Repeatedly heading a soccer ball increases the risk for brain injury and cognitive impairment, a new study has found.
Researchers from the Albert Einstein College of Medicine of Yeshiva University and Montefiore Medical Center, the University Hospital and academic medical center for Einstein, used diffusion tensor imaging (DTI), an advanced MRI-based imaging technique, on 38 amateur soccer players with an average age of 30.8 years who had all played the sport since childhood.
They were asked to recall the number of times they headed the ball during the past year, and the researchers ranked the players based on heading frequency and then compared the brain images of the most frequent headers with those of the remaining players.
The researchers found that frequent headers showed brain injury similar to that seen in patients with concussion, also known as mild traumatic brain injury (TBI).
Further analysis revealed a threshold level of approximately 1,000 to 1,500 heads per year. Once players in the study exceeded that number, researchers observed significant injury.
"While heading a ball 1,000 or 1,500 times a year may seem high to those who don't participate in the sport, it only amounts to a few times a day for a regular player," Michael Lipton, lead author of the study, said.
"Heading a soccer ball is not an impact of a magnitude that will lacerate nerve fibers in the brain.
"But repetitive heading may set off a cascade of responses that can lead to degeneration of brain cells," Lipton said.
Researchers identified five areas, in the frontal lobe and in the temporo-occipital region of the brain that were affected by frequent heading, areas that are responsible for attention, memory, executive functioning and higher-order visual functions.
In a related study, Lipton and Molly Zimmerman, assistant professor in the Saul R. Korey Department of Neurology at Einstein, gave the same 38 amateur soccer players tests designed to assess their neuropsychological function.
Players with the highest annual heading frequency performed worse on tests of verbal memory and psychomotor speed relative to their peers.
"These two studies present compelling evidence that brain injury and cognitive impairment can result from heading a soccer ball with high frequency.
"These are findings that should be taken into consideration in planning future research to develop approaches to protect soccer players," he added.
The study was recently presented at the annual meeting of the Radiological Society of North America (RSNA) in Chicago.