Concussion has been characterized by the 4th International Conference on Concussion in Sport (CIS) as a “subset of traumatic brain injury” and is defined as “a complex pathophysiological process affecting the brain, induced by biomechanics forces.”¹ The Centers for Disease Control and Prevention, through the National Electronic Injury Surveillance System—All Injury Program (NEISS-AIP), during the period of 2001 to 2009, estimated that 173,285 persons younger than 19 years old were treated for nonfatal traumatic brain injury (TBI).² Overall there has been an increase in TBI-related emergency department (ED) visits from 153,375 in 2001 to 248,418 in 2009.² Concussion and TBI represent a significant injury for athletes at all levels, including youth, high school, college, and professional. The diagnosis of a concussion can be challenging and remains a clinical diagnosis based on a constellation of subjective and objective data. After a concussion, there are typically alterations in function that cover several domains, including athlete-reported symptoms; physical signs; and behavioral, postural, and cognitive changes. Risk factors for concussion as well as risk factors that may prolong recovery, often termed “modifiers,” have been reviewed,^3,4,5,6,7,8 and return to play (RTP) protocols after concussion have been published,^{1,8,9,10,11,12} though much is still unknown regarding the natural history of concussion. This chapter focuses on the current understanding of RTP decision making and short-term prognosis after concussion.

The diagnosis of concussion and sideline management are discussed in the chapter by Herring et al. After the diagnosis of a concussion is made, there is clear consensus that an athlete should not return to activity or play the same day, and this holds true at all levels of competition, including youth, college, and professional sports.^1,8,13,14 Each concussion should be treated individually, taking into account the characteristics of the athlete (e.g., age, sport, position, gender, specific modifying variables), as well as his or her injury and prior history.^1,6,8 There is likely a spectrum of concussive injury that exists, from mild to more severe, and at this point, it remains unclear as to what factors definitively predict recovery.

The role of imaging initially and in the first several weeks after concussion is frequently considered. Current research and guidelines do not support obtaining imaging when an athlete is diagnosed with concussion without any other indication of potential serious brain injury.^1,6,8,10 However, if at initial presentation the history or clinical examination findings are concerning for cervical spine, intracranial bleeding, or skull fracture, then advanced imaging—in most cases, a CT scan—should be obtained emergently given the ability to demonstrate both bony injury as well as bleeding.¹

Several studies have compared MRI with CT findings after minor head injury.^15,16,17,18 Abudul Rahman and coworkers evaluated 152 patients with blunt head trauma and Glasgow Coma Scale (GCS) scores of 13 to 15 and found that the most common symptoms were headache (61%) followed by loss of consciousness (LOC) (45%), vomiting (39%), amnesia (29%), and convulsions (4%).¹⁸ Although this patient setting may include more severe brain injury, convulsions were the most predictive of positive CT finding (80%), and history of
LOC was least predictive (29%). The presence of two or more clinical findings increased the likelihood of abnormality.¹⁸ In another study, abnormal MRI findings were noted in 10% of patients with mild head injury who had normal CT results, and abnormalities on imaging were most common in patients with LOC, symptoms longer than 2 weeks, those with skull fracture, and those with multiple associated injuries.¹⁷

Lyttle et al¹⁹ evaluated three pediatric clinical decision rules—CATCH (Canadian Assessment of Tomography for Childhood Head Injury), CHALICE (Children’s Head Injury Algorithm for the Prediction of Important Clinical Events Rule), and PECARN (Pediatric Emergency Care Applied Research Network)—to determine what clinical findings warrant imaging in the setting of head trauma. They concluded that a GCS score less than 15 two hours after the injury, worsening headache, irritability on examination, LOC for more than 5 minutes, vomiting more than three times, and seizure activity were the findings in which imaging should be obtained. When an athlete with suspected cervical spine or more serious brain injury is transported for more advanced care, it is important to consider a facility with both emergent imaging as well as specialty physician (e.g., onsite spine surgeons and neurosurgeons) capabilities.

In less acute settings (e.g., after 2–3 weeks), with persistent or worsening symptoms, an MRI should be considered, given this modality’s predilection for demonstrating subtle abnormalities and the avoidance of radiation exposure.²⁰ The decision making regarding when MRI is indicated should be individualized. If there are abnormal findings on MRI, depending on if they are causative versus incidental, referral to additional members of the healthcare team, such as neurologists or neurosurgeons, should be considered.

The assessment often includes documenting symptoms, cognitive function, and balance. It also involves using several standardized tools, such as the Sideline Concussion Assessment Tool 3 (SCAT 3),²¹ which has been shown to be both sensitive and specific to concussion.²² When baseline assessments are available and compared with postinjury assessments, a drop in score of 3.5 points on the SCAT 2 demonstrated a sensitivity and specificity of the SCAT 2 of 96% and 81%, respectively. When a baseline assessment is not available, sensitivity and specificity were 91% and 83%, respectively, when a cutoff value is used.²² The utility of a sideline assessment in predicting severity is unknown at this time. As important as the sideline assessment, the in-office evaluation should include a thorough history of the concussion, including the mechanism of injury, immediate treatment, the athlete’s sport and position, and any symptoms immediately thereafter and progression or regression since onset. The presence of amnesia or LOC should be explored and documented.

Additionally, a complete personal and family medical, social, and academic history should be obtained. The clinician should also have a clear understanding of all current and upcoming academic demands. An evaluation for the presence of any concussion risk factors or modifiers³ should occur, and a standardized symptom checklist should be completed. A complete neurologic examination, including ocular motor screening, cognitive assessment, and balance and postural examination, should be performed. A symptom checklist (either Post Concussion Symptom Scale [PCSS] or SCAT 3) that can be compared with the sideline assessment, and ideally with a baseline, preinjury assessment, is useful to evaluate for improving or worsening symptoms across domains: cognitive-sensory (sensitivity to light, difficulty concentration), sleep arousal (drowsiness, sleeping more than usual), vestibular-somatic (headache, dizziness), and affective (sadness, nervousness).²³ The role of symptoms in diagnosis of concussion is reviewed elsewhere.^24,25

The cognitive assessment is important, and the SAC,²⁶ which is a component of the SCAT 3, can be used in the office. Consideration should be given for more sophisticated postinjury computerized or paper-pencil neuropsychological (NP) testing. These tests are more comprehensive measures of brain behavior relationship that assess cognitive function, and they can provide an additional value to the brief cognitive tests performed on the sideline or at baseline. In addition, compared with similar tests performed at baseline, they can provide additional information that can be used to assess the severity of injury as well as recovery from injury.^27,28 The evidence for or against NP testing and the timing is being addressed by Melissa et al in Chapter 26.

During the initial in-office visit after the diagnosis of a concussion, a balance and postural examination should be conducted. This may vary from the on-field assessment, as demonstrated by Herring et al in Chapter 24. The in-office postural assessment may be completed in a variety of manners, including using the Balance Error Scoring System (BESS) or Biosway.^29,30 The BESS includes postural testing, with eyes closed, for 20 seconds on a hard surface and foam, in three different stance positions.
A trained observer records errors, inclusive but not limited to, opening eyes, removing hands from hips, and stumbling or swaying from midline. BESS testing has been shown to have varying inter- and intrarater reliability (0.57–0.85 and 0.60–0.92, respectively),³⁰ and having the same individual administer serial and repeated testing is useful. Additionally, there is a “learning effect”³¹ with multiple administrations of BESS testing. An alternative is to assess postural sway using a Clinical Test for Sensory Interaction and Balance (CTSIB) combined with a force platform as integrated in the Biosway system. Additional research is needed to determine if the CTSIB combined with the BESS protocol is a reliable way to assess postural sway and if it addresses the learning effect of BESS testing alone. The utility of using a multimodal approach of symptoms, cognitive function, and balance testing in assessing and tracking recovery in concussion has been demonstrated using meta-analysis.^32,33

The final examination that should be considered in the in-office evaluation is a vestibular-ocular motor screen (VOMS) as detailed by Mucha et al.³⁴ Concussion may lead to impairment in postural control as well as ocular impairments, with up to 30% of concussed individuals reporting visual problems, including “blurry vision, diplopia, difficulty reading, dizziness, headache, ocular pain and poor visual concentration, all within the first week following a concussion.”³⁴ Screening includes five domains, with near-point convergence of 5 cm or greater increasing the diagnosis of concussion by 34%.³⁴ Beyond the initial screening and diagnosis, Heitger et al³⁵ explored the presence of impaired ocular function in postconcussion syndrome (PCS). Comparing 36 individuals with postconcussion syndrome at 140 days postinjury with matched control participants showed that the postconcussion syndrome group scored worse on saccades and smooth pursuits. This research is very encouraging and begins to explore the role of serial ocular screening in tracking recovery from concussion. At the present time, it is yet unknown how important ocular screening is in the RTP decision; therefore, in the interim, reliance on more validated modalities is recommended.

The diagnosis of a concussion is a multifaceted clinical decision requiring evaluation of mechanism, presence of symptoms and severity, presence of risk factors or modifiers and any resultant cognitive, and postural impairment. The same in-depth clinical thinking should occur during follow-up examinations, which should occur serially and at weekly intervals or time frames that are flexible, including when the athlete is back to his or her baseline level of symptoms; when the athlete is able to tolerate cardiovascular activities without difficulties; and when the athlete has tolerated noncontact, sport-specific activities and is ready to participate in contact play. In general, when an athlete reports being back to her or his baseline level of symptoms; when results of neurologic examination, including NP testing and postural examinations, have returned to baseline; and when the athlete is functioning at her or his baseline with academics, then she or he can be cleared to begin their RTP protocol. An exception to this, as discussed later, cardiovascular exercise may be considered a component of treatment, prior to resolution of symptoms and separate from the RTP protocol.

The RTP decision after concussion is ideally a gradual, stepwise progression that includes an incremental increase in both the level of exertion and the risk for contact. Each step typically occurs over 24 hours, while a PCSS is documented before and after activity.⁹ Although several position statements have supported this concept,^{1,6,7,8,10,11,12} it is worth noting that there is little evidence-based data to support this approach. Nonetheless, all of the RTP guidelines agree with the CIS group statements^1,9 that recommends a graduated RTP protocol beginning with light aerobic activity of sufficient intensity to maintain a heart rate below 70% of maximum. If the athlete tolerates this activity, the following day he or she is progressed to sport-specific exercises and then noncontact drills. If at any point the athlete develops symptoms of any severity level, she or he is returned to the previous level of exertion that caused no symptoms. Before returning to full contact sport, the athlete should fell like they are back to feeling normal, and they should be considered back to their baseline level of function in terms of their cognitive and balance function. If baseline tests of cognitive or postural function are performed, the postinjury tests should be compared with the baseline tests. Overall, the RTP progression is individualized to take into account the severity of injury (e.g., the nature, burden, and duration of symptoms) as well as other “modifiers” such as the concussion history or a history of attention deficit hyperactivity disorder (ADHD) or other learning disabilities, history of depression or anxiety, or history of migraine headaches.^1,8 As detailed later, risk factors and modifiers can affect an athlete’s baseline scores, progression, and recovery from a concussion. Therefore, a comprehensive treatment plan, sometimes in concert with an athlete’s parents, will need to be developed, including focused rehabilitation if necessary. For
example, if the athlete has evidence of persistent ocular findings or irregularities as determined by the VOMS,³⁴ he or she may benefit from specialized vestibulo-ocular rehabilitation. Generally, concussive symptoms resolve within 7 to 10 days^{5,29,36,37,38}; however, in some cases, symptoms can persist for weeks or months, known as postconcussion syndrome. Predictors for the development of postconcussion syndrome in young athletes include a prior history of concussion, premorbid mood disorder, and other psychiatric illness or significant life stressors, along with a family history of mood disorders, other psychiatric illness, and migraine.³⁹ For the management of postconcussion syndrome, it is helpful and recommended to institute a multidisciplinary treatment program, including neuropsychology, rehabilitation, psychology and psychiatry, and academic support. Chapter 27 provides a very detailed description and management strategy for athletes with postconcussion syndrome.