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Background/objectives: Impulsiveness is linked to cocaine history (CH) in the general population and greater fight exposure in professional fighters. Among fighters, no previous studies have quantified CH or investigated its relationship with impulsiveness., Methods: Adjusted multivariable regressions were utilized to examine the relationship between CH and impulsiveness in 335 fighters from the Professional Fighters Brain Health Study., Results: Twenty percent of fighters reported CH. CH was significantly associated with impulsiveness overall and on three subscales., Discussion/conclusion: Cocaine's prevalence and significant association with impulsiveness in fighters merit further study., Scientific Significance: We quantify CH and demonstrate its significant association with impulsiveness in professional fighters for the first time., (© 2023 The American Academy of Addiction Psychiatry (AAAP).)

Background: Mixed martial arts (MMA) fighters, due to exposure to repetitive head impacts, are at risk for brain atrophy and neurodegenerative sequelae. Simultaneously, motor skills training and cognition-rich activities have been linked with larger regional brain volumes. The majority of an MMA fighter's sporting activity occurs during practice (e.g., sparring) rather than formal competition. This study, therefore, aims to be the first to explore regional brain volumes associated with sparring in MMA fighters., Methods: Ninety-four active, professional MMA fighters from the Professional Fighters Brain Health Study met inclusion criteria for this cross-sectional analysis. Adjusted multivariable regression analyses were utilized to examine the relationship between the number of sparring practice rounds per week during typical training and a select number of regional brain volumes (i.e., caudate, thalamus, putamen, hippocampus, amygdala)., Results: A higher number of weekly sparring rounds during training was significantly associated with larger left (beta = 13.5 µL/round, 95% CI 2.26-24.8) and right (beta = 14.9 µL/round, 95% CI 3.64-26.2) caudate volumes. Sparring was not significantly associated with left or right thalamus, putamen, hippocampus, or amygdala volumes., Conclusions: More weekly rounds of sparring was not significantly associated with smaller volumes in any of the brain regions studied in active, professional MMA fighters. Sparring's significant association with larger caudate volume raises questions about whether fighters who spar more experience attenuated trauma-related decreases in caudate volume relative to fighters who spar less, whether fighters who spar more experience minimal or even positive changes to caudate volume, whether baseline differences in caudate size may have mediated results, or whether some other mechanism may be at play. Given limitations inherent to the cross-sectional study design, more research is needed to further explore the brain effects of sparring in MMA., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Objectives : Determine, through video reviews, how often concussions occur in combat sport matches, what influence they have on the outcome, and how well non-physician personnel can be trained to recognize concussions. Methods : This is a retrospective video analysis by an 8-person panel of 60 professional fights (30 boxing and 30 mixed martial arts). Through video review, physician and non-physician personnel recorded details about each probable concussion and determined if and when they would have stopped the fight compared to the official stoppage time. Results : A concussion was recorded in 47/60 fights. The mean number of concussions per minute of fight time was 0.061 (0.047 for boxers and 0.085 for MMA). When stratifying by outcome of the bout, the mean number of concussions per minute for the winner was 0.010 compared to the loser at 0.111 concussions per minute. The fighter that sustained the first concussion ultimately lost 98% of the time. The physician and non-physician raters had high agreement regarding the number of concussions that occurred to each fighter per match. The physician raters judged that 24 of the 60 fights (11 boxing [37%]; 13 MMA [43%]) should have been stopped sooner than what occurred. Conclusion : Recognizing that the concussions often occur in combat sport matches, that the losing fighter almost always is concussed first and tends to sustain more concussions during the fight, along with the demonstration that non-physician personnel can be taught to recognize concussion, may guide policy changes that improve brain health in combat sports.

Objective: Repetitive head impacts (RHIs) in combat sports are associated with cognitive decline and brain volume reduction. While fighting style differences between boxers, mixed martial artists (MMAs), and martial artists (MAs) have resulted in a broader spectrum of injury, the effects of RHIs on MAs relative to other fighters have not yet been explored. This study aimed to determine a differential effect of fighting style on cognition and brain., Setting: A large outpatient medical center specializing in neurological care., Participants, Design, and Main Measures: In total, 40 MAs, 188 boxers, and 279 MMAs were compared on baseline measures of subcortical regional brain volumes, after controlling for total brain volumes, and cognitive performance., Results: Significant differences between MAs, MMAs, and boxers were observed in subcortical brain structure volumes and cognitive measures. MMAs and MAs consistently had larger volumes and higher scores than boxers. Fighting style significantly moderated the relationship between the number of professional fights and the volumes of various subcortical brain structures and performance on a measure of processing speed at baseline., Conclusions: Differences in RHIs across fighting styles may be of clinical significance. Exploring changes over time within the MA, boxer, and MMA cohorts may provide insight into longer-term discrepancies in subcortical regional brain volumes and cognitive functioning across fighting styles.

It has long been established that fighting sports such as boxing and mixed martial arts can lead to head injury. Prior work from this group on the Professional Fighters Brain Health Study found that exposure to repetitive head impacts is associated with lower brain volumes and decreased processing speed in fighters. Current and previously licensed professional fighters were recruited, divided into active and retired cohorts, and matched with a control group that had no prior experience in sports with likely head trauma. This study examined the relationship between age of first exposure (AFE) to fighting sports and brain structure (MRI regional volume), cognitive performance (CNS Vital Signs, iComet C3), and clinical neuropsychiatric symptoms (PHQ-9, Barratt Impulsiveness Scale). Brain MRI data showed significant correlations between earlier AFE and smaller bilateral hippocampal and posterior corpus callosum volumes for both retired and active fighters. Earlier AFE in active fighters was correlated with decreased processing speed and decreased psychomotor speed. Retired fighters showed a correlation between earlier AFE and higher measures of depression and impulsivity. Overall, the results help to inform clinicians, governing bodies, parents, and athletes of the risks associated with beginning to compete in fighting sports at a young age.

Importance: Many studies have investigated the imaging findings showing sequelae of repetitive head trauma, with mixed results., Objective: To determine whether fighters (boxers and mixed martial arts fighters) with cavum septum pellucidum (CSP) and cavum vergae (CV) have reduced volumes in various brain structures or worse clinical outcomes on cognitive and mood testing., Design, Setting, and Participants: This cohort study assessed participants from the Professional Fighters Brain Health Study. Data were collected from April 14, 2011, to January 17, 2018, and were analyzed from September 1, 2018, to May 23, 2019. This study involved a referred sample of 476 active and retired professional fighters. Eligible participants were at least 18 years of age and had at least a fourth-grade reading level. Healthy age-matched controls with no history of trauma were also enrolled., Exposures: Presence of CSP, CV, and their total (additive) length (CSPV length)., Main Outcomes and Measures: Information regarding depression, impulsivity, and sleepiness among study participants was obtained using the Patient Health Questionnaire depression scale, Barrett Impulsiveness Scale, and the Epworth Sleepiness Scale. Cognition was assessed using raw scores from CNS Vital Signs. Volumes of various brain structures were measured via magnetic resonance imaging., Results: A total of 476 fighters (440 men, 36 women; mean [SD] age, 30.0 [8.2] years [range, 18-72 years]) and 63 control participants (57 men, 6 women; mean [SD] age, 30.8 [9.6] years [range, 18-58 years]) were enrolled in the study. Compared with fighters without CV, fighters with CV had significantly lower mean psychomotor speed (estimated difference, -11.3; 95% CI, -17.4 to -5.2; P = .004) and lower mean volumes in the supratentorium (estimated difference, -31 191 mm3; 95% CI, -61 903 to -479 mm3; P = .05) and other structures. Longer CSPV length was associated with lower processing speed (slope, -0.39; 95% CI, -0.49 to -0.28; P < .001), psychomotor speed (slope, -0.43; 95% CI, -0.53 to -0.32; P < .001), and lower brain volumes in the supratentorium (slope, -1072 mm3 for every 1-mm increase in CSPV length; 95% CI, -1655 to -489 mm3; P < .001) and other structures., Conclusions and Relevance: This study suggests that the presence of CSP and CV is associated with lower regional brain volumes and cognitive performance in a cohort exposed to repetitive head trauma.

Objective : For concussions to be effectively managed in sports, they need to be correctly identified and reported. The extent to which professional athletes correctly recognize concussions, and their willingness to report symptoms, is not yet well understood. Given the risk of head injuries leading to concussions across combat sports, insight into professional fighters' knowledge and reporting of concussive symptoms is essential to improve concussion management. Methods : To investigate understanding and reporting patterns of concussions sustained while training or competing, 257 fighters completed a self-report questionnaire assessing self-perception of concussion knowledge, trust of ringside medical providers, and reported number of previous head injuries. Fighting history, including number of knockouts, was obtained from self-report (amateur) and published (professional) records. Results : Significant gaps in fighters' perceived knowledge of concussion symptoms and long-term effects of multiple concussions emerged. Approximately 40% of fighters reported returning to training or competition the same day a head injury was sustained, while 21% of fighters endorsed concealing symptoms of head injury from medical providers and coaches. Conclusions : Confusion surrounding terms used to describe head injuries amongst fighters (e.g., concussions, knockouts), coupled with limited understanding of concussive symptoms and a desire to return to competition, likely contributes to significant underreporting of symptoms.

The aim of this study is to evaluate longitudinal change in plasma neurofilament light (NF-L) and tau levels in relationship to clinical and radiological measures in professional fighters. Participants (active and retired professional fighters and control group) underwent annual blood sampling, 3-Tesla magnetic resonance imaging (MRI) brain imaging, computerized cognitive testing, and assessment of exposure to traumatic brain injury. Plasma tau and NF-L concentrations were measured using Simoa assays. Multiple linear regression models were used to compare the difference across groups in regard to baseline measurements, whereas mixed linear models was used for the longitudinal data with multiple measurements for each participant. Plasma samples were available on 471 participants. Baseline NF-L measures differed across groups (F 3,393  = 6.99; p = 0.0001), with the active boxers having the highest levels. Higher NF-L levels at baseline were correlated with lower baseline MRI regional volumes and lower cognitive scores. The number of sparring rounds completed by the active fighters was correlated with NF-L (95% confidence interval, 0.0116-0.4053; p = 0.0381), but not tau, levels. Among 126 subjects having multiple yearly samples, there was a significant difference in average yearly percentage change in tau across groups (F 3,83  = 3.87; p = 0.0121). We conclude that plasma NF-L and tau behave differently in a group of active and retired fighters; NF-L better reflects acute exposure whereas the role of plasma tau levels in signifying chronic change in brain structure over time requires further study.

Combat sports are growing in popularity, viewership, and participation. The nature of these sports involves repetitive head contact, yet unlike most other professional contact sports, there are no endorsed guidelines or mandates for graduated and systematic return to play following concussion. Here, we review the literature related to concussion and fighting sports, and propose guidelines for concussion management and safe return to play following concussion.

The role of the apolipoprotein e4 allele in moderating cognitive and neuroanatomical degeneration following repeated traumatic brain injury is controversial. Here we sought to establish the presence or absence of such a moderating relationship in a prospective study of active and retired boxers and mixed martial arts fighters. Fighters (n = 193) underwent cognitive evaluations, interviews regarding fight history, MRI of the brain, and genetic testing. We used a series of moderator analyses to test for any relationship of apolipoprotein genotype on structural volumes of brain regions previously established to be smaller in those with the most fight exposure, and on cognitive abilities also established to be sensitive to fight exposure. No moderating relationship was detected in any of the analyses. The results of this study suggest that there is no impact of apolipoprotein genotype on the apparent negative association between exposure to professional fighting and brain structure volume or aspects of cognition., Competing Interests: Author Disclosure Statement Drs Bernick, Banks, and Miller have no competing financial interests. Dr. Rissman is the Biomarker Core Director for the ADCS and his research is supported by National Institutes of Health (NIH) grants AG032755, AG047484, and AG010483. He receives research funds from Araclon, DiamiR, and Neurovision and is a paid consultant for Dart Neurosciences.

Objectives: Cumulative head trauma may alter brain structure and function. We explored the relationship between exposure variables, cognition and MRI brain structural measures in a cohort of professional combatants., Methods: 224 fighters (131 mixed martial arts fighters and 93 boxers) participating in the Professional Fighters Brain Health Study, a longitudinal cohort study of licensed professional combatants, were recruited, as were 22 controls. Each participant underwent computerised cognitive testing and volumetric brain MRI. Fighting history including years of fighting and fights per year was obtained from self-report and published records. Statistical analyses of the baseline evaluations were applied cross-sectionally to determine the relationship between fight exposure variables and volumes of the hippocampus, amygdala, thalamus, caudate, putamen. Moreover, the relationship between exposure and brain volumes with cognitive function was assessed., Results: Increasing exposure to repetitive head trauma measured by number of professional fights, years of fighting, or a Fight Exposure Score (FES) was associated with lower brain volumes, particularly the thalamus and caudate. In addition, speed of processing decreased with decreased thalamic volumes and with increasing fight exposure. Higher scores on a FES used to reflect exposure to repetitive head trauma were associated with greater likelihood of having cognitive impairment., Conclusions: Greater exposure to repetitive head trauma is associated with lower brain volumes and lower processing speed in active professional fighters., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Education has a protective effect against cognitive deficits following various forms of brain insult. Professional fighting (boxing and mixed martial arts) provides a model for assessing the impact of cumulative brain injuries on cognition and brain health. In the current cross-sectional observational study, we explore whether education would be protective against cognitive loss in fighters. We tested 141 professional fighters using a computerized neurocognitive battery, in addition to structural MRI. We used automated segmentation software to compute the volumes of various brain structures. We found fighters with high school education or less to show more associations between fight exposure and cognitive test scores. The relationship between brain structure volume and exposure did not differ based on education. These results are interpreted as putatively showing a protective effect of education on functional integrity in fighters, although longitudinal data and a larger sample size are required to further understand this relationship.

Repetitive head trauma is a risk factor for Alzheimer's disease and is the primary cause of chronic traumatic encephalopathy. However, little is known about the natural history of, and risk factors for, chronic traumatic encephalopathy or about means of early detection and intervention. The Professional Fighters Brain Health Study is a longitudinal study of active professional fighters (boxers and mixed martial artists), retired professional fighters, and controls matched for age and level of education. The main objective of the Professional Fighters Brain Health Study is to determine the relationships between measures of head trauma exposure and other potential modifiers and changes in brain imaging and neurological and behavioral function over time. The study is designed to extend over 5 years, and we anticipate enrollment of more than 400 boxers and mixed martial artists. Participants will undergo annual evaluations that include 3-tesla magnetic resonance imaging scanning, computerized cognitive assessments, speech analysis, surveys of mood and impulsivity, and blood sampling for genotyping and exploratory biomarker studies. Statistical models will be developed and validated to predict early and progressive changes in brain structure and function. A composite fight exposure index, developed as a summary measure of cumulative traumatic exposure, shows promise as a predictor of brain volumes and cognitive function.

Objective: As part of a larger study dedicated to identifying speech and language biomarkers of neurological decline associated with repetitive head injury (RHI) in professional boxers and mixed martial artists (MMAs), we examined articulation rate, pausing, and disfluency in passages read aloud by participants in the Professional Athletes Brain Health Study. Setting: A large outpatient medical center specializing in neurological care. Participants, Design, and Main Measures: Passages read aloud by 60 boxers, 40 MMAs, and 55 controls were acoustically analyzed to determine articulation rate (the number of syllables produced per second), number and duration of pauses, and number and duration of disfluencies in this observational study. Results: Both boxers and MMAs differed from controls in articulation rate, producing syllables at a slower rate than controls by nearly half a syllable per second on average. Boxers produced significantly more pauses and disfluencies in passages read aloud than MMAs and controls. Conclusions: Slower articulation rate in both boxers and MMA fighters compared with individuals with no history of RHI and the increased occurrence of pauses and disfluencies in the speech of boxers suggest changes in speech motor behavior that may relate to RHI. These speech characteristics can be measured in everyday speaking conditions and by automatic recognition systems, so they have the potential to serve as effective, noninvasive clinical indicators for RHI-associated neurological decline. [ABSTRACT FROM AUTHOR]

Objective: Incidence of concussions and report of symptoms are greater among women across sports. While structural brain changes and cognitive declines are associated with repetitive head impact (RHI), the role of sex is not well-understood. This study aimed to determine if there is a moderating effect of sex on the relationship the number of professional fights has with cognitive functioning and regional brain volumes in a cohort of boxers, mixed martial artists, and martial artists. Methods: A total of 55 women were matched with 55 men based on age, years of education, ethnicity, and fighting style. Cognition was assessed via the CNS Vital Signs computerized cognitive battery and supplemental measures. Structural brain scans, demographic data, and number of professional fights (NoPF) were also considered. The matched pairs were compared via analysis of covariance, accounting for total brain volume. Within-subject moderation models were utilized to assess the moderating effect of sex on the relationship between NoPF and brain volumes and cognitive performance. Results: Men were observed to have poorer performance on measures of psychomotor speed when compared to women. On a series of analyses assessing the role of sex as a moderator of the relationship between NoPF and regional brain volumes/cognitive performance, a significant moderation effect was observed across multiple measures of cognitive functioning, such that men had poorer performance. Differences in numerous regional brain volumes were also observed, such that the relationship between NoPF and brain volumes was steeper among men. Conclusion: Sex was observed to be an important moderator in the relationship between NoPF, aspects of cognitive functioning, and volumes of numerous brain regions, suggesting that sex differences in neuroanatomic and cognitive response to RHI deserve further attention. [ABSTRACT FROM AUTHOR]