History of biological, mechanistic, and clinical understanding of concussion.

The history behind the biological, mechanistic, and clinical insights into concussion provides awareness of the current understanding and future areas for study. Although the initial description of concussion appeared in the 10th century, the potential long-term structural consequences were first defined by Harrison Martland, M.D., who performed a postmortem study of former boxers in 1928. He found evidence of perivascular microhemorrhage that he believed eventually evolved into a "replacement gliosis" underlying a clinical syndrome that he named "punch drunk," which was characterized by acute confusion with chronic cognitive and physical symptoms developing in those with prolonged exposure. Further research into the potential long-term consequences of repetitive concussions, particularly in athletics and the military, led to an understanding of chronic traumatic encephalopathy. To ameliorate possible long-term risks, research has been focused on preventative and therapeutic measures for concussion. In this review article, the authors present the history of concussion and the long-term sequelae of repeated head injury. Specifically, they consider how the understanding of concussion has evolved from antiquity into the modern era, and how this change in understanding of head injury has led to an appreciation of the fact that its long-term implications sometimes manifest as the clinical and histopathological entity of chronic traumatic encephalopathy.

History of Chronic Traumatic Encephalopathy.

The long-term effects of repetitive head impacts have been recognized for close to a century. What is now referred to as chronic traumatic encephalopathy (CTE) was first described by Martland in 1928 in a series of boxers. Over the years, several important articles were published, including Critchley's 1957 report where he introduced the term "chronic traumatic encephalopathy," Robert's study in 1969 which provided evidence of the prevalence of neurological impairment in retired fighters, and Corsellis' initial description of the pathology of CTE. However, what brought public attention to the issue of CTE in sports were the postmortem findings of CTE pathology in professional American football players, initially reported by Omalu and subsequently in a large series by McKee. There is now standardization of pathological criteria for CTE and recognition that it can be seen across all activities that involve repetitive head impacts.

Cleomedes of Astypalaea: A possible early sufferer of chronic traumatic encephalopathy.

Dementia pugilistica was the term adopted by H. Martland in 1928 to identify boxers with cognitive decline. In more recent years, the syndrome of dementia pugilistica with pathological correlates has been defined as chronic traumatic encephalopathy (CTE). A number of sportsmen have been recently diagnosed with CTE; and we may have identified an ancient Greek athlete of pankration who presented with the symptoms that have been associated with CTE. Our study reports the history and the known clinical information about Cleomedes of Astypalaea, possibly the first athlete ever affected by CTE.

Beyond the game: the legacy of Bill Masterton.

Bill Masterton is the only man to die of injuries sustained in a National Hockey League (NHL) game. He remains the last fatality in any professional team sport involving a direct in-game injury in North America. While Masterton was originally thought to have suffered a fatal brain injury while being checked on the ice, later analysis of the case revealed evidence of second-impact syndrome and the effects of prior concussions. Masterton's death sparked both an immediate debate in the NHL on whether helmets should be compulsory and the NHL's first vote on mandatory helmet use. Although the subject of mandated helmet use met with resistance in the 10 years after Masterton's death, especially from hockey owners and coaches, the NHL finally legislated helmet use by all players entering the league beginning in the 1979-1980 season. Several awards, including one recognizing the NHL player who best exemplifies the qualities of perseverance, sportsmanship, and dedication to hockey, have been created in memory of Masterton. However, his legacy extends far beyond the awards that bear his name. His death was the seminal event bringing head safety to the forefront of a game that was both unready and unwilling to accept change. An increase in mainstream media attention in recent years has led to unprecedented public awareness of brain injury and concussion in hockey and other sports. Advances in the diagnosis and treatment of head injury in sports have occurred recently, the impetus for which started over 45 years ago, when Bill Masterton died.

A Clinical Approach to the Diagnosis of Traumatic Encephalopathy Syndrome: A Review.

IMPORTANCE: Chronic traumatic encephalopathy (CTE) refers to pathologic changes that have been found in some individuals with a history of repetitive traumatic impact to the head (hereinafter referred to as head trauma). These changes cannot be assessed during the clinical evaluation of a living patient. OBSERVATIONS: The neuropathologic features, taxonomy, history, role of biomarkers in diagnosis, and existing criteria of CTE are reviewed. Previous criteria have been proposed to approach the living patient; however, a unified, specific approach is needed for the practicing clinician. We propose a new diagnostic construct for the clinical syndrome associated with repetitive exposure to head trauma: traumatic encephalopathy syndrome. This clinical paradigm will provide the framework for a diagnosis of probable, possible, and unlikely traumatic encephalopathy syndrome, with included discussion regarding the minimum exposure, nature of the clinical course, and additional clinical features needed for diagnosis. CONCLUSIONS AND RELEVANCE: While prospective longitudinal studies are ongoing to further elucidate the association of exposure to head trauma, clinical features, and the development of pathologic changes, a corresponding clinical construct for diagnosis is necessary.