Youth Concussion: What is it, who gets it, and how is it diagnosed?
What is it?
The definition of concussion has changed many times over the last 50 years, however, in general, concussion in a subset of mild traumatic brain injury and represents a traumatically induced transient disturbance in how our brains function that cannot be otherwise explained by the effects of other events/substances (alcohol, medications, other health comorbidities). Contrary to popular belief, this does not necessarily mean that there has to be a physical impact to the head.
Despite decades of intense research on concussion, the biology and physiology of concussion remains incompletely understood and the exact mechanism for all its effects is being widely studied. Research on the biology and physiology of concussion has been understandably limited due to the bulk of the research being performed on animal models. Of the many complex proposed mechanism of the effects seen during and after concussion, in general, it is thought that during concussion a force is delivered to the brain that creates a stretch of the different parts of the brain cells (neurons) which in-turn disrupts the way these neurons are able to perform many of their functions and communicate with one another. This disruption also results in some extent of direct structural cell injury and impairs their ability repair themselves. This weakened ability to repair helps to explain why concussed brains are more vulnerable and susceptible to a second and more harmful later concussion.
Who gets it?
Professional societies and organizations such as the American Medical Society for Sports Medicine (AMSSM), the American Academy of Neurology, and the Center of Disease Control and Prevention (CDC) help to oversee statistics on concussion as well as create and publish guidelines for concussion care and prevention. Recently statistics reported by the AMSSM stated that 1.0 – 1.8 million sports concussion occur yearly in individuals <18 years old and approximately 400,000 of these occur while playing high school sports. Recently published statistics state that 15% of all U.S. high school students reported experiencing at least on concussion during sports or recreation in the past year (CDC). However, before questioning the safety of our organized youth sports teams, it was also reported by the AMSSM that only ~20% of all concussion in those <18 years old are related to playing on these teams and only 2-15% of these athletes are likely to experience a concussion yearly. This being the case, statistically speaking, minors appear to be much less likely experience concussion in organized sports than other activities.
How is it diagnosed?
The diagnosis of concussion can be challenging because concussion is what healthcare providers call a “clinical diagnosis”. This means that providers have to make the diagnosis based on the history of the event as well as self-reported symptoms of the patient, and their physical exam. To date there are not widely used or definitively sensitive or specific tests that can be performed by a health care provider to conclusively diagnosis concussion. Additionally, common symptoms of concussion such as headache, dizziness, fatigue, “fogginess”, and mood changes are non-specific to concussion and can result from many other conditions. Further complicating the ability to reliably diagnose concussion is the fact that many symptoms of concussion can have delayed onset and not be entirely noticeably immediately after the event.
A key part of helping to diagnose concussion after it occurs is the ability to compare a patient’s symptoms to a preseason evaluation. This is called the pre-participation physical examination (PPE), that serves as a baseline evaluation that logs and takes into consideration patients’ prior history of head injury and premorbid conditions such as mood or learning disorders, headache disorders, etc. The PPE often also helps create a pre-participation symptom checklist and includes a balance and cognitive evaluation. The tested components of the PPE overlap significantly with the assessments that can be performed and compared later, either on the field or in a care providers office, in the case that a concussion is suspected.
Later, during sports play or in a care providers office after concern for concussion, evaluation of the player takes place using at least on of several standardized measures prior to deciding an eventual plan to return to sports participation. If the patient is evaluated immediately after an potentially concussive event, for example, on the game sidelines, it is generally accepted for them to be removed from play if the event resulted in any loss of consciousness, imbalance or coordination issues, as well as a blank stare on the players face, and per recommendations from the AMSSM, it is recommended to keep the player out of the game until evaluated by a healthcare professional in an environment that is a distraction-free as possible.
The symptoms the patient/athlete reports along with the re-evaluation comparison to the PPE is the most sensitive indicator or concussion. Standard evaluation tools, such as the commonly used Sports Concussion Assessment Tool (SCAT5) incorporate exam findings, cognitive and balance testing, and a symptoms checklist to help assess the likelihood of concussion. After provision of assessment tools like the SCAT5, the likelihood of a concussion is determined to either unlikely, probable, or definite, with athletes found unlikely to have experienced a concussion often allowed to continue sports participation while athletes found to have probable or definite concussion immediately removed from play and no same day play recommended. At that time the provider and the athlete work together to create a plan for gradual and safe return to play.
Given the delay of symptoms onset and diagnosis of concussion, many times young athletes are first assessed for concussion in a medical providers office days later. At these appointments, a detailed event history and physical exam are imperative, in addition to symptom-specific testing if indicated. These outpatient appointments can be excellent opportunities for healthcare providers to complete more in-depth assessments for concussion including the use of the Vestibular/Ocular Motor Screening (VOMS). This tool can be particularly helpful as approximately 67%-77% of patients with sports-related concussion will have symptoms of vestibular (balance) impairment, and approximately 45% will have impairment in eye movement and function.
Though the treatment of concussion will be addressed in a future newsletter, it should be noted that approximately 80%-90% of concussed adolescent and young adult patients experience a complete resolution of their new post-concussive symptoms within 2 weeks after the event without treatment, though younger adolescent athletes may take slightly longer (2-4 weeks). Future newsletters will address topics such as the treatment and long-term effects of concussion.
James Dolbow DO
Neurology Resident
Case Western Reserve University
University Hospitals-Cleveland Medical Center.