It takes a linear acceleration of 60 to 160 g of the head to cause a concussion, but only 4.5 g to cause a mild cervical strain injury, so it’s safe to say that every concussion results in a whiplash injury. Symptoms of a concussion and whiplash injury are quite similar - headache, dizziness, balance, cognitive impairments, visual disturbances, fatigue, and psychological changes. The cervical spine is often overlooked and can be the cause of persistent symptoms. Moreover, the cervical spine is closely connected with the visual and vestibular systems and they need to provide consistent sensory information. If there is a conflict of information among the sensory systems, you can feel “off”. That is why many symptoms associated with the visual and vestibular systems can manifest if the cervical spine is not properly addressed.

There are 2 main cervicogenic (related to the cervical spine) mechanisms of injury that can be associated with a concussion:

Pain-related:

Pain-related mechanisms predominate in the development of headaches. Cervicogenic headaches (which are headaches that are caused by injury to the musculoskeletal tissues of the cervical spine) commonly occur after a concussion. They usually occur on one side, can sometimes result in decreased range of motion, and can be provoked by neck movements or pressure applied to the muscles in the back of the skull. The pain is usually described as radiating from the neck to the front of the head. In addition to the symptoms described above, it can be associated with other symptoms, including nausea, vomiting, light or noise sensitivity, and blurred vision in one eye.   

Proprioceptive-related:

Proprioceptive mechanisms predominate in cervicogenic dizziness and oculomotor control deficits (issues with eye movement). The cervical spine has intimate connections with the visual and vestibular systems in order to stabilize gaze, head, and trunk during head and neck movements. Disturbances in these connections can result in visual difficulties (i.e. eye gaze control during movement) and balance issues. With conflict of information coming from the cervical spine, visual, and vestibular systems, symptoms such as dizziness and vertigo can occur.

The goal with assessing the cervical spine following a concussion is to recreate the headaches and dizziness associated with injury to the cervical spine. Besides assessing the amount of movement in the neck and ruling out more serious pathologies, manual palpation of the musculoskeletal tissues of the cervical spine can assist in determining which affected structures trigger the headaches or dizziness. There are also often changes to the motor control of the neck muscles, such that it can affect balance and postural control, so assessing for head-neck motor control and balance and gait deficits are crucial. Furthermore, due to the close connections between the cervical spine and eyes, conducting oculomotor testing may demonstrate problems with smooth eye movements.

Treatment for whiplash injury is a component of a comprehensive post-concussion treatment plan and is focused on impairments found in the assessment. It is imperative to reproduce a mild level of symptoms to achieve improvements. The main areas of treatment can include:

• Manual therapy for the cervical spine and other associated areas (i.e. thoracic spine)

• Cervical strengthening and endurance training

• Cervical proprioception and head-neck motor control training

• Balance and gait training

• Visual and vestibular training (for desensitization and habituation)

It is clear that there is a relationship between concussions and whiplash injuries as there is a high degree of overlap between their symptoms. It is important to consider their relationship as it can increase the risk of further injury if not properly addressed.

If there are persistent symptoms that are present for many months after a concussion, the cervical spine should be more closely looked at!