after the seasons but I can't tell you what their cognitive tests are going to show 30 years from now. We don't know whether some of these effects are chronic or delayed and may show up later."
Investigators found that the younger age and the presence of attention deficit-hyperactivity disorder were two factors that predicted an inferior change — for instance, not as great an improvement — in certain aspects of the neurocognitive testing, but Dr. Rose said he was hesitant to draw any firm conclusions from that. Confirming and exploring these findings will require additional studies, he said.
As researchers continue to explore possible links between football head impacts and neurocognition, he said, it's important not to rely too heavily on retrospective findings.
"The reason we did this study was because this depth of neurocognitive testing over the course of multiple seasons has not really been done before," he said. "And drawing conclusions from retrospective studies — and studies with very limited neurocognitive testing — is difficult."
Commenting on the study, Meeryo Choe, MD, assistant clinical professor of pediatric neurology at the University of California, Los Angeles, who studies sports concussion, said that the baseline prevalence of concussion in the cohort seemed high compared to what is normally seen, even among football players.
But she said it's a "much needed" study, especially since this age range is a vital period for brain development.
"There are still very few studies looking at grade school student athletes," she said. "But this is where there are the largest number of organized and recreational sport participants."
"It would be great to see prospective results over time as well as a little more information on the impacts to help interpret the data a little better," she said. "Studying this population longitudinally is a great step towards advancing youth concussion research and, more specifically, to determine the long-term effects on the developing brain."
The study was conducted in conjunction with the Sports Neurology Clinic and the MORE Foundation. Drs. Rose and Choe had no disclosures.
LINK UP FOR RELATED INFORMATION:
Rose SC, Yeates KO, Fuerst DR, et al. Head impact burden and change in neurocognitive function during a season of youth football. J Head Trauma Rehabil 2018; Epub 2018 Oct 12.