Sport-related concussions

Ianof, Jéssica Natuline; Freire, Fabio Rios; Calado, Vanessa Tomé Gonçalves; Lacerda, Juliana Rhein; Coelho, Fernanda; Veitzman, Silvia; Schmidt, Magali Taino; Machado, Sergio; Velasques, Bruna; Ribeiro, Pedro; Basile, Luis Fernando Hindi; Paiva, Wellingson Silva; Amorim, Robson; Anghinah, Renato

doi:10.1590/S1980-57642014DN81000003

ABSTRACT

Traumatic brain injury (TBI) is a major cause of lifelong disability and death worldwide. Sport-related traumatic brain injury is an important public health concern. The purpose of this review was to highlight the importance of sport-related concussions. Concussion refers to a transient alteration in consciousness induced by external biomechanical forces transmitted directly or indirectly to the brain. It is a common, although most likely underreported, condition. Contact sports such as American football, rugby, soccer, boxing, basketball and hockey are associated with a relatively high prevalence of concussion. Various factors may be associated with a greater risk of sport-related concussion, such as age, sex, sport played, level of sport played and equipment used. Physical complaints (headache, fatigue, dizziness), behavioral changes (depression, anxiety, irritability) and cognitive impairment are very common after a concussion. The risk of premature return to activities includes the prolongation of post-concussive symptoms and increased risk of concussion recurrence.

Key words:
TBI; traumatic brain injury; concussion; sports

RESUMO

O traumatismo cranioencefálico (TCE) é uma das principais causas de deficiência ao longo da vida e de morte no mundo. As lesões cerebrais traumáticas relacionadas ao esporte são um problema de saúde pública de grande impacto. O intuito desta revisão foi expor a importância das concussões relacionadas ao esporte. A concussão é uma alteração transitória da consciência induzida por forças biomecânicas externas que podem ser direta ou indiretamente transmitidas ao cérebro. Sua ocorrência é comum, mas provavelmente é subnotificada. Esportes de contato, como futebol americano, rugby, futebol, boxe, basquetebol e hóquei, estão associados a uma prevalência relativamente alta de concussão. Diferentes fatores podem estar associados a um maior risco de concussão relacionada ao esporte, como idade, sexo, esporte jogado, categoria de esporte jogado e equipamentos utilizados. Queixas físicas (dores de cabeça, fadiga, tonturas), alterações comportamentais (depressão, ansiedade, irritabilidade) e comprometimento cognitivo são muito comuns após uma concussão. O risco de retorno prematuro às atividades inclui o prolongamento dos sintomas pós-concussionais e o aumento do risco de recorrência de concussão.

Palavras-chave:
TCE; traumatismo cranioencefálico; concussão; esportes

Texto completo disponível apenas em PDF.

Full text available only in PDF format.

REFERENCES

¹
Jang SH. Review of motor recovery in patients with traumatic brain injury. Neuro Rehabilitation 2009;24:349-353.
²
Quevedo, MJ. Internações em UTI por trauma cranioencefálico (TCE) na cidade de Porto Alegre. Porto Alegre, 2009. Monografia apresentada à Escola de Enfermagem da Universidade Federal do Rio Grande do Sul para obtenção do título de especialista em Saúde Pública.
³
Langlois JA, Rutland-Brown W, Wald MM. The epidemiology and impact of traumatic brain injury: a brief overview. J Head Trauma Rehabil 2006;21:375-378.
⁴
Jordan BD. The clinical spectrum of sport-related traumatic brain injury. Nat Rev Neurol 2013;9:222-230.
⁵
Giza CC, Kutcher JS, Ashwal S, et al. Summary of evidence-based guideline update: evaluation and management of concussion in sports: report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology 2013;80:2250-2257.
⁶
McCrory P, Meeuwisse W, Johnston K, et al. Consensus Statement on Concussion in Sport: The 3rd International Conference on Concussion in Sport held in Zurich 2009;1:406-420.
⁷
Aubry M, et al. Summary and agreement statement of the 1st International Symposium on Concussion in Sport, Vienna 2001. Clin J Sport Med 2002;12:6-11.
⁸
McCrory P, et al. Summary and agreement statement of the 2nd International Conference on Concussion in Sport, Prague 2004. Clin J Sport Med 2005;15:48-55.
⁹
McCrea M, et al. Acute effects and recovery time following concussion in collegiate football players: the NCAA Concussion Study. JAMA 2003;290:2556-2563.
¹⁰
Echemendia RJ, Putukian M, Mackin RS, Julian L, Shoss N. Neuropsychological test performance prior to and following sports-related mild traumatic brain injury. Clin J Sport Med 2001;11:23-31.
¹¹
Bleiberg J, et al. Duration of cognitive impairment after sports concussion. Neurosurgery 2004;54:1073-1080.
¹²
McCrea M, Kelly JP, Randolph C, Cisler R, Berger L. Immediate neurocognitive effects of concussion. Neurosurgery 2002;50:1032-1042.
¹³
Makdissi M, et al. Natural history of concussion in sport: markers of severity and implications for management. Am J Sports Med 2010;38: 464-471.
¹⁴
Spain A, Daumas S, Lifshitz J, et al. Mild fluid percussion injury in mice produces evolving selective axonal pathology and cognitive deficits relevant to human brain injury. J Neurotrauma 2010;27:1429-1438.
¹⁵
Giza CC, Hovda DA. The neurometabolic cascade of concussion. J Athl Train 2001;36:228-235.
¹⁶
Barkhoudarian G, Hovda DA, Giza CC. The molecular pathophysiology of concussive brain injury. Clin Sports Med 2011;30:33-48, vii-iii.
¹⁷
Miller LP, Hayes RL (Eds). Head Trauma: Basic, Preclinical, and Clinical Directions (John Wiley & Sons, New York, 2001).
¹⁸
Chen XH, Johnson VE, Uryu K, Trojanowski JQ, Smith DH. A lack of amyloid b plaques despite persistent accumulation of amyloid b in axons of long-term survivors of traumatic brain injury. Brain Pathol 2009;19:214-223.
¹⁹
Gessell LM, Fields SK, Collins CL, Dick RW, Comstock RD. Concussions among United States high school and collegiate athletes. J Athl Train 2007;42:495-503.
²⁰
Guskiewicz KM, Weaver NL, Padua DA, Garrett WE Jr. Epidemiology of concussion in collegiate and high school football players. Am J Sports Med 2000;28:643-650.
²¹
Barr WB, McCrea M. Sensitivity and specificity of standardized neurocognitive testing immediately following sports concussion. J Int Neuropsychological Soc 2001;7:693-702.
²²
Emery CA, Meeuwisse WH. Injury rates, risk factors, and mechanisms of injury in minor hockey. Am J Sports Med 2006;34:1960-1969.
²³
Covassin T, Swanik CB, Sachs ML. Sex differences and the incidence of concussions among collegiate athletes. J Athl Train 2003;38:238-244.
²⁴
Powell JW, Barber-Foss KD. Traumatic brain injury in high school athletes. JAMA 1999;282:958-963.
²⁵
Fuller CW, Junge A, Dvorak J. A six year prospective study of the incidence and causes of head and neck injuries in international football. Br J Sports Med 2005;suppl 39:i3-i9.
²⁶
Lincoln AE, Caswell SV, Almquist JL, Dunn RE, Norris JB, Hinton RY. Trends in concussion incidence in high school sports: a prospective 11-year study. Am J Sports Med 2011;39:958-963.
²⁷
Kerr ZY, Collins CL, Fields SK, Comstock RD. Epidemiology of player-player contact injuries among US high school athletes, 2005-2009. Clin Pediatr 2011;50:594-603.
²⁸
Hollis SJ, Stevenson MR, McIntosh AS, Shores EA, Collins MW, Taylor CB. Incidence, risk, and protective factors of mild traumatic brain injury in a cohort of Australian nonprofessional male rugby players. Am J Sports Med 2009;37:2328-2333.
²⁹
Kemp SPT, Hudson Z, Brooks JHM, Fuller CW. The epidemiology of head injuries in English professional rugby union. Clin J Sport Med 2008;18:227-234.
³⁰
Delaney TS, Lacroix VJ, Leclerc S, Johnston KM. Concussions among university football and soccer players. Clin J Sport Med 2002;12:331-338.
³¹
Guskiewicz KM, McCrea M, Marshall SW, et al. Cumulative effects associated with recurrent concussion in collegiate football players: the NCAA concussion study. JAMA 2003;19:2549-2555.
³²
Emery CA, Kang J, Shrier I, et al. Risk of injury associated with body checking among youth ice hockey players. JAMA 2010;303:2265-2272.
³³
Hollis SJ, Stevenson MR, McIntosh AS, et al. Mild traumatic brain injury among a cohort of rugby union players: predictors of time to injury. Br J Sports Med 2011;45:997-999.
³⁴
Luther N, et al. Diffusion tensor and susceptibility-weighted imaging in concussion assessment of National Football League players. Neurosurgery 2012;71:E558.
³⁵
Bazarian JJ, Zhu T, Blyth B, Borrinio A, Zhong J. Subject-specific changes in brain white matter on diffusion tensor imaging after sports-related concussion. Magn Reson Imaging 2012;30:171-180.
³⁶
Lovell MR, et al. Functional brain abnormalities are related to clinical recovery and time to return to play in athletes. Neurosurgery 2007;61: 352-359.
³⁷
Henry LC, Tremblay S, Boulanger Y, Ellemberg D, Lassonde M. Neurometabolic changes in acute phase after sports concussions correlate with symptom severity. J. Neurotrauma 2010;27:65-76.
³⁸
Lau B, Lovell MR, Collins MW, Pardini J. Neurocognitive and symptom predictors of recovery in high school athletes. Clin J Sport Med 2009; 19:216-221.
³⁹
Lovell MR, Collins MW, Iverson GL, et al. Recovery from mild concussion in high school athletes. J Neurosurg 2003;98:296-301.
⁴⁰
Lovell MR, Collins MW, Iverson GL, Johnston KM, Bradley JR. Grade 1 or "ding" concussions in high school athletes. Am J Sports Med 2004; 32:47-54.
⁴¹
Kampen DA, Lovell MR, Pardini JE, Collins MW, Fu FH. The "value added" of neurocognitive testing after sports-related concussion. Am J Sports Med 2006;34:1630-1635.
⁴²
McCrea M, Kelly JP, Kluge J, Ackley B, Randolph C. Standardized assessment of concussion in football players. Neurology 1997;48:586-588.
⁴³
McCrea M. Standardized mental status testing on the sideline after sport-related concussion. J Athl Train 2001;36:274-279.
⁴⁴
McCrea M, Kelly JP, Randolph C. Standardized assessment of concussion (SAC): on-site mental status evaluation of the athlete. J Head Trauma Rehabil 1998;13:27-35.
⁴⁵
Nassiri JD, Daniel JC, Wilckens J, Land BC. The implementation and use of the standardized assessment of concussion at the U.S. Naval Academy Mil Med 2002;167:873-876.
⁴⁶
McCrea M, Barr WB, Guskiewicz K, et al. Standard regression-based methods for measuring recovery after sport-related concussion. J Int Neuropsychological Soc 2005;11:58-69.
⁴⁷
Collie A, Makdissi M, Maruff P, Bennell K, McCrory P. Cognition in the days following concussion: comparison of symptomatic versus asymptomatic athletes. J Neurol Neurosurg Psychiatry 2006;77:241-245.
⁴⁸
Erlanger D, Feldman D, Kutner K, et al. Development and validation of a web-based neuropsychological test protocol for sports-related return-to-play decision-making. Arch Clin Neuropsychol 2003;18:293-316.
⁴⁹
Peterson CL, Ferrara MS, Mrazik M, Piland S, Elliot R. Evaluation of neuropsychological domain scores and postural stability following cerebral concussion in sports. Clin J Sport Med 2003;13:230-237.
⁵⁰
Register-Mihalik J, Guskiewicz KM, Mann JD, Shields EW. The effects of headache on clinical measures of neurocognitive function. Clin J Sport Med 2007;17:282-288.
⁵¹
Lau BC, Kontos AP, Collins MW, Mucha A, Lovell MR. Which on-field signs/symptoms predict protracted recovery from sport-related concussion among high school football players? Am J Sports Med 2011; 39:2311-2318.
⁵²
Pellman EJ, Viano DC, Casson IR, Arfken C, Powell J. Concussion in professional football: injuries involving 7 or more days out - Part 5. Neurosurgery 2004;55:1100-1119.
⁵³
Benson BW, Rose MS, Meeuwisse WH. The impact of face shield use on concussions in ice hockey: a multivariate analysis. Br J Sports Med 2002;36:27-32.
⁵⁴
Benson BW, Meeuwisse WH, Rizos J, Kang J, Burke CJ. A prospective study of concussions among National Hockey League players during regular season games: the NHL-NHLPA Concussion Program. Can Med Assoc J 2011;183:905-911.
⁵⁵
Collins MW, Grindel SH, Lovell MR, et al. Relationship between concussion and neuropsychological performance in college football players. JAMA 1999;282:964-970.
⁵⁶
Wall SE, Williams WH, Cartwright-Hatton S, et al. Neuropsychological dysfunction following repeat concussions in jockeys. J Neurol Neurosurg Psychiatry 2006;77:518-520.
⁵⁷
Shuttleworth-Edwards AB, Radloff SE. Compromised visuomotor processing speed in players of Rugby Union from school through to the national adult level. Arch Clin Neuropsychol 2008;23:511-520.
⁵⁸
Jordan BD, Relkin NR, Ravdin LD, Jacobs AR, Bennett A, Gandy S. Apoliproprotein E epsiolon4 associated with chronic traumatic brain injury in boxing. JAMA 1997;278:136-140.
⁵⁹
Guskiewicz KM, Marshall SW, Bailes J, et al. Association between recurrent concussion and late-life cognitive impairment in retired professional football players. Neurosurgery 2005;57:719-724.
⁶⁰
Matser JT, Kessels AG, Lezak MD, Troost J. A dose-response relation of headers and concussions with cognitive impairment in professional soccer players. J Clin Exp Neuropsychol 2001;23:770-774.
⁶¹
Matser JT, Kessels AG, Jordan BD, Lezak MD, Troost J. Chronic traumatic brain injury in professional soccer players. Neurology 1998;51: 791-796.
⁶²
Straume-Naesheim TM, Andersen TE, Dvorak J, Bahr R. Effects of heading exposure and previous concussions on neuropsychological performance among Norwegian elite footballers. Br J Sports Med 2005; 39 Suppl 1:i70-7.
⁶³
Kutner KC, Erlanger DM, Tsai J, Jordan B, Relkin NR. Lower cognitive performance of older football players possessing apolipoprotein E epsilon 4. Neurosurgery 2000;47:651-657.
⁶⁴
Meehan WP. 3rd. Medical therapies for concussion. Clin Sports Med 2005;30:115-124.
⁶⁵
Petraglia AL, Maroon JC, Bailes JE. From the field of play to the field of combat: a review of the pharmacological management of concussion. Neurosurgery 2012;70:1520-1533.
⁶⁶
Reddy CC, Collins M, Lovell M, Kontos P. Efficacy of amantadine treatment on symptoms and neurocognitive performance among adolescents following sports-related concussion. J. Head Trauma Rehabil. http://dx.doi.org/10.1097/HTR.0b013e318257fbc6.
» https://doi.org/10.1097/HTR.0b013e318257fbc6
⁶⁷
Gagnon I, Galli C, Freidman D, Grilli L, Iverson GL. Active rehabilitation for children who are slow to recover following sport-related concussion. Brain Inj 2009;23:956-964.
⁶⁸
Leddy JJ, et al. A preliminary study of subsymptom threshold exercise training for refractory post-concussion syndrome. Clin J Sport Med 2012;20:21-27.

Publication Dates

Publication in this collection
Jan-Mar 2014

History

Received
21 Aug 2013
Accepted
20 Nov 2014

This is an open-access article distributed under the terms of the Creative Commons Attribution License

[1] ¹
Jang SH. Review of motor recovery in patients with traumatic brain injury. Neuro Rehabilitation 2009;24:349-353.

[2] ²
Quevedo, MJ. Internações em UTI por trauma cranioencefálico (TCE) na cidade de Porto Alegre. Porto Alegre, 2009. Monografia apresentada à Escola de Enfermagem da Universidade Federal do Rio Grande do Sul para obtenção do título de especialista em Saúde Pública.

[3] ³
Langlois JA, Rutland-Brown W, Wald MM. The epidemiology and impact of traumatic brain injury: a brief overview. J Head Trauma Rehabil 2006;21:375-378.

[4] ⁴
Jordan BD. The clinical spectrum of sport-related traumatic brain injury. Nat Rev Neurol 2013;9:222-230.

[5] ⁵
Giza CC, Kutcher JS, Ashwal S, et al. Summary of evidence-based guideline update: evaluation and management of concussion in sports: report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology 2013;80:2250-2257.

[6] ⁶
McCrory P, Meeuwisse W, Johnston K, et al. Consensus Statement on Concussion in Sport: The 3rd International Conference on Concussion in Sport held in Zurich 2009;1:406-420.

[7] ⁷
Aubry M, et al. Summary and agreement statement of the 1st International Symposium on Concussion in Sport, Vienna 2001. Clin J Sport Med 2002;12:6-11.

[8] ⁸
McCrory P, et al. Summary and agreement statement of the 2nd International Conference on Concussion in Sport, Prague 2004. Clin J Sport Med 2005;15:48-55.

[9] ⁹
McCrea M, et al. Acute effects and recovery time following concussion in collegiate football players: the NCAA Concussion Study. JAMA 2003;290:2556-2563.

[10] ¹⁰
Echemendia RJ, Putukian M, Mackin RS, Julian L, Shoss N. Neuropsychological test performance prior to and following sports-related mild traumatic brain injury. Clin J Sport Med 2001;11:23-31.

[11] ¹¹
Bleiberg J, et al. Duration of cognitive impairment after sports concussion. Neurosurgery 2004;54:1073-1080.

[12] ¹²
McCrea M, Kelly JP, Randolph C, Cisler R, Berger L. Immediate neurocognitive effects of concussion. Neurosurgery 2002;50:1032-1042.

[13] ¹³
Makdissi M, et al. Natural history of concussion in sport: markers of severity and implications for management. Am J Sports Med 2010;38: 464-471.

[14] ¹⁴
Spain A, Daumas S, Lifshitz J, et al. Mild fluid percussion injury in mice produces evolving selective axonal pathology and cognitive deficits relevant to human brain injury. J Neurotrauma 2010;27:1429-1438.

[15] ¹⁵
Giza CC, Hovda DA. The neurometabolic cascade of concussion. J Athl Train 2001;36:228-235.

[16] ¹⁶
Barkhoudarian G, Hovda DA, Giza CC. The molecular pathophysiology of concussive brain injury. Clin Sports Med 2011;30:33-48, vii-iii.

[17] ¹⁷
Miller LP, Hayes RL (Eds). Head Trauma: Basic, Preclinical, and Clinical Directions (John Wiley & Sons, New York, 2001).

[18] ¹⁸
Chen XH, Johnson VE, Uryu K, Trojanowski JQ, Smith DH. A lack of amyloid b plaques despite persistent accumulation of amyloid b in axons of long-term survivors of traumatic brain injury. Brain Pathol 2009;19:214-223.

[19] ¹⁹
Gessell LM, Fields SK, Collins CL, Dick RW, Comstock RD. Concussions among United States high school and collegiate athletes. J Athl Train 2007;42:495-503.

[20] ²⁰
Guskiewicz KM, Weaver NL, Padua DA, Garrett WE Jr. Epidemiology of concussion in collegiate and high school football players. Am J Sports Med 2000;28:643-650.

[21] ²¹
Barr WB, McCrea M. Sensitivity and specificity of standardized neurocognitive testing immediately following sports concussion. J Int Neuropsychological Soc 2001;7:693-702.

[22] ²²
Emery CA, Meeuwisse WH. Injury rates, risk factors, and mechanisms of injury in minor hockey. Am J Sports Med 2006;34:1960-1969.

[23] ²³
Covassin T, Swanik CB, Sachs ML. Sex differences and the incidence of concussions among collegiate athletes. J Athl Train 2003;38:238-244.

[24] ²⁴
Powell JW, Barber-Foss KD. Traumatic brain injury in high school athletes. JAMA 1999;282:958-963.

[25] ²⁵
Fuller CW, Junge A, Dvorak J. A six year prospective study of the incidence and causes of head and neck injuries in international football. Br J Sports Med 2005;suppl 39:i3-i9.

[26] ²⁶
Lincoln AE, Caswell SV, Almquist JL, Dunn RE, Norris JB, Hinton RY. Trends in concussion incidence in high school sports: a prospective 11-year study. Am J Sports Med 2011;39:958-963.

[27] ²⁷
Kerr ZY, Collins CL, Fields SK, Comstock RD. Epidemiology of player-player contact injuries among US high school athletes, 2005-2009. Clin Pediatr 2011;50:594-603.

[28] ²⁸
Hollis SJ, Stevenson MR, McIntosh AS, Shores EA, Collins MW, Taylor CB. Incidence, risk, and protective factors of mild traumatic brain injury in a cohort of Australian nonprofessional male rugby players. Am J Sports Med 2009;37:2328-2333.

[29] ²⁹
Kemp SPT, Hudson Z, Brooks JHM, Fuller CW. The epidemiology of head injuries in English professional rugby union. Clin J Sport Med 2008;18:227-234.

[30] ³⁰
Delaney TS, Lacroix VJ, Leclerc S, Johnston KM. Concussions among university football and soccer players. Clin J Sport Med 2002;12:331-338.

[31] ³¹
Guskiewicz KM, McCrea M, Marshall SW, et al. Cumulative effects associated with recurrent concussion in collegiate football players: the NCAA concussion study. JAMA 2003;19:2549-2555.

[32] ³²
Emery CA, Kang J, Shrier I, et al. Risk of injury associated with body checking among youth ice hockey players. JAMA 2010;303:2265-2272.

[33] ³³
Hollis SJ, Stevenson MR, McIntosh AS, et al. Mild traumatic brain injury among a cohort of rugby union players: predictors of time to injury. Br J Sports Med 2011;45:997-999.

[34] ³⁴
Luther N, et al. Diffusion tensor and susceptibility-weighted imaging in concussion assessment of National Football League players. Neurosurgery 2012;71:E558.

[35] ³⁵
Bazarian JJ, Zhu T, Blyth B, Borrinio A, Zhong J. Subject-specific changes in brain white matter on diffusion tensor imaging after sports-related concussion. Magn Reson Imaging 2012;30:171-180.

[36] ³⁶
Lovell MR, et al. Functional brain abnormalities are related to clinical recovery and time to return to play in athletes. Neurosurgery 2007;61: 352-359.

[37] ³⁷
Henry LC, Tremblay S, Boulanger Y, Ellemberg D, Lassonde M. Neurometabolic changes in acute phase after sports concussions correlate with symptom severity. J. Neurotrauma 2010;27:65-76.

[38] ³⁸
Lau B, Lovell MR, Collins MW, Pardini J. Neurocognitive and symptom predictors of recovery in high school athletes. Clin J Sport Med 2009; 19:216-221.

[39] ³⁹
Lovell MR, Collins MW, Iverson GL, et al. Recovery from mild concussion in high school athletes. J Neurosurg 2003;98:296-301.

[40] ⁴⁰
Lovell MR, Collins MW, Iverson GL, Johnston KM, Bradley JR. Grade 1 or "ding" concussions in high school athletes. Am J Sports Med 2004; 32:47-54.

[41] ⁴¹
Kampen DA, Lovell MR, Pardini JE, Collins MW, Fu FH. The "value added" of neurocognitive testing after sports-related concussion. Am J Sports Med 2006;34:1630-1635.

[42] ⁴²
McCrea M, Kelly JP, Kluge J, Ackley B, Randolph C. Standardized assessment of concussion in football players. Neurology 1997;48:586-588.

[43] ⁴³
McCrea M. Standardized mental status testing on the sideline after sport-related concussion. J Athl Train 2001;36:274-279.

[44] ⁴⁴
McCrea M, Kelly JP, Randolph C. Standardized assessment of concussion (SAC): on-site mental status evaluation of the athlete. J Head Trauma Rehabil 1998;13:27-35.

[45] ⁴⁵
Nassiri JD, Daniel JC, Wilckens J, Land BC. The implementation and use of the standardized assessment of concussion at the U.S. Naval Academy Mil Med 2002;167:873-876.

[46] ⁴⁶
McCrea M, Barr WB, Guskiewicz K, et al. Standard regression-based methods for measuring recovery after sport-related concussion. J Int Neuropsychological Soc 2005;11:58-69.

[47] ⁴⁷
Collie A, Makdissi M, Maruff P, Bennell K, McCrory P. Cognition in the days following concussion: comparison of symptomatic versus asymptomatic athletes. J Neurol Neurosurg Psychiatry 2006;77:241-245.

[48] ⁴⁸
Erlanger D, Feldman D, Kutner K, et al. Development and validation of a web-based neuropsychological test protocol for sports-related return-to-play decision-making. Arch Clin Neuropsychol 2003;18:293-316.

[49] ⁴⁹
Peterson CL, Ferrara MS, Mrazik M, Piland S, Elliot R. Evaluation of neuropsychological domain scores and postural stability following cerebral concussion in sports. Clin J Sport Med 2003;13:230-237.

[50] ⁵⁰
Register-Mihalik J, Guskiewicz KM, Mann JD, Shields EW. The effects of headache on clinical measures of neurocognitive function. Clin J Sport Med 2007;17:282-288.

[51] ⁵¹
Lau BC, Kontos AP, Collins MW, Mucha A, Lovell MR. Which on-field signs/symptoms predict protracted recovery from sport-related concussion among high school football players? Am J Sports Med 2011; 39:2311-2318.

[52] ⁵²
Pellman EJ, Viano DC, Casson IR, Arfken C, Powell J. Concussion in professional football: injuries involving 7 or more days out - Part 5. Neurosurgery 2004;55:1100-1119.

[53] ⁵³
Benson BW, Rose MS, Meeuwisse WH. The impact of face shield use on concussions in ice hockey: a multivariate analysis. Br J Sports Med 2002;36:27-32.

[54] ⁵⁴
Benson BW, Meeuwisse WH, Rizos J, Kang J, Burke CJ. A prospective study of concussions among National Hockey League players during regular season games: the NHL-NHLPA Concussion Program. Can Med Assoc J 2011;183:905-911.

[55] ⁵⁵
Collins MW, Grindel SH, Lovell MR, et al. Relationship between concussion and neuropsychological performance in college football players. JAMA 1999;282:964-970.

[56] ⁵⁶
Wall SE, Williams WH, Cartwright-Hatton S, et al. Neuropsychological dysfunction following repeat concussions in jockeys. J Neurol Neurosurg Psychiatry 2006;77:518-520.

[57] ⁵⁷
Shuttleworth-Edwards AB, Radloff SE. Compromised visuomotor processing speed in players of Rugby Union from school through to the national adult level. Arch Clin Neuropsychol 2008;23:511-520.

[58] ⁵⁸
Jordan BD, Relkin NR, Ravdin LD, Jacobs AR, Bennett A, Gandy S. Apoliproprotein E epsiolon4 associated with chronic traumatic brain injury in boxing. JAMA 1997;278:136-140.

[59] ⁵⁹
Guskiewicz KM, Marshall SW, Bailes J, et al. Association between recurrent concussion and late-life cognitive impairment in retired professional football players. Neurosurgery 2005;57:719-724.

[60] ⁶⁰
Matser JT, Kessels AG, Lezak MD, Troost J. A dose-response relation of headers and concussions with cognitive impairment in professional soccer players. J Clin Exp Neuropsychol 2001;23:770-774.

[61] ⁶¹
Matser JT, Kessels AG, Jordan BD, Lezak MD, Troost J. Chronic traumatic brain injury in professional soccer players. Neurology 1998;51: 791-796.

[62] ⁶²
Straume-Naesheim TM, Andersen TE, Dvorak J, Bahr R. Effects of heading exposure and previous concussions on neuropsychological performance among Norwegian elite footballers. Br J Sports Med 2005; 39 Suppl 1:i70-7.

[63] ⁶³
Kutner KC, Erlanger DM, Tsai J, Jordan B, Relkin NR. Lower cognitive performance of older football players possessing apolipoprotein E epsilon 4. Neurosurgery 2000;47:651-657.

[64] ⁶⁴
Meehan WP. 3rd. Medical therapies for concussion. Clin Sports Med 2005;30:115-124.

[65] ⁶⁵
Petraglia AL, Maroon JC, Bailes JE. From the field of play to the field of combat: a review of the pharmacological management of concussion. Neurosurgery 2012;70:1520-1533.

[66] ⁶⁶
Reddy CC, Collins M, Lovell M, Kontos P. Efficacy of amantadine treatment on symptoms and neurocognitive performance among adolescents following sports-related concussion. J. Head Trauma Rehabil. http://dx.doi.org/10.1097/HTR.0b013e318257fbc6.
» https://doi.org/10.1097/HTR.0b013e318257fbc6

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