The neuropathology of sport

Abstract

The benefits of regular exercise, physical fitness and sports participation on cardiovascular and brain health are undeniable. Physical activity reduces the risk for cardiovascular disease, type 2 diabetes, hypertension, obesity, and stroke, and produces beneficial effects on cholesterol levels, antioxidant systems, inflammation, and vascular function. Exercise also enhances psychological health, reduces age-related loss of brain volume, improves cognition, reduces the risk of developing dementia, and impedes neurodegeneration. Nonetheless, the play of sports is associated with risks, including a risk for mild TBI (mTBI) and, rarely, catastrophic traumatic injury and death. There is also growing awareness that repetitive mTBIs, such as concussion and subconcussion, can occasionally produce persistent cognitive, behavioral, and psychiatric problems as well as lead to the development of a neurodegeneration, chronic traumatic encephalopathy (CTE). In this review, we summarize the beneficial aspects of sports participation on psychological, emotional, physical and cognitive health, and specifically analyze some of the less common adverse neuropathological outcomes, including concussion, second-impact syndrome, juvenile head trauma syndrome, catastrophic sudden death, and CTE. CTE is a latent neurodegeneration clinically associated with behavioral changes, executive dysfunction and cognitive impairments, and pathologically characterized by frontal and temporal lobe atrophy, neuronal and axonal loss, and abnormal deposits of paired helical filament (PHF)-tau and 43 kDa TAR deoxyribonucleic acid (DNA)-binding protein (TDP-43). CTE often occurs as a sole diagnosis, but may be associated with other neurodegenerative disorders, including motor neuron disease (CTE-MND). Although the incidence and prevalence of CTE are not known, CTE has been reported most frequently in American football players and boxers. Other sports associated with CTE include ice hockey, professional wrestling, soccer, rugby, and baseball.

Chronic traumatic encephalopathy: A paradigm in search of evidence?

“…94 The improved mortality in the Lehman et al study is also interesting in that it raises the issue of health benefit of sport, which is only rarely discussed in the context of CTE. 16 Regardless, the available evidence does not support a causeeffect relationship between exposure to head trauma in contact sports and neurodegenerative disease.…”

“…16 In the case of American football, however, CTE is reported in essentially all professional athletes examined to date. In the absence of subclassification, such a high percentage precludes genetic susceptibility studies, as no one is genetically resistant.…”

“…Indeed, the recent, heightened awareness of concussion and subconcussion as potentially important 15 comes from studies in National Football League (NFL) players. Rare cases of CTE have been suggested in hockey player, 1 professional wrestlers, rugby players, 16 soccer players, 12 a professional baseball player, and a circus performer. 17 The issue of CTE possibly resulting from combat-related traumatic brain injury (TBI) has also been raised; however, its existence as an entity in combat veterans and potential mechanisms of injury, have yet to be confirmed.…”

Type and occurrence of serious complications in patients after mild traumatic brain injury

“…SIS was described in young athletes, predominantly males (90 %) at age of 10 to 24 (mean 17.9 years). Among affl icted athletes were American football players (71%), boxers (14%), and occasionally martial artists, skiers, and ice-hockey players (13,14). It is assumed, that SIS is caused by catastrophic cerebral oedema resulting from post-traumatic loss of cerebral blood-fl ow autoregulation combined with stress-induced catecholamine release with high blood pressure (15).…”

Do as I say: contradicting beliefs and attitudes towards sports concussion in Australia

“…However, emerging evidence suggests that repeated impacts to the head may lead to increased risk of cognitive and mental health issues, and/or movement disorders later in life (McKee, Daneshvar, Alvarez, & Stein, 2014;Ozolins B, Aimers N, Parrington L, & Pearce AJ, In Press; Pearce et al, 2014;Smith, Johnson, & Stewart, 2013), and associated deterioration in brain tissue (McKee et al, 2016).…”