The gist of the paper is that traumatic brain injury is not an event but a process. 

• MORTALITY - The paper states that individuals with a TBI were twice as likely to die as a similar non-brain injured cohort and had a life expectancy reduction of seven years.
• ETIOLOGY - There is an indirect effect on other organs from traumatic brain injury.
• MORBIDITY - Individuals with a TBI are 1.5-17 times (depending on the severity of the TBI) more likely than the general population to develop seizures.  Chances of getting epilepsy after traumatic brain injury increase and account for 5% of all epilepsy in the general population.
• INCONTINENCE
• PSYCHIATRIC DISEASE
• SEXUAL DYSFUNCTION
• MUSCULOSKELETAL DYSFUNCTION
   

This adds to the medical literature that supports the reality that brain injury need not involve loss of conciousness but rather an alteration of conciousness.  And, that mild brain injury can be due to variety of mechanisms. 

Of particular interest to me is the language "alteration in brain function" which leaves room for the brain injuries where a person is not knocked out.  How many times do we see opponents of traumatic brain injury relying on loss of concious as a necessary element.  The world famous case of Phineas Gage, and the railroad tie through his brain, did not involve loss of conciousness.

Imaging technology has improved our understanding and diagnostic clarification of the impact of mild traumatic brain injury.  We better understand the more subtle neurocognitive and neuroaffective deficits that may result from traumatic brain injury in general.

In April 2009, the United States Department of Veterans Affairs and Department of Defense issued a Clinical Practice Guideline for management of concussion/mild traumatic brain injury.  In civilian, military, and veteran populations, there is increased recognition of the interrelationship between traumatic brain injury (TBI) and some psychological health (PH) disorders and the need to better understand the relationships by integrating research for these topics.

Simply stated, the definition is"

TBI is defined as an alteration in brain function, or other evidence of brain pathology, caused by an external force.

 Concussion is also known as mild brain injury, mild traumatic brain injury (MTBI), mild head injury and minor head trauma. Some experts define concussion as a head injury with temporary loss of brain function, which can cause cognitive, physical and emotional symptoms. Concussion may also be defined as an injury to the brain generally caused by a jolt or blow to the head - in the majority of cases the individual does not lose consciousness.

According to Medilexicon's medical dictionary, concussion is "An injury of a soft structure, as the brain, resulting from a blow or violent shaking."

In sports medicine the term concussion is commonly used, while in general medicine MTBI (mild traumatic brain injury) may be used as well. Lay people are more familiar with the term concussion.

According to the Brain Injury Association of America males are twice as likely as females to sustain a brain injury. Those at highest risk of a brain injury are males aged 15 to 24 years. People who have had a brain injury are more likely to experience a subsequent brain injury. In 2008 there were 351,992 sports-related head injuries that were treated in hospital emergency rooms in the USA, according to the U.S. Consumer Product Safety Commission.

Researchers from the Centre de recherche en neuropsychologie et cognition, Université de Montréal, Canada found evidence that athletes who were concussed during their earlier sporting life show a decline in their mental and physical processes more than 30 years later.

What are the causes of concussion?

The brain floats in cerebral fluid which protects it from jolts and bumps. A violent jolt or a severe blow to the head can cause the brain to bump hard against the skull. This can result in the tearing of fiber nerves as well as blood vessel rupture under the skull, leading to an accumulation of blood.

• Automobile accidents - concussions commonly occur from severe jolts to the head; this can happen when a vehicle suddenly loses speed or stops dead, causing the brain to jar (bash, bump hard) against the skull.
   
• Sports injuries - especially contact sports, such as martial arts, boxing, rugby, American football, and hokey. Non-contact sports such as snowboarding and skiing as well.
   
• Falls - any fall that results in a blow to the head or a severe jolt. The majority of concussion cases in very young children and elderly individuals in the USA and UK occur as a result of a fall in the home.
   
• Horseback riding accidents - there were 11,749 cases of head injuries resulting from horseback riding accidents in 2008 in the USA, according to the U.S. Consumer Product Safety Commission.
   
• Playground accidents - especially in playgrounds that do not have proper soft underlays.
   
• Cycling accidents - according to the U.S. Consumer Product Safety Commission there were 70,802 cases of head injuries that resulted from cycling accidents.
   
• Assaults - 11% of traumatic brain injuries in the USA are caused by assaults (people being attacked), according to the CDC (Centers for Disease Control and Prevention).

Different grades of concussion

Concussion is usually classified into 3 different grades. Below are three of the most widely used ways of classifying concussion:

• Cantu guidelines
  (Devised by Dr. Robert Cantu, medical director of the National Center for Catastrophic Sports Injury Research)
  Grade 1 - Some amnesia lasting no longer than 30 minutes, no loss of consciousness.
  Grade 2 - Loss of consciousness lasting no longer than 5 minutes. Amnesia lasting from 30 minutes to 24 hours.
  Grade 3 - Loss of consciousness lasting more than 5 minutes. Amnesia lasting more than 24 hours.
   
• Colorado Medical Society guidelines:
  Grade 1 - Confusion. No loss of consciousness.
  Grade 2 - Confusion. Amnesia. No loss of consciousness.
  Grade 3 - Any loss of consciousness.
   
• American Academy of Neurology guidelines:
  Grade 1 - Confusion that lasts less than 15 minutes. No loss of consciousness.
  Grade 2 - Confusion last lasts for more than 15 minutes. No loss of consciousness.
  Grade 3 - Loss of consciousness (IIIa coma lasts seconds, IIIb coma lasts for minutes)

What are the signs and symptoms of concussion?

Signs and symptoms of concussion may not be noticeable straight away. (A sign is what a doctor can see, hear or feel, such as a rash, or slurred speech. A symptom is something the patient describes, such as a headache, or ringing in the ears.)
Immediate signs and symptoms may include:

• Loss of consciousness.
• Confusion.
• Headache.
• Slurred speech.
• Dizziness.
• Ringing in the ears.
• Nausea.
• Vomiting.
• Amnesia.
• Tiredness (fatigue).

The following signs and symptoms may not be noticeable for several hours, or even days:

• Amnesia.
• Depression.
• Disturbed sleep.
• Hyperacusis - sensitivity to sounds.
• Irritability.
• Lack of concentration, focus.
• Moodiness.
• Photophobia - sensitivity to light.

The following signs and symptoms may be linked to a more serious injury and medical help should be sought:

• Prolonged headache.
• Prolonged dizziness.
• Dilated pupils.
• The two pupils are not the same size.
• Prolonged nausea and vomiting.
• Memory loss does not improve.
• Ringing in the ears.
• Loss of sense of smell.
• Loss of sense of taste.

Concussion signs and symptoms in children - this may be more difficult to detect in very young children because they may not yet have the ability to adequately explain how they feel or identify what needs to be reported. Signs may include:

• Lethargy, listlessness.
• Irritability - the child gets cross easily.
• Changing sleeping patterns.
• Altered appetite.
• Walking and/or standing unsteadily (any signs of balance, dizziness problems).

Children - the following signs usually mean the child needs medical attention:

• The child loses consciousness.
• After attempting to stem the bleeding, a cut continues to bleed.
• Any change in the way the child walks.
• Bleeding from the ears.
• Bleeding from the nose.
• Blurred vision.
• Confusion - the child does not know where he/she is, may not recognize familiar people.
• Continuous crying.
• Convulsion (seizure).
• Discharge from the ears.
• Discharge from the nose.
• Dizziness.
• Loss of appetite.
• Prolonged headache.
• Prolonged irritability.
• Prolonged listlessness, fatigue, lethargy.
• Repeated or forceful vomiting.
• Speech is slurred.
• Worsening headache.

How is concussion diagnosed?

Some sources say that most people can diagnose concussion if the symptoms are present immediately. If an individual has experienced a severe jolt or blow to the head which has left them dazed, confused, or wobbly they have concussion. However, a Canadian study revealed that most minor league hokey players are unable to identify a concussion or its related symptoms . Dr. Cusimano, a professor of neurosurgery, education and public health at the University of Toronto said "Serious misconceptions exist among minor league hockey players, athletes, coaches and parents when it comes to understanding the signs and symptoms of a concussion and its treatment."

Determining the severity of the concussion is more difficult because the signs and symptoms may not become evident until later. Mark R. Lovell, Ph.D., director of the University of Pittsburgh Medical Center (UPMC) Sports Medicine Concussion program, said that athletes may have severe concussion without becoming unconscious. In a report published in The American Journal of Sports Medicine Lovell explained that amnesia and confusion on the field after injury may be as important, if not more important, in making a return-to-play decision.

A GP (general practitioner, primary care physician) or hospital doctor will ask the patient details about the trauma (the blow to the head, the accident). It may be necessary to question the people who accompanied the patient. A neurological examination will also be done, which will include evaluating the patient's:

• Balance
• Concentration
• Coordination
• Hearing
• Memory
• Reflexes
• Vision

If the patient is over 65 years old, fell from a height of over 3 feet, was involved in a vehicle accident, has been consuming alcohol or drugs, cannot remember what happened 30 minutes or longer after the incident, has short-term memory problems, has been vomiting, had a seizure, has bruising or cuts and scrapes on the head and/or neck, or appears to have a fractured skull, the doctor may order a CT scan.

Glasgow Coma Scale

Doctors often use the Glasgow Coma Scale (GCS) before deciding whether to use a CT scan. The GCS is a way for doctors and nurses to assess the severity of brain damage following a head injury. It scores patients according to verbal responses, motor responses (physical reflexes), and how easily they can open their eyes.

• Eyes - Glasgow Coma Scale
  
  Score of 1 - does not open eyes.
  Score of 2 - opens eyes in response to painful stimuli (when given pain).
  Score of 3 - opens eyes in response to voice.
  Score of 4 - opens eyes spontaneously.
  
  
   
• Verbal - Glasgow Coma Scale
  
  Score of 1 - makes no sound.
  Score of 2 - incomprehensible sounds (mumbles).
  Score of 3 - utters inappropriate words.
  Score of 4 - confused, disorientated.
  Score of 5 - oriented, chats normally.
  
   
• Motor (physical reflexes) - Glasgow Coma Scale
  
  Score of 1 - makes no movements.
  Score of 2 - extension to painful stimuli (straightens limb when given pain).
  Score of 3 - abnormal flexion to painful stimuli (moves in a strange way when given pain).
  Score of 4 - flexion/withdrawal to painful stimuli (moves away when given pain).
  Score of 5 - localizes painful stimuli (can pinpoint where pain is).
  Score of 6 - obeys commands.
  
  
   
• Brain injury will be classified in the Glasgow Coma Scale as:
  
  Coma = a score of 8 or less.
  Moderate = a score of 9 to 12.
  Minor = a score of 13 or more.
  

A computerized tomography (CT) scan - this is a medical imaging method that employs tomography. Tomography is the process of generating a two-dimensional image of a slice or section through a 3-dimensional object (a tomogram). The medical device (the machine) is called a CTG scanner; it is a large machine and uses X-rays. A CT scan is generally accepted as better at looking at bleeding in the brain due to injury than an MRI (magnetic resonance imaging) scan. However, an MRI scan measures changes in brain function from concussion, helping structure return-to-play guidelines, researchers from University of Pittsburgh School of Medicine revealed.

Depending on how the doctor has assessed the patient, he/she may have to stay in hospital overnight. If the patient is allowed to go home the doctor will ask somebody to monitor symptoms for at least 24 hours - this may involve waking the patient up at specific times to check for consciousness.

What is the treatment for concussion?

Most concussion or mild traumatic brain injury (MTBI) symptoms will go away without treatment. In the USA approximately 1% of patients with MTBI require surgery.

Sex and prior history - prior history of concussion and gender account for significant differences in test results following injury, researchers from the Department of Orthopaedics at the University of Pittsburgh Medical Center, reported. Because of these differences, the researchers urge physicians and coaches to take an individualized approach to treating people with concussion.

• Rest - experts say that the most important treatment is rest. It takes time for the brain to recover, which will happen more rapidly if the body is resting and getting a good night's sleep each night. The International Conference on Concussion in Sports stressed that children and teens must be strictly monitored and activities restricted until fully healed. These restrictions include no return to the field of play, no return to school, and no cognitive activity - including academic activities and at-home/social activities including text messaging, video games, and television watching.
   
• Headaches - acetaminophen (paracetamol, Tylenol) is the best painkiller for headache due to a head injury. Drugs such as aspirin, ibuprofen and other NSAIDs should be avoided because they thin the blood and increase the risk of internal bleeding (hemorrhage).
   
• Sports - it is important not to return to any sporting activity too soon. If you or your child had concussion, only do so when your doctor says it is OK. A study by researchers at the University of North Carolina, USA, found that athletes engaging in high levels of activity following concussion demonstrated impaired brain function, while those who engaged in moderate levels of activity demonstrated the best performance.
   
• Alcohol - patients should avoid consuming alcohol, which can impede healing, until all symptoms have completely disappeared.
   
• Migraine - migraine after concussion may indicate an increased risk of neurocognitive impairment, researchers at the University of Pittsburgh Sports Medicine Concussion Program found. They said that doctors need to exercise increased vigilance when deciding about managing a concussed athlete with post-traumatic migraine. They need to be extremely cautious about deciding when the patient can return to their sport.
   
• Worsening symptoms - if symptoms worsen patients should see their doctor.

A person with a grade three concussion will probably be hospitalized if symptoms persist.

Concussion and long term depression

In a report authored by Robert C. Cantu, M.D., FACSM and published in Medicine & Science in Sports & Exercise, a study of 2,552 retired professional football players revealed that recurrent sport-related concussion appears to be related to an increased risk of clinical depression in retired professional football players.

Prevention of concussion

• Helmets and other protective headgear - such activities as cycling, motorcycling, skiing, hokey, horse riding should only be done if you wear protective headgear. It is important to buy new protective headgear - not second-hand ones. Headgear will need to be replaced periodically.
   
• Seat belt - wearing a seat belt has been proven to massively reduce the risk of head injury during vehicle accidents.
   
• Driving under influence - avoiding drinking and driving, or driving under the influence of illegal drugs or as well as some medications.
   
• Mouthguard - a good mouthguard can help prevent concussion in such contact sports as boxing, martial arts, rugby, American football, etc.
   
• Your home - consider adding lighting to areas that may be hazardous. Be alert for clutter that may cause people to fall over. Most head injuries among very young children and elderly people occur in the home. If there are toddlers in the house place pads on sharp edges of furniture, place a gate on the stairs, install window guards.
   
• Playgrounds - there should be an underlay of soft material, either sand or special matting.
   
• Jogging in busy streets - wear bright colored clothing and use both your eyes and ears when crossing the road. Keep to the sidewalk (UK/Ireland/Australia: pavement).
   
• Cycling at night - make sure your bicycle has good lighting both in front and behind. Wear bright clothing with reflectors.
   
• Nutrition and exercise - a well balanced diet and plenty of exercise can help maintain good bone mass and bone density. This is especially important for seniors (elderly people) and post-menopausal women. Stronger bones may reduce the severity of brain injury following a blow to the head.

The extent and effect of brain injury is often assessed by the use of neurological examination, neuroimaging, and neuropsychological assessment.

Brain injury does not necessarily result in long-term impairment or disability, although the location and extent of damage both have a significant effect on the likely outcome. In serious cases of brain injury, the result can be permanent disability, including neurocognitive deficits, delusions (often specifically monothematic delusions), speech or movement problems, and mental handicap. There may also be personality changes. Severe brain damage may result in persistent vegetative state, coma, or death.

Various professions may be involved in the medical care and rehabilitation of someone who suffers impairment after brain damage. Neurologists, neurosurgeons, and physiatrists are physicians who specialise in treating brain injury. Neuropsychologists (especially clinical neuropsychologists) are psychologists who specialise in understanding the effects of brain injury and may be involved in assessing the extent of brain damage or creating rehabilitation programmes. Occupational therapists may be involved in running rehabilitation programs to help restore lost function or help re-learn essential skills.

It is a common misconception that brain damage sustained during childhood has a better chance of successful recovery than similar injury acquired in adult life. It is contested that in recent studies, severe brain damage inflicted upon children can be alleviated by the interaction of nicotinamide repropagation in nerve cells. In fact, the consequences of childhood injury may simply be more difficult to detect in the short term. This is because different cortical areas mature at different stages, with some major cell populations and their corresponding cognitive faculties remaining unrefined until early adulthood. In the case of a child with frontal brain injury, for example, the impact of the damage may be undetectable until that child fails to develop normal executive functions in his or her late teens and early twenties.

The effects of impairment or disability resulting from brain injury may be treated by a number of methods, including medication, psychotherapy, neuropsychological rehabilitation, snoezelen, surgery, or physical implants such as deep brain stimulation.