A concussion is a type of mild traumatic brain injury that is caused by a direct or indirect hit to the head, body, neck, or face. Concussions can be caused by various mechanisms, is a common injury associated with sports and can affect people of all ages. A concussion is defined as a "complex pathophysiological process affecting the brain, induced by biomechanical forces". A concussion should be suspected in any person who falls or has a hit to their face or their body and has a visible sign/clue that they may have a concussion or experiences any symptoms of concussion. The Concussion Recognition Tool 6 (CRT6) can be used to help non-medically trained people manage sport related concussion on the sideline to ensure that they are directed to the appropriate care. Symptoms of concussion can be felt right away or appear over the first 1–2 days after an accident. If an athlete has a suspected sport-related concussion they should not return to play that day, not be left alone for the first three hours after their injury, not drive until cleared by a medical professional, and not return to any activity that has a risk of hitting their head or falling (i.e. gameplay or scrimmages) until they have a medical assessment. If the person has worsening symptoms or any 'red flag symptoms', they need immediate medical attention (urgent care or an emergency department). A few of these 'red flag' symptoms include: loss of vision or double vision, loss of consciousness, increased confusion, weakness or tingling, severe or increasing headaches, and/or repeated vomiting.
As of 2012, the four major professional sports leagues in the United States and Canada included policies for managing concussion risk. Sports-related concussions are generally analyzed by athletic training or medical staff on the sidelines using an evaluation tool for cognitive function known as the Sport Concussion Assessment Tool (SCAT), a symptom severity checklist, and a balance test. Concussions cannot be seen on X-rays or CT scans.
Repeated concussions are known to cause neurological disorders, particularly chronic traumatic encephalopathy (CTE), which in professional athletes has led to premature retirement, erratic behavior and even suicide. The danger of repeated concussions has long been known for boxers and wrestlers. A form of CTE common in these two sports, dementia pugilistica (DP), was first described in 1928. An awareness of the risk of concussions in other sports began to grow in the 1990s, and especially in the mid-2000s, in both the medical and the professional sports communities, as a result of the study of brains of prematurely deceased American football players, that showed an extremely high incidence of CTE (see concussions in American football).
Prognosis Most people fully recover from a concussion within 4 weeks. But the recovery time can vary. Up to about 1/3 of people experience persisting symptoms after concussion (PHAC) or persistent post concussion symptoms (PPAC), defined as symptoms that last more than 4 weeks. After an injury, concussion symptoms can begin immediately or be and delayed by 1–2 days at most. The immediate symptoms experienced after concussions include memory loss, disorientation, and poor balance. Delayed symptoms experienced in the later stages include sleeping disorders and behavioral changes. Both immediate and delayed symptoms can continue for long periods of time and have a negative impact on recovery.
Post-concussion syndrome / persisting symptoms after concussion There is the potential of persisting symptoms after concussion (sometimes called post-concussion syndrome), defined as a set of symptoms that continue for more than 4 weeks a concussion is sustained. Persisting symptoms can be classified as physical, cognitive, emotional, and sleep symptoms. Physical symptoms include headache, nausea, and vomiting. Athletes may experience cognitive symptoms that include speaking slowly, difficulty remembering and concentrating. Emotional and sleep symptoms include irritability, sadness, drowsiness, and trouble falling asleep. Persisting symptoms interfere with day-to-day functions, particularly in adolescents, such as academic performance, activity levels, and the duration in which they can return to their sport.
Second-impact syndrome Subsequent impact can cause a rare condition known as second-impact syndrome, which can result in severe injury or death. Second-impact syndrome is a result of a second head injury before the brain has adequate time to heal between concussions. It typically give signs and symptoms of a post-concussion syndrome (visual, motor, or sensory abnormalities and difficulties with cognitive processes). Even minor repeated head blow may result in malignant cerebral edema and even death. Nonetheless, second-impact syndrome is an infrequent finding, predominately involving young athletes, and only rarely is fatal.
Risk from repeated concussions The risks associated with repeated concussions and also repeated sub-concussive impacts in sport, including the potential risk for neurological disorders, are not clear and consensus statements reveal a "spectrum of perspectives" in the medical literature. Repeated concussions have been linked to a variety of neurological disorders among athletes, including chronic traumatic encephalopathy (CTE), Alzheimer's disease, Parkinsonism and amyotrophic lateral sclerosis (ALS).
Repeated concussions or mild-to-moderate traumatic brain injuries (TBI) have also been established to have long-effects on the motor dysfunction and movement disorders, however a systematic review has concluded that more investigation is needed to fully understand the long term effects of concussions and TBIs.
Other risks In addition, returning to sports with impaired sensorimotor function after experiencing a sports-related concussion increases the risk of sustaining musculoskeletal (MSK) injuries. In addition, athletes that experience a concussion are twice as likely to sustain a musculoskeletal injury compared to non-concussed athletes. Students, at all age levels, that deal with sports-related concussions may suffer from symptoms that impact their focus in school, grades, and attendance.
Incidence It is estimated that as many as 1.6–3.8 million concussions occur in the US per year in competitive sports and recreational activities; this is a rough estimate, since as many as 50% of concussions go unreported. Concussions occur in all sports with the highest incidence in American football, ice hockey, rugby, soccer, and basketball. In addition to concussions caused by a single severe impact, multiple minor impacts may also cause brain injury. Less than 10% of cases experience a loss of consciousness, and many typical symptoms appear after the initial concussion evaluation. The overall incidence risk of concussion is higher in adults than in youth, as the injury rate per 1,000 athletic exposures for youth is 0.23, compared to 0.28 in collegiate athletes.
An analysis of National Collegiate Athletic Association (NCAA) injury reports estimated concussion rates among student athletes who participate in NCAA sports during the 2011–2012 through 2014–2015 academic years:
SportRates per 1000 Athlete-Exposures (95% Confidence Interval) Overall Competition PracticeMen's Baseball 0.09 0.16 0.04 Basketball 0.38 0.53 0.34 Football 0.75 3.25 0.48 Ice hockey 0.74 2.40 0.20 Lacrosse 0.30 0.91 0.19 Soccer 0.26 0.67 0.14 Wrestling 0.89 4.31 0.48Women's Basketball 0.53 1.00 0.39 Ice hockey 0.78 2.11 0.31 Lacrosse 0.45 1.28 0.25 Soccer 0.54 1.65 0.18 Softball 0.26 0.42 0.18 Volleyball 0.37 0.64 0.27
Women in sport Numerous reports have indicated that female athletes suffer more concussions than male athletes. A December 2008 report states that 29,167 female high school soccer players in the United States suffered from concussions in 2005, compared to 20,929 male players. In high school basketball, 12,923 girls suffered from concussions while only 3,823 boys did. Girls also sustained more concussions in softball, compared to boys in baseball. Female athletes also had longer recovery times than males, and also had lower scores on visual memory tests. Girls also have longer recovery times for concussions, which may be due to a greater rate of blood flow in the brain.
Women's ice hockey was reported as one of the most dangerous sports in the NCAA, with a concussion rate of 2.72 per 1,000 player hours. Even though men's ice hockey allows body checking, while women's ice hockey does not, the rate of concussions for men is 46% lower, at 1.47 per 1,000 player hours. College football also has lower concussion rates than women's hockey, with a rate of 2.34 per 1,000.
Women's basketball is one of the women's sports with the highest risks of getting a concussion. Women have a greater risk of getting a concussion by dribbling/ball handling rather than defending. Also it was found that female college basketball players typically receive concussions during games rather than practices."The Epidemiology of Sport-Related Concussion." Clin Sports Med, 1 January 2012. Web. 8 February 2013.
Studies have also linked long-term cognitive effects in women's sports as a result of repeated concussions. A cross-sectional study demonstrated women's professional football players with a past of multiple concussions that struggled with attention-related neurocognitive functions.
By sport American football
American football causes 250,000 concussions annually, and 20% of high-school football players experience a concussion every year. In 2000, researchers from the Sports Medicine Research Laboratory at the University of North Carolina at Chapel Hill analyzed 17,549 players from 242 different schools. 888 (5.1%) of the players analyzed have at least one concussion a season, and 131 (14.7%) of them have had another concussion the year later. Division III and high-school players have a higher tendency to sustain a concussion than Division II and Division I players. In , the National Football League Players Association partnered with the UNC to determine whether professional football players suffer any health effects after any injuries, although the findings were criticized by the NFL for being unreliable due to being based on self-reporting by the players.
National Football League policy
The National Football League's (NFL) policy began in 2007, with injured players examined on field by the medical team. The league's policy included the "NFL Sidelines Concussion Exam", which requires players who have taken hits to the head to perform tests of concentration, thinking and balance. In 2011, the league introduced an assessment test which combines a symptoms checklist, a limited neurological examination, a cognitive evaluation, and a balance assessment. For a player to be allowed to return, he must be asymptomatic.
As of October 2022, the NFL and the NFLPA updated their concussion protocol once again following an incident that occurred with Miami Dolphin's quarterback Tua Tagovailoa. Tagovailoa suffered a hit in a game against the Buffalo Bills on September 25, 2022, in the first half, causing him to lose balance which resulted in him exiting the game and being evaluated. He was then placed back in the game after halftime since he passed the protocol despite the signs of gross motor instability (GMI). Following this game, Tagovailoa suffered another brutal hit in a game against the Cincinnati Bengals on September 29, 2022. His head hit the ground and his upper extremities locked into a fencing response. As a result of these events, it was determined that Tagovailoa should have never returned to play after halftime against the Buffalo Bills and caused the NFL and NFLPA to update the concussion protocol so that if any player displays any signs of gross motor instability, they are not to return to play.