Return to athletic competition following concussion.

Review Article

Return to athletic competition following concussion H. HUGENHOLTZ, MD, FRCS[C] M.T. RICHARD, MD, FRCS[C]

To establish guidelines for the examination of patients and the resumption of athletic activity after concussion, the injury is characterized as mild, moderate or severe (unconscious only transiently, for less than 5 minutes or for more than 5 minutes). The basic recommendation is that return to training and competition should be deferred until all associated symptoms such as headaches have completely resolved. The decision to return must take into account the nature of the sport, the athlete's level of participation and the cumulative effect of previous concussions. Some athletes will have to avoid any further participation in their sport. Afin d'etablir des directives quant a l'examen du patient et la reprise des activit6s athl6tiques aprAs une commotion, la blessure est qualifi6e de l1g6re, modAr6e ou grave selon que l'inconscience est transitoire ou qu'elle dure moins ou plus de 5 minutes. La recommandation fondamentale est de retarder le retour a l'entrainement ou a la competition jusqu'A disparition complete des sympt8mes associ6s, tels les maux de tate. La dAcision d'autoriser un retour doit prendre en ligne de compte la nature du sport, le niveau de participation de l'athl6te 'et les effets cumulatifs des commotions pr6c6dentes. Certains athletes doivent s'abstenir de toute autre participation a leur sport.

um. They may be classified according to the duration of either unconsciousness2 or post-traumatic amnesia.3 Unconsciousness is not an essential feature of concussion. The concussed athlete has sustained a major impact. Concussion will result from a blow to the head that is equivalent to a linear acceleration 80 to 90 times the force of gravity for more than 4 ms.4 This is several times the force that causes discomfort in a football player wearing a helmet. Concussions have always been regarded as minor injuries not causing visible brain damage, yet widespread microscopic changes have been documented. These include petechial hemorrhages in periventricular regions, axonal changes suggestive of shear injuries throughout the white matter of the hemispheres and brain stem, and chromatolysis and cell loss throughout the cortical grey matter and brain stem nuclei.57 These abnormalities may evolve into gross atrophy after repeated injury. A number of physicochemical abnormalities have also been observed following concussion. They include transient and long-lasting electroencephalographic (EEG) changes, abnormalities in electrocardiogram tracings and respiration, slowing of the cerebral circulation,8 release of acetylcholine and potassium into the cerebrospinal fluid,9 alterations in the blood-brain barrier,'0 changes in water and electrolyte distribution" and altered metabolism of glucose, pyruvate'2 and adenosine

triphosphate.'3 Head injuries are fairly comVhon in combative and contact sports but can also occur in a recreational setting.' Even when the injury is considered to be minor, as are concussions, allowing an athlete to return to full activity too soon can have serious consequences. Associated symptoms such as headache, dizziness and impaired concentration are likely to be exacerbated and prolonged, and athletic performance and health may suffer permanently. The nature of concussion

Concussions are characterized by immediate, though transient, impairment of neuronal function, generally reflected in impairment of consciousness or of equilibriFrom the University of Ottawa and the division of neurosurgery, Ottawa General Hospital

Reprint requests to: Dr. H. Hugenholtz, Division of neurosurgery, Ottawa General Hospital, 501 Smyth Rd., Ottawa, Ont. K1H 8L6 '-For prescribing information

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The concussed athlete, although conscious and without "gross" neurologic signs, may be significantly impaired in higher functions such as short-term memory.'4 Meggyesy,'5 a professional football player, wrote that "your memory is affected although you can still walk around and sometimes continue playing. If you don't feel pain, the only way other players and the coaches know that you have been 'dinged' is when they realize you can't remember the plays." Gronwall and Wrightson'6 demonstrated that the ability to process information is reduced immediately after the injury, as measured in the Paced Auditory Serial Addition Test. They also showed that functional impairment from repeated concussions was cumulative.'7 Significant differences have been observed between the two scores on the Wechsler Adult Intelligence Scale following concussion, with performance lagging an average of 19 points behind verbal.'8 Concussion may lead to a post-traumatic syndrome of headache, dizziness, fatigue, irritability, and impaired memory and concentration. The severity CMA JOURNAL/NOVEMBER 1, 1982/VOL. 127 827

and persistence of these symptoms are related to the duration of the post-traumatic amnesia19 and reflect altered neurotransmitter function. It is surprising that the structural abnormalities do not clinically manifest themselves more dramatically. The apparent integrity of brain function can be dangerously misleading. A minor concussion may simply represent the lucid phase of a more serious injury. The late Mark Donahue, a popular US Grand Prix driver, walked around in the pits talking to his crew for half an hour following his apparent "concussion" before collapsing with a fatal extradural hematoma. Evaluation of concussions It is essential that each concussion be carefully evaluated to determine its severity, the full extent of associated symptoms, such as headache, confusion and dysequilibrium, and the effect oh the athlete's performance. A thorough neurologic examination must be performed as soon as possible and repeated at intervals. In the case of a mild concussion this should require little more than a few minutes. Short-term memory should be assessed by questions pertaining to an athlete's assignments or "game plan" and events that followed the injury. Questions about names, places, spelling and digit recall do not adequately test the capacity to process information."4 Athletes who were unconscious for only a few minutes with a moderate concussion and whose injuries were not reliably witnessed should have roentgenograms made of the skull and also the cervical spine to identify unexpected fractures or instability. In severe concussion, when unconsciousness lasts more than 5 minutes, the athlete should be observed in hospital for intracranial bleeding.20 If neurologic examination at any time reveals an abnormality suggestive of brain contusion or laceration, if a skull fracture is identified or if associated symptoms, such as headache, nausea, vomiting, visual disturbances and dysequilibrium persist for 12 hours, then computer-assisted tomography (CT) is indicated. Occasionally it will reveal an intracranial hemorrhage that has caused little more than headache or vague neurologic complaints. Furthermore, the first CT scan may be normal, only to become abnormal after a few days as microscopic hemorrhages coalesce, confirming the athlete's continuing complaints. While the EEG may have been overemphasized in the past, it remains useful for documenting the diffuse cerebral disorganization that may accompany concussions.2'22 Athletes who complain of persistent postconcussion vertigo may suffer from labyrinthine dysfunction or central lesions.23 Electronystamography and brain stem auditory evoked responses will document these lesions and, with serial testing, their resolution. Athletic performance may be markedly impaired following even minor concussions. A battery of neuropsychologic tests can help detect specific deficiencies.

Withdrawal from athletic activity An understanding of the injured athlete's degree of involvement in competition and training and familiarity 828 CMA JOURNAL/NOVEMBER 1, 1982/VOL. 127

with the demands of the particular sport are important in deciding how long to keep the patient out of training and competition. The ability to assimilate information and act with split-second timing is more likely to be impaired following concussion than are strength and endurance.6"8 For a downhill ski racer, a skydiver or an automobile racer the implications of performance and failure are totally different from those for a hockey player, who can readily be observed and removed from the game. Norrell24 did not differentiate between various grades of concussion but recommended that any football player with residual effects such as headache, confusion and unexplained behaviour be removed from the remainder of the contest. Ryan25 also stressed the importance of headache as a symptom of brain damage and recommended that training and competition be avoided until the headache has resolved. Vanderfield26 suggested a 3-week elimination from competition. With respect to fitness to drive, however, the Canadian Medical Association2" has recommended that a motor vehicle not be driven by any person with a head injury and post-traumatic amnesia of 2 to 4 hours' duration for at least 3 months, and then only after examination results are normal. If we are so concerned about keeping a concussed person from behind a steering wheel, should we not also protect the ski racer, the skydiver, the gymnast and the motorcycle racer, whose demands for concentration and stamina exceed those of the average driver? Boxing has been studied separately because of the repetition of concussions, which tend to be mild to moderate. Vanderfield26 recommended prohibition of boxing for at least 4 weeks if the victim was knocked out by a blow to the head. The New York State Athletic Commission's medical advisory board imposes an automatic 30-day suspension from competition for any boxer who is knocked out and terminates any but championship bouts if a boxer suffers three knockdowns.28 Recently the Ontario Athletic Commission recommended an automatic 60-day suspension for any fighter knocked out from a blow to the head, suspension from contest and contact training for at least 6 months after a second knockout within 6 months, and automatic suspension for at least 1 year following three successive knockouts.29 The problem of repetitive concussions and their cumulative effect on an athlete's performance applies to a variety of other sports. Thorndike30 concluded that three concussions should preclude further participation in contact sport. However, in some cases even a single concussion with evidence of damage on a CT scan should eliminate a player from further contact sports. Athletes who have undergone previous intracranial surgery or who have hydrocephalus should not enter contact sports at all.3'

Guidelines for return to competition Our guidelines are based on a determination of the severity of concussion (Table I). Recovery from a mild concussion is usually rapid but may take several weeks.'6 The athlete should not return to training or competition until he or she is fully

oriented and dexterity, strength and speed have returned. If associated symptoms such as headaches appear, training and competition should be deferred until they have resolved. After a moderate concussion training and competition should be avoided for at least several days, until all associated symptoms and any structural abnormalities have completely resolved. Athletes with severe concussions should be observed in hospital, as the concussion may mask an expanding hematoma. Training and competition should be avoided for at least a month, until all symptoms and signs of fresh structural damage have resolved. Most of these patients are able to resume normal activities after 30 days, but a return to intensive training and competition may precipitate headache and dysequilibrium; the reappearance of these associated symptoms requires further convalescence. Serial neuropsychologic testing is indicated if symptoms persist for a week or more, and the results can then serve as a guide in determining the optimum time to resume training and competition. Such testing may prove invaluable for athletes who compete in high-performance sports in which there is risk to life. Post-traumatic seizures occur in the first week following concussions in 4% or 5% of cases, as well as after more serious injuries.32 Therefore, the more hazardous activities and sports should be avoided during this interval.23 If there are two or more seizures in the first week after injury a persistent seizure pattern is likely to develop" and anticonvulsant therapy is warranted. The athlete should not resume participation until therapeutic serum levels of the anticonvulsant are attained and the patient has adjusted to side effects, such as somnolence. Post-traumatic seizures are not a contraindication to a return to contact or team sports, however, especially when informed personnel are available to render assistance. Each case has to be evaluated individually. Who should be advised to abstain from his or her sport permanently? Some athletic governing bodies have issued strict guidelines, and three concussions are often .J..tI

PO

.4flVft.ia I J.OIir. to ( ..IRtf., poit4ra amnesia 1 to 24bourt) Severe (unconscious .5 mm; post-traumatic amnesia .24 hours)

Avoid vrous'tiui.g.t Resume trarniiig only .I& symptoms Mw resolv4 Avoid vigorous triw*ig. for I month or more. Await complete resolution of deficit and of evidenceirt damage detected by tomography. Await resolution of functional as shown in serial neuralog. Resume trarmogonly when symptoms have resolved. *Wlth afl resume participation if full orientation and dectarity. strength and speed return, and withdraw if sy reappear.

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cited as the tolerable limit.2 In general, however, it will be up to the individual physician to document cumulative structural and functional changes and then reach an informed consensus with the athlete, family and coaches. Conclusion

Concussions occur in a wide spectrum of sports. Occasionally they mask more serious injuries. Athletes should not return to competition until all associated symptoms such as headache have resolved completely. Severely concussed athletes and those who have suffered repeated concussions should be carefully evaluated with CT, electroencephalography and neuropsychologic testing whenever there is any doubt about their fitness to resume competition. References 1. LA CAVA G: Indagine Clinico-Statistica Sulle Lesioni Traumaisehe da Sport, Eidzioni Minerva Medica, Milano, 1960 2. MAROON JC, STEELE PB. BERLIN R: Football head and neck injuries - an update. Clin Neurosurg 1980; 27: 414-429 3. JENNET B: Late effects of head injuries. In CRITCHLEY M, O'LEARY JL, JENNET B (eds): Scientific Foundations of Neurology, Davis Co, Philadelphia, 1971: 441-451 4. GURDJIAN ES: Prevention and mitigation of injuries. Clin Neurosurg 1972; 19: 43-57 5. NEvIN NC: Neuropashological changes in the white matter following head injury. J

Neuropath Exp Neurol 1967; 26: 77-84 6. PEERLESS SJ, REWCASTLE NB: Shear injuries of the brain. Can Med Assoc J 1967; 96: 577-582 7. CHASON JL, HARDY WG, WEBSTER JE, GURDJIAN ES: Alterations in cell structure of the brain associated with experimental concussion. JNeurosurg 1958; 15: 135-139 8. FLAMM ES, OMMAYA AK, COE J, DRuEGER TP, FASS FH: Cardiovascular effects of experimental head injury in the monkey. Surg Forum 1966; 17: 414-416 9. BORNSTEIN MB: Presence and action of acetylcholine in experimental brain trauma. J Neurophysiol 1946; 9: 349-366 10. OMMAYA AK, ROCKOFF SD, BALDWIN M: Experimental concussion; a first report. J Neurosurg 1964; 21: 249-265 11. FAAS FH, OMMAYA AK: Brain tissue electrolytes and water content in experimental concussion in the monkey. J Neurosurg 1968; 28: 137-144 12. KURZE T: In CAVENESS WF, WALKER AE (eds): Head Injury: Conference Proceedings, Lippincott, Philadelphia, 1966: 254 13. ISCHII 5: bid: 276 14. YARNELL PR, LYNCH 5: The "ding": amnestic states in football trauma. Neurology (Minneap) 1973; 23: 196-197 15. MEGGYESY D: Out of Their League, Ramparts, Berkeley, Ca, 1970: 125 16. GRONWALL D, WRIGHTSON P: Delayed recovery of intellectual function after minor head injury. Lancet 1974; 2: 605-609 17. Idem: Cumulative effect of concussion. Lancet 1975; 2: 995-997 18. MANDELBERG IA, BROOKS DN: Cognitive recovery after severe head injury. 1. Serial testing on the Wechnler Adult Intelligence Scale. J Neurol Neurosurg Psychiatry 1975; 38: 1121-1126 19. GUTHKELCH AN: Posttraumatic amnesia, poss-concussional symptoms and accident neurosis. EurNeurol 1980; 19: 91-102 20. LINDSAY KW, MCLATCHIE 6, JENNETT B: Serious head injuries in sport. Br Med J 1980; 281: 789-791 21. HUGHES JR. WILMS JH, ADAMS CL, COMBS LW: Football helmet evaluation based on players' EEGs. Physician Sportsmed 1977; 5(5): 73-77 22. KAPLAN HA, BROWDER J: Observations on the clinical and brain wave patterns of professional boxers. JAMA 1954; 156: 1138-1144 23. BECKER DP, GROSSMAN RG, MCLAURIN RL, CAVENESS WF: Head injuries - Panel 3. Arch Neural 1979; 36: 750-758 24. NORELL H: The neurosurgeon's responsibility in the prevention of sports injuries. Clin Neurosurg 1972; 19: 208-219 25. RYAN AJ: A hit in the head (E). Physician Sporismed 1979; 7(9): 49-51 26. VANDERFIELD G: Head injuries. In Basic Book of Sports Medicine, International Olympic Committee, Lausanne, 1978: 239-243

27, To Drive? Or Not to Drive? The Medical Answer. Guide for Physicians in Determining Fitness to Drive a Motor Vehicle, 3rd ed, Canadian Medical Association, Ottawa, 1981: 21 28. MCCowN IA: Boxing safety and injuries. Physician Sportsmed 1979; 7(3): 74-82 29. McDANIEL CG: AMA takes a jab at regulations on boxing. Med Post 1982; 18 (15): 16 30. THORNDIKE A: Serious recurrent injuries of athletes: Contraindications to further competitive participation. N EngI J Med 1952; 247: 554-556 31. MURPHEY F, SIMMONS JC: Initial management of athletic injuries to the head and neck. Am J Surg 1959; 98: 379-383

32. JENNETT B: Epilepsy After Non-Missile Head Injuries. 2nd ed, Year Bk Med. Chicago. 1976 33. WEISS GH, CAVENESS WF: Prognostic factors in the persistence of posttraumatic epilepsy. J Neurosurg 1972; 37: 164-169

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