Concussion is defined as a complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces. The brain has the consistency of gelatin. It’s cushioned from everyday jolts and bumps by cerebrospinal fluid inside the skull. A violent blow to the head and neck or upper body can cause the brain to slide back and forth forcefully against the inner walls of the skull. Concussion is currently a major area of study in medical circles, particularly surrounding the wellbeing of athletes’ long term health. Concussion is particularly prevalent in contact sports as it’s mechanism of injury is often associated with transmission of forces on the head, as well as the rapid acceleration and deceleration forces on the brain. This is not necessarily due to direct contact with the head.
Several common features that incorporate clinical, pathologic, and biomechanical injury constructs that may be utilised in defining the nature of a concussive head injury include the following:
- Concussion may be caused either by a direct blow to the head, face, neck or elsewhere on the body with an “impulsive” force transmitted to the head.
- Concussion typically results in the rapid onset of short-lived impairment of neurologic function that resolves spontaneously.
- Concussion may result in neuropathological changes, but the acute clinical symptoms largely reflect a functional disturbance rather than a structural injury.
- Concussion results in a graded set of clinical symptoms that may or may not involve loss of consciousness. Resolution of the clinical and cognitive symptoms typically follows a sequential course; however, it is important to note that in a small percentage of cases, post-concussive symptoms may be prolonged.
- No abnormality in standard structural neuroimaging studies is seen in concussion.
Symptoms:
The symptoms of concussion can vary from case to case, and can be numerous in nature. Symptoms that may arise can include:
- Headaches
- Fogginess
- Loss of consciousness
- Balance impairment
- Irritable behaviour
- Slowed reaction times
- Sleep/wake disturbance
- Dizziness
- Difficulty concentrating
- Word-finding problems
- Depression
- Impulsiveness
- Nausea and vomiting
Only one of these symptoms is required following a head injury to diagnose an individual with a concussion. Symptoms often last for 7-10 days following the incident, however can last for several months in severe circumstances, in these cases the patient is then diagnosed with “post-concussion syndrome”.
Concussion Prevention
There is no good clinical evidence currently available that shows protective equipment will prevent concussion. Biomechanical studies have shown a reduction in impact forces to the brain with the use of head gear and helmets, but these findings have not been translated to show a reduction in concussion incidence in randomised control trials. Instead helmets are proven to be effective at preventing other forms of head trauma such as skull fracture as a result of a fall.
A major concern with the recommendation of helmet use in sport is “risk compensation”, whereby athletes take on more reckless behaviour with the misguided belief that the protective equipment will stop all injury, resulting in the adoption of more dangerous playing techniques. This is particularly a concern in children’s sports where head injury rates are often higher than in adults (Hagel & Meeuwisse, 2004).
In a study performed by Hrysomallis in 2016, it was found that isometric neck strength was directly related to an individuals’ injury risk. This study also found that athletes with a history of concussion had decreased values for isometric neck strength in pre-season compared to athletes with no history of concussion. It has been demonstrated that greater isometric neck strength reduced the kinematic response of the head upon impact in male and female athletes who play contact sports. Collins et al performed a study in 2014 which ascertained that a one pound increase of neck strength was associated with a 5% decrease in the risk of concussion.
Graduated Return to Play Protocol following Concussion:
| Rehabilitation Stage | Functional exercise at each stage of rehabilitation | Objective at each stage |
| No activity. | Complete physical and cognitive rest. | Recovery. |
| Light aerobic exercise. | Walking, swimming, or stationary cycling at approximately 50% intensity. No resistance training. | Increase heart rate. |
| Sport-specific exercise. | Running drills. | Add movement. |
| Non-contact training drills. | Passing drills. | Exercise, coordination and cognitive load. |
| Full contact practice. | Normal training activities. | Restore confidence and assess functional skills. |
| Return to play. | Normal game play |
It is recommended that a player remains asymptomatic for 24 hours at stage 1 before progressing to stage 2 of rehabilitation. If any symptoms resurface during the progression of stages, athletes should revert back to the previous stage for a further 24 hours before attempting to re-progress.
Risk of Premature Return to Play:
- Risk of further injury: The principal concern of premature return to play of a concussed athlete is that, because of impaired cognitive function the athlete will sustain further injury (either concussive or other musculoskeletal injury) when returning to a dangerous playing environment.
- Second Impact Syndrome (SIS): A term used to describe the potential catastrophic consequences resulting from a second concussive blow to the head before an individual has fully recovered from the symptoms of a previous concussion. This is believed to result in loss of cerebrovascular auto-regulation, which in turn leads to brain swelling secondary to increased cerebral blood flow.
- Concussive convulsions: A variety of immediate motor phenomena or convulsive movements may accompany a concussion. Although dramatic, these clinical features are generally benign and require no specific management beyond the standard treatment of the underlying concussive injury. This phenomenon is a non-epileptic manifestation of concussion.
- Prolongation of symptoms: If a player recommences playing while symptomatic, post-concussive symptoms may be prolonged. This may also increase the chance of developing “post-concussive syndrome,” in which fatigue, difficulty in concentration, and headaches persist for some time, often months, following the original injury. Exercise appears to prolong the condition.
- Chronic Traumatic Encephalopathy (CTE): A risk of recurrent concussions during contact sporting careers. Athletes who are subjected to recurrent concussions, disproportionately suffer from mild cognitive impairment, and other mental health problems. Research is demonstrating that a small percentage of these athletes seem to suffer from chronic or long-term sequelae from recurrent head injury. At this stage, little is understood regarding CTE.
If you are concerned regarding the potential possibility of concussion in your sport, talk to one of our physiotherapists today for an assessment and some management strategies to reduce your risk of concussion. If you are currently experiencing symptoms of concussion please contact your local doctor.
Hrysomallis, C., 2016. Neck muscular strength, training, performance and sport injury risk: a review. Sports Medicine, 46(8), pp.1111-1124.
Collins, C.L., Fletcher, E.N., Fields, S.K., Kluchurosky, L., Rohrkemper, M.K., Comstock, R.D. and Cantu, R.C., 2014. Neck strength: a protective factor reducing risk for concussion in high school sports. The journal of primary prevention, 35(5), pp.309-319.
Hagel B., Meeuwisse W., 2004. Risk compensation: a “side effect” of sport injury prevention? Clin J Sport Med; 14(4): 193-6