A Chiropractic Adjustment Has a Direct Effect of the Pre-Frontal Cortex of the Brain

 

Verifying a positive effect of the chiropractic spinal adjustment on reflexes, memory, coordination and decision making

 

By: Mark Studin

William J. Owens

 

A report on the scientific literature

For most of the 20th century, based upon results in individual chiropractic offices, the profession’s success was founded on a patient-based model. This model drove utilization at predominantly a “grass roots” level and over the last 10-20 years, research has started to give reasons to why patients not only get out of pain, but executive functions such as decision making, anxiety, managing tasks and being able to focus at a higher level are improving. It is these types of results that have driven many patients to appreciate chiropractic as a “miracle cure” while others, mostly from organized medicine and insurers, who in the past have considered it an "invalid claim” because of the lack of credible evidence despite mounting feedback from patients over the last century. Factually, their arguments had merit on many issues in the past, but as research has been published through the years, those arguments are outdated and incorrect.

"Evidence-based behavioral practice (EBBP) entails making decisions about how to promote health or provide care by integrating the best available evidence with practitioner expertise and other resources, and with the characteristics, state, needs, values and preferences of those who will be affected. This is done in a manner that is compatible with the environmental and organizational context. Evidence is comprised of research findings derived from the systematic collection of data through observation and experiment and the formulation of questions and testing of hypotheses" (Evidence-Based Practice, http://en.wikipedia.org/wiki/Evidence-based_practice).

When considering a purely “evidenced-based” approach, it often precludes advances through a doctor’s immediate experiences in “breakthroughs” that has historically saved lives and then set up the research to render the evidence of what doctors have found on an “experiential level.” This is formally termed best medical practice.

“Abest practice is a method or technique that has consistently shown results superior to those achieved with other means and that is used as a benchmark. In addition, a "best" practice can evolve to become better as improvements are discovered. Best practice is considered by some as a business buzzword, used to describe the process of developing and following a standard way of doing things that multiple organizations can use" (Best Practice, http://en.wikipedia.org/ wiki/Best_practice).

Sackett, Rosenberg, Gray, Haynes and Richardson (1996) stated, 

 “Criticism has ranged from evidence based medicine being old hat to it being a dangerous innovation, perpetrated by the arrogant to serve cost cutters and suppress clinical freedom (p. 71)."  They go on to comment “Good doctors use both individual clinical expertise and the best available external evidence, and neither alone is enough. Without clinical expertise, practice risks becoming tyrannized by evidence, for even excellent external evidence may be inapplicable to or inappropriate for an individual patient. Without current best evidence, practice risks becoming rapidly out of date, to the detriment of patients" (Sackett et al, 1996, p. 72).  The point is that the provider plays a huge role and ultimately is the check and balance of this process. Without the provider, the payor becomes the determining factor in the delivery of healthcare by "tying the doctor's hands" with the limitation of evidence. 

They further stated:

“External clinical evidence can inform, but can never replace, individual clinical expertise, and it is this expertise that decides whether the external evidence applies to the individual patient at all and, if so, how it should be integrated into a clinical decision" (Sackett et al, 1996, p. 73).  Lastly, they state, “Evidence based medicine is not restricted to randomized trials and meta-analyses. It involves tracking down the best external evidence with which to answer our clinical questions" (Sackett et al, 1996, p. 73). This is often a process that takes years, preventing the final papers from being published in a timely enough fashion to meet the ever-changing advancement of medicine and the technologies that support the current needs of the patients.  

When considering executive function at the central (brain) level, based upon contemporary literature, we can now go beyond the “best medical practice” model of purely patient feedback and as Sackett et. Al. suggested, add the evidence as verification. In order to better understand how chiropractic plays a role in executive function, we must start at neural plasticity. According to Leung et. Al (2015) Neural plasticity refers to the capacity of our brain to change in response to internal demand and/or external experience. Burgeoning research has corroborated that the neural plastic changes induced in our brains and behaviors are specific to the experiences. [pg. 1] 

Neuroplasticity, also known as brain plasticity or neural plasticity, is an umbrella term that describes lasting change to the brain throughout an individual's life course. The term gained prominence in the latter half of the 20th century, when new research showed that many aspects of the brain can be altered (or are "plastic”) even into adulthood. (https://en.wikipedia.org/wiki/Neuroplasticity) 

This article focuses on the actions and effects of neuroplasticity on the pre-frontal cortex of the brain. According to Lelic et. Al (2016) 

The prefrontal cortex is known to play a vital role in SMI and is also responsible for a number of other functions. The prefrontal cortex is known to be a key structure responsible for the performance of what is known as “executive functions.” Executive function is the mechanism by which the brain integrates and coordinates the operations of multiple neural systems to solve problems and achieve goals based on the ever-changing environment around us. Executive function is considered to be a product of the coordinated operation of various neural systems and is essential for achieving any particular goal. The prefrontal cortex is believed to be the main brain structure responsible for enabling this coordination and control. It requires planning a sequence of subtasks to accomplish a goal, focusing attention on relevant information as well as inhibiting irrelevant distractors, being able to switch attention between tasks monitoring memory, initiation of activity, and responding to stimuli. [pg. 7] 

Lelic et. Al.’s study resulted in two major findings. Firstly, the study reproduced previous findings of somatosensory evoked potential (SEPs) studies that have shown that chiropractic spinal adjusting of dysfunctional spinal segments alters early sensorimotor integration (SMI) of input from the upper limb. The second major finding of this study was that we were able to show, using dipole source localization, that this change in SMI that occurs after spinal manipulation predominantly happens in the prefrontal cortex. The SEP peak showed multiple neural generators including primary sensory cortex, basal ganglia, thalamus, premotor areas, and primary motor cortex. The frontal N30 peak is therefore thought to reflect early SMI.

The current study adds to previous work by not only confirming that spinal manipulation [chiropractic spinal adjustment] of dysfunctional joints decreases the N30 SEP peak amplitude but also demonstrating that this decrease occurs predominantly in one of the known neural generators of N30, that is, the prefrontal cortex. This suggests that, at least in part, the mechanisms by which spinal manipulation improves performance are due to a change in function at the prefrontal cortex.

Lelic et. Al (2016) continued,

The prefrontal cortex is known to play a vital role in SMI and is also responsible for a number of other functions. The prefrontal cortex is known to be a key structure responsible for the performance of what is known as “executive functions.” Executive function is considered to be a product of the coordinated operation of various neural systems and is essential for achieving any particular goal. The prefrontal cortex is believed to be the main brain structure responsible for enabling this coordination and control. It requires planning a sequence of subtasks to accomplish a goal, focusing attention on relevant information as well as inhibiting irrelevant distractors, being able to switch attention between tasks, monitoring memory, initiation of activity, and responding to stimuli. A change in prefrontal activity following chiropractic care may therefore explain and/or link some of the varied improvements in neural function previously observed in the literature, such as improved joint position sense error, reaction time, cortical processing, cortical sensorimotor integration, reflex excitability, motor control, and lower limb muscle strength.

To accomplish the coordinated operations of multiple neural systems and structures, the prefrontal cortex must monitor the activities in other cortical and subcortical structures and control and integrate their operations by sending command signals in a so-called “top-down” manner. This is a complex operation, and the importance of this monitoring, integration, and coordination is highlighted in studies where damage to the prefrontal cortex has been shown to impair the ability to create new and adaptive action programs or choose the best among several equally probable alternatives, despite such individuals displaying normal IQs in most psychological tests, having normal long-term memory functions, and exhibiting normal perceptual, motor, and language skills

 To accomplish the coordinated operations of multiple neural systems and structures, the prefrontal cortex must monitor the activities in other cortical and subcortical structures and control and integrate their operations by sending command signals in a so-called “top-down” manner. This is a complex operation, and the importance of this monitoring, integration, and coordination is highlighted in studies where damage to the prefrontal cortex has been shown to impair the ability to create new and adaptive action programs or choose the best among several equally probable alternatives, despite such individuals displaying normal IQs in most psychological tests, having normal long-term memory functions, and exhibiting normal perceptual, motor, and language skills [43].The change in prefrontal cortex as seen in this study therefore suggests that the altered input from dysfunctional joints that leads to altered processing of somatosensory inputs can influence processing of somatosensory information by the prefrontal cortex.

Chiropractic care, by treating the joint dysfunction, appears to change processing by the prefrontal cortex. This suggests that chiropractic care may as well have benefits that exceed simply reducing pain or improving muscle function and may explain some claims regarding this made by chiropractors.

Although the change in N30 due to chiropractic treatment is an important finding, it is not clear how long this finding lasts. To date, some of the authors of this study have shown that the N30 changes on average are present for at least 20–30 minutes after spinal manipulation. For some subjects, the changes were still evident at 30 minutes after spinal manipulation and we have not yet followed up for longer than 30 minutes, due to the length of the study as is.

The literature has clearly suggested that a chiropractic spinal adjustment has a clear and reproducible effect on brain physiology and function and is consistent with reports from Reed, Pickjar, Sozio and Long (2014) and Gay, Robinson, George, Peristen and Bishop (2014) on a chiropractic spinal adjustment effecting brain function. These results, in addition to chiropractic patient’s feedback since 1895, have combined both “best practice” and evidenced based” models and start to explain through science, why people are experiencing so much more than their beck or neck pain resolving.

References:

  1. Best Practice. (n.d.). In Wikipedia. Retrieved January 3, 2012, fromhttp://en.wikipedia.org/wiki/Best_practice
  2. Evidence-Based Practice. (n.d.). In Wikipedia. Retrieved January 3, 2012, fromhttp://en.wikipedia.org/wiki/Evidence-based_practice
  3. Leung, N. T., Tam, H. M., Chu, L. W., Kwok, T. C., Chan, F., Lam, L. C., ... & Lee, T. (2015). Neural plastic effects of cognitive training on aging brain.Neural plasticity,2015.
  4. Neuroplasticity (2017), Retrieved from: https://en.wikipedia.org/wiki/Neuroplasticity
  5. Lelic, D., Niazi, I. K., Holt, K., Jochumsen, M., Dremstrup, K., Yielder, P., ... & Haavik, H. (2016). Manipulation of dysfunctional spinal joints affects sensorimotor integration in the prefrontal cortex: A brain source localization study.Neural plasticity,2016
  6. Reed, W. R., Pickar, J. G., Sozio, R. S., & Long, C. R. (2014). Effect of spinal manipulation thrust magnitude on trunk mechanical activation thresholds of lateral thalamic neurons.Journal of Manipulative and Physiological Therapeutics, 37(5), 277-286.
  7. Gay, C. W., Robinson, M. E., George, S. Z., Perlstein, W. M., & Bishop, M. D. (2014). Immediate changes after manual therapy in resting-state functional connectivity as measured by functional magnetic resonance imaging in participants with induced low back pain. Journal of Manipulative and Physiological Therapeutics, 37(9), 614-627..

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