Decreased Brain Volume and Cognitive Dysfunction Documented in Professional Fighters

In my ongoing efforts to highlight relevant safety studies addressing combat sports,  a recent study was published in the Journal of Neurology documenting decreased brain volume with associated cognitive dysfunction in professional fighters.

The recent study, titled Longitudinal MRI and Cognitive Change in Professional Fighters, is part of the Professional Fighter Brain Health study which is perhaps the biggest ongoing study to date of fighter brain health.   It is funded in part by a host of combat sports stakeholders including the UFC, Haymon Boxing, the UCLA Dream Fund, Bellator and Top Rank.

The authors reviewed MRI brain imaging of 76 professional fighters with a mean number of professional fights of 14.46.  These fighters were followed, on average, between 2-5 years.  The fighters also underwent cognitive testing.

The data revealed decreased brain volume coupled with cognitive dysfunction related to these findings.  The full abstract reads as follows:

Objective: To assess the relationship between change in MRI measured regional brain volumes and cognitive performance in professional fighters.

Background: Previous cross sectional research has demonstrated a relationship between lower brain volumes in specific regions and poorer performance on certain tests of cognitive function in a cohort of professional fighters. Little is known as to whether longitudinal decline in brain volumes are associated with cognitive performance.

Design/Methods: 76 subjects participating in the Professional Fighters Brain Health Study and who have been followed over at least 2 years were included in this study. Subjects underwent MRI brain imaging, along with computerized cognitive testing (CNS Vital Signs), at baseline and on an annual basis for a minimum of 2 subsequent visits.

Rate of decline in volumes was assessed both as a continuous and categorical variable. Analyses were performed to assess the relationship between decline in regional volume and decline in each of the cognitive spheres tested (processing speed, reaction time, psychomotor speed and memory), adjusting for age, race and years of education.

Results: The mean age of the cohort was 29.54 years, with mean number of professional fights 14.46, and years of education 13.06. Duration of follow up ranged from 2–5 years. Decline in the anterior corpus collusum, left cerebellum, left hippocampus, and right thalamus were significantly associated with decline in processing speed; whereas decline in right and left thalamus and left and right cerebellum was associated with decline in memory. Comparing the decliner v. non-decliner groups, subjects in the decliner group for left hippocampus and posterior corpus collusum showed a significant association with decline in performance in processing speed.

Conclusions: MRI brain volumetric measures may warrant further study as a tool to follow accumulating brain injury over time.


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