What is the evidence for chronic concussion-related changes in retired athletes: behavioural, pathological and clinical outcomes?

The Florey Institute of Neuroscience and Mental Health, , Heidelberg, Australia.
British Journal of Sports Medicine (Impact Factor: 5.03). 04/2013; 47(5):327-30. DOI: 10.1136/bjsports-2013-092248
Source: PubMed

ABSTRACT The purpose of this paper was to review the current state of evidence for chronic traumatic encephalopathy (CTE) in retired athletes and to consider the potential differential diagnoses that require consideration when retired athletes present with cognitive and psychiatric problems.
MEDLINE, CINAHL, EMBASE, Mosby's Index, PsycEXTRA, PsycINFO and Scopus. Key words included CTE, dementia pugilistica, punch drunk syndrome, traumatic encephalopathy, CTE, repetitive head injury, sports concussion, multiple concussions, chronic concussions, subconcussive blow and sports-related traumatic brain injury.
At present, there are no published epidemiological, cross-sectional or prospective studies relating to modern CTE. Owing to the nature of the published studies, being case reports or pathological case series, it is not possible to determine the causality or risk factors with any certainty. As such, the speculation that repeated concussion or subconcussive impacts cause CTE remains unproven. The extent to which age-related changes, psychiatric or mental health illness, alcohol/drug use or coexisting dementing illnesses contribute to this process is largely unaccounted for in the published literature.
At present, the interpretation of causation in the modern CTE case studies should proceed cautiously. The causal assumptions require further prospective or longitudinal studies on the topic.

Download full-text


Available from: Paul McCrory, Apr 27, 2014
1 Follower
  • Source
    • "In some cases, the neurologic consequences may extend across the life course (Kerr et al., 2012, 2014; McCrory et al., 2013a; Seichepine et al., 2013). Ongoing efforts to reduce the public health burden of concussions from sport span multiple levels, ranging from attempting to modify individual safety behaviors to changing the rules of sports to reduce exposure to potentially injurious head impacts (Benson et al., 2013; Graham et al., 2014; McCrory et al., 2013b). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Concussions from sport present a substantial public health burden given the number of youth, adolescent and emerging adult athletes that participate in contact or collision sports. Athletes who fail to report symptoms of a suspected concussion and continue play are at risk of worsened symptomatology and potentially catastrophic neurologic consequences if another impact is sustained during this vulnerable period. Understanding why athletes do or do not report their symptoms is critical for developing efficacious strategies for risk reduction. Psychosocial theories and frameworks that explicitly incorporate context, as a source of expectations about the outcomes of reporting and as a source of behavioral reinforcement, are useful in framing this problem. The present study quantifies the pressure that athletes experience to continue playing after a head impact-from coaches, teammates, parents, and fans-and assesses how this pressure, both independently and as a system, is related to future concussion reporting intention. Participants in the study were 328 male and female athletes from 19 teams competing in one of seven sports (soccer, lacrosse, basketball, softball, baseball, volleyball, field hockey) at four colleges in the northeast region of the United States. Results found that more than one-quarter of the sample had experienced pressure from at least one source to continue playing after a head impact during the previous year. Results of a latent profile mixture model indicated that athletes who experienced pressure from all four of the measured sources were significantly more likely to intend to continue playing in the future than were athletes who had not experienced pressure from all sources, or only pressure from coaches and teammates. These findings underscore the importance of designing interventions that address the system in which athletes make decisions about concussion reporting, including athletes' parents, rather than focusing solely on modifying the individual's reporting cognitions. Copyright © 2015. Published by Elsevier Ltd.
    Social Science [?] Medicine 06/2015; 134. DOI:10.1016/j.socscimed.2015.04.011 · 2.56 Impact Factor
  • Source
    • "See Supplementary Fig. 3 for effect size maps. other risk factors that are currently confusing the picture of the persistent effects of concussion on brain health (Mccrory et al., 2013). Further, multiple neurocognitive and brain integrity variables were correlated with the uncovered white matter abnormalities , which further emphasizes the clinical pertinence of the current findings. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Sports-related concussions have been shown to lead to persistent subclinical anomalies of the motor and cognitive systems in young asymptomatic athletes. In advancing age, these latent alterations correlate with detectable motor and cognitive function decline. Until now, the interacting effects of concussions and the normal ageing process on white matter tract integrity remain unknown. Here we used a tract-based spatial statistical method to uncover potential white matter tissue damage in 15 retired athletes with a history of concussions, free of comorbid medical conditions. We also investigated potential associations between white matter integrity and declines in cognitive and motor functions. Compared to an age- and education-matched control group of 15 retired athletes without concussions, former athletes with concussions exhibited widespread white matter anomalies along many major association, interhemispheric, and projection tracts. Group contrasts revealed decreases in fractional anisotropy, as well as increases in mean and radial diffusivity measures in the concussed group. These differences were primarily apparent in fronto-parietal networks as well as in the frontal aspect of the corpus callosum. The white matter anomalies uncovered in concussed athletes were significantly associated with a decline in episodic memory and lateral ventricle expansion. Finally, the expected association between frontal white matter integrity and motor learning found in former non-concussed athletes was absent in concussed participants. Together, these results show that advancing age in retired athletes presenting with a history of sports-related concussions is linked to diffuse white matter abnormalities that are consistent with the effects of traumatic axonal injury and exacerbated demyelination. These changes in white matter integrity might explain the cognitive and motor function declines documented in this population.
    Brain 09/2014; 137(11):2997-3011. DOI:10.1093/brain/awu236 · 10.23 Impact Factor
  • Source
    • "An animal model of sports-related rmTBI would have another important benefit. At present, it has been difficult to form a direct link between repeated head impacts in sports and the development of psychiatric and/or neuropathological disorders in athletes (McCrory et al. 2013b). Co-existing or complicating conditions such as genetic predispositions to disease, abuse of illicit drugs and alcohol, and intake of performanceenhancing steroids are often not cataloged in human athletes and each these factors, alone or in combination, could contribute to chronic and persistent health problems, including CNS disorders (Iverson 2014). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Sports-related head impact and injury has become a very highly contentious public health and medico-legal issue. Near-daily news accounts describe the travails of concussed athletes as they struggle with depression, sleep disorders, mood swings and cognitive problems. Some of these individuals have developed chronic traumatic encephalopathy, a progressive and debilitating neurodegenerative disorder. Animal models have always been an integral part of the study of traumatic brain injury in humans but, historically, they have concentrated on acute, severe brain injuries. This review will describe a small number of new and emerging animal models of sports-related head injury that have the potential to increase our understanding of how multiple mild head impacts, starting in adolescence, can have serious psychiatric, cognitive and histopathological outcomes much later in life. This article is protected by copyright. All rights reserved.
    Journal of Neurochemistry 02/2014; 129(6). DOI:10.1111/jnc.12690 · 4.24 Impact Factor
Show more