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Zhuang X, Bennett L, Nandy R, Cordes D, Bernick C, Ritter A. Longitudinal Changes in Cognitive Functioning and Brain Structure in Professional Boxers and Mixed Martial Artists After They Stop Fighting. Neurology 2022; 99:e2275-e2284. [PMID: 36104283 PMCID: PMC9694836 DOI: 10.1212/wnl.0000000000201158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 07/11/2022] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND AND OBJECTIVES This study compares longitudinal changes in cognitive functioning and brain structures in male fighters who transitioned to an inactive fighting status without any further exposure to repetitive head impacts (RHIs) and fighters remaining active with continual exposure to RHIs. METHODS Participants were recruited from the Professional Fighters Brain Health Study. At time point (TP)1, all fighters were active, with continual exposure to RHIs. At 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. All fighters underwent cognitive testing and 3T MRI at both TPs. A subset of our fighters (50%) underwent blood sampling for the characterization of neurofilament light (NfL) levels at both TPs. Linear mixed-effect 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 Forty-five male transitioned fighters (aged 31.69 ± 6.27 years [TP1]; 22 boxers, 22 mixed martial artists, and 1 martial artist) and 45 demographically matched male active fighters (aged 30.24 ± 5.44 years [TP1]; 17 boxers, 27 mixed martial artists, and 1 martial artist) were included in the analyses. Significantly different longitudinal trajectories between transitioned and active fighters were observed in verbal memory (p FDR = 4.73E-04), psychomotor speed (p FDR = 4.73E-04), processing speed (p FDR = 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. DISCUSSION After fighters' cessation of RHI exposure, cognitive function and brain thickness measures may stabilize and blood NfL levels may decline. This study could be a starting point to identify potential predictors of individuals who are at a higher risk of RHI-related long-term neurologic conditions.
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Affiliation(s)
- Xiaowei Zhuang
- From the Lou Ruvo Center for Brain Health (X.Z., D.C., C.B., A.R.), Cleveland Clinic, Las Vegas; Interdisciplinary Neuroscience PhD Program (X.Z.), University of Nevada, Las Vegas; Pickup Family Neurosciences Institute (L.B.), Hoag Memorial Hospital Presbyterian, Newport Beach, CA; Department of Biostatistics & Epidemiology (R.N.), School of Public Health, University of North Texas Health Science Center, Fort Worth; University of Colorado Boulder (D.C.); and UW Medicine (C.B.), Seattle
| | - Lauren Bennett
- From the Lou Ruvo Center for Brain Health (X.Z., D.C., C.B., A.R.), Cleveland Clinic, Las Vegas; Interdisciplinary Neuroscience PhD Program (X.Z.), University of Nevada, Las Vegas; Pickup Family Neurosciences Institute (L.B.), Hoag Memorial Hospital Presbyterian, Newport Beach, CA; Department of Biostatistics & Epidemiology (R.N.), School of Public Health, University of North Texas Health Science Center, Fort Worth; University of Colorado Boulder (D.C.); and UW Medicine (C.B.), Seattle
| | - Rajesh Nandy
- From the Lou Ruvo Center for Brain Health (X.Z., D.C., C.B., A.R.), Cleveland Clinic, Las Vegas; Interdisciplinary Neuroscience PhD Program (X.Z.), University of Nevada, Las Vegas; Pickup Family Neurosciences Institute (L.B.), Hoag Memorial Hospital Presbyterian, Newport Beach, CA; Department of Biostatistics & Epidemiology (R.N.), School of Public Health, University of North Texas Health Science Center, Fort Worth; University of Colorado Boulder (D.C.); and UW Medicine (C.B.), Seattle
| | - Dietmar Cordes
- From the Lou Ruvo Center for Brain Health (X.Z., D.C., C.B., A.R.), Cleveland Clinic, Las Vegas; Interdisciplinary Neuroscience PhD Program (X.Z.), University of Nevada, Las Vegas; Pickup Family Neurosciences Institute (L.B.), Hoag Memorial Hospital Presbyterian, Newport Beach, CA; Department of Biostatistics & Epidemiology (R.N.), School of Public Health, University of North Texas Health Science Center, Fort Worth; University of Colorado Boulder (D.C.); and UW Medicine (C.B.), Seattle
| | - Charles Bernick
- From the Lou Ruvo Center for Brain Health (X.Z., D.C., C.B., A.R.), Cleveland Clinic, Las Vegas; Interdisciplinary Neuroscience PhD Program (X.Z.), University of Nevada, Las Vegas; Pickup Family Neurosciences Institute (L.B.), Hoag Memorial Hospital Presbyterian, Newport Beach, CA; Department of Biostatistics & Epidemiology (R.N.), School of Public Health, University of North Texas Health Science Center, Fort Worth; University of Colorado Boulder (D.C.); and UW Medicine (C.B.), Seattle
| | - Aaron Ritter
- From the Lou Ruvo Center for Brain Health (X.Z., D.C., C.B., A.R.), Cleveland Clinic, Las Vegas; Interdisciplinary Neuroscience PhD Program (X.Z.), University of Nevada, Las Vegas; Pickup Family Neurosciences Institute (L.B.), Hoag Memorial Hospital Presbyterian, Newport Beach, CA; Department of Biostatistics & Epidemiology (R.N.), School of Public Health, University of North Texas Health Science Center, Fort Worth; University of Colorado Boulder (D.C.); and UW Medicine (C.B.), Seattle.
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Mańka-Malara K, Mierzwińska-Nastalska E. Head Trauma Exposure in Mixed Martial Arts. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph192013050. [PMID: 36293623 PMCID: PMC9603147 DOI: 10.3390/ijerph192013050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 10/05/2022] [Accepted: 10/09/2022] [Indexed: 05/06/2023]
Abstract
Combat sports training involves a high risk of head injury. Previously published research on head trauma exposure in MMA evaluated only the knockouts (KO), without calculating all head strikes. The aim of the research was to evaluate the total head trauma exposure during MMA competitions among male and female fighters. Two thousand four hundred and eighty-eight MMA fights from all numbered UFC events between 2000 and 2021 were analyzed. A database containing the results from officially published scorecards with information such as the outcome of a fight, its duration, number of strikes (significant and total amount of hits) depending on location and knockdowns was created. Additional video verification of the knockout technique was carried out. The athletes received an average of 2.41 significant head strikes out of a total of 6.30 head strikes per minute. Head strikes were more common in female fights than in male. Women executed more total and significant head strikes per minute than men. Head trauma caused the ending of 31.6% of all fights-more often in male fights (32.2%) than female (23.1%). It was the most common cause of knockouts-88.1%. Professional fights in mixed martial arts involve high exposure to head trauma. A careful evaluation of the risk involved in training in such a discipline is necessary to provide adequate prevention methods.
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Hamdan JL, Rath M, Sayoc J, Park JY. A brief descriptive outline of the rules of mixed martial arts and concussion in mixed martial arts. J Exerc Rehabil 2022; 18:142-154. [PMID: 35846227 PMCID: PMC9271642 DOI: 10.12965/jer.2244146.073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 04/08/2022] [Indexed: 11/22/2022] Open
Abstract
Mixed martial arts (MMA), a combat sport consisting of wrestling, box-ing, and martial arts, is a popular activity associated with danger and vi-olence. Of concern are the repetitive head impacts, both subconcussive and concussive, sustained by MMA athletes. The rules of MMA en-courage head strikes, but there was no formal concussion protocol in the Ultimate Fighting Championship (UFC) until 2021. Because the UFC was established less than 30 years, the long-term consequences of these repetitive concussive head blows are lacking. In this review, we focus on current literature sought to summarize the current knowledge of repetitive head impacts and concussions in MMA. The objectives were to outline (a) the rules of MMA; (b) the postconcussion protocol for UFC athletes; (c) current behavioral and biochemical diagnostic measures; (d) epidemiology and prevalence of concussion in MMA; (e) long-term effects of subconcussive repetitive head impacts; (f) biome-chanics of head impacts; and (g) considerations and research topics that warrant future research.
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Affiliation(s)
| | | | | | - Joon-Young Park
- Corresponding author: Joon-Young Park, Department of Kinesiology, College of Public Health; Cardiovascular Research Center, Lewis Katz School of Medicine, Temple University, 3500 N. Broad Street, Philadelphia, PA 19140, USA,
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