A new study finds that poorer cognitive function sometimes found among soccer players may stem primarily from frequent ball heading rather than unintentional head impacts due to collisions.
Although previous studies have linked soccer ball heading to transient cognitive problems, the new study by researchers at Albert Einstein College of Medicine in New York is the first to compare the cognitive effects of heading to unintentional head impacts such as collisions.
The findings, published online in the journal Frontiers in Neurology, suggest that efforts to reduce long-term brain injuries among players may be focusing too narrowly on accidental head collisions and should expand to include heading as well.
“Unintentional head impacts are generally considered the most common cause of diagnosed concussions in soccer, so it’s understandable that current prevention efforts aim at minimizing those collisions,” said study leader Michael Lipton, M.D., Ph.D., F.A.C.R., professor of radiology and of psychiatry and behavioral sciences at Einstein.
“But intentional head impacts — that is, soccer ball heading — are not benign. We showed in a previous study that frequent heading is an underappreciated cause of concussion symptoms. And now we’ve found that heading appears to alter cognitive function as well, at least temporarily.”
For the study, 308 amateur soccer players in New York City completed questionnaires in which they reported their recent (previous two weeks) soccer activity, including heading and unintentional head impacts. Participants also completed neuropsychological tests of verbal learning, verbal memory, psychomotor speed, attention and working memory. The players ranged in age from 18 to 55, and 78 percent were male.
The findings show that participants headed soccer balls an average of 45 times during the two-week period. During that time, about one-third of the players suffered at least one unintentional head impact (e.g., kicks to the head or head-to head, head-to-ground, or head-to-goalpost collisions).
Those who reported the most headings showed the poorest performance on psychomotor speed and attention tasks, which are areas of functioning known to be affected by brain injury. Heading frequency was also linked to poorer performance on the working memory task, although the association was of borderline significance. In contrast, unintentional head collisions were not linked to any aspect of cognitive performance.
The changes in cognitive function did not cause obvious clinical impairment, the Einstein team reported. “However, we’re concerned that subtle, even transient reductions in neuropsychological function from heading could translate to microstructural changes in the brain that then lead to persistently impaired function. We need a much longer-term follow-up study of more soccer players to fully address this question,” said Lipton.
In the meantime, soccer players should consider reducing heading during practice and soccer games, Lipton said. “Heading is a potential cause of brain injury,” he added, “and since it’s under control of the player, its consequences can be prevented.”