Researchers estimate likelihood of brain recovery in injured boxers after they stop fighting

Boxers and mixed martial arts (MMA) fighters may show some recovery in thinking and memory skills and brain structure after they stop fighting, according to a new study published in the journal Neurology.

For the study, researchers selected 45 men who had not fought in two years, with an average age of 32, including 22 boxers, 22 MMA fighters and one martial arts master. They also identified 45 active male fighters whose average age was 30, including 17 boxers, 27 mixed martial arts fighters and one martial arts master. The groups were matched by age, education, race and number of fights at the beginning of the study.

All fighters had fought professionally within a year of the study's start. However, the retired fighters then did not fight for two years, while the active fighters continued to participate in professional fights.

For three years, all fighters had brain scans and filled out tests to determine how well their brains worked at the beginning and the end of the study. Researchers also looked at the participants' fight history. 

Participants also took tests to measure verbal memory, executive function, motor speed and information processing speed.

In the areas of verbal memory, motor speed and information processing speed, fighters who stopped fighting improved over time, while active fighters remained stable or decreased slightly.

The researchers also measured brain thickness in areas of the brain that control emotion, memory and executive function, that is, a person's ability to plan, concentrate and cope with multiple tasks. Of the 68 brain regions in which measurements were taken, 54 areas showed consistent trajectory changes, with thickness scores stabilizing in career-ending fighters and barely decreasing over time in active fighters.