A sports-related traumatic brain injury is a serious accident which may lead to significant morbidity or mortality. Traumatic brain injury (TBI) in sports are usually a result of physical contact with another person or stationary object, These sports may include boxing, gridiron football, field/ice hockey, lacrosse, martial arts, rugby, soccer, wrestling, auto racing, cycling, equestrian, rollerblading, skateboarding, skiing or snowboarding.
The most common TBIs in sports are cerebral contusions, second-impact syndrome concussions, chronic traumatic encephalopathy, and hematomas.Head injury
Epidemiology Sport TBI has been shown to be an important issue of global public health importance. A systematic review in 2020 showed that the incidence rate of TBI due to sports in hospitalized settings was between 3.5 to 31.5 per 100,000 persons, while a community-based analysis had a much higher incidence rate of 170 per 100,000 persons, which shows significant underestimation in the data from hospitals only. The majority of documented injuries are mild TBI, such as concussions. Men and adolescents have been shown to be at high risk of developing such conditions. Incidence rates across studies are not comparable due to varying definitions.
Concussions
Definition
A concussion is defined as a stunning, damaging, or shattering effect from a hard blow; especially: a jarring injury of the brain resulting in disturbance of cerebral function. Concussions are also sometimes referred to as mTBI (Mild Traumatic Brain Injury). Concussions are injuries to the head which cause a temporary lapse in the normal operation of brain function. Concussions have many symptoms which could be displayed in a physical, psychological or emotional manner. Concussions symptoms can sometimes be hard to determine because they present in a subtle manner. A symposium was held in 2008 in Zurich, Switzerland, where a definition for concussions was developed. A concussion is now defined as "a complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces."
There are five major features in conjunction with the definition:
Concussion may be caused either by a direct blow to the head, face, or neck or elsewhere on the body with an "implosive" force transmitted to the head. Concussion typically results in the rapid onset of short-lived impairment of neurologic function that resolves spontaneously. Concussion may result in neuropathological changes, but the acute clinical symptoms largely reflect a functional disturbance rather than a structural injury. Concussion results in a graded set of clinical symptoms that may or may not involve loss of consciousness. Resolution of the clinical and cognitive symptoms typically follows a sequential course; however, in a small percentage of cases, post-concussive symptoms may be prolonged. No abnormality on standard structural neuroimaging studies is seen in concussion.
Signs and symptoms in sports
Signs and symptoms of concussions can be hard to determine because they may not present strongly and because they may not present for several hours after the incident has occurred. There are 4 categories that symptoms of a concussion can be classified within: physical, cognitive, emotional and sleep disturbance. The most common symptom is a headache as well as the feeling of being "fog like". Other, more subtle symptoms that can accompany headaches are emotional changes, irritability, slowed reaction times and drowsiness. Accompanying symptoms can include sensitivity to light, and noise, fatigue, dizziness, nausea and vomiting. The loss of consciousness is another identifiable characteristic of concussions but it is not a required symptom to diagnose it. The loss of consciousness occurs in only 10% of concussions, so it cannot be a reliable sign of a concussion. Other distinguishing characteristics of concussions are retrograde amnesia (loss of memory just prior to injury) and posttraumatic amnesia (impaired recall of time between the injury or resumption of consciousness and the point at which new memories are stored and retrieved).
Diagnosis in sports
There are many diagnostic tools and tests within sports. While the tests and scales may vary greatly from sport to sport, in the end, they effectively gain the same information regardless. The first initial assessment that should take place with every athlete found to be unconscious after head or neck trauma is the "ABC's" (airway, breathing, and circulation). There is an array of initial sideline evaluations that can be conducted after a possible concussive incident such as Maddocks questions, Standardized Assessment of Concussion (SAC), Balance Error Scoring System (BESS), or Sport Concussion Assessment Tool 2 (SCAT2). "The Maddocks questions are a brief set of questions to evaluate orientation as well as short and long-term memory related to the sport and current game. The questions are for sideline use only and are included in the SCAT2." The BESS test is a test based on an athlete's posture. There are 3 positions that the athlete tests in and a composite score of their errors over the 6 rounds of testing determines their scores. The SCAT2 uses both the BESS and SAC test. The SAC and SCAT-2 evaluations also contain symptoms checklists which can determine immediate cognitive and motor deficits, although many symptoms may present hours after the initial injury. 85% of certified athletic trainers use symptom checklists as part of a concussion assessment according to a recent survey.
Limited research of the test since its release from the Zurich Concussion statement has not allowed it to be verified as a successful testing method. The SAC however, does have sufficient evidence regarding its reliability, with researchers finding the test having a test-retest reliability of 53%. Many major professional sports organizations like the NFL, NHL, MLB and NBA have taken stronger looks at in game concussions through extensive studies to develop safer equipment and playing conditions for the players. In doing this they have developed their own initial sideline testing and concussion protocols. The NFL has adopted a standardized testing evaluation form based on the SCAT2 that it has implemented into all head and neck trauma incidents. In 2011 the NFL changed their concussion protocol and built upon their previous SCAT2 standardized test. "The new implementations include a focused screening neurological examination to exclude cervical spine and intracranial bleeding, assessment of orientation, immediate and delayed recall, concentration, as well as a balance evaluation."
Similarly, in 2011, the NHL adopted a new league-wide concussion protocol which would remove players from the bench, who may have possibly sustained head or neck trauma, and bring them back to an undisclosed quiet room. Players would be held there for a minimum of 15 minutes while completing tests similar of those to the NFL's testing protocol. In 2007 Major League Baseball also adopted a concussion program for umpires and players. In 2011 the policy was revised and 4 new features were added to the program. The first of which is that all umpires and players are to conduct baseline testing during spring training or after a player signing. Secondly, the SCAT2 has been adopted as the official sideline test for all MLB teams. Thirdly, a 7-day disabled list has been set up for players with concussions; players on the list for 14 days are moved to the 15-day disabled list. Lastly, the leagues medical director must clear all players who have suffered a concussion before they can return to play. Of the four major professional sports in the U.S., the NBA is the only league to have not adopted a sideline concussion policy. Each team and their medical staff proceed differently with their policies.
A study led by Marc Weisskopf, Cecil K., and Philip Drinker Professor of Environmental Epidemiology and Physiology at the Harvard Chan School looked at 6,000 athletes between the years of 1979 and 2013. During that period, there were 517 deaths among NFL players and 431 deaths among MLB players, translating into a 26% higher mortality rate among football players compared with baseball players. The findings showed that while NFL players died of neurodegenerative diseases at a higher rate than MLB players, both groups of athletes were more likely to die of cardiovascular disease than brain diseases. Overall NFL players had rates of neurodegenerative mortality that were three times higher than the general population.
Prognosis (short/long-term effects)
Short-term effects
Short-term effects deal mostly with Post-concussion Syndrome, which has no clearly defined definition. A person with a single concussive incident typically has a strong recovery rate. The most common Post-concussion symptom is a persistent headache which usually disappears within 1–2 weeks. Other common short-term effects include dizziness, vomiting, nausea, sensitivity to light and sound, irritability, cognitive lapses and memory impairment. 20-90% of the persons affected develop one symptom within a month of the incident, after 3 months 40% of the affected persons show at least 3 symptoms.
Long-term effects
Receiving multiple concussive incidents has long been known to cause a cumulative effect on the brain. It is also known that each successive concussion makes it easier to obtain another concussion in the future. Receiving multiple concussions can lead to long-term memory loss, psychiatric disorders, brain damage and other neurological disorders. There are no clearly defined guidelines for the retirement of an athlete, but it has been proposed that an athlete who sustains 3 concussive incidents in a single season or has post-concussion symptoms for more than 3 months should consider a lengthy period away from the sport. Especially with sports, when multiple concussions are received it is likely that a doctor will advise the player in question to avoid returning to sports where contact is possible. A specific research study targeting adolescents provides a slightly different view. In a meta-analysis of studies published in 2023 and carried out by Hou et al., it was determined that whereas adolescents who suffered from sports concussion showed cognitive impairment during the acute stage, none of those individuals demonstrated objective cognitive impairment after the injury if there were no repeat injuries. Short-term impairments of functions like visual memory and processing speed were found, but recovery time was within weeks. Persistent cognitive impairments were only observed in adolescents who had suffered multiple concussions.
Second-impact syndrome
Second-impact syndrome (SIS) occurs when an athlete sustains a second concussive incident before the symptoms of a prior concussive incident have fully healed. It does not take a severe concussion to cause SIS, even a mild grade concussion can lead to it. The condition is often fatal, and if death does not occur severe disability is probable. SIS is most often developed in young athletes, who are thought to be particularly vulnerable.
Prevention in sports
Helmets
Throughout the progression of contact sports, there have been continual innovations in protective gear, especially in terms of limiting head and neck traumas. The earliest known use of football helmets is documented in an 1893 Army–Navy game. Early helmets were typically only constructed of leather padding. Throughout the early 1900s helmets developed to include metal and plastics to better protect the player. In 1939 helmets became mandatory for college players, and a year later the NFL adopted the same policy. The increasing development and standardization of helmets along with rule changes that would protect players, would eventually cut down on head and neck traumas.