Frequent heading of the ball during football training and competition is associated with worse cognitive function than unintentional head impacts, a new study reveals.
The findings suggest that efforts to reduce long-term brain injuries may be focusing too narrowly on preventing accidental head collisions, according to researchers at Albert Einstein College of Medicine.
“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 minimising those collisions,” said study leader Dr Michael Lipton, professor of radiology and of psychiatry and behavioural sciences at Einstein and medical director of MRI Services at Montefiore. “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.”
The latest study is the first to compare the cognitive effects of heading to unintentional head impacts such as collisions.
For the research, 308 amateur football (soccer) players in New York City completed questionnaires detailing their recent (previous two weeks) football 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% were male.
Players headed the ball an average of 45 times during the two weeks covered by the questionnaire. During the same period, 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).
Results showed that players who reported the most headings had the poorest performance on psychomotor speed and attention tasks, which are areas of functioning known to be affected by brain injury. Heading frequency also correlated with poorer performance on the working memory task, although the association was of borderline significance, the medical school reported.
In contrast, unintentional head impacts were not related to any aspect of cognitive performance.
The changes in cognitive function did not cause overt clinical impairment, the team noted. “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,” Dr Lipton said. “We need a much longer-term follow-up study of more soccer players to fully address this question.”
In the meantime, he advised players to consider reducing heading during practice and football games.
The findings have been published online in Frontiers in Neurology.