Concussion grading systems
Encyclopedia
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, and there is little agreement among professionals about which is the best to use. Several of the systems use loss of consciousness and amnesia
as the primary determinants of the severity of the concussion.
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 test
s 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 and over 40,000 youth concussions occur annually. Concussions account for nearly 10% of sport injuries, and are the second leading cause of brain injury for young people ages 15–24.
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
.
In a 2001 update, Cantu changed the guidelines to include other concussion signs and symptoms in addition to amnesia in the grading criteria. 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. 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.
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.
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:
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. Otherwise, the return to play rules are the same for the AAN and Colorado Medical Society guidelines.
Traumatic brain injury
Traumatic brain injury , also known as intracranial injury, occurs when an external force traumatically injures the brain. TBI can be classified based on severity, mechanism , or other features...
. At least 16 such systems exist, and there is little agreement among professionals about which is the best to use. Several of the systems use loss of consciousness and amnesia
Amnesia
Amnesia is a condition in which one's memory is lost. The causes of amnesia have traditionally been divided into categories. Memory appears to be stored in several parts of the limbic system of the brain, and any condition that interferes with the function of this system can cause amnesia...
as the primary determinants of the severity of the concussion.
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 test
Neuropsychological test
Neuropsychological tests are specifically designed tasks used to measure a psychological function known to be linked to a particular brain structure or pathway. Tests are used for research into brain function and in a clinical setting for the diagnosis of deficits. They usually involve the...
s are normal again, in order to avoid a risk of cumulative effects such as decline in mental function and second-impact syndrome
Second-impact syndrome
Second-impact syndrome is a condition in which the brain swells rapidly and catastrophically after a person suffers a second concussion before symptoms from an earlier one have subsided. This deadly second blow may occur days, weeks or minutes after an initial concussion, and even the mildest...
, 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 and over 40,000 youth concussions occur annually. Concussions account for nearly 10% of sport injuries, and are the second leading cause of brain injury for young people ages 15–24.
Three grading systems are followed most widely: one was developed by Robert Cantu, one by the Colorado Medical Society
Colorado Medical Society
The Colorado Medical Society is the largest group of organized physicians in Colorado.This nonprofit organization is composed of physicians, residents and medical students. It was founded in 1871 to promote the art and science of medicine and to improve public health...
, and a third by the American Academy of Neurology
American Academy of Neurology
The American Academy of Neurology is a professional society for neurologists and neuroscientists. As a medical specialty society it was established in 1949 by A.B. Baker of the University of Minnesota to advance the art and science of neurology, and thereby promote the best possible care for...
.
Cantu guidelines
The Cantu guidelines, published in 1986, 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. The most commonly seen type of concussion is a grade I by this guideline.In a 2001 update, Cantu changed the guidelines to include other concussion signs and symptoms in addition to amnesia in the grading criteria. 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. 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.
Cantu, a medical doctor, clinical professor of neurosurgery at Boston University School of Medicine
Boston University School of Medicine
Boston University School of Medicine is one of the graduate schools of Boston University. Founded in 1848, the medical school holds the unique distinction as the first institution in the world to formally educate female physicians. Originally known as the New England Female Medical College, it was...
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
National Football League
The National Football League is the highest level of professional American football in the United States, and is considered the top professional American football league in the world. It was formed by eleven teams in 1920 as the American Professional Football Association, with the league changing...
Head, Neck and Spine Committee.
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. 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.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:
| 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. 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. 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. 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. Otherwise, the return to play rules are the same for the AAN and Colorado Medical Society guidelines.
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.See also
- Concussion
- Sports injury
- Head injury criterionHead injury criterionThe Head Injury Criterion is a measure of the likelihood of head injury arising from an impact. The HIC can be used to assess safety related to vehicles, personal protective gear, and sport equipment....
- Sport-related concussion
- Chronic traumatic encephalopathyChronic traumatic encephalopathyChronic traumatic encephalopathy is a progressive degenerative disease found in individuals who have been subjected to multiple concussions and other forms of head injury. A variant of the condition, dementia pugilistica, is primarily associated with boxing...
- Frontotemporal dementiaFrontotemporal dementiaFrontotemporal dementia is a clinical syndrome caused by degeneration of the frontal lobe of the brain and may extend back to the temporal lobe...