Definitions Concussion is a mild traumatic brain injury, frequently defined as a head injury with a temporary loss of brain function. Concussion causes a variety of physical, cognitive, and emotional symptoms, which can be subtle and difficult to recognize. The specific definition of what constitutes a concussion is still evolving. Box 6.1 shows a recently updated definition from the 4th International Conference on Concussion in Sport. Box 6.1 Definition of Concussion from the 4th International Conference on Concussion in Sport Concussion is a brain injury and is defined as a complex pathophysiological process affecting the brain, induced by biomechanical forces. Several common features that incorporate clinical, pathologic, and biomechanical injury constructs that may be utilized in defining the nature of a concussive head injury include the following: Concussion may be caused by a direct blow to either the head, face, neck, or elsewhere on the body with an “impulsive” force transmitted to the head. Concussion typically results in the rapid onset of short-lived impairment of neurologic function that resolves spontaneously. However, in some cases, symptoms and signs may evolve over a number of minutes to hours. Concussion may result in neuropathological changes, but the acute clinical symptoms largely reflect a functional disturbance rather than a structural injury and, as such, no abnormality is seen on standard structural neuroimaging studies. 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, it is important to note that in some cases symptoms may be prolonged. Symptoms of concussion can come and go at various times after the initial head injury and there are many additional symptoms ( ▶ Table 6.1). Because of this, it is important to take a comprehensive approach that includes clinical examination, cognitive testing, assessment of balance and vestibular function, and symptom reports. Research shows that concussion assessments need to be repeated over time and it is best to have preseason testing for comparison with acute injuries. Headache 78.5% Feeling slowed down 66.8% Difficulty concentrating 65% Dizziness 61.3% Drowsiness 66.1% Fatigue 69.2% Visual problems 29.5% Light sensitivity 24.3% Memory dysfunction 55% Balance problems 49.2% Most on-field (Sport Concussion Assessment Tool 3rd Edition [SCAT3]) or follow-up concussion tools (Immediate Post-Concussion Assessment and Cognitive Testing [ImPACT], CogSport, Automated Neuropsychological Assessment Metrics [ANAM], Concussion Resolution Index [CRI], the King–Devick test) include self-reports of symptom estimation. Symptom clustering on these assessments can help provide a targeted approach to assessment, management, and treatment. Checklists and systems usually cluster symptoms as physical, neuropsychiatric, cognitive, and sleep disturbances ( ▶ Fig. 6.1). A player presenting with predominantly physical symptoms such as light/noise sensitivity may benefit from different treatment strategies compared to a player with mostly cognitive symptoms such as memory problems or difficulty concentrating. Careful evaluation of symptoms by category can guide the choice of management approaches, treatment plans, and rehabilitation strategies. Fig. 6.1 Common symptoms associated with concussion in acute and subacute phase. A concussion is caused by a direct or indirect, linear or rotational force to the head, face, or other area of the body in which the force is transmitted to the brain. The neural structures undergo a shearing strain leading to short-term neurological impairment and functional disturbances of the nervous system. In the brain, these shear forces seem to damage deep white matter tracts and microscopic injuries to the nerve axons neurons; this is also known as diffuse axonal injury. The functional disturbances, often referred to as a neurometabolic cascade, seem to cause an imbalance between energy supply and demand due to mitochondrial changes and decreased flow of blood to the brain. A corresponding increase in energy consumption occurs to reestablish homeostasis. Recovery from this imbalance requires limiting physical and cognitive activity, which may take minutes to days with subsequent symptoms lasting days to weeks. Not only is it difficult to identify brain injury/concussion, but also the complex and highly individualized nature of the symptoms makes it difficult to precisely diagnose and manage. For this reason, it is important to assess individual’s normal (standard) function before the injury with standardized baseline testing to use as a comparison after a potential concussion occurs ( ▶ Fig. 6.2). Fig. 6.2 Evaluation and management process. There are many recommendations for the use of neuropsychological assessments as part of managing concussion. Baseline testing and postconcussion testing aid the clinical decision-making process but are not the sole basis for management decisions. The ultimate return-to-play decision is a medical one in which a multidisciplinary approach should be employed. Baseline testing is the preseason evaluation of player’s cognitive function including learning, memory skills, concentration, and problem-solving abilities. It also identifies any residual concussion symptoms from previous seasons. Baseline testing can easily be incorporated as part of the normal screening process during the preseason conditioning period. Results from baseline tests can later be compared to testing after a suspected concussion, and also to evaluate the player’s recovery back to this baseline, which assists in return-to-play decisions. Comparing postinjury test scores of an individual to their own baseline test scores from before the concussion is considered best practice. Without a baseline test to use for comparison, an individual’s post-injury test scores can only be compared to those of the general population. Computerized testing of neuropsychological function decreases time spent by the clinician on preseason testing, improves test accuracy, and allows trained sports medicine clinician to interpret results without consulting a neuropsychologist. Other advantages include accessibility via internet, highly standardized test administration and scoring, the ability to compare results on multiple test forms, repeat testing, and storage of performance data for comparison purposes. The tests themselves may have higher sensitivity compared to traditional pencil-and-paper assessments. The tests measure reaction time, memory capacity, speed of mental processing, and executive functioning. They also provide a means of assessing and storing the player’s history of concussion, including number, severity, and duration of previous concussion symptoms, the age of the athlete, and any preexisting conditions such as history of headaches, migraines, presence of attention deficit disorder (ADD/ADHD), anxiety, or any learning disabilities, including dyslexia. There are a number of baseline tests available for sports teams to consider when implementing an overall concussion detection and management policy. To date, there is insufficient evidence to conclude that one instrument or approach is superior to another. ImPACT (ImPACT Applications, Inc.) is the most widely used computerized concussion evaluation system in sports today. ImPACT takes approximately 30 minutes to complete and includes a section with health history, a symptom checklist, and six neuropsychological tests, which produce four composite scores of verbal and visual memory, processing speed, and reaction time. Each composite score is compared with normative data for age and sex to provide a percentile score. The Post-Concussion Symptom Scale (PCSS), a self-reported inventory of 22 symptoms associated with concussions, is embedded into ImPACT and reported as a separate score. ImPACT test is reported to have an 82% sensitivity to detect a concussion when administered within 72 hours of trauma. CogSport or Axon Sports Test (CogState) is another computer-based test with good test retest reliability and a sensitive measure of cognitive recovery postconcussion. CogSport measures reaction time, accuracy to evaluate simple and complex attention, working memory, short-term memory, and ability to new learning, incidental memory, adaptive problem-solving, continuous performance, and spatial abilities. CogSport comprises a 24-item symptom checklist and 6 computerized tasks, assessing reaction time, decision-making, matching, working memory, and attention, and takes approximately 25 minutes to complete. ANAM (Vista LifeSciences) is designed to evaluate several neurocognitive domains and provide data on an individual’s neurocognitive status at a point in time and changes in cognitive status over time. ANAM has been shown to be reliable and valid and measures speed and accuracy of attention, memory, and thinking abilities. ANAM includes five subset of variables such as simple reaction time, continuous performance test measuring attention and concentration, math processing measuring mental processing speed and efficiency, matching to sample measuring visual memory, and Sternberg memory measuring working memory. CRI measures reaction time and speeded decision-making. CRI has been found to be sensitive in identifying postconcussive symptoms, while remaining resistant to retest effects including changes in test performance attributed to increasing familiarity with and exposure to test. CRI consists of six subtests measuring reaction time, visual recognition, and speed of information processing. The King–Devick test is a fairly new promising test that has been reported to have high test–retest and inter-rater reliability, although to date, limited normative data have yet been published. The King–Devick test measures processing speed, visual tracing, and saccadic eye movements, and has been suggested to be an addition to sideline evaluation as well as baseline testing. A tool recommended by the latest consensus in sports concussion to aid in on-field or sideline evaluation is SCAT3, a standardized tool for evaluating athletes over the age of 13 for concussion. SCAT3 is available in an app form and also as a card to make sideline evaluation easier. SCAT3 also exists in a pediatric version (Child-SCAT3). SCAT3 can be used for baseline testing as a complement to computerized neuropsychological tests. However, to date only a few normative reference populations exists. This is however a minor detail as the players’ own results, during preseason testing, should optimally be compared to the results after a sustained concussion. SCAT3 has one observational section, one for background information, and a section of seven tests. The observational section screens for potential signs of concussion such as loss of consciousness, and amnesia. The background information section contains self-reported concussion history, risk factors for prolonged recovery, and medication history. The questions refer to known risk factors for prolonged recovery from concussion and will aid in prognosis after a sustained concussion. The test section includes the following: Glasgow Coma Scale to exclude severe brain trauma. Maddocks five questions to test orientation and amnesia with high specificity for concussion. PCSS, a standardized evaluation of 22 symptoms common to concussion. Standardized Assessment of Concussion (SAC) to rapidly assess orientation, immediate memory, concentration, and delayed recall. Note that the SAC cannot be substituted for comprehensive neuropsychological assessment or neurological examination beyond the field when it comes to diagnosing concussion, measuring recovery, or making return-to-play decisions. Neck examination with range of motion, tenderness, and upper and lower limb sensation and strength. Modified balance error scoring system (BESS), double, single, and tandem leg stance, and tandem gait. Coordination assessment using the finger-to-nose task. The initial assessment is crucial for making the right call and is made when team medical personnel enter the field of play after being summoned by the referee. Fédération Internationale de Football Association (FIFA) and Union of European Football Associations (UEFA) have improved concussion management by reinforcing the team physician’s role to ensure correct management of potential cases of concussions. In the event of a head injury, the referee may stop the game for 3 minutes, allowing the team physician to complete an on-field assessment. The referee may only allow the player to continue if the physician authorizes it. The following section has been divided in a short on-pitch evaluation that needs to take less than 3 minutes performed to exclude serious injuries and make a quick decision regarding risk for concussion. If a concussion is suspected, the player should be removed from the game so a more thorough assessment can be performed off-pitch. It is difficult to rapidly assess for concussion and make a return-to-play decision in only 3 minutes. Assessment on the field can also be difficult due to the emotion and pressure around the match and because diagnostic criteria can be subtle. It is therefore advisable to use a standardized approach to clarify the acute effects of injury and establish an index of severity for increased objectivity in tracking recovery. With loss of consciousness, first evaluate Airway, Breathing and Circulation and perform a physical examination to rule out cervical spine or other serious injuries. Perform basic neurologic screening. If cervical spine injury is suspected or cannot be ruled out, immobilize the player’s neck and transfer them to an emergency department immediately. If the player scores less than 15 on the Glasgow Coma Scale, has deteriorating mental status, or progressive worsening symptoms (for example, neurological symptoms, persistent vomiting, suspected skull fracture, or seizures), initiate urgent transportation to the nearest hospital. If none of these are present, proceed to the concussion evaluation. Diagnosing concussion is straightforward if the symptoms involve loss of consciousness or if the player is obviously disoriented or anamnestic. However, in more than 90% of concussions milder deficits in cognitive function occur, making diagnosis more challenging. On approach to the player, the medical staff should observe whether there are any obvious signs of concussion, e.g., slow to get up, staggering gait, or a vacant look. A blow to the head can give a variety of symptoms that need to be checked for, including cognitive status, posture, vestibular and ocular symptoms, and abnormal behavior. If the player has had any loss of consciousness, loss of balance, motor incoordination, disorientation, confusion, amnesia, headache, or a vacant look, the player should not be allowed to return to play that day and should be referred to emergency management of hospital. The latest consensus in sports concussion recommends using SCAT3. ▶ Table 6.2 shows the first two tests for concussion in SCAT3. If the answer to any of these questions is yes, take the player out of play. The later sections of the SCAT3 are more suitable for off-field evaluation due to the restrictive 3-minute time frame on field. If there is initial uncertainty over the diagnosis, before making an irreversible call for substitution or if all substitutions have been used, an expedited in-depth evaluation is possible before making the return-to-play decision. A full examination takes at least 15 minutes to perform and the recommendation is to complete the SCAT3 test in case of suspicion of concussion. If the player has any symptoms on SCAT3, the player should not be allowed to return to play. If possible, perform concussion evaluation in the privacy of the locker room to allow for quality evaluation after the first on-pitch evaluation. If the first two sections have been used on pitch as suggested, a good strategy is to start a new SCAT3 in privacy in case there have been any deteriorations since the time of trauma. If an emergency situation has been ruled out, complete the SCAT3 evaluation starting with the seven test sections ( ▶ Table 6.2). Complete the SCAT3 even if the call has been made to bench the player as it establishes a postinjury baseline that later can be used to track recovery and aid in evaluating if symptoms are deteriorating and a more severe injury has occurred. Neurological examination Glasgow Coma Scale less than 15 Yes No Deteriorating mental status Yes No Potential spinal injury Yes No Progressive symptoms Yes No Loss of consciousness Yes No Loss of memory Yes No Blank or vacant look Yes No Visible facial injury in combination with any of above Yes No Maddocks score less than 5 points Yes No A few apps are emerging as a complement to locker room screening tool with SCAT3. For example, the ImPACT system mentioned earlier also contains an app for aid in sideline evaluation measuring concentration, short-term memory, and orientation that could be useful. Another test that has developed an app for locker room screening is the previously mentioned King–Devick test evaluating visual tracking and saccadic eye movements. Neither of those app-based tests can be used for return-to-play decisions. These apps may, however, be useful in capturing important information that can assist in ongoing management and care of the suspected injury. If there is a suspicion of concussion, the player should be monitored over the next 24 hours for worsening symptoms or delayed responses. If symptoms worsen or new ones arise, the player should be referred to emergency medical care to rule out complications such as intracranial bleeding or edema. Ideally, a written notification would be given to the player with pertinent information regarding signs or symptoms that should prompt an emergency evaluation along with advice to avoid any physical or cognitive exertion that worsens or mimics signs of a concussion, including avoiding alcohol and medication such as aspirin and nonsteroidal anti—inflammatory drugs (NSAIDs) due to a theoretical risk of bleeding. Despite all progress in the medical field, there is to date not a blood test, imaging, or X-ray that can detect or rule out a concussion by itself. The assessment is clinical and made by physicians trained in the identification and management of concussion. Physicians should take a careful history and assess the patient’s symptoms especially whether these have improved or deteriorated since the trauma. Physical examination and additional tests, including neuroradiology, to confirm a diagnosis of concussion and exclude any structural damage to the brain should then be arranged as required. The medical examination should include the players’ medical history as well as a detailed neurological examination, including cognitive functioning, mental status, gait, and balance. Comparison can be made between the evaluation performed in the hospital setting with the initial examination made on the pitch to evaluate whether the symptoms have alleviated or worsened since the injury. A computed tomography (CT) imaging is the recommended test for ruling out skull fracture, intracranial bleeding, or swelling of the brain within the first 48 hours of injury due to cost effectiveness and availability. CT does require exposure to radiation and cannot detect microscopic injury to the axons, which is a cause of symptoms in more severe traumatic brain injuries. Magnetic resonance imaging (MRI) is a more powerful tool for detecting microbleeds, contusions, or gliosis. While CT is the preferred test for acute trauma, it is advisable to follow it up with an MRI in a subacute phase if symptoms persist. Follow-up of suspected concussion should occur within 24 hours, and should include both SCAT3 and a more complete neuropsychological assessment using the tools referred to earlier in the chapter. A player who has sustained a concussion should be instructed to rest both physically and cognitively. Cognitive rest means no reading, TV, computers, games, loud noises, or bright lights. Rest should be continued until all signs and symptoms have resolved. A gradual return-to-play protocol that will take at least 7 days to complete is the recommended management for these players (see below). Computerized concussion screening tools may aid in discerning any lingering cognitive deficits and serial follow-up tests can be administered over days or weeks so that the medical staff can continue to track the injury. Sometimes symptoms cluster in areas such as physical, neuropsychiatric, cognitive, and sleep disturbances (see ▶ Fig. 6.1). Symptoms after a concussion usually linger on for 10 days, sometimes up to 3 weeks. Sometimes the symptoms persist and can develop into a postconcussion syndrome. If there is difficulty in managing symptoms or a recovery takes more than a month, refer the player to a specialized sports concussion clinic or neurology department. If team medical personnel have cleared the player, a follow-up should be performed using SCAT3 and preferred cognitive tests such as ImPACT, CogSport, ANAM, CRI, or the King–Devick test. When test scores have returned to baseline and the player has been cleared, stepwise return to sport may begin. After a player who has sustained concussion is symptom free at rest, a gradual six-step protocol as described below and shown in ▶ Fig. 6.3 is recommended. This protocol includes a 24-hour gap between steps to ensure that late symptoms in response to exertion do not develop. The player can progress through each step as long as no symptoms return. If any symptoms occur, the player must return to the previous step after a minimum of a 24-hour symptom-free period and pass it without any symptoms appearing before progressing. No activity. The intention is to start a gradual return to play regardless of level or age first when the player is symptom free (without any medication) for 24 hours. Light aerobic exercise. The second step is light aerobic exercise with the purpose to increase heart rate and assess recovery. If the player experiences headache after the exercise and has a hard time to be symptom free, try to evaluate the environment in which the exertion takes place. Management of concussions should focus on both the physical demands and the cognitive/mental exertion placed on the recovering brain. If possible, choose a location where the surrounding environment gives as little impression as possible, for example, light aerobic activity on bike in a separate room where you can control light and noise and minimize visual impressions. Sport-specific exercise. The third step is football-specific activities and more aerobic demanding activities with the purpose to add movement and assess recovery. Try to incorporate dynamic warm-ups, agility drills, and movement that challenges positional changes and the vestibular, proprioceptive, and visual systems such as burpees. Try to gradually increase the cognitive load on the player, for example, go from training in separate room to the general gym where noise, light, and movements will challenge the player. If the player manages in a quiet setting, take them outdoors. Try to integrate strength, conditioning, and balance/proprioceptive exercises. Noncontact training drills. The fourth step includes maximal exertion without contact with the purpose to add exercise and coordination together with cognitive load to assess recovery. Players can attend regular noncontact practices as a way to test them for both aerobic and cognitive exertion. Begin with reduced training volume and intensity and gradually increase load. Full contact practice. The fifth step is participation in full training including contacts and aims at restoring confidence and evaluation of functional skills by the coaching staff and allow for recovery assessment. The sixth step is medical clearance and return to matches. Fig. 6.3 Gradual return-to-play protocol.
6.3 Symptoms and Signs of Concussion
6.4 Causes and Mechanisms of Concussion
6.5 Evaluation and Management of Concussion
6.5.1 Baseline Testing
Computerized Neuropsychological Instruments
Immediate Post-Concussion Assessment and Cognitive Testing
CogSport
Automated Neuropsychological Assessment Metrics
Concussion Resolution Index
The King–Devick Test
Paper and Pencil Test
Sport Concussion Assessment Tool 3rd Edition
6.5.2 On-Pitch and Locker Room Acute Assessment and Management
On-Pitch Evaluation
Exclude Acute Serious Injuries
Concussion Evaluation
Sideline and Locker Room Evaluation
6.5.3 Evaluation in Emergency Room or Doctor’s Office
Brain Imaging
6.5.4 Follow-Up Evaluation and Management
Return to Play
Gradual Return-to-Play Protocol
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