Author(s): Timothy Tiu, MD, Joann Pan, MD
Originally published: November 11, 2011 Last updated: May 28, 2026
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Disease/Disorder

Definition

Sport related concussion (SRC) is defined as “a traumatic brain injury caused by a direct blow to the head, neck or body resulting in an impulsive force being transmitted to the brain that occurs in sports and exercise-related activities.”1

Etiology

In a concussion, the impulsive force transmitted to the brain is theorized to initiate a neurotransmitter and metabolic cascade. There may be axonal injury, alterations in cerebral blood flow, and inflammatory processes causing immediate symptoms or symptoms that can present immediately or evolve within hours. Signs and symptoms of SRC cannot be explained by drug, alcohol or medication usage nor other comorbidities, such as psychiatric or other medical conditions. The clinical presentation of SRC is variable and occurs with or without loss of consciousness and typically there is no abnormality on structural imaging studies (MRI or CT).1

Epidemiology including risk factors and primary prevention

Harmon et al. report that there are 1.0-1.8 million SRC in US children ≤18 years with an estimated 20% of these concussions from organized school team sports.2 There are reported gender differences and studies demonstrated a significantly higher incidence of prolonged symptoms and more post-concussive symptoms in females compared with males, and also higher overall rates of SRCs among females compared to males.5 Other factors that may influence SRC susceptibility include history of prior concussion, initial symptoms and their severity, history of migraines, and premorbid psychiatric conditions which include learning disorders and ADHD.5 History of a SRC is a clear risk factor for future SRC.1,5

Patho-anatomy/physiology

The pathophysiology of concussion is theorized to be secondary to disruptive stretching of neuronal cell membranes after a direct or indirect head trauma.2 There is an interaction between blood-brain-barrier disruption, metabolic disturbance, and neuroinflammation.12

Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)

The onset of symptoms following a concussion can be immediate or within minutes after the initial impact. The most common reported symptoms are headache and dizziness. Acutely, the athlete may also describe a feeling of fogginess, complain of tinnitus, confusion, flashing lights, nausea, or amnesia. Other commonly reported symptoms are sensitivity to bright lights, altered sleep patterns, poor concentration, and irritability. In addition, an athlete may notice increasing fatigue and delayed reaction time with physical and mental tasks. Long-term effects might include neurobehavioral or cognitive impairments.

Following a SRC, there is typically a gradual reduction in symptoms. The majority of concussive symptoms resolve within 1-4 weeks, but some cases may evolve to persistent post-concussive syndrome (PPCS) through a process that is poorly understood. PPCS should be suspected if there is a failure of clinical recovery, defined by symptoms lasting >14 days in adults and >28 days in children.2

Specific secondary or associated conditions and complications

Complications of a concussion in the absence of other significant medical diagnoses or injuries are usually related to cognitive impairments. The athlete may experience insomnia, emotional lability, memory impairments, depression, anxiety, fatigue, headache, and/or dizziness.1

Essentials of Assessment

History

It is essential to understand that direct head trauma is not necessary for a concussion to occur. The goal of the sideline evaluation is to screen for suspected SRC and determine disposition. After a suspected concussion, the athlete should be immediately removed from play to be assessed and examined. Ideally, the injury is witnessed by the covering physician or other medical professional on the field who can describe the mechanism and identify immediate signs of injury, trauma, or LOC. A graded symptoms checklist (GCS) and Sports Concussion Assessment Tool (SCAT) provide devices for the initial assessment and tracking of symptoms over subsequent evaluations, which will be further discussed in the “Functional Assessments” section. The Center for Disease Control’s Heads Up Concussion Signs and Symptoms Checklist provides four domains

  • Observed signs (e.g., LOC, posttraumatic amnesia),
  • Physical symptoms (e.g., headaches, nausea committing),
  • Cognitive symptoms (e.g., feeling foggy, “does not feel right”), and
  • Emotional symptoms (e.g., irritable, sad, more emotional).6

The athlete may not be able to recall the incident; thus spectators may need to be questioned or game tapes reviewed.

Physical examination

Initially, the on-field examination should focus on evaluating for emergent injuries and symptoms. Red flag symptoms that, at the minimum, require removal from play include neck pain or tenderness, paresthesias, worsening headache, convulsion, vomiting, worsening confusion, deteriorating consciousness, visible deformity of skull, or increase in agitation.7The cervical spine, skull, and facial bones need to be palpated for any evidence of fracture. If the athlete is stable the remainder of the examination may be performed on the sideline. If the athlete is unstable, immediate hospital transport for stabilization and further evaluation is necessary. A thorough neurological evaluation needs to be performed that includes cranial nerves, sensation, strength, coordination, balance, and cognition.

Functional assessment

Functional assessment of the concussed athlete includes a thorough neuromuscular and cognitive evaluation. Standardized assessment tools are available, and they are designed to reduce the degree of subjectivity encountered by medical providers responsible for making a rapid and precise injury assessment and concussion diagnosis decision. When possible, tests can be compared to a reliable pre-injury baseline.2 The primary endpoint for sideline assessment in suspected athletes with SRC is to determine the probability that an athlete has sustained a concussion. If there is definite or probable evidence of concussion, then the athlete should be removed from competition and serially assessed.

The Sports Concussion Assessment Tool 6th edition (SCAT6) includes neurological assessment that includes modified Balance Error Scoring System (mBESS), and timed tandem gait, and delayed recall using 10 word list after 5 minutes.7 The mBESS is used to assess balance using 3 stance conditions (including single leg stand) to test for objective neurologic functioning. The timed tandem gait assesses balance during movement (heel-toe walking).9 The Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) is another assessment tool. This approximately 20-25 minute computer based assessment uses a baseline assessment and in the event of a SRC, a post-injury test is used to help aid in the diagnosis of an SRC. Athletes are generally not allowed to return to play until the post-injury scores are closer to baseline, but that is up to the discretion of the healthcare professional.20

The Vestibular Ocular Motor Screening (VOMS) tool is another tool used by practitioners that allows for a standardized method of assessing vestibular-ocular function. It uses 5 domains: 1) smooth pursuit, 2) horizontal and vertical saccades, 3) near point of convergence distance, 4) horizontal vestibular ocular reflex, and 5) visual motion sensitivity.9

The athlete will often have cognitive deficits after sustaining an SRC. The length of the deficits can be highly variable. Concentration, attention, mood, and sleep can be affected, which can further impact school, work, and daily activities. The athlete’s school performance should be closely followed after an SRC. A comprehensive neuropsychological evaluation can be used to identify subtle cognitive deficits as cognitive recovery may either come before or after clinical symptom resolution.2

Further description of standardized assessment tools will be discussed below under Supplemental Assessments Tools.

Laboratory studies

There are currently no recommendations for laboratory studies directly related to an SRC.3 As SRC remains largely a clinical diagnosis, there is a desire to uncover biochemical and genetic markers that can assist with diagnosis, prognosis, and recovery monitoring. In 2018, the FDA approved two biomarkers: ubiquitin carboxy terminal hydrolase L1 (UCH-L1) and glial fibrillary acid protein (GFAP) to help evaluate for suspected mild TBI and on deciding for obtaining head CT.14

Imaging

Traditional neuroimaging (i.e., CT or MRI) is normal immediately following an SRC. There has been some evidence on functional or metabolic imaging, but this has only been demonstrated so far in a research setting

Supplemental assessment tools

SCAT6 is one of the most commonly utilized tools for evaluating concussions on the field and especially among sports medicine clinicians.19 This is performed in the acute setting at the side line, best performed within 72 hours of injury.1,9 This is completed in two different settings with an immediate on field neuro screen including 1) red flag signs 2) Glasgow Coma Scale 3) cervical spine evaluation 4) Maddocks questions 5) observable signs of ocular motor screen. It is followed by an off field with symptoms assessment and expanded extensive symptom evaluation, with balance tests.7

Recently in 2023, there is an additional guideline for >72 h after concussion assessment known as Sport Concussion Office Assessment Tool 6, SCOAT6 for office-based assessment. Compared to the more acute test SCAT6, SCOAT6 has additional testing that can be performed outside of the immediate acute phase including orthostatic vitals, Modified VOMS, and consideration of screening of mood disorders (anxiety, depression) and sleep concerns.9

Another tool used is the King–Devick (KD) test. The KD test is a 2-minute sideline assessment of rapid number naming and vision assessment where the athlete reads numbers on three cards. This requires eye movements, language function and attention – all of which are usually affected in SRC. Eye movement is not well tested in ImPACT nor SCAT assessments, making KD an effective tool for supplementation.8 The KD test is easy to perform and has high sensitivity and specificity; however, the recommendation remains that it be used in conjunction with the SCAT6 to diagnose a SRC and should not be used alone.10

Baseline testing pre-injury may help identify SRC in the athlete, but is not routinely performed, nor is it fully supported in the literature. Of the neurocognitive tools, the one that shows the greatest benefit from baseline testing is the KD test, as it evaluates more individualized cognitive processes that are expected to be altered in concussion.11

Early predictions of outcomes

Early predictions of outcomes continue to be an area of evolving research that may help in identifying more vulnerable populations after SRC, especially as SRC-related morbidity typically occurs in the first weeks to months following injury. Iverson et al. described 5 relationships that are commonly asked and are of significant clinical relevance:

  • The relationship between age and clinical recovery: The authors report that professional athletes may have a faster recovery when compared to amateur athletes. Moreover, the rate of those affected by SRC that continue to have symptoms past 4 weeks are 5–7 year-olds = 17.9%, 8–12 year-olds = 26.3% and 13–17 year-olds = 39.9% indicating that older children may have longer recovery times. Interestingly, this discrepancy may arise from the ability of older children to communicate more succinctly than younger children who cannot because of the normal intellectual differences between a 17-year-old and a 7-year-old.
  • The relationship between sex and clinical recovery: After a SRC, females tend to take longer to recover and have more persistent symptoms > 4 weeks. This discrepancy is multifactorial and continues to require further research.
  • The relationship between history of concussion and clinical recovery: After an athlete has sustained an initial SRC, they are more likely to have a second SRC. Those who have sustained a first SRC will have higher pre-injury symptoms prior to their second SRC. More research is needed in this area, but there is research to suggest that history of concussions may result in symptoms lasting greater than 4 weeks.
  • Relationship between neurodevelopmental disorders, mental health, migraine and clinical recovery: This is a unique population as children with neurodevelopmental disorders, such as ADHD and learning disabilities, report more concussion symptoms without ever having a SRC, thus their pre-injury scores may be unreliable. Pre-morbid depression and migraine may also prolong recovery with symptoms lasting greater than 4 weeks. 20 However, a recent study found that ADHD medication usage is associated with a shorter return to play.3
  • Relationship between surrogate measures of injury severity and clinical recovery: LOC, retrograde amnesia, and post-traumatic amnesia are not consistent or strong predictors of recovery. The strongest predictor of longer recovery time is severity of the acute and sub-acute symptom burden after the SRC.20

Social role and social support system

Individuals may notice that attempting tasks in the home and at work/school often increase their concussive symptoms. For student athletes, teachers need to have the understanding that they may need additional time with homework or testing due to problems with attention and concentration. Cognitive rest is very important in the acute recovery from a concussion, and includes restrictions on cell phone use, texting, video games, physical activity and schoolwork until symptoms abate.

Some athletes experience mental health-related consequences including anxiety, depression and sleep disturbances. Contributing factors may include frustration over uncertain recovery time, isolation from teammates and sport and lack of social support. Prior to pharmacologic or psychotherapy, treatment involves behavioral management interventions, such as regulated sleep schedule, proper nutrition and stress reduction.1,2

The new SCOAT6 aims to address some of these concerns with an optional depression and anxiety screening as well as sleep screen.9 As management of SRC requires an interdisciplinary approach, this highlights the importance of patients’ getting appropriate psychological care.

Professional issues

The 6th Consensus Statement in Amsterdam 2022 International Consensus Statement published by the Concussion in Sports Group (CISG) updated guidelines on the steps to “Remove” an athlete-player from the sideline after a suspected concussion has occurred.1 The Amsterdam 2022 Statement emphasizes first recognizing a possible concussion, removing the athlete immediately, and next assessing at the sideline in a “multimodal assessment”. This assessment ties in the SCAT6 as previous versions of SCAT and SCAT6 are designed to support acute sideline evaluation within the first 72 h. Subsequently, the SCOAT6 is next designed for serial evaluations after the first 72 h in the subacute phase in an office setting.1  

If athletes are returned to play prior to full cognitive and physical recovery, they are at risk for worsening symptoms, prolonged recovery and an increased risk of suffering additional concussions. “Second impact syndrome” is a potentially life-threatening and catastrophic injury, resulting from a second concussion where the athlete never fully recovered from the first concussion.2 Concussion legislation emerged in this country after the state of Washington passed the Lystedt Law in 2009 in response to a case of a football player suffering a severe brain injury after returning to play during the same game in which he suffered a concussion. The law requires athletes to be removed immediately from athletic activities if it is suspected they have sustained a concussion. Within 5 years, all 50 states have passed a similar law.21 In order to return to play, athletes must be evaluated and receive written clearance from a health care provider trained in concussion assessment.

The Consensus Statement from Berlin 2016 included 11 R’s to sports related concussion (SRC) management. The new more updated Amsterdam 2022 Statement included another R known as “Retire,” referring to the decision to permanently retire from a sport after concussion. The decision to permanently retire from a sport after concussion is individualized and made through shared decision making between a patient and health care provider. The discussion should include the patient’s risk tolerance and informed decision as well as whether the patient is in the right psychological mindset to make this decision. If the health care provider has conflicts of interests, it should be clearly listed. According to the Amsterdam 2022 International Consensus Statement, there are no set of definitive clinical guidelines for retiring after concussion. Instead, the decision to retire will include a comprehensive clinical exam, specific patient specific factors (injury severity), and this shared decision-making and individualized plans. It is crucial to discuss with patients that even if they retire from a specific contact sport, patients should still establish regular exercise with safe non-contact physical activity.1

Rehabilitation Management and Treatments

The rehabilitation of concussion is updated under the 6th Consensus Statement in Amsterdam 2022 International Consensus Statement published by the Concussion in Sports Group (CISG). Rehabilitation continues to be part of the mainstay in SRC treatment when indicated, with emphasis placed on cervicovestibular rehabilitation, balance control and cognitive function.1

Following immediate removal from play, a physical and cognitive relative rest period of 24-48 hours is recommended. Patients can then undergo gradual return to activity, including return to school and return to play.1

Activity and exercise intolerance may result from impaired autonomic regulation. As such, it is important to increase activity at a sub-symptom threshold.2 The Buffalo Concussion Exercise Treatment Protocol, which is a progressive, sub-symptom threshold, aerobic exercise program monitors cardiac status and symptoms using the Buffalo Concussion Treadmill Test. A systematic review by Reid et al. further examined the role of subthreshold aerobic exercise in SRC patients and concluded that it led to lower symptom scores but did not reduce the time to recovery.17

Return to learn is the transition back to school and the classroom. It is important to keep an open line of communication with professors, teachers and school administrators as to the student-athlete’s recent injury. Although most student athletes recover quickly some with persistent symptoms may require more time to complete schoolwork which will require accommodations. The protocol for return to learn as outlined by CISG is as follows: 1) ADLs with light cognitive activity outside of the classroom, 2) school-related cognitive activities outside the classroom, 3) part-time return to school and 4) full time return to school.

Return to sport (RTS) should progress in an individualized manner based on the athlete’s injury, age and level of play. For student-athletes, a return to the classroom takes precedence.2 The CISG suggests a 6 stage RTS protocol which includes: 1) symptom limited activities of daily living, 2) light aerobic exercise, 3) sports specific exercise, 4) non-contact drills, 5) full-contact drills, and 6) return to sport. Each stage should allow for 24 hours of symptom free activity. If the patient becomes symptomatic at any stage, the activity is stopped for the day and, upon symptom resolution, the patient may start at the previously asymptomatic stage the following day.1 Interestingly, return to sport takes more of an empiric approach rather than evidence-based approach as there are limited data to support how long an athlete should remain in each stage.2,14 A recent study by Broglio et al. suggests that the normal recovery window may extend up to 1 month.3

There is significantly limited data on return to driving and no guidelines currently exist for those patients passing the symptom-free 24-48 hours of recommended physical and cognitive rest.2

At different disease stages

As previously described, most concussions and sequelae resolve within 2 weeks for adults and 4 weeks for adolescents and children.2 It is important to keep in mind that clinical recovery may not correlate with physiologic recovery.20 Treatment of SRC has remained controversial, but clearer clinical guidelines are emerging. Prolonged total physical and cognitive rest is no longer recommended. Consensus guidelines now endorse 24-48 hours of symptom-limited cognitive and physical rest, followed by gradual increase in activity as long as the athlete remains symptom free throughout the progression.1,2 As per the consensus statement in Berlin, treatment should be individualized, including a symptom-limited aerobic exercise program, targeted physical therapy program, and a multidisciplinary approach including neuropsychology and cognitive behavioral therapy.1

Coordination of care

The approach to an athlete with a SRC should integrate multiple disciplines. A physician familiar with SRC should be directing care and decisions, often involving collaboration with physical/occupational therapists and neuropsychologists. Additionally, athletic trainers, family, coaching staff, teachers and friends are integral in the well-being of the athlete.

Patient & family education

The athlete, family, friends, teachers and coaches need to be educated on the effects of SRC. There needs to be an understanding of the injury in order to protect the athlete and support him/her through the recovery process.2

Emerging/unique interventions

Neuropsychological testing is used to evaluate cognitive impairment. Newer forms of testing utilizing computer-based programs are simple and sensitive but are not substitutes for formal neuropsychological batteries.1 These computerized tests evaluate an athlete’s visual memory, verbal memory, processing speed and reaction time and can follow the resolution of cognitive deficits with serial testing.2 Although there is insufficient evidence to recommend the widespread use of baseline neuropsychological testing, this may be more important in high-risk athletes with a prior history of concussion, confounding conditions (learning disability, mood and attention disorders, migraine headaches) or those in high-risk sports.1,2

Translation into practice: Practice “pearls”/performance improvement in practice (PIPs)/changes in clinical practice behaviors and skills

Concussion is a clinical diagnosis; neither a normal physical examination nor standardized test (e.g., SCAT6) will rule out concussion. As such, clinicians must use their judgment and consider the whole clinical picture. One of the most important aspects of SRC recovery is the removal of athletes from play. There are many useful tools for monitoring symptom resolution and cognition recovery to inform the clinician on an individual athlete’s readiness to return to play that were discussed. Return to sport should progress in an individualized manner based on the athlete’s injury, age, history and level of play. Most athletes >18 years old recover within 10-14 days while athletes <18 years old are expected to return back to baseline cognitive and athletic function in <4 weeks.

Cutting Edge/Emerging and Unique Concepts and Practice

There is increasing concern that recurrent concussions contribute to long-term impairment. Some studies have suggested an association between previous concussions and chronic cognitive dysfunction.2 Others have reported that SRC might lead to long term mental health symptoms, specifically depression, in former athletes.2 Chronic Traumatic Encephalopathy (CTE) represents an interesting and unique entity in concussion research. Its incidence and prevalence are unknown. A cause and effect relationship between postmortem CTE changes and antemortem behavioral and cognitive manifestations has not been demonstrated. It is also unknown if CTE is a progressive disease, and if tau deposition is a cause, byproduct, or marker.1,2 Similarly, even initial symptoms in a concussion are nonspecific and can be both influenced by underlying mental health issues, and cause the development mental health issues, or both.2 

New, emerging treatments for concussion include high dose omega-3 fatty acids, Vitamin D, progesterone, N-methyl-D-aspartate, and ketogenic diets. Currently, all studies are inconclusive, but research is continuing in those areas.2

Another interesting, but not yet validated tool, are helmet monitors. These monitors allow for sensors to monitor linear and angular acceleration forces to the brain. A limitation of the monitors is that some athletes experience high forces with no resultant concussion, while others have lower impact forces with concussion.2

Imaging, such as CT and MRI, are usually not necessary in concussion workup1 unless there is concern for intracranial bleeding or there is prolonged recovery. Newer, advanced MRI technologies, including diffusion tensor imaging, resting state functional MRI1, arterial spin labeling, are being actively researched.

Fluid biomarkers, including those found in blood, saliva, and cerebrospinal fluid, are also being investigated. More recently in 2018, the Federal Drug Administration approved biomarkers for aiding in the diagnosis of TBI and helping guide if CT imaging should be obtained. The biomarkers approved were ubiquitin carboxy-terminal hydrolase L1 and glial fibrillar acidic protein in patients with Glasgow scores from 9-15.14 There are currently no SRC-specific tests to recommend.2

As previously mentioned, activity and exercise are currently being evaluated to establish a more definitive protocol for athletes to return to play, but clear protocols and guidelines still require more research.

Gaps in the Evidence-Based Knowledge

One of the major questions in SRC research is determining when an athlete should retire from sport after multiple concussions. Limited data is available, and more research is needed on sub-concussive impacts and neurological health. There are currently no evidenced-based guidelines on retiring athletes from their sport based on the number of concussions sustained.1,2 One publication recommends that health care providers review with athletes a series of questions that can help guide the retirement discussion, which include whether there is a reduced threshold for injury, persistent injury effects, abnormal findings on neuroimaging and the potential risks and benefits of continued participation. After these questions are asked, information should be provided to the athlete and options can be considered prior to making a shared decision.18

Further study on objective neuroimaging techniques and fluid biomarkers are needed for both assessing SRCs, as well as identifying factors that may prolong recovery. Nutraceuticals are another domain in SRC research that is evolving but still lack a clear evidence-based foundation.2

Additional research is needed to validate current assessment tools, further delineate the role of neuropsychologic and balance testing, validate return-to-play guidelines and improve identification of those at risk for prolonged concussive symptoms. Large-scale, epidemiological studies are needed to clearly define risk factors and causation of long-term neurological impairment, as well as establishing prevalence and incidence in amateur and professional athletes with SRC.2

References

  1. Patricios JS, Schneider KJ, Dvorak J, et al. Consensus statement on concussion in sport: the 6th International Conference on Concussion in Sport—Amsterdam, October 2022. Br J Sports Med. 2023;57:695–711. doi:10.1136/bjsports-2023-106898.
  2. Harmon KG, Clugston JR, Dec K, et al. American Medical Society for Sports Medicine position statement on concussion in sport. Br J Sports Med. 2019;53(4):213–225. doi:10.1136/bjsports-2018-100338.
  3. Broglio SP, McAllister T, Katz BP, et al. The natural history of sport-related concussion in collegiate athletes: findings from the NCAA-DoD CARE Consortium. Sports Med. 2022;52(2):403–415. doi:10.1007/s40279-021-01541-7.
  4. Cheng J, Ammerman B, Santiago K, et al. Sex-based differences in the incidence of sports-related concussion: a systematic review and meta-analysis. Sports Health. 2019;11:486–491.
  5. McKeithan L, Hibshman N, Yengo-Kahn A, Solomon GS, Zuckerman S. Sport-related concussion: evaluation, treatment, and future directions. Med Sci (Basel). 2019;7(3):44. doi:10.3390/medsci7030044.
  6. Centers for Disease Control and Prevention. Concussion signs and symptoms checklist. CDC HEADS UP. 2019.
  7. Echemendia RJ, Meeuwisse W, et al. Sport Concussion Assessment Tool 6 (SCAT6). Br J Sports Med. 2023.
  8. Dessy AM, et al. Review of assessment scales for diagnosing and monitoring sports-related concussion. Cureus. 2017. doi:10.7759/cureus.1922.
  9. Kontos AP, Zynda AJ, Trbovich AM, et al. Clinical utility of the Sport Concussion Office Assessment Tool 6 (SCOAT6) and other select multidomain assessments for subacute sport-related concussion. Sports Med. 2025;55:2915–2932.
  10. Arca KN, Starling AJ, Acierno MD, Demaerschalk BM, Marks L, O’Carroll CB. Is King-Devick testing, compared with other sideline screening tests, superior for the assessment of sports-related concussion? Neurologist. 2020;25(2):33–37. doi:10.1097/NRL.0000000000000268.
  11. Visser K, Koggel M, Blaauw J, van der Horn HJ, Jacobs B, van der Naalt J. Blood-based biomarkers of inflammation in mild traumatic brain injury: a systematic review. Neurosci Biobehav Rev. 2022;132:154–168. doi:10.1016/j.neubiorev.2021.11.036.
  12. Hicks SD, Onks C, Kim RY, et al. Refinement of saliva microRNA biomarkers for sports-related concussion. J Sport Health Sci. 2021. doi:10.1016/j.jshs.2021.08.003.
  13. Shahim P, Politis A, van der Merwe A, et al. Neurofilament light as a biomarker in traumatic brain injury. Neurology. 2020;95(6):e610–e622. doi:10.1212/WNL.0000000000009983.
  14. Bazarian JJ, et al. Serum GFAP and UCH-L1 for prediction of absence of intracranial injuries on head CT (ALERT-TBI): a multicentre observational study. Lancet Neurol. 2018;17(9):782–789. doi:10.1016/S1474-4422(18)30231-X.
  15. Tayebi M, Holdsworth SJ, Champagne AA, et al. The role of diffusion tensor imaging in characterizing injury patterns in athletes with concussion and subconcussive injury: a systematic review. Brain Inj. 2021;35(6):621–644. doi:10.1080/02699052.2021.1895313.
  16. Leddy JJ, Haider MN, Ellis M, et al. Exercise is medicine for concussion. Curr Sports Med Rep. 2018;17:262–270.
  17. Reid SA, Farbenblum J, McLeod S. Do physical interventions improve outcomes following concussion: a systematic review and meta-analysis. Br J Sports Med. 2021. doi:10.1136/bjsports-2020-103470.
  18. Wilson JC, Patsimas T, Cohen K, Putukian M. Considerations for athlete retirement after sport-related concussion. Clin Sports Med. 2021;40(1):187–197. doi:10.1016/j.csm.2020.08.008.
  19. Ferry B, DeCastro A. Concussion. StatPearls. StatPearls Publishing; 2023.
  20. Iverson GL, et al. Predictors of clinical recovery from concussion: a systematic review. Br J Sports Med. 2017;51(12):941–948. doi:10.1136/bjsports-2017-097729.
  21. Lowrey KM. State laws addressing youth sports-related traumatic brain injury and the future of concussion law and policy. J Bus Tech Law. 2015;10:61.

Original Version of the Topic

Ken Mautner, MD, Matthew Axtman, DO. Sports Concussion. 11/15/2011.

Previous Revision(s) of the Topic

Timothy Tiu, MD , Rakhi Sutaria MD, Se Won Lee, MD. Sports Concussion. 5/5/2016.

Timothy Tiu, MD, Armando Alvarez MD, MPH. Sports Concussion. 7/31/2020

Timothy Tiu, MD, Sandra De Mel, MD, Edwin Amirianfar, DO. Sports Concussion. 5/11/2023

Author Disclosure

Timothy Tiu, MD
Nothing to Disclose

Joann Pan, MD
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