Editing Concussion (section)

===Classification===
No single definition of concussion, minor head injury,<ref name="SatzZaucha">
{{cite journal | vauthors = Satz P, Zaucha K, McCleary C, Light R, Asarnow R, Becker D | title = Mild head injury in children and adolescents: a review of studies (1970-1995) | journal = Psychological Bulletin | volume = 122 | issue = 2 | pages = 107–131 | date = September 1997 | pmid = 9283296 | doi = 10.1037/0033-2909.122.2.107 }}</ref> or mild traumatic brain injury is universally accepted.<ref name="ComperBisschop">{{cite journal | vauthors = Comper P, Bisschop SM, Carnide N, Tricco A | title = A systematic review of treatments for mild traumatic brain injury | journal = Brain Injury | volume = 19 | issue = 11 | pages = 863–880 | date = October 2005 | pmid = 16296570 | doi = 10.1080/02699050400025042 | s2cid = 34912966 }}</ref> In 2001, the expert Concussion in Sport Group of the first International Symposium on Concussion in Sport<ref name="aubry"/> defined concussion as "a complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces."<ref name="canturc06">{{cite journal | vauthors = Cantu RC, Aubry M, Dvorak J, Graf-Baumann T, Johnston K, Kelly J, Lovell M, McCrory P, Meeuwisse W, Schamasch P, Kevin M, Bruce SL, Ferrara MS, Kelly JP, McCrea M, Putukian M, McLeod TC | display-authors = 6 | title = Overview of concussion consensus statements since 2000 | journal = Neurosurgical Focus | volume = 21 | issue = 4 | pages = E3 | date = October 2006 | pmid = 17112193 | doi = 10.3171/foc.2006.21.4.4 | doi-access = free }}<!-- No PMID found --></ref> It was agreed that concussion typically involves temporary impairment of neurological function that heals by itself within time, and that [[neuroimaging]] normally shows no gross structural changes to the brain as the result of the condition.<ref name="AndersonT"/>

However, although no structural brain damage occurs according to the classic definition,<ref>
{{cite journal|author=Parkinson D |year=1999 |title=Concussion confusion |journal=Critical Reviews in Neurosurgery |volume=9 |issue=6 |pages=335–39 |issn=1433-0377 |doi=10.1007/s003290050153|s2cid=195203684 }}</ref> some researchers have included [[injury|injuries]] in which structural damage has occurred, and the [[National Institute for Health and Clinical Excellence]] definition includes physiological or physical disruption in the brain's [[chemical synapse|synapse]]s.<ref name="NICE">{{cite book |url=http://www.nice.org.uk/nicemedia/pdf/CG56guidance.pdf |publisher=National Institute for Health and Clinical Excellence |title=Head Injury: Triage, Assessment, Investigation and Early Management of Head Injury in Infants, Children and Adults |isbn=978-0-9549760-5-7 |date=2007 |access-date=2008-01-26 |archive-date=2013-02-22 |archive-url=https://web.archive.org/web/20130222032536/http://www.nice.org.uk/nicemedia/pdf/CG56guidance.pdf |url-status=live }}</ref> Also, by definition, concussion has historically involved a loss of consciousness. However, the definition has evolved over time to include a change in consciousness, such as amnesia,<ref name="RuffGrant">{{cite book |vauthors=Ruff RM, Grant I |chapter=Postconcussional disorder: Background to DSM-IV and future considerations |veditors=Varney NR, Roberts RJ |title=The Evaluation and Treatment of Mild Traumatic Brain Injury |publisher=Lawrence Erlbaum Associates |location=Hillsdale, New Jersey |year=1999 |page=320 |isbn=978-0-8058-2394-3 |chapter-url=https://books.google.com/books?id=i4Tpx6wHvJ4C&pg=PA21 }}{{Dead link|date=December 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> although controversy continues about whether the definition should include only those injuries in which [[unconsciousness|loss of consciousness]] occurs.<ref name="Pearce"/> This debate resurfaces in some of the best-known concussion grading scales, in which those episodes involving loss of consciousness are graded as being more severe than those without.<ref name="cobb">{{cite journal | vauthors = Cobb S, Battin B | title = Second-impact syndrome | journal = The Journal of School Nursing | volume = 20 | issue = 5 | pages = 262–267 | date = October 2004 | pmid = 15469376 | doi = 10.1177/10598405040200050401 | s2cid = 38321305 }}<!--doi 10.1622/1059-8405(2004)20[262:SS]2.0.CO;2 apparently broken--></ref>

Definitions of mild traumatic brain injury (mTBI) were inconsistent until the [[World Health Organization]]'s [[ICD-10|International Statistical Classification of Diseases and Related Health Problems]] (ICD-10) provided a consistent, authoritative definition across specialties in 1992.<ref name="Petchprapai07"/> Since then, various organizations such as the American Congress of Rehabilitation Medicine<ref name="Kushner98">{{cite journal | vauthors = Kushner D | title = Mild traumatic brain injury: toward understanding manifestations and treatment | journal = Archives of Internal Medicine | volume = 158 | issue = 15 | pages = 1617–1624 | year = 1998 | pmid = 9701095 | doi = 10.1001/archinte.158.15.1617 | doi-access = free }}</ref> and the [[American Psychiatric Association]] in its ''[[Diagnostic and Statistical Manual of Mental Disorders]]''<ref name="Petchprapai07"/> have defined mTBI using some combination of [[loss of consciousness]], [[post-traumatic amnesia]], and the [[Glasgow Coma Scale]].

Concussion falls under the classification of mild TBI,<ref name="LeeLK07">
{{cite journal | vauthors = Lee LK | title = Controversies in the sequelae of pediatric mild traumatic brain injury | journal = Pediatric Emergency Care | volume = 23 | issue = 8 | pages = 580–83; quiz 584–86 | date = August 2007 | pmid = 17726422 | doi = 10.1097/PEC.0b013e31813444ea | s2cid = 33766395 }}</ref> but it is not clear whether concussion is implied in mild brain injury or mild head injury.<ref name=LevinHS>{{cite book|vauthors=Benton AL, Levin HS, Eisenberg HM |title=Mild Head Injury |publisher=Oxford University Press |location=Oxford [Oxfordshire] |year=1989 |page=v |isbn=978-0-19-505301-2 }}</ref>{{update inline|date=December 2012}} "mTBI" and "concussion" are often treated as synonyms in medical literature<ref name="Kushner98"/> but other injuries such as [[intracranial hemorrhage]]s (e.g. [[intra-axial hematoma]], [[epidural hematoma]], and [[subdural hematoma]]) are not necessarily precluded in mTBI<ref name="AndersonT"/> or mild head injury,<ref name="vanderNaalt">{{cite journal | vauthors = van der Naalt J | title = Prediction of outcome in mild to moderate head injury: a review | journal = Journal of Clinical and Experimental Neuropsychology | volume = 23 | issue = 6 | pages = 837–851 | date = December 2001 | pmid = 11910548 | doi = 10.1076/jcen.23.6.837.1018 | s2cid = 146179592 }}</ref><ref name="Savitsky00">{{cite journal | vauthors = Savitsky EA, Votey SR | title = Current controversies in the management of minor pediatric head injuries | journal = The American Journal of Emergency Medicine | volume = 18 | issue = 1 | pages = 96–101 | date = January 2000 | pmid = 10674544 | doi = 10.1016/S0735-6757(00)90060-3 }}</ref> as they are in concussion.<ref name="ParikhKoch">{{cite journal | vauthors = Parikh S, Koch M, Narayan RK | title = Traumatic brain injury | journal = International Anesthesiology Clinics | volume = 45 | issue = 3 | pages = 119–135 | year = 2007 | pmid = 17622833 | doi = 10.1097/AIA.0b013e318078cfe7 | s2cid = 46012183 }}</ref> mTBI associated with abnormal neuroimaging may be considered "complicated mTBI".<ref name="Iverson2005"/> "Concussion" can be considered to imply a state in which brain function is temporarily impaired and "mTBI" to imply a [[pathophysiology|pathophysiological]] state, but in practice, few researchers and clinicians distinguish between the terms.<ref name="AndersonT"/> Descriptions of the condition, including the severity and the area of the brain affected, are now used more often than "concussion" in clinical neurology.<ref name="LarnerAJ">{{cite book|vauthors=Larner AJ, Barker RJ, Scolding N, Rowe D |title=The A–Z of Neurological Practice: a Guide to Clinical Neurology |publisher=Cambridge University Press |location=Cambridge|year=2005 |page=199 |isbn=978-0-521-62960-7 }}</ref>