This blog is meant to give you the skinny; the short and simple; the low-down on a noteworthy scholarly article from a number of different scientific journals to give you the knowledge and power to take your health into your own hands (within reason).
Today we are going to go over “Differences in brain processing of proprioception related to postural control in patients with recurrent non-specific low back pain and healthy controls” written by Nina Goossens, who is part of the department of rehabilitation sciences at KU Leuven University in Leuven, Belgium along with her colleagues.
It was published in the journal NeuroImage: Clinical on 05/28/2019. The journal NeuroImage: Clinical has an average impact factor of around 4. The impact factor basically gives you an estimation of how popularly cited the articles in the journal are and by proxy its reputation in the academic community. The most popular journal in the world, The New England Journal of Medicine, has an impact factor of around 70. It is important to note, the impact factor does not tell you anything about the content or validity of each of the articles written in the journal, just its popularity. Just like social media, the more popular journals have more reach and publicity than less popular journals.
This means that the information in this article might not be known by your healthcare provider due to the amount of time the publication has been out and the lack of reach of the journal. With those caveats out of the way, let’s dive into it.
Low back pain is a very common condition that is the leading cause of disability worldwide. 90-95% of those with low back pain get the diagnosis of “non-specific low back pain” (NSLBP); meaning that the pain can’t be pinned to a specific cause like a fracture or infection. That means that it is more likely that functional and/or psychosocial factors are driving the development and recurrence of NSLBP.
With all this NSLBP going on, scientists and clinicians want to find ways to help patients. In this article, researchers look at the differences in sensory processing of people with NSLBP versus healthy individuals in three different scenarios; Static posture/balance, Squatting, and generic proprioceptive stimulation to help find what we can do to reduce the burden NSLBP places on individuals and the world.
20 individuals with NSLBP and 20 healthy controls volunteered for this study. Each group answered a number of different questionnaires to assess different aspects of their Low Back Pain (LBP) including questions on disability, severity, and physical activity.
These participants then completed two tasks on a force plate that calculates and analyses pressure. They were also blindfolded to take out any visual information which we know affects balance, posture, and motor programming.
The first task was assessing postural control on a stable surface (just the force plate) and an unstable surface (force plate plus a foam pad). Their ankles and low back were then stimulated with either two vibrational devices on the ankles or on the back. The force plate data was then analyzed to assess the postural sways elicited by the vibration. That data was then processed to calculate the Relative Proprioceptive Weighting (RPW) which basically shows you how much are you listening to your ankles or back for balance.
The second task was a Sit-to-Stand-to-Sit (STSTS) test where the participants sat on a height-controlled stool and, as quickly as possible, stood up and sat down 5 times. This task was then repeated again with the foam pad placed on top of the force plate just like the first task.
The final experimental procedure performed was an fMRI study showing brain blood flow and, indirectly, brain activity. Participants laid on the MRI table with both an ankle and low back vibrational device. They then ran through 6 fMRI readings, three with ankle vibration and three with low back vibration. That data was then analyzed to give the researchers a window into the difference in proprioceptive processing in those with NSLBP and those without.
This study showed a number of things that were already known in the medical literature but also shed some new light on the differences in processing for people with NSLBP.
First, both the NSLBP group and control group relied less on ankle proprioception when on the foam pads. The reason this happens is your brain has a predictive model of what your ankles should be saying at any point and time. When you are on a foam mat, your ankles are constantly shifting to try to keep yourself balanced on what should be a stable surface. The predicted information and the information actually received are constantly saying different things so your brain reweighs that sensory information to be less important.
Second, those with NSLBP had increased activation of the amygdala from proprioceptive information and higher levels of fear in response to motion as compared to the control group. They also found that the higher activation of the amygdala the less the individual was able to reweight proprioception based on the circumstance. These results could show the possibility of proprioceptive stimulation causing a shift towards threat detection which reduces your ability to control posture.
Finally, patients with NSLBP might require increased activation of sensory-processing regions of the brain. The brains of NSLBP patients had increased activation over a larger surface area showing increased processing requirements. This combined with the amygdalar “threat detection” findings, gives us the impression that postural control for those with NSLBP takes much more energy and awareness than compared to healthy individuals.
We all walk on unstable surfaces to varying degrees almost every day and we thus have to bounce between an ankle and low back strategies to accommodate. If someone has a cognitive load, like the multitasking we all do in life on top of unconscious threat detection, and is unable to properly switch from an ankle balance strategy to a back strategy; the likelihood you are going to make a motion error and cause micro trauma that ultimately leads to low back injuries.
Stopping the repetitiveness of these motor miscalculations is key to reducing the shear forces that occur in the low back when patients move inappropriately. There are a number of ways we can reduce our risks for motion errors.
Motion is life for the body but especially for the spine. If you don’t keep moving and lose range of motion a few things happen. You rob range of motion from other parts of your body to get the motor task done and that increases the injury risk in those joints; you increase the cognitive load of threat detection; you decrease proprioceptive information that inhibits pain. All a bad combination, so creating and increasing your pain-free range of motion is vital
Reducing motion restrictions in tissues supports our first strategy. By removing any barriers to the motion we are able to expand the pain-free range of motion to the joint. This will give us better movement strategies for the movements that we execute every day like a squat, overhead press, and deadlift.
You can do this through a number of different methods including chiropractic adjusting, acupuncture, massage; as well as at-home strategies like foam rolling, lacrosse ball work, and voodoo flossing.
If your representation of gravity and your motion in relation to it is inappropriate, or different from where actual gravity is, You will consistently make motor errors. Imagine you outside and the wind is blowing violently at you. You will position yourself to meet that force and stay stable. Now imagine that same stance but instead of the wind in your face, it is to your back. You will fall down because you are not postured to appropriately resist those at force. This is exactly what happens if you don’t interpret gravity or motion (of you and your environment) properly.
Accurate perception of these things is linked to not only body proprioception but your visual and vestibular systems. The intersection of all three of these gives us an accurate representation of the environment so we may react to the situation with the right motor patterns.
Having a plan on how to best support these factors should be something you discuss with your healthcare provider. If you or someone you know is dealing with back pain, share this blog and spread the knowledge. For access to the article Click Here. If you have any other questions or comments, please leave a comment so a discussion can take place and those answers can help other people.
Dr. Chase Davidson, DC is a Board Eligible Chiropractic Neurologist and specializes in concussion and sports rehab, as well as functional medicine and immunology. He is the Director of Neuroscience and Metabolics at Action Potential – Sports and Neurological Rehab. He also is a member of the International Association of Functional Neurology and Rehabilitation (IAFNR). Stay connected with Dr. Davidson on Linkedin: @dr-davidson / Instagram: @thatneurologyguy / Email: firstname.lastname@example.org
Goossens, N., Janssens, L., Caeyenberghs, K., Albouy, G., & Brumagne, S. (2019). Differences in brain processing of proprioception related to postural control in patients with recurrent non-specific low back pain and healthy controls. NeuroImage. Clinical, 23, 101881. https://doi.org/10.1016/j.nicl.2019.101881
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