What is a concussion?
Concussion is a type of brain injury defined as a "complex pathophysiological process affecting the brain, induced by biomechanical forces." [1-3]
The nature of concussive head injuries include:
- A concussion represents a disturbance to brain function caused by a blow or a "violent shaking" of the head, neck, or body. A concussion can result even if a person is not hit directly in the head, as an "impulsive" force may be transmitted to the brain from a blow elsewhere on the body.
- Concussions typically result in the rapid onset of short lived impairments of brain function that most often resolves spontaneously. Concussions represent a disruption of brain function rather than a structural injury, and no abnormalities are seen during standard brain imaging, such as MRI and CT scans.
- Loss of consciousness does not need to occur for a person to be concussed.
Is a concussion a brain injury?
- Trauma or forceful impact to the body or head can cause damage to our brain tissue.
- At the cellular level, impact forces cause injury to neuron cell membranes and disrupt the normal metabolic function of these brain cells.
- Any change or temporary alteration the brain's neurometabolic function from an impact force is referred to as a mild traumatic brain injury.
What happens when our brain's chemicals are disrupted?
- Our brain controls all of our "thinking" and "doing" by conducting millions and millions of chemical reactions per second.
- A disruption in any of these chemical reactions in our brain can result in temporary changes in our ability to think and function normally.
- A person may have difficulty with memory, processing information quickly, and reaction time. This may result in diminished academic performance and athletic performance and social & emotional behavior changes.
How is a concussion diagnosed?
Only a Licensed Health Care Provider trained in concussion management should diagnose a concussion.
- The diagnosis is based off a comprehensive clinical evaluation and supported by specialized concussion assessment tools.
- Concussion assessment tools alone do not diagnosis a concussion; they are used in conjunction with a medical evaluation to identify concussions and to assist the medical professional in devising a specific treatment plan for an athlete's injury.
- The severity of a concussion is no longer diagnosed on a grading scale (i.e. mild, moderate, or severe concussion). Concussions are graded retrospectively once a person has fully recovered, and they are categorized based on the recovery time.
Is there any imaging or specialized test that can detect a concussion?
The injuries sustained by brain cells during a concussion are chemical, not "structural" and are not visible. Therefore, concussions cannot be detected by any standard imaging such as X-Ray, CT scan or MRI. These scans will be normal in concussion. X-Ray, CT or MRI is helpful, when appropriate, to rule out structural damage like brain bleeds or skull fractures.
A Licensed Health Care Provider can determine if an individual has a sustained a concussion.
- Licensed Health Care Providers are Physicians, Certified Athletic Trainers, Neuropsychologists, Physician Assistants, or Advanced Practice Registered Nurses.
- Everyone may exhibit different signs & symptoms with each unique concussion injury, and the treatment and recovery will be different and tailord specifically for each person.
- A licensed Health Care provider shall provide medical clearance before a person may engage in any type of physical activity, practice, game, or competition after being diagnosed with a concussion.
- This is mandated by Hawaii State Law ACT 262
Why is the treatment and recovery different?
- Each concussion may cause different degrees of injury to different parts of the brain which control different body functions. Every concussion is unique.
- The treatment depends on the specific signs & symptoms a person is exhibiting and experiencing.
- Recovery from a concussion is multifactorial.
 Broglio, S.P., et al., National Athletic Trainers' Association position statement: management of sport concussion. J Athl Train, 2014. 49(2): p. 245-65.
 Cantu, R.C., Consensus statement on concussion in sport--the 3rd International Conference on Concussion, Zurich, November 2008. Neurosurgery, 2009. 64(5): p. 786-7.
 Harmon, K.G., et al., American Medical Society for Sports Medicine position statement: concussion in sport. Br J Sports Med, 2013. 47(1): p. 15-26.