Concussion grading systems

Concussion grading systems are sets of criteria used in sports medicine to determine the severity, or grade, of a concussion, the mildest form of traumatic brain injury. At least 16 such systems exist,^[1] and there is little agreement among professionals about which is the best to use.^[2] Several of the systems use loss of consciousness and amnesia as the primary determinants of the severity of the concussion.^[2]

The systems are widely used to determine when it is safe to allow an athlete to return to competition. Concern exists that multiple concussions received in a short time may present an added danger, since an initial concussion may leave the brain in a vulnerable state for a time. Injured athletes are prohibited from returning to play before they are symptom-free during rest and exertion and their neuropsychological tests are normal again, in order to avoid a risk of cumulative effects such as decline in mental function and second-impact syndrome, which may occur on very rare occasions after a concussion that occurs before the symptoms from another concussion have resolved.

It is estimated that over 40% of high school athletes return to action prematurely^[3] and over 40,000 youth concussions occur annually.^[4] Concussions account for nearly 10% of sport injuries, and are the second leading cause of brain injury for young people ages 15–24.^[5]

Three grading systems are followed most widely: one was developed by Robert Cantu, one by the Colorado Medical Society, and a third by the American Academy of Neurology.^[6]

Cantu guidelines

The Cantu guidelines, published in 1986,^[2] classify an injury associated with no loss of consciousness and less than 30 minutes of post-traumatic amnesia as grade I. In grade II, the patient loses consciousness for less than 5 minutes or experiences amnesia for between 30 minutes and 24 hours. In grade III, loss of consciousness lasts longer than 5 minutes or amnesia lasts longer than 24 hours.^[2] The most commonly seen type of concussion is a grade I by this guideline.^[7]

In a 2001 update, Cantu changed the guidelines to include other concussion signs and symptoms in addition to amnesia in the grading criteria.^[2] He also changed the grade II criteria to include only concussions with loss of consciousness for less than 1 minute, and included those with loss of consciousness for greater than 1 minute, or with signs or symptoms lasting over a week, under grade III.^[2] More than one grade III concussion during a professional or collegiate athlete's career may lead health professionals to recommend that the player cease playing the sport.^[7]

Cantu, a medical doctor, clinical professor of neurosurgery at Boston University School of Medicine and co-founder in 2008 and co-director of the Center for the Study of Traumatic Encephalopathy at BUSM, is also senior advisor to the NFL Head, Neck and Spine Committee.^[8]

Colorado Medical Society guidelines

The Colorado Medical Society guidelines were published in 1991 in response to the death of a high school athlete due to what was thought to be second-impact syndrome.^[9] According to the guidelines, a grade I concussion consists of confusion only, grade II includes confusion and post-traumatic amnesia, and grade III and IV involve a loss of consciousness.^[2]

By these guidelines, an athlete who has suffered a concussion may return to sports after having been free of symptoms, both at rest and during exercise, as shown in the following table:^[10][11]

Colorado Medical Society guidelines for return to play

Grade	First concussion	Subsequent concussions
I	15 minutes	1 week
II	1 week	2 weeks, with physician approval
IIIa (unconscious for seconds)	1 month	6 month, with physician approval
IIIb (unconscious for minutes)	6 month	1 year, with physician approval

American Academy of Neurology guidelines

The guidelines devised in 1997 by the American Academy of Neurology (AAN) are based on those by the Colorado Medical Society.^[12] According to these guidelines, a grade I concussion is associated with no loss of consciousness and symptoms of confusion last less than 15 minutes. Grade II is the same, except symptoms last longer than 15 minutes. In grade III, loss of consciousness does occur.^[2] Grade III can be further divided into grades IIIa and IIIb, with brief loss of consciousness (measured in seconds) and prolonged loss of consciousness (measured in minutes) respectively.^[10] According to the AAN, permanent brain injury can occur with either Grade II or Grade III concussion.

By these guidelines, an athlete suffering a single, grade I concussion is given a neurological evaluation every five minutes starting immediately after the injury and may return to the competition if signs and symptoms resolve within a quarter of an hour.^[13] Otherwise, the return to play rules are the same for the AAN and Colorado Medical Society guidelines.^[10][11][13]

Impact on training of coaches

It is now being recommended by the Centers for Disease Control and state athletic organizations that coaches be trained in managing athlete concussions according to current guidelines.^[14][15]

See also

• Concussion
• Sports injury
• Head injury criterion
• Sport-related concussion
• Chronic traumatic encephalopathy
• Frontotemporal dementia

References

1. ^ Hayden MG, Jandial R, Duenas HA, Mahajan R, Levy M (2007). "Pediatric Concussions in Sports: A Simple and Rapid Assessment Tool for Concussive Injury in Children and Adults". Child's Nervous System 23 (4): 431–435. doi:10.1007/s00381-006-0277-2. PMID 17219233. 
2. ^ ^{a b c d e f g h} Cantu RC (2001). "Posttraumatic Retrograde and Anterograde Amnesia: Pathophysiology and Implications in Grading and Safe Return to Play". Journal of Athletic Training 36 (3): 244–248. PMC 155413. PMID 12937491. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=155413. 
3. ^ Concussions Extra Dangerous to Teen Brains, CNN, 4 February 2010
4. ^ Heading Off Sports Injuries, Newsweek, 5 Feb 2010
5. ^ High School Athletes Face Serious Concussion Risks, USA Today, 4 May 2009
6. ^ Cobb S, Battin B (2004). "Second-Impact Syndrome". The Journal of School Nursing 20 (5): 262–7. doi:10.1177/10598405040200050401. PMID 15469376. 
7. ^ ^{a b} Terrell TR (2004). "Concussion in Athletes" (PDF). Southern Medical Journal 97 (9): 837–42. doi:10.1097/01.SMJ.0000140091.58338.1E. PMID 15455966. http://www.sma.org/pdfs/objecttypes/smj/2438A51C-BCD4-FF26-DE27672C13233C44/Concussion%20in%20Athletes.pdf. 
8. ^ "Researchers Discover Brain Trauma in Sports May Cause a New Disease That Mimics ALS", BUSM press release, August 17th, 2010 3:41 pm. Retrieved 2011-09-11.
9. ^ Collins MW, Iverson GL, Gaetz M, Lovell MR (2006). "24: Sport-Related Concussion.". In Zasler ND, Katz DI, and Zafonte RD. Brain Injury Medicine: Principles And Practice. Demos Medical Publishing, LLC. ISBN 1888799935. 
10. ^ ^{a b c} "Heads Up: Concussion in High School Sports: Management of Concussion in Sports". Centers for Disease Control and Prevention. Archived from the original on 2007-10-12. http://web.archive.org/web/20071012105310/http://health.state.ok.us/program/injury/updates/concussion.html. Retrieved 2008-01-07. 
11. ^ ^{a b} Cuccurullo S, Ed. "Table 2-16. When to Return to Play—Colorado Medical Society Guidelines.". Physical Medicine and Rehabilitation Board Review. Demos Medical Publishing, Inc. http://www.ncbi.nlm.nih.gov/books/bv.fcgi?indexed=google&rid=physmedrehab.table.1898. Retrieved 2008-01-09. 
12. ^ Silver JM, McAllister TW, Yudofsky SC (2005). Textbook Of Traumatic Brain Injury. American Psychiatric Pub., Inc. ISBN 1585621056. 
13. ^ ^{a b} Quality Standards Subcommittee of the American Academy of Neurology (1997). "Practice Parameter: The Management of Concussion in Sports (Summary Statement)" (PDF). American Academy of Neurology. http://www.aan.com/professionals/practice/pdfs/pdf_1995_thru_1998/1997.48.581.pdf. Retrieved 2008-01-28. 
14. ^ Washington Interscholactic Activities Association Concussion Management Guidelines
15. ^ Legislation

External links

• Heads Up: Concussion in Youth Sports