Study shows long-term damage from repeated head hits

Repeated blows to the head common in sports or combat cause structural damage to the brain that fails to clear up even after a rest period of six months, according to a small study that looked at college football players.

The research adds to evidence from other findings suggesting that treatment procedures — pulling football players off the playing field or soldiers from combat for a week or two to allow time for a concussion to heal — may not be enough to provide full recovery.

"The concern is that a subsequent season will lead to cumulative brain injury," says Jeffrey Bazarian, lead author and an associate professor at the University of Rochester School of Medicine and Dentistry. "The concern is that it just adds up."

The findings were published last week in the online medical research site Plos One.

Bazarian cautioned that it remains unclear whether long-term illnesses, such as the early onset of dementia, are linked to cumulative damage caused by head hits.

The study at the University of Rochester of 10 members of its football team found that each suffered from 431 to 1,850 head hits in the course of a single season. The hits were tabulated by helmet gauges the players wore.

None was diagnosed during the season with a concussion.

Imaging scans done at the end of the football season and six months later revealed physical brain damage damage that did not heal, according to the study.

None of the students showed any outward signs of neurological problems such as dizziness, disorientation or forgetfulness.

Professional football policy and medical protocol on the battlefield require that anyone suffering a concussion — from a blow to the head that is far more serious than the head hits experienced by the Rochester football players — be allowed time to rest until symptoms go away. The medical assumption is that when symptoms are gone, the brain has healed.

The Rochester findings show that even with several less-severe head hits, the brain suffers damage that does not heal even after a period of months.

Bazarian said the study results clearly point to the need for additional research to determine whether a history of repeated head impacts are linked to early deterioration of the brain over an extended time.