|
Debates regarding the health effects of concussions on American football players have caused considerable controversy. Concussions and other types of play-related traumatic brain injuries have been proposed as a major cause of player suicides and other symptoms after retirement, including memory loss, depression and chronic traumatic encephalopathy (CTE). The list of ex-NFL players that have either presented ''post-mortem'' with CTE, or otherwise have either reported symptoms or been diagnosed with CTE, continues to grow. ==Concussions in the National Football League== There has been a problem for about 20 years regarding the longterm damage of repeated concussions among National Football League (NFL) players, often as a result of contradicting study results published by the NFL. However, by 2010, the NFL finally acknowledged that many of its ex-players were suffering from chronic traumatic encephalopathy (CTE). On September 30, 2014, it was announced that 76 of the 79 brains of former NFL players studied by Dr. Ann McKee and her colleagues tested positive for CTE. The study conducted was the largest brain bank study to date and was a twofold increase in the number of confirmed cases of CTE. In 1994, then NFL Commissioner Paul Tagliabue approved the creation of the Mild Traumatic Brain Injury (MTBI) Committee with the stated goal of studying the effects of concussions and sub-concussive injury in NFL players. Tagliabue appointed rheumatologist Dr. Elliot Pellman to chair the committee. Pellman's appointment was met with harsh criticism, because he is not a neurologist or neuropsychologist and often admitted ignorance about head injuries.〔 The same year, the National Institute for Occupational Safety and Health (NIOSH) reported a statistically significant increase in the risk of neurological disorders such as amyotrophic lateral sclerosis (ALS) in retired football players, which furthered public knowledge about the risk of long-term neurocognitive disease related to repeated head impacts. Despite the NIOSH study, Pellman and the MTBI Committee drew their own conclusions that continued to contradict these findings and those of other organizations. Biomechanical engineers and neurosurgeons informed the Committee that the helmet safety standard at that time was insufficient to minimize the risk of concussions. The MTBI Committee began studying the nature of tackle plays resulting in concussive impacts and developing its own biomechanical analysis of the effect of these forces on the brain. It started publishing study results in 2003 that stated there were no long-term negative health consequences associated with concussions sustained by NFL players. A six-year study by the Committee concluded that, "Players who are concussed and return to the same game have fewer initial signs and symptoms than those removed from play. Return to play does not involve a significant risk of a second injury either in the same game or during the season."〔(【引用サイトリンク】title=Concussion in professional football: players returning to the same game--part 7. )〕 Other organizations continued to publish study results that linked repeated concussions and long-term health problems contrary to reports by the MTBI Committee. A 2003 report by the Center for the Study of Retired Athletes at the University of North Carolina, for example, found a connection between numerous concussions and depression among former professional football players. Further, the Center's follow-up study in 2005 associated both brain impairment and Alzheimer's disease with retired NFL players who had histories of concussions.〔(【引用サイトリンク】title=Association between recurrent concussion and late-life cognitive impairment in retired professional football players. )〕 A 2004 doctoral dissertation by Don Brady examined NFL Players' knowledge of concussions, studying both active and retired National Football League Players' knowledge of concussions. Dr. Brady's findings concluded: that many NFL players lacked accurate and essential knowledge pertaining to various aspects of a concussion; that the preponderance of credible experimental and clinical evidence pertaining to the adverse effects of concussion indicates that the brain is injured as a result of a concussion; that the altered cell functioning and cell death along with subtle to more visible neurological, neurocognitive, psychological, and other medical problems reflect a diverse range of lifelong negative consequences of a concussion / brain injury; and that sports team health-care personnel need to focus primarily on the athletes’ health and well-being, and not minimize an injury or primarily concentrate on the players’ capacity to perform on the field. This expanded focus of health care is necessary in order to avoid any real or perceived conflicts of interest emerging in the concussion research, concussion management and related return to play decision-making process. During November 2014 Don Brady filed objections to the proposed NFL concussion settlement offer. Dr. Brady sent a cover letter and detailed objections on behalf of NFL retired players to the presiding US district court judge, Anita Brody. In addition to the studies that continued to contradict the work of the MTBI Committee, renowned experts and sports journalists wrote critical reviews of the Committee's studies. Dr. Robert Cantu of the American College of Sports Medicine noted bias in the committee's extremely small sample size and held that no conclusions should be drawn from the NFL's studies. In an ESPN Magazine article titled "Doctor Yes," Peter Keating criticized Pellman and the MTBI Committee's work and argued that the "... Committee has drawn a number of important conclusions about head trauma and how to treat it that contradict the research and experiences of many other doctors who treat sports concussions, not to mention the players who have suffered them."〔 More studies continued to associate repetitive head injuries with neurological problems later in life. Kevin Guskiewicz, Director of the Center for the Study of Retired Athletes in the Department of Exercise and Sport Science at the University of North Carolina, analyzed data from a 2007 study of nearly 2,500 former NFL players. He found about 11 percent of the study participants suffered from clinical depression, with a threefold increased risk in former players who had a history of three or four concussions. The following year, the NFL commissioned the University of Michigan Institute for Social Research to conduct a study involving more than 1,000 former NFL players. The results reported that Alzheimer's disease or similar diseases appear to have been diagnosed in former NFL players vastly more often than in the general population at a rate of 19 times the normal rate for men ages 30 through 49. The NFL responded to these results by claiming the study was incomplete. In October 2009, NFL Commissioner Roger Goodell and the NFL Concussion Committee were called before Congress to defend their policies against allegations of neglect. Goodell provided testimony, but was unable to answer many questions, as none of the primary authors of the league's research, Ira Casson, David Viano, or Elliot Pellman were present.〔〔 As a result of this incident and pressure from the NFL Players Association, the NFL released a comprehensive overhaul of the league concussion policy in November and December 2009. The policy expanded the list of symptoms that would prevent a player from returning to a game or practice on the same day their injury occurred.〔 With continued pressure to protect players, the NFL began preventing players knocked unconscious by a concussion from returning to a game or practice, a policy that applied to Detroit Lions running back Jahvid Best in . Various players have filed lawsuits against the league for the concussions, accusing the league of hiding information that linked head trauma to permanent brain damage, Alzheimer's disease, and dementia. Some teams chose not to draft certain players in the NFL Draft due to their past concussion history. According to an Outside the Lines report, the head impact telemetry system (HITS) was in question by the League, although Kevin Guskiewicz, a professor at the University of North Carolina, said the system is functional.〔 The technology could detect and measure the impact of blows to the head in real time during a game, but no such measurement exists in the league at this time. Former Pittsburgh Steelers receiver and current NBC Sports analyst Hines Ward stated the use of the system would be "opening a Pandora's Box," and that the data recorded by the system could be used by team owners to give players lower salaries.〔 In November 2011, the Cleveland Clinic Center for Spine Health created an online study released by the ''Journal of Neurosurgery'' in which various football helmets were compared with each other via crash test dummies. It was also found that leather helmets provided similar results to modern helmets, and in some cases, the leather helmets proved to have superior protection against concussive blows. However, the leather helmets did not provide as much protection against skull fractures.〔(Study reveals leather helmets may help reduce concussions ), ''USA Today'', Erik Brady, 11/4/2011.〕〔(Why Leather Football Helmets Could Provide a Better Defense Against Concussion ), ''Time'' magazine, Sean Gregory, November 7, 2011.〕〔(Impact test comparisons of 20th and 21st century American football helmets ), ABSTRACT, ''Journal of Neurosurgery'', Adam Bartsch, Ph.D., Edward Benzel, M.D., Vincent Miele, M.D., and Vikas Prakash, Ph.D., Jan. 2012 (published online November 4, 2011).〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Concussions in American football」の詳細全文を読む スポンサード リンク
|