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Mild Traumatic Brain Injury: A Comprehensive Review

by Marshall et al. and Ontario Neurotrauma Foundation.

12 Credit Hours - $179
Last revised: 07/24/2020

Course content © Copyright 2020 - 2022 by Marshall et al. and Ontario Neurotrauma Foundation. All rights reserved.


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TBI Image 

Overview of the Course


The course involves reading the following introductory materials adapted from (1) the CDC website regarding Traumatic Brain Injury and Concussion and (2) Guideline for Concussion/Mild Traumatic Brain Injury and Prolonged Symptoms (3rd Edition for adults over 18 years of age). After reviewing the following introductory materials, the remainder of the course involves reading the pdf version of: Guideline for Concussion/Mild Traumatic Brain Injury and Prolonged Symptoms (3rd Edition for adults over 18 years of age). (or click here if you have trouble with the above pdf link). Please note that the test help prompts will not be available for information in the Guideline. However, the source of the question information is documented after each question.


Reference for Guideline


Marshall S, Bayley M, McCullagh S, Berrigan L, Fischer L, Ouchterlony D, Rockwell C, Velikonja D, et al. Guideline for Concussion/Mild Traumatic Brain Injury and Prolonged Symptoms: 3nd Edition (for Adults 18 years of age). Ontario Neurotrauma Foundation, 2018. 





Discuss the Diagnosis and Assessment of mTBI


List 3 common symptoms of mTBI from each domain of physical, behavioral, and cognitive


Explain the primary and secondary targets of treatment


Explain how the symptoms of PCS overlap with those of depression and chronic pain.


List 5 self-report or interviewer tests commonly used to assess mTBI and PCS



Course Outline

Overview from the CDC website

Overview from the Guidelines


Diagnosis/Assessment of Concussion/mTBI

Initial Management of Concussion/mTBI

Sport-Related Concussion/mTBI

General Recommendations Regarding Diagnosis/Assessment of Persistent Symptoms

General Recommendations Regarding Management of Persistent Symptoms

Post-Traumatic Headache

Persistent Sleep-Wake Disturbances

Persistent Mental Health Disorders

Persistent Cognitive Difficulties

Persistent Vestibular (Balance/Dizziness) and Vision Dysfunction

Persistent Fatigue

Return-To-Activity/Work/School Considerations


1.1: Initial Diagnosis/Assessment of Adult mTBI

2.1: Initial Management of Symptoms Following mTBI

5.1: Management of Persistent Symptoms Following mTBI

6.1: Assessment and Management of Post-Traumatic Headache Following mTBI

7.1: Assessment and Management of Persistent Sleep-Wake Disturbances Following mTBI

8.1: Assessment and Management of Persistent Mental Health Disorders Following mTBI

12.1: Return-to-Work Considerations

12.2: Return-to-School (Post-Secondary) Considerations


Section 1: Diagnosis/Assessment of Concussion/mTBI

Section 2: Management of Concussion/mTBI

Section 3: Sport-Related Concussion/mTBI

Section 4: General Recommendations Regarding Diagnosis/Assessment and Persistent Symptoms

Section 6: Post-Traumatic Headache

Section 7: Sleep-Wake Disturbances

Section 8: Mental Health Disorders

Section 10: Vestibular (Balance/Dizziness) and Vision Dysfunction

Section 11: Fatigue

Section 12: Return-to-Activity/Work/School Considerations



Overview from the CDC website


Traumatic brain injury (TBI) is a major cause of death and disability in the United States. From 2006 to 2014, the number of TBI-related emergency department visits, hospitalizations, and deaths increased by 53%. In 2014, an average of 155 people in the United States died each day from injuries that include a TBI.  Those who survive a TBI can face effects that last a few days, or the rest of their lives. Effects of TBI can include impairments related to thinking or memory, movement, sensation (e.g., vision or hearing), or emotional functioning (e.g., personality changes, depression). These issues not only affect individuals but also can have lasting effects on families and communities.


What is a TBI?


A TBI is caused by a bump, blow, or jolt to the head that disrupts the normal function of the brain. Not all blows or jolts to the head result in a TBI. The severity of a TBI may range from “mild” (i.e., a brief change in mental status or consciousness) to “severe” (i.e., an extended period of unconsciousness or memory loss after the injury).  Most TBIs that occur each year are mild, commonly called concussions.


How big is the problem?


In 2014,1 about 2.87 million TBI-related emergency department (ED) visits, hospitalizations, and deaths occurred in the United States, including over 837,000 of these health events among children. TBI contributed to the deaths of 56,800 people, including 2,529 deaths among children. TBI was diagnosed in approximately 288,000 hospitalizations, including over 23,000 among children.  These consisted of TBI alone or TBI in combination with other injuries. In 2014, an estimated 812,000 children (age 17 or younger) were treated in U.S. EDs for concussion or TBI, alone or in combination with other injuries. Over the span of eight years (2006–2014), while age-adjusted rates of TBI-related ED visits increased by 54%, hospitalization rates decreased by 8% and death rates decreased by 6%.


What are the leading causes of TBI?


In 2014, falls were the leading cause of TBI. Falls accounted for almost half (48%) of all TBI-related emergency department visits. Falls disproportionately affect children and older adults: Almost half (49%) of TBI-related ED visits among children 0 to 17 years were caused by falls. Four in five (81%) TBI-related ED visits in older adults aged 65 years and older were caused by falls. Being struck by or against an object was the second leading cause of TBI-related ED visits, accounting for about 17% of all TBI-related ED visits in the United States in 2014. Over 1 in 4 (28%) TBI-related ED visits in children less than 17 years of age or less were caused by being struck by or against an object. Falls and motor vehicle crashes were the first and second leading causes of all TBI-related hospitalizations (52% and 20%, respectively). Intentional self-harm was the first leading cause of TBI-related deaths (33%) in 2014.


What are the Symptoms of TBI?


Most people with a TBI recover well from symptoms experienced at the time of the injury. Most TBIs that occur each year are mild, commonly called concussions, which is a mild TBI.1  But for some people, symptoms can last for days, weeks, or longer. In general, recovery may be slower among older adults, young children, and teens. Those who have had a TBI in the past are also at risk of having another one. Some people may also find that it takes longer to recover if they have another TBI.










Difficulty thinking clearly



Fuzzy or blurry vision





Sleeping more than usual



Feeling slowed down   


Nausea or vomiting

(early on)







Sleep less than usual



Difficulty concentrating


Sensitivity to noise or light


Balance problems



More emotional


Trouble falling asleep



Difficulty remembering new information



Feeling tired, having no energy


Nervousness or anxiety     




Some of these symptoms may appear right away. Others may not be noticed for days or months after the injury, or until the person resumes their everyday life. Sometimes, people do not recognize or admit that they are having problems. Others may not understand their problems and how the symptoms they are experiencing impact their daily activities. The signs and symptoms of a concussion can be difficult to sort out. Early on, problems may be overlooked by the person with the concussion, family members, or doctors. People may look fine even though they are acting or feeling differently.


Overview from the Guidelines


Concussion/Mild Traumatic Brain Injury


Concussion/Mild traumatic brain injury (mTBI) is a significant cause of morbidity and mortality, with many survivors of concussion/mTBI dealing with persisting difficulties for years post-injury. Over the years, various terms have been used synonymously with mild traumatic brain injury, such as mild head injury and concussion. It is important to note that all concussions are considered to be a mTBI however mTBI is distinguished from concussion when there is evidence of intracranial injury on conventional neuroimaging or there is persistent neurologic deficit.


Definition of Concussion/mTBI


Concussion/mTBI denotes the acute neurophysiological event related to blunt impact or other mechanical energy applied to the head, neck, or body (with transmitting forces to the brain), such as from sudden acceleration, deceleration, or rotational forces. Concussion can be sustained from a motor vehicle crash, sport, or recreational injury, falls, workplace injury, assault, or incident in the community. Clinical signs of concussion immediately following the injury include any of the following:


1. Any period of loss of or a 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).

5. No evidence of Intracranial lesion on standard imaging (if present, suggestive of more severe brain injury)


Concussion is a traumatic brain injury at the beginning of the brain injury spectrum ranging from mild to severe brain injury. Mild TBI is among the most common neurological conditions with an estimated annual incidence of 500/100,000 in the United States. One Canadian study examining both hospital-treated cases as well as those presenting to a family physician calculated the incidence of mTBI in Ontario to lie between 493/100,000 and 653/100,000, depending on whether diagnosis was made by primary care physicians or a secondary reviewer. There has been much research in the role of structural imaging in diagnosing concussion/mTBI and persistent symptoms, however studies have yet to find a consistent pattern in structural brain changes to diagnose concussion/mTBI and further research is needed. Computed Tomography (CT) and conventional Magnetic Resonance Imaging (MRI) usually fail to detect evidence of structural brain abnormalities in mTBI. Research in Diffusion Tensor Imaging (DTI) to detect white matter changes post-concussion/mTBI has detected structural changes acutely following, but results have not been shown to be consistent across groups, the resolution does not get at the submillimeter level and is only detecting macroscopic changes, therefore these tests are unable to accurately diagnose concussion/mTBI. DTI has also been researched in people with chronic persistent symptoms however more research is needed as the association with persistent symptoms has not been established. Reviews of recent advances in the biomechanical modeling of mTBI in humans and animals conclude that mTBI leads to functional neuronal disruption, and at times structural damage. There are several criteria commonly used to index severity of traumatic brain injuries. One of the most commonly used is the Glasgow Coma Scale (GCS), which assesses a patient’s level of consciousness. GCS scores can range from 3 to 15; mTBI is defined as a GCS score of 13-15, typically measured at 30 minutes post-injury or “on admission.” Post-traumatic amnesia (PTA), measured as the time from when the trauma occurred until the patient regains continuous memory, is another criterion used to define injury severity, and the cut-off for mild injuries is usually placed at 24 hours or less. Finally, a loss of consciousness of less than 30 minutes has also served as an index of mTBI. However, it should be noted that mTBI can occur in the absence of any loss of consciousness.


Acute symptoms


The acute symptoms that may follow mTBI are often categorized according to the following domains: 1) physical, 2) behavioral/emotional and 3) cognitive. Disparities exist in the definitions used for mTBI, and several organizations have created formal diagnostic criteria in order to try to overcome inconsistencies. Due to this fact the Expert Consensus Group (see Methodology) established a sub-committee to review the diagnostic criteria of concussion/mTBI. Experts reviewed recent definitions of concussion/mTBI as published by established mTBI consensus groups (sport, military) and from clinical practice guidelines. Depending on the population studied the literature would suggest that minimally 15% of persons with concussion may experience persisting symptoms beyond the typical 3-month time frame. The consequences for these individuals may include reduced functional ability, heightened emotional distress, and delayed return to work or school. In a Canadian longitudinal study, they found that only 27% of patients diagnosed with concussion and with symptoms lasting greater than 3 months at clinic presentation eventually recovered and 67% of those who recovered did so within the first year. They also found that no patient recovered who had post-concussion syndrome lasting 3 years or longer. When symptoms persist beyond the typical recovery period of three months, the term post-concussion syndrome or disorder may be applied.


Persistent symptoms


Just as there is confusion surrounding the definition of mTBI, this is also the case with the definition of post-concussion syndrome. There has been debate as to whether persistent symptoms are best attributed to biological or psychological factors. It now appears that a variety of interacting neuropathological and psychological contributors both underlie and maintain post-concussive symptoms. One source of controversy has been the observation that the symptoms found to persist following mTBI are not specific to this condition. They may also occur in other diagnostic groups, including those with chronic pain, depression and post-traumatic stress disorder, and are observed to varying extent among healthy individuals. For the purposes of this guideline persistent symptoms refer to: A variety of physical, cognitive, emotional, and behavioral symptoms that may endure for weeks or months following a concussion.


Overall approach to treatment:


Phase of recovery should be considered in regard to treatment approaches:


  • Acute: (0-4 weeks): Emphasis should be placed on facilitation of recovery including education, reassurance, subsymptom threshold training and non-pharmacological interventions.
  • Post-Acute: (4-12 weeks): If patient not improving or symptoms worsening, then referral to an interdisciplinary clinic should be made. Focus should be placed on managing symptoms of sleep impairment, headache, mood, fatigue, and memory/attention. The focus is on a graduated return to activity which may include work and school.
  • Persistent: (3 mo. ): If symptoms persist for more than 3 months, patients require an interdisciplinary team for symptom management using an individualized management approach with focus on returning to pre-injury activities.


Another area of controversy is the potential influence of related litigation and financial compensation on the presentation and outcome for persons who have sustained mTBI. While there is consistent evidence of an association between seeking/receiving financial compensation (i.e., via disability benefits or litigation) and the persistence of post-concussive symptoms, this relationship is complex and the mechanisms through which litigation/financial compensation issues affect rate of recovery are not well studied. Further, it must not be assumed that the initiation of a compensation claim arises solely from the pursuit of secondary gain. The intentional exaggeration or manufacturing of symptoms (i.e., malingering) is relatively rare, whereas there are many potential factors which can contribute to symptom expression and accentuation, including levels of emotional distress, fatigue, and pain, as well as pre- and post-injury coping/adaptation. The focus within the healthcare provider-patient interaction must be upon the development of a collaborative therapeutic alliance, as it is from this vantage point that an accurate understanding of the patient’s beliefs and experience of symptoms can arise and, in turn, form the basis for an appropriate treatment plan.


The remainder of the course


For the remainder of the course please review the following document: It can be reviewed directly from the website at this link:  Guideline for Concussion/Mild Traumatic Brain Injury and Prolonged Symptoms (3rd Edition for adults over 18 years of age).


You can review a pdf version of the document at the following link: Guideline for Concussion/Mild Traumatic Brain Injury and Prolonged Symptoms (3rd Edition for adults over 18 years of age). (or click here if you have trouble with the above pdf link).


Please note that the test-help prompts will not be available for information in the Guidelines. However, the source of the questions' information is documented after each question. You can take the test at any time by clicking the Take Test button. It is visible only if you are logged in. Enjoy the course!




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