- Risk factors for concussion predispose athletes and make them susceptible to concussion. Knowing the risk factors can help clinicians appraise individual athletes as well as direct injury prevention efforts.
BACKGROUND & OBJECTIVE
In 1994 Dr. Willem Meeuwisse developed a multifactorial model of athletic injury etiology . The model highlighted the role of risk factors for injury that precede the inciting event (i.e. mechanism of injury). It broke these risk factors down into those internal to the athlete (e.g. previous injury, age), which predispose them to injury, and those external to the athlete (e.g. equipment, opponent behavior), which increase susceptibility to injury.
In 2007 Meeuwisse and colleagues updated the model to reflect the dynamic, recursive nature of injury . The updated model emphasized the constantly evolving (i.e. dynamic) nature of risk factors for an athlete. It used the outcome of every athletic exposure – injury or no injury – to recalibrate the athlete’s internal and external risk factors (i.e. recursive). In this way, every athletic exposure provides an opportunity for the athlete to positively or negatively adapt and, in conjunction, decrease or increase their injury risk.
The purpose of this clinical commentary was to examine concussion under the lens of that dynamic, recursive model of sports injury. The commentary discussed risk factors for concussion as well as detection and management strategies.
If symptoms increase at any stage, the athlete should back off their activity until the symptoms subside.
Risk Factors for Concussion The inciting event for a concussion is typically a head impact or a blow to the body that transmits force up to the head. Before the inciting event occurs though, every athlete has a unique combination of factors that can increase their risk. Emerging evidence has found the items listed in Table 1 to be risk factors for concussion.
Understanding these risk factors helps clinicians appraise individual athletes’ risk and also directs prevention efforts towards mitigating modifiable factors. For example, neuromuscular control training may reduce the incidence of concussion.
Concussion Detection/Screening When a concussion is suspected following an inciting event, the signs and symptoms listed in Table 2 should be screened for.
Two evidence-based tools for concussion screening are the Concussion Recognition Tool (for sideline use)  and the Sport Concussion Assessment Tool (for on-field and off-field use) . When a concussion is detected, the athlete should be removed from activity immediately. However, it’s not uncommon for there to be a delay between the inciting event and onset of symptoms. Interestingly, longer delays in symptoms have been associated with longer recovery times.
Concussion Management/Recovery The first step in concussion management is 1-2 days of cognitive and physical rest. Following rest, graded return to activities of daily living can begin. Once symptoms have resolved with activities of daily living (usually within a few days following the injury), graded return to school and sport can commence.
Return to school should occur in several stages, with each stage lasting at least a day: (1) school activities outside of school, (2) school activities at school on a part-time basis, and (3) full return to school. Academic accommodations such as extra time to take exams, a quiet environment, extended deadlines, and reduced screen time may be required.
Return to sport can occur at the same time as return to school. It should also occur in several stages: (1) light aerobic exercise, (2) sport-specific exercise, (3) non-contact practice, (4) contact practice, and (5) full return to sport. Exercise can help aid the recovery process, but if symptoms increase in any of the above stages, the athlete should back off their activity until the symptoms subside.
In general, athletes can expect longer recovery times when symptoms are more severe. In cases where symptoms last longer than 1-2 weeks, a multifaceted assessment should be implemented, with input and targeted rehabilitation from a multidisciplinary care team. For example, the athlete might be referred to specialists in vestibular rehabilitation, cervical spine rehabilitation, and/or (neuro)psychology.
In terms of the physical therapist’s role, differential diagnosis of headaches and dizziness is especially important for determining the best treatment approach. For example, cervicogenic headaches, benign paroxysmal positional vertigo, and unilateral peripheral vestibular hypofunction have all been shown to be responsive to physical therapy.