April/May 2000

Concussion Management on the Field

By Tory R. Lindley, MA, ATC

One of the most difficult problems facing sports medicine practitioners is the recognition, treatment, and management of athletes with head injuries. The occurrence of severe neurological injury in sports is not a new phenomenon. The National Collegiate Athletic Association (NCAA) was established in the early 1900s partially in response to President Theodore Roosevelt’s indignation over the 19 college athletes killed or paralyzed playing American football in 1904.1 Fatalities from all levels of football play peaked at 30 in 1964—the majority from head and neck injury.1 Recent rule changes, improvements in protective equipment, and coaching techniques emphasizing injury prevention have been helpful in reducing the incidence of traumatic brain injury, but an estimated 300,000 sports-related traumatic brain injuries (TBIs) of mild to moderate severity still occur in the United States each year.2,3

Despite the vast literature that exists on athletic head injuries, there is no universally accepted definition of concussion. One of the most popular working definitions is “a traumatic induced alteration in mental status that may or may not be accompanied by a loss of consciousness.”4 The Traumatic Brain Injury Act of 1996 introduced the term TBI into federal law.5 TBI, broadly defined as brain injury due to externally inflicted trauma, may result in significant impairment of an individual’s physical, cognitive, and psychosocial functioning.5

Although sports injuries account for only 3% of hospitalizations for TBI, approximately 90% of sports-related TBIs are mild and may go unreported, thus leading to an underestimation of the actual incidence rate of sports-related TBI.5 The danger of this high incidence is that, once an athlete receives a TBI, the likelihood of sustaining a second one increases by four.6 This phenomenon is commonly known as second impact syndrome. The term mild TBI (MTBI) has been used to describe brain injuries, especially those common to athletics.

Mechanism, Signs, and Symptoms

Any direct or indirect (rotation) force transmitted to the head can lead to an MTBI. Although protected by a thick, nonexpanding bony vault, the brain is susceptible to several types of injury forces. Direct compressive forces, such as a forceful blow to the resting head, are generally well tolerated unless they cause focal pathology (fractures, hematomas). Rotational acceleration and/or deceleration, on the other hand, creates tensile shearing forces between the brain and its surrounding attachments, resulting in more serious injury.7 Such an injury might occur from the athlete’s moving head striking a fixed object, such as the ground or another athlete. Lastly, MTBI can result from a sharp blow to the athlete’s torso or pelvis.

Rarely are the consequences of an MTBI limited to one set of symptoms. Observable symptoms may be consistent with altered neurological function, a change in cognitive function, noticeable behavioral deficits, and decreased social capabilities. Signs and symptoms of an MTBI can include one or more of the following: brief loss of consciousness, light-headedness, vertigo, cognitive and memory dysfunction, tinnitus, blurred vision, difficulty concentrating, amnesia, headache, nausea, vomiting, photophobia, or balance disturbance. Delayed signs and symptoms may also include sleep irregularities, fatigue, mood disorders, an inability to perform usual daily activities, depression, or lethargy.8

The onset rate, duration, and severity of these symptoms commonly determine the MTBI classification. Unfortunately, attempts to uniformly characterize and classify the levels of MTBI by utilizing signs and symptoms as indicators of relative severity have been difficult. Sixteen different systems are currently being used in sports medicine to classify or grade MTBI.9 The three most common systems vary slightly, but each is based on two common parameters—consciousness and amnesia.

Clinical Assessment

The clinical assessment of an athlete with an MTBI is essentially no different from any other emergency procedure. The objectives in evaluating the potentially head-injured athlete are threefold: recognize that a head injury has occurred, determine which athletes require transport to a medical facility for further treatment or diagnostic testing (CT scan or MRI), and following the appropriate treatment, decide when the athlete may safely return to participation.10 Due to the serious nature of MTBI and the concern for second impact syndrome, it is recommended that a physician make this decision.8

Although there is not one universally recognized evaluation progression, all athletes suspected of having sustained a MTBI should undergo neurological screening (eye, ear, cranium, cervical spine, sensory, and motor examination), mental status testing, and exertional proactive testing.8 These groups of tests not only determine severity and classification of the MTBI, but they may help the return-to-participation decision to be more objective. In addition, findings may lead the physician to refer the athlete for diagnostic testing before any decision on return to participation is made. Critical analysis of mental status testing and the return-to-participation decision are necessary for practitioners to develop their own management techniques for the MTBI.

Mental Status Testing

Mental status examinations must include short-term memory tests to assess the athlete’s ability to process new information. Memory loss of the events preceding the injury (retrograde amnesia) or of events following the injury (posttraumatic amnesia) constitutes a common mental status abnormality.

Practitioners have struggled to standardize their approach to mental status testing. The Standardized Assessment of Concussion (SAC) provides certified athletic trainers (ATCs) and physicians with a rapid (5 minute) and simple sideline evaluation instrument for assessing athletes with MTBI.11 The instrument tests attention, concentration, short-term memory, and delayed recall. However, it does not replace a neurological examination.

More detailed mental status testing with a battery of standardized neuropsychological tests is being used in a similar fashion in many levels of athletics.12 These evaluations, some computerized, can measure cognitive deficits objectively. Results can be compared with both preseason and/or normative data to help determine the status of an athlete’s MTBI. Research using neuropsychological testing is designed to delineate the acute recovery curves associated with specific signs and symptoms of MTBI.13

The neuropsychological evaluation is most effective when it includes a baseline assessment of the athlete’s preinjury level of cognitive functioning. Evaluation, after the injury has occurred, should be completed within 24 hours. This involves a careful assessment of specific cognitive functioning such as memory, attention, and information processing speed. Researchers believe that detailed standardized neuropsychological evaluations more adequately assess these domains than do the sideline mental status tests like SAC.13

More research and normative data are needed before practitioners are able to accurately interpret results from injured athletes. For instance, cognitive test performance can be an indicator of mental status improvement during subsequent evaluation, or the neuropsychological improvement could be attributed to possible learning effects. Correlations between various cognitive tests should also be questioned. Additional research in this area will enhance the practitioner’s ability to use these tests and subsequently improve decisions on return to participation.

Return-to-Play Guidelines

Just as with the definition of MTBI, there are no universally accepted criteria for determining—on the basis of symptoms—when an athlete may safely return to participation. Return to play is not based on the classification or severity of the MTBI rather, return to participation on the same day as the injury is recommended if: signs and symptoms clear within 15 minutes or less, both at rest and exertion; the neurological evaluation is normal; and there is no documented loss of consciousness. The athlete is not allowed to return to participation on the same day if signs and symptoms do not clear within 15 minutes at rest or exertion, or if there is any documented loss of consciousness.

There continues to be ongoing concern, however, regarding the lack of scientific method used in constructing each of these management guidelines. Some argue that the guidelines are empirical and reflect the biases of their creators, as well as an overall fear of second impact syndrome or death.9 For example, there are no data to support the 15-minute distinction for return to participation, nor is there any accounting for individual variability in symptoms. Further, they assume a standard for all athletes regardless of age or skill level.

ATCs and, in some cases, physicians are the front-line health care providers. They have the highest likelihood of observing a MTBI as it occurs and examining the athlete during its immediate effects. Continually reevaluating the signs and symptoms until they disappear, as well as monitoring the athlete’s mental status through neuropsychological testing, may lead to greater success in preventing reinjury. Not all MTBIs can be prevented. Still, the sports medicine community continues to strive for more accurate and consistent management, as well as an appreciation for the need to treat each case individually, thus decreasing the potential for reinjury and subsequently reducing the long-term effects associated with MTBI. N Tory R. Lindley, MA, ATC, is a staff athletic trainer at Michigan State University, Lansing.

References

1. Schneider RC. Football head and neck injury. Surg Neurol. 1987;27:505-508.
2. Albright JP, McCauley E, Martin RK, et al. Head and neck injuries in college football: an eight year analysis. Am J Sports Med. 1985;13:147-152.
3. Sosin DM, Sniezek JE, Thurman DJ. Incidence of mild and moderate brain injury in the United States, 1991. Brain Inj. 1996;10:47-54.
4. Quality Standards Subcommittee, American Academy of Neurology. Practice parameters. Neurobiology. 1997;48:1-5.
5. NIH Consensus Development Panel on Rehabilitation of Persons With Traumatic Brain Injury. Rehabilitation of persons with traumatic brain injury. JAMA. 1999;282:974-983.
6. Cantu RC. Guidelines for return to sports after a cerebral concussion. Physician Sportsmed. 1986;14(10):75-83.
7. Bruno LA, Gennarelli TA, Torg JS. Management guidelines for head injuries in athletics. Clin Sports Med. 1987;6(2):17-29.
8. Wojtys EW, Bailes J, Boland A, et al. Current concepts: concussion in sports. Am J Sports Med. 1999;27:676-687.
9. McKeag DB. The head injured athlete. In: Proceedings at the Annual Meeting for the American Medical Society for Sports

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