indicate fight exposure-related damage to cerebral white matter in boxers and
mixed martial arts fighters
W, Mahmoud SY, Sakaie K, Banks SJ, Lowe M, Phillips M, Modic MT, Bernick C.
AJNR Am J Neuroadiol. 2013; ahead of print.
number of knockouts, among boxers and mixed martial arts fighters predicted
structural damage in the brain. This finding suggests that the number of
knockouts a fighter endures in their career can predict how much
microstructural damage the brain suffered.
is a degenerative brain tissue disease caused by cumulative head trauma that
can only be definitively diagnosed postmortem. Due to the frequency of blows to
the head, boxers and mixed martial arts fighters are prone to this syndrome.
There are limited studies that investigate structural changes in brain tissues
in fighters, and diffuse tensor imaging
may be able to detect subtle structural changes that may reflect microstructural
damage to the brain. Therefore, the authors assessed previous fight history and
diffusion magnetic resonance (MR imaging to evaluate the relationship between
microstructural brain damage and fight-related exposure. A total of 155 male
fighters (74 boxers and 81 mixed martial arts fighters),who had no visible
abnormalities in the central nervous system on typical MR images had a baseline
diffusion tensor imaging scan, and were followed up annually with diffusion tensor
images for 4 years. For this initial study, the authors focused on the baseline
MR images of the brain. The number knockouts among boxers and mixed martial
arts fighters predicted damage within the white matter of the brain. There
were more regions of the brain affected amongst boxers (e.g., corpus callosum, cingulate, amygdala) compared with mixed martial arts
fighters (i.e., corpus callosum & posterior cingulate); however, there was
a larger level of decreased diffusion (connectivity)
within the region of the brain affected within mixed martial arts fighters. The
number of fights did not predict structural changes in the brain of boxers or
mixed martial arts fighters.
number of knockouts, most predominantly among the boxers, predicted microstructural
damage in the brain. This finding suggests that the number of knockouts a
fighter endures in their career may predict how much microstructural damage the
brain suffered. Specifically, it is not just how often they take on a
professional fight, but how often they receive a severe blow. The style of
fighting may reflect why more regions of the brain were affected in boxers
compared to mixed martial arts fighters, since boxers specifically target the
head. It was also interesting to note that in both groups the corpus callosum
was affected. The corpus callosum is involved in allowing the right- and left-brain
hemispheres to communicate; therefore, damage to this region could lead to
cognitive dysfunction, which is one of the symptoms that characterize chronic
traumatic encephalopathy. Future studies should include cognitive testing to
evaluate if cognition is impaired down the line with future fights and
potential knockouts. Health care providers should note that the number of
knockouts the fighter has received when caring for them after a brain injury,
and should educate the fighter about the possible repercussions of future knockouts.
by: Jane McDevitt PhD
by: Jeffrey Driban
Do you think the length of their fights or concussion history would be
predictors of structural damage? Do you think there should be a cut-off for how
many knockouts a fighter can endure in their career?
Shin W, Mahmoud SY, Sakaie K, Banks SJ, Lowe MJ, Phillips M, Modic MT, & Bernick C (2013). Diffusion Measures Indicate Fight Exposure-Related Damage to Cerebral White Matter in Boxers and Mixed Martial Arts Fighters. AJNR. American Journal of neuroradiology PMID: 23928146