|Both concussion and whiplash are due to acceleration and/or deceleration forces. Concussion is due to acceleration or deceleration of the brain, while whiplash is due to acceleration or deceleration of the neck.|
Studies on high school and college football players (using instrumented helmets) have demonstrated that concussions occur between 60-120G of linear acceleration (where G = Force of Gravity).4 (Broglio et al 2011) Studies examining whiplash injuries have shown that it only takes 4.5G of acceleration to result in strain injury to the neck.5(Spitzer et al 1995) Based on these forces, we can easily see how every concussion likely has some degree of associated/concurrent neck injury!
Following upper cervical trauma there may be an inaccuracy in sensory information from the upper cervical spine about head and neck position. Even a mild dysfunction will cause a lot of problems; Imagine if you moved your head 10 degrees and your vestibular system reported this movement of 10 degrees and your vision reported this movement of 10 degrees but your neck reported it was a 15 degree movement. This disagreement between the data from the different sensory systems about head and neck position in space makes it difficult for the brain to accurately control postural and visual reflexes resulting in symptoms of:
- dizziness (a sensation of movement of the self or the environment) that is worse during head movements or after maintaining one head position for a long time.
- a general imbalance that may increase with head movements and with movement in the environment
- nausea and visual disturbance may also be reported
As with concussion, sometimes the symptoms are vague and non specific. With a cervicogenic dysfunction, clients may report a sensation of not being ‘grounded’ or feeling ‘disconnected’
When we assess post concussion injuries it is important to check the cervical spine. Cervicogenic dizziness can be present with or without neck pain. It is a diagnosis of exclusion and so we first rule out any vestibular contribution to dizziness.
|Head Repositioning Accuracy (HRA) tests are useful in assessing the accuracy of sensory information from the upper cervical spine on head and neck position. This is a proprioceptive test using a target that tests your ability to move your head and neck within a set ROM without relying on your vision.|