Brain effects seen in soccer ‘heading’

Routine heading of a soccer ball can damage brain structure and function, according to a new study from the United Kingdom that is the first to detect direct neurological changes by impacts too minor to cause a concussion. The research, published in

EBioMedicine, studied brain changes among amateur players, ages 19 to 25, who headed machine-projected soccer balls at speeds modeling a typical practice. Though the results seen were temporary, they trigger questions about possible cumulative damage done over time.

Changes in motor response and memory were observed in the five women and 14 men participating in the study. Each was asked to perform a rotational header — redirecting the soccer ball — 20 consecutive times during 10-minute sessions. The researchers found that immediately afterward, subjects’ error scores on short- and long-term memory tests were significantly higher than subjects’ base line performances.

Even after a single session of heading, memory-test performance was reduced by as much as 67 percent, although the alterations appeared to subside within 24 hours. The researchers caution against taking that recovery as a sign of no long-term damage.

The research, which used transcranial magnetic stimulation to measure brain function, builds on similar work that has found biochemical markers of brain injury in soccer players suffering the accumulated effects of sub-concussive head impacts. In these players, an initial injury triggered a pathological process, a cascade of cellular events, that led to brain degeneration.

Soccer is the most popular sport in the world, with more than 265 million amateur and professional players. Competitive players head the ball an average of six to 12 times per game, according to experts.