All in the head: How football affects thought

Heading a soccer ball can,on the plus side,score goals and impress fans.

Heading a soccer ball can,on the plus side,score goals and impress fans. But it may also adversely affect a players ability to think,a new study of high school soccer players suggests.

The neurological effect of concussions and other serious head trauma in sports is,of course,a topic of considerable interest to scientists,as well as to athletes. But there has been less attention paid to the potential effects of so-called preconcussive impacts,or more minor hits to the head,like those that might be sustained when someone heads a soccer ball.

A 2011 brain-scan study of experienced,adult soccer players found subtle structural changes in certain parts of the brain that might be associated with repeated slight impacts.

But it has been difficult to measure the actual cognitive functioning of soccer players right after they have been heading the ball,in part because the equipment required is complicated or lab-based.

However,after the iPad entered the markets,Anne B Sereno a professor of neurobiology at the University of Texas Health Science Center in Houston,who led the new study,and her colleagues developed an iPad version of a well-accepted cognitive test,in which volunteers are told to focus on an image of four boxes grouped in a roughly square shape.

In one part of the test,the volunteers are asked to touch a box when it lights up on screen. In another task they are asked to ignore the box that glows and instead touch the box immediately opposite from the lit box. This second task,known as the anti-point response,tests how well volunteers can control their reactions and impulses and intellectually override a natural response to look at and reach for the lit box and correctly touch its opposing counterpart.

The anti-point response is a good test of executive function in the brain,Sereno said.

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Next,she and her colleagues recruited a girls high school varsity soccer team in the Houston area.

The team was female,because female soccer players are second only to football players in the number of concussions that they develop each year,Sereno said.

Sereno and her colleagues waited for the team to finish practice,during which each girl repeatedly headed the ball,some as many as 20 times.

The scientists also had recruited 12 non-soccer-playing high school girls,some of them athletes,but none of them currently involved in contact sports,to serve as a control group.

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After both,the soccer players and the control group had taken the test,it turned out that the soccer players were not as adept at the anti-point test. As a group,their responses were slightly but significantly slower,suggesting some degree of cognitive impairment. Also,the more times a girl had headed the ball in the immediately preceding practice,the worse her scores were on the anti-point test.

Wondering whether the effects might,potentially,be cumulative,the researchers then re-ran their analysis.They found that the more years a girl had played,the slower she tended to be on the anti-point test. Similarly,the more hours per week a girl played,the worse she performed on the test.

These results,although troubling,are not cause for panic among the parents of soccer-playing girls,Sereno said. The study was small,involving just one team,one practice,one age group and one gender. And the differences in test scores were slight,although statistically significant.

For now,then,the primary takeaway of her study would seem to be that far more study is needed on the effects of heading and other seemingly minor impacts to the head during sports. At this point, she said,we dont know the risks to cognitive function,or if there are risks.