Ontario Neurotrauma Foundation

Guideline For Concussion/Mild Traumatic Brain Injury & Prolonged Symptoms

3rd Edition, for Adults over 18 years of age

Ontario Neurotrauma Foundation

Sport-Related Concussion/mTBI

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In the sports literature, the effects of traumatic biomechanical forces on the brain have traditionally been referred to as a concussion. In this Guideline, the term concussion/mTBI will be used to maintain consistency within this document. A sport-related concussion/mTBI is a traumatic brain injury that may be caused by either a direct blow to the head, face, neck or elsewhere on the body as an indirect force being transmitted to the head during sports activity. A sport-related concussion/mTBI can result in a range of clinical signs and symptoms that may or may not involve a loss of consciousness. While the injury may result in neuropathological changes, the acute clinical signs and reported symptoms largely reflect a functional disturbance rather than a structural injury. Sport-related concussion/mTBIs often present without neurological signs, and can cause a variety of symptoms making the injury complex and potentially difficult to assess and manage. Due to rapidly changing clinical signs and symptoms in the acute phase, sport-related concussion/mTBIs are considered to be among the most complex injuries in sports medicine to diagnose, assess and manage.1 Sport-related concussion/ mTBIs can occur in any population playing sport. A concussion/mTBI injury is more likely to occur when the force or impact suffered is not anticipated by the athlete. Concussion/mTBI’s are more likely to occur in contact sports, with the highest incidences (excluding combat sports) being in soccer, football, ice hockey, rugby and basketball.2,3 However, nonsport- related concussion/mTBI’s also occur in athletes, and can impact their return-to-sport as well. The majority of sport concussion/mTBI symptoms in adults resolve within 10-14 days, although the recovery time frame may be longer in children and adolescents.1,3-5 For more information on the management of concussion/mTBI in children and adolescents aged 5-18 years please see the ONF Guidelines for Pediatric Concussion.

Accurate diagnosis, management, and return-to-sport decisions are essential at all levels of participation (i.e., amateur to professional) and for all types of sport. Experts unanimously agree that any player suspected of having experienced a concussion/mTBI should be immediately removed from play, must not return to the game or practice and should be referred for Medical Assessment.2,6

Concussion/mTBI can be recognized in the community by all sport stakeholders including athletes, parents, coaches, officials, teachers, trainers, and licensed healthcare providers, however a formal diagnosis should be made by a physician following a thorough medical assessment. Athletes with a sport-related concussion/mTBI may require onsite (on-field) medical assessments by emergency medical professionals for a more severe head injury, cervical or spine injury, or loss of consciousness.

In cases in which a concussion/mTBI is suspected without a more severe head or spine injury, a player should be removed from the field of play and a sideline assessment can be performed. The Concussion in Sport Group has created a revised Sport Concussion Assessment Tool (SCAT5 and the Concussion Recognition Tool 5, presented in Appendix 3.1 and Appendix 3.2 respectively)3 to aid with this; these tools can also be used during sideline evaluation and include information that can be handed to the athlete. If a player shows any of the signs or symptoms of a concussion/mTBI outlined in Table A, concussion/mTBI should be suspected and a referral for a comprehensive evaluation and medical assessment is required.1,4,6

Athletes diagnosed with a concussion/mTBI should be provided with education about the signs and symptoms of concussion/ mTBI, strategies about how to manage initial symptoms, guidance on how to gradually return to school, work, and sport, and risks of returning to sport before a concussion/mTBI has resolved and without medical clearance.6 Historically, most consensus statements and guidelines have recommended that concussed athletes rest until they are symptom-free, and prescribed physical and cognitive rest had been a mainstay of care in this population. However, there is currently insufficient evidence that that prescribing complete rest is beneficial for recovery. Therefore, after a brief period of rest during the acute phase (24-48 hours) after injury, patients should be encouraged to become gradually and progressively more active while not increasing symptoms. In fact the term relative rest is more appropriate as patients may partake in activity in the initial stages as long as symptoms do not worsen. A reasonable approach involves the gradual return to daily tasks, school, and light physical activity in a way that does not result in a significant exacerbation of symptoms. Vigorous exertion or return to contact sport should be avoided while athletes are recovering.1

Most athletes who sustain a sport-related concussion/mTBI will make a complete recovery in 1-4 weeks after injury. However, athletes who do not recover within this time frame may benefit from a referral to a physician with experience in concussion/ mTBI in a medically-supervised interdisciplinary concussion clinic that has access to professionals with licensed training in mTBI. Individualized medical and rehabilitative care will be provided for the athlete and medical clearance is required before the athlete can return-to-sport.6 The Buffalo Concussion Treadmill Test (Appendix 3.3) can be used to investigate exercise tolerance in people with persistent symptoms.

Healthcare professionals should counsel amateur athletes with a history of multiple concussion/mTBIs and subjective persistent neurobehavioural impairments about the risk of further concussion/mTBIs, prolonged symptoms and slower recoveries. Return-to-sport and retirement decision-making in patients with persistent symptoms and multiple concussion/ mTBIs requires an individualized approach within an interdisciplinary healthcare team. This may involve a clinical neuropsychologist with certified training in the administration of comprehensive neuropsychological testing, consideration for neuroimaging, and a physician with experience in sport concussion/mTBI management. Considerations for retirement from play: multiple concussion/mTBIs >3, increasing duration of symptoms, subsequent concussion/mTBIs requiring lesser force, inability to return to full-time school or work.7,8

It should be noted that sport-related concussion/mTBI represents one area of study in the mTBI field. Given that the current guideline is not specific to sport-related injuries, the information and guidance included herein for acute and subacute management is limited. Thus, readers interested in further guidance on the assessment and management of concussion/ mTBIs in this specific patient population should consult the latest Consensus Statement on Concussion in Sport: the Fifth International Conference on Concussion in Sport held in Berlin, October 20161, American Academy of Neurology Evidence-based Guideline for Clinicians: Evaluation and Management of Concussion in Sports7, the Concussion Management Guidelines for Certified Athletic Therapists in Quebec9, or the Canadian Guideline on Concussion in Sport.6 Many sports organizations also formally provide specific guidance and recommendations that are unique to their sport and parallel the principles of existing guidelines; this information can provide further clarity and assistance when making decisions about how to proceed with progressive return to an activity/sport (see resource links in Appendix F). Further, as discussed above, differences exist between the nature of injuries sustained during sport compared with other types of injuries. Therefore, the application of clinical guidance for sport-related concussion/mTBI may not be appropriate for patients who have sustained other types of injuries.

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Assessment and Management of Sport-Related Concussion

New Key Section Level of evidence A B C Updated Evidence

3.1* icon key recommendation C

Patients with sport-related concussion may develop symptoms acutely or subacutely. If any one of the following signs/symptoms are observed/reported at any point following a blow to the head, or elsewhere on the body leading to impulsive forces transmitted to the head, concussion should be suspected and appropriate management instituted.

  1. Any period of loss of or decreased level of consciousness less than 30 min
  2. Any lack of memory for events immediately before or after the injury (post-traumatic amnesia) less than 24 hours
  3. Any alteration in mental state at the time of the injury (e.g., confusion, disorientation, slowed thinking, alteration of consciousness/mental state)
  4. Physical symptoms (e.g., vestibular, headache, weakness, loss of balance, change in vision, auditory sensitivity, dizziness) Note: No evidence of intracranial lesion on standard imaging (if present, it is suggestive of more severe brain injury)

Refer to Table A for a comprehensive list of signs for possible concussion.

*Note that this definition was adapted for the purposes of this guideline. For the definition of Concussion as defined by the 2017 Concussion in Sport please visit HERE.

Adapted from McCrory P, Meeuwisse W, Dvořák J, et al. Consensus statement on concussion in sport. Br J Sports Med 2017;51:838-847

3.2 icon key recommendation icon

When a player shows any symptoms or signs of a Sport-Related Concussion (SRC):

  • The player should be medically evaluated by a physician or other licensed healthcare professional onsite using standard emergency management principles and particular attention should be given to excluding a cervical spine injury. (A)
  • The appropriate disposition of the player must be determined by the treating healthcare professional in a timely manner. If no healthcare professional is available, the player should be safely removed from practice or play and urgent referral to a physician arranged. (C)
  • Once the first-aid issues are addressed, an assessment of the concussive injury should be made by a healthcare professional using a sideline assessment tool (e.g., SCAT5 - Appendix 3.2). Non-medical professionals should use the Sport Concussion Recognition Tool (Appendix 3.3). (C)
  • The player should not be left alone following the injury, and serial monitoring for increasing symptoms or signs of deterioration is essential over the initial few hours after injury with the aim of detecting an evolving injury. (C)
  • A player with suspected SRC should not be allowed to return-to-play on the day of injury. (C)

Taken from McCrory P, Meeuwisse W, Dvořák J, et al. Consensus statement on concussion in sport. Br J Sports Med 2017;51:838-847

3.3 A

The need for early neuroimaging should be determined according to the Canadian CT Head Rule (Figure 1.1). For patients who fulfill these criteria, CT scanning is the most appropriate investigation for the exclusion of neurosurgically significant lesions, such as hemorrhage. Plain skull x-rays are not recommended.*


3.4 icon key recommendation A icon

There is currently insufficient evidence that prescribing complete rest may ease discomfort during the acute recovery period by mitigating post-concussion symptoms and/or that rest may promote recovery by minimizing brain energy demands following concussion.

  • An initial period of rest in the acute symptomatic period following injury (24-48 hours) may be of benefit.
  • After a brief period of rest, a sensible approach involves the gradual return to school and social activities (prior to contact sports) as tolerated (i.e., in a manner that does not result in a significant or prolonged exacerbation of symptoms. See Table 12.2).

Adapted from McCrory P, Meeuwisse W, Dvořák J, et al. Consensus statement on concussion in sport. Br J Sports Med 2017;51:838-847

3.5 icon new recommendation C

Schools, teachers, family members, coaches and athletes should be educated on concussion risk factors/ risks.

3.6 C

A range of "modifying" factors may influence the investigation and management of concussion and, in some cases, may predict the potential for prolonged or persistent symptoms. These modifiers would be important to consider in a detailed concussion history and should be managed in an interdisciplinary manner by healthcare professionals with experience in sport-related concussion (see Table 3.1).

Taken from McCrory P, Meeuwisse W, Dvořák J, et al. Consensus statement on concussion in sport. Br J Sports Med 2017;51:838-847

3.7 C

Primary care providers should perform a clinical neurological assessment (including evaluation of mood, mental status/cognition, oculomotor function, gross sensorimotor, coordination, gait, vestibular function and balance) on all concussed athletes as part of their overall management (see Appendix 3.4).

Adapted from McCrory P, Meeuwisse W, Dvořák J, et al. Consensus statement on concussion in sport. Br J Sports Med 2017;51:838-847


New Key Section Level of evidence A B C Updated Evidence

3.8 C

Return-to-play (RTP) protocol following a concussion follows a stepwise process as outlined in Table 3.2. With this stepwise progression, the athlete should continue to proceed to the next level if asymptomatic at the current level. Generally, each step should take 24 hours so that an athlete would take approximately 1 week to proceed through the full rehabilitation protocol once they are asymptomatic at rest and with provocative exercise. If any post-concussion symptoms occur while in the stepwise program, then the patient should drop back to the previous asymptomatic level and try to progress again after a further 24- hour period of rest has passed.

Adapted from McCrory P, Meeuwisse WH, Aubry M, et al. Consensus statement on concussion in sport: the 4th International Conference on Concussion in Sport held in Zurich, November 2012. British Journal of Sport Medicine. 2013;47(5):250-8.

3.9 C

If pharmacotherapy is used, then an important consideration in return-to-sport is that concussed athletes should not only be free from concussion-related symptoms, but also should not be taking any pharmacological agents/medications that may mask or modify the symptoms of SRC. When pharmacological therapy is begun during the management of an SRC, the decision to return-to-play while still on such medication must be considered carefully by the primary care provider.

Adapted from McCrory P, Meeuwisse W, Dvořák J, et al. Consensus statement on concussion in sport. Br J Sports Med 2017;51:838-847

Appendix 3.1

Sport Concussion Assessment Tool (SCAT5)

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Appendix 3.2

Concussion Recognition Tool 5

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Appendix 3.3

Buffalo Concussion Treadmill Testing

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Appendix 3.4

Important Components of a Neurological Exam

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Appendix F

Other Links/Resources to Consider

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Figure 1.1

Canadian CT Head Rule

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Table A

Common Symptoms of mTBI

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Table 3.1

Concussion Modifiers

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Table 3.2

Graduated Return-to-Sport Strategy

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Table 12.2

Stepwise Approach to Return-to-Work Planning for Patients with Concussion/mTBI

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Sharp AL, Nagaraj G, Rippberger EJ, et al. Computed Tomography Use for Adults With Head Injury: Describing Likely Avoidable Emergency Department Imaging Based on the Canadian CT Head Rule. Acad Emerg Med. 2017;24(1):22-30.
Country: USA
Design: Observational Study
Quality Rating: DOWNS & BLACK: 15/32 *7 of the sections were not applicable

Nygren-de Boussard C, Holm LW, Cancelliere C, et al. Nonsurgical interventions after mild traumatic brain injury: a systematic review. Results of the International Collaboration on Mild Traumatic Brain Injury Prognosis. Arch Phys Med Rehabil. 2014;95(3 Suppl):S257-264.
Country: Sweden
Design: Systematic Review
Quality Rating: PRISMA: 17/27 *Additional analyses were not undertaken (i.e., meta-analyses), so 5 of the items were not applicable

Asken BM, McCrea MA, Clugston JR, Snyder AR, Houck ZM, Bauer RM. "Playing Through It": Delayed Reporting and Removal From Athletic Activity After Concussion Predicts Prolonged Recovery. J Athl Train. 2016;51(4):329-335.
Country: USA
Design: Cross-Sectional
Quality Rating: DOWNS & BLACK: 12/32 *7 of the sections were not applicable

Thesleff T, Kataja A, A-hman J, Luoto TM. Head injuries and the risk of concurrent cervical spine fractures. Acta Neurochir (Wien). 2017;159(5):907-914.
Country: Finland
Design: Retrospective Cohort
Quality Rating: DOWNS & BLACK: 16/32 *6 of the sections were not applicable

Kennedy E, Quinn D, Tumilty S, Chapple CM. Clinical characteristics and outcomes of treatment of the cervical spine in patients with persistent post-concussion symptoms: A retrospective analysis. Musculoskelet Sci Pract. 2017;29:91-98.
Country: New Zealand
Design: Retrospective Cohort
Quality Rating: DOWNS & BLACK: 16/32 *5 of the sections were not applicable

Buckley TA, Munkasy BA, Clouse BP. Acute Cognitive and Physical Rest May Not Improve Concussion Recovery Time. J Head Trauma Rehabil. 2016;31(4):233-241.
Country: USA
Design: Retrospective Cohort
Quality Rating: DOWNS & BLACK: 15/32 *6 of the sections were not applicable

Schneider KJ, Leddy JJ, Guskiewicz KM, et al. Rest and treatment/rehabilitation following sport-related concussion: a systematic review. Br J Sports Med. 2017;51(12):930-934.
Country: Canada
Design: Systematic Review
Quality Rating: PRISMA: 18/27 *Additional analyses were not undertaken (i.e., meta-analyses), so 5 of the items were not applicable

Silverberg ND, Iverson GL. Is rest after concussion "the best medicine?": recommendations for activity resumption following concussion in athletes, civilians, and military service members. J Head Trauma Rehabil. 2013;28(4):250-259.
Country: Canada
Design: Discussion/Review Article
Quality Rating: N/A *No checklists were appropriate to score this article design

Varner CE, McLeod S, Nahiddi N, Lougheed RE, Dear TE, Borgundvaag B. Cognitive Rest and Graduated Return to Usual Activities Versus Usual Care for Mild Traumatic Brain Injury: A Randomized Controlled Trial of Emergency Department Discharge Instructions. Acad Emerg Med. 2017;24(1):75-82.
Country: Canada
Design: Randomized Control Trial
Quality Rating: PEDro: 8/11

Maerlender A, Rieman W, Lichtenstein J, Condiracci C. Programmed Physical Exertion in Recovery From Sports-Related Concussion: A Randomized Pilot Study. Dev Neuropsychol. 2015;40(5):273-278.
Country: USA
Design: Pilot Randomized Control Trial
Quality Rating: PEDro: 6/11

Schneider KJ, Iverson GL, Emery CA, McCrory P, Herring SA, Meeuwisse WH. The effects of rest and treatment following sport-related concussion: a systematic review of the literature. Br J Sports Med. 2013;47(5):304-307.
Country: Canada
Design: Systematic Review
Quality Rating: PRISMA: 10/27 *Additional analyses were not undertaken (i.e., meta-analyses), so 5 of the items were not applicable

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