The damage done by repeated blows to the head in boxing and other combat sports is highlighted by a new study from researchers at the Cleveland Clinic. They looked at 78 boxers and mixed martial arts athletes in an attempt to identify the “breaking point” at which head trauma leads to problems with memory or thinking. Researchers split the athletes into two groups based upon the years of fighting. In both groups, those with more fights or years of fighting under their belt were more likely to have lower brain volume in three areas, as diagnosed with an MRI. For athletes with more than nine years of fighting, having a greater number of fights was linked to worse performance on computerized tests of memory and thinking abilities. There was no similar link, however, for the group of fighters with less experience. “Our study shows there appears to be a threshold at which continued repetitive blows to the brain begin to cause measurable changes in memory and thinking, despite brain volume changes that can be found earlier,” said the study’s author, Charles Bernick, MD, in a press release. While boxing and combat sports have already been linked to brain damage, the severity of the injuries is not always known until after death. Autopsies of athletes’ brains, including hockey and football players, can show evidence of a brain disorder known as chronic traumatic encephalopathy (CTE). This condition results from repeated blows to the head, and can cause memory loss, difficulty thinking, and eventually dementia. Researchers hope that, by identifying the breaking point at which memory and thinking problems start to develop, fighters can take steps to avoid more serious, long-term damage. This may include limiting the number of fights or undergoing more frequent brain evaluations.