Data was recently published in the Journal Neurology demonstrating that some boxers and MMA fighters experience cognitive and even some brain structure improvement once they retire from fighting.
The data was presented earlier this year at the Association of Ringside Physicians 2022 annual conference. It has now been published in the Journal Neurology titled Longitudinal Changes in Cognitive Functioning and Brain Structure in Professional Boxers and Mixed Martial Artists After They Stop Fighting.
The data, which intuitively makes sense given that active fighters often are suffering from the acute effects of brain trauma (concussions or otherwise) in both training and competition, often experience some level of improvement once repetitive head impacts stop.
The authors used data from the Professional Fighters Brain Health Study canvassing both MMA athletes and boxers. (note all the participants were male and the Study authors are actively seeking women to please participate). The fighters were broken down into two categories (active and ‘transitioned’ meaning they were retired and have not been sparring or competing for at least 2 years). MRI’s and cognitive testing were performed. When comparing the groups the authors found improved cognitive function and some objective structural improvement in the retired groups of fighters compared to those actively still exposed to repetitive head impacts.
The abstract and access to the full study can be found here. The abstract reads as follows:
Study Question
How does cognitive functioning and brain structure change
longitudinally in professional boxers and mixed martial artists
who stop fighting in their early 30s?
What Is Known and What This Paper Adds
Repetitive head hits (RHIs), both concussive and subconcussive, increase the risk of long-term neurologic conditions.
However, the outcome remains unclear for individuals who
have been exposed to RHI and then discontinued the exposure. This study’s results show that after fighters’ cessation of
RHI exposure, cognitive function and brain thickness measures may stabilize and blood neurofilament light (NfL) levels
may decline.
Methods
Participants were recruited from the Professional Fighters
Brain Health Study. At time point 1 (TP1), all fighters were
active, with continual exposure to RHI. At time point 2 (TP2),
fighters were considered “transitioned” if they had no sanctioned professional fights and had not been sparring for the
past 2 years. Fighters were considered “active” if they continued to train and compete. Forty-five male transitioned
fighters (31.69 ± 6.27 years old [TP1]) and 45 demographically matched male active fighters (30.24 ± 5.44
years old [TP1]) were included in the analyses. All fighters
underwent cognitive testing and 3 T MRI at both TPs. A
subset of our fighters (50%) underwent blood sampling for
characterization of NfL levels at both TPs. Linear mixed effects models were applied to investigate the potentially
different longitudinal trajectories (interaction effect between
group and time) of cognitive function measures, NfL levels,
and regional thickness measures (derived from structural
MRI) between transitioned and active fighters.
Results and Study Limitations
Different longitudinal trajectories between transitioned and
active fighters were observed in verbal memory (pFDR =
4.73E-04, Figure), psychomotor speed (pFDR = 4.73E-04),
processing speed (pFDR = 3.90E-02), and NfL levels (p =
0.02). Transitioned fighters demonstrated longitudinally
improved cognitive functioning and decreased NfL levels, and
active fighters demonstrated declines in cognitive performance and stable NfL levels. Of 68 cortical regions inspected,
54 regions demonstrated a consistently changing trajectory,
with thickness measures stabilizing on a group level for
transitioned fighters and subtly declining over time for active
fighters. The present study’s limitations include the inability
to quantify the precise amount of RHI each participant sustained, restricted interpretation to male fighters only, and no
sensitivity analyses.
Study Funding and Competing Interests
This study was supported by the NIH, Lincy Foundation,
Belator, Ultimate Fighting Championship Company (UFC),
the August Rapone Family Foundation, Top Rank, and
Haymon Boxing. The authors report no competing interests.
Go to Neurology.org/N for full disclosures.
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