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.
Today’s two quotes come from inspirational leaders, which I have encountered through leadership training.
“The moral test of government is how that government treats those who are in the dawn of life, the children; those who are in the twilight of life, the aged, and those in the shadows of life, the sick, needy and handicapped.” American Senator Hubert Humphrey
“Decay is automatic. To reorganise and be able to grow takes intention. So if there is a ‘what’ to improvement, then you better have a ‘how’. “
Don Berwick – former president & chief executive of the Institute of healthcare improvement
A common symptom post concussion is dizziness and feeling off balance. We explored in the last section what this may mean if it is linked to exercise but what if the dizziness is at rest and less predictable?
This is where your physiotherapist will be able to assess where the source of the problem lies… and this is sometimes quite challenging as dizziness can be caused by many factors post concussion.
A thorough subjective history into aggravating factors, easing factors, duration of dizziness, frequency of dizziness and a description of the symptoms, will help guide our assessment.
Areas to check during an assessment for dizziness post concussion is the peripheral vestibular system, the central vestibular system and the upper cervical spine.
Let’s start with what we mean by the ‘vestibular system’?
The vestibular system is the sensory system that provides the leading contribution to the sense of balance and spatial orientation for the purpose of coordinating movement with balance. The vestibular organs located in the inner ear are in a state of symmetrically tonic activity, that when excited stimulate the central vestibular system. This information, along with proprioceptive and ocular input, is processed by the central vestibular pathways and maintains our sense of balance and position.
The vestibular system is broadly categorized into both peripheral and central components. The peripheral system is bilaterally composed of three semicircular canals (posterior, superior, lateral) and the otolithic organs (saccule and utricle). The semicircular canals detect rotational head movement while the utricle and saccule respond to linear acceleration and gravity, respectively. Peripheral Vestibular Disorders are limited to the vestibulocochlear nerve (CN VIII) and all distal structures.
The central vestibular pathways are those information highways otherwise known as neural tracts that relay this information from the vestibulocochlear nerve to other parts of our brain, about our position in space. This information is vital for maintaining our posture (so we don’t fall over when we move) and our gaze stability (so our vision does not blur when we move)
The information about where we are in space from the vestibular nerve helps our cerebellum coordinate the correct postural muscles to keep us upright via the vestibulospinal and reticulospinal tracts.
‘Gaze stability’ is achieved by the Vestibular Ocular Reflex (VOR) which uses information from the vestibular nerve about our head position, to stimulate the correct eye muscles to maintain your focus on a target- try focusing on an object and shaking your head- it doesn’t matter what speed or direction, your focus stays very true, all thanks to this reflex 🙂
After a concussion, we may see trauma to the peripheral vestibular organs or a dysfunction to the central vestibular pathways. Due to the complexity of the system, even a mild dysfunction in the information processing may lead to feelings of instability, dizziness and/or visual disturbances. Our clever cerebellum tries to correct any inaccuracies but this can take time and so we teach you strategies and training exercises to help speed up the process.
The BCTT (Buffalo Concussion Treadmill Test) which we talked about in our last article has been the most reliable and safe way to assess exercise tolerance post concussion however If the idea of getting on a treadmill makes you uncomfortable, then you are not alone…many of my clients have been unable to participate in this assessment due to the following issues:
• Vestibular- ocular dysfunction • Balance impairments • Frequent and disabling symptoms of dizziness, nausea and vertigo • Musculoskeletal Injuries preventing safe or comfortable use of a treadmill.
We now have the Buffalo Concussion Bike Test (BCBT) which has been researched and assessed against the BCTT by Haider et al this year and found to have concurrent validity – the test results show the BCBT measured exercise tolerance just as well as the BCTT, which is great news… Except… i think it will take me a while to get my head around how to work out the resistance! Anyone out there used the BCBT yet?
The reasoning for physical and cognitive rest following a concussion is based on evidence of temporary chemical changes in the brain that occur immediately after a concussion to help the affected brain tissue recover. The recovery time can last for days to weeks and involves a period of inflammation and increased nutritional demand to the affected brain tissue. This contributes to the common symptoms of concussion.
For a successful recovery, the advice is to avoid non essential physical or cognitive activity that diverts essential nutrition from injured brain tissue, so as not to delay recovery. Therefore clinicians advise a period of rest in the early days following a concussion to reduce the risk of worsening symptoms and delaying recovery.
Recent evidence has shown that the return to normal brain chemistry did not always coincide with resolution of symptoms. Prolonged symptoms past the normal healing time is often referred to as Post Concussion Syndrome (PCS) and has now been associated with a prolonged dysfunction in certain pathways of the brain. Resting until symptoms have fully resolved is not advised and may even be detrimental to your recovery: We need to be active for our brain to figure out what it is doing wrong and re-learn how to function normally again. Activity also boosts chemicals in the brain that promotes healing makes you feel good. Getting active as soon as possible after a concussion has been shown to improve recovery time and well being, as long as this activity does not exacerbate symptoms.
To work out what level of activity is safe post concussion is vey individual and clinicians commonly use the Buffalo Concussion Treadmill Test (BCTT) to assess where you can comfortably exercise and then create a program to help you improve your activity tolerance without exacerbating symptoms.
As a Clinician who has used the BCTT with clients experiencing PCS, i have witnessed the effectiveness in facilitating a full return to exercise and speeding up recovery post concussion.
If you are 6 weeks post concussion and struggling to get back to your usual physical activity because of symptoms, then it would be worth contacting a Health Care Professional who is experienced in this test and help you back to your active self 🙂
Concussion can not be diagnosed through any one question, sign, symptom or test. It requires multiple modes of assessment that may well need repeating.
Concussion symptoms can present after 24 – 48hrs. Only 50% occur immediately and 47% occur in the absence of physical signs* This is what makes it such a difficult injury to diagnose and manage, especially in sport. (*ECB guidelines 2018) There are useful pitch side tools available to assist in concussion recognition http://https://bjsm.bmj.com/content/bjsports/47/5/267.full.pdf
These tools help recognise a concussion, however, a referral to a doctor is required to make a concussion diagnosis. Any adult or child returning to sport after a suspected concussion should be cleared by a doctor to do so, as pitch side assessment tools are not valid in their use to rule out a concussion.
Because this is a complex process, concussion is not only easily missed and under-diagnosed, but often results in an unsuccessful return to school, work and sport. This is why seeking advice from a health care professional is vital to a full recovery post concussion. Post concussion recovery guidelines are coming up next..