Neuroplastic Responses to Chiropractic Care:
Broad Impacts on Pain, Mood, Sleep, and Quality of Life
Brain Science
November 7, 2024; Vol. 14; No. 11; Article 1124
Heidi Haavik, Imran Khan Niazi, Imran Amjad, Nitika Kumari, Usman Ghani, Moeez Ashfaque, Usman Rashid, Muhammad Samran Navid, Ernest Nlandu Kamavuako, Amit N. Pujari, Kelly Holt; the authors are from the New Zealand College of Chiropractic, Auckland University, Aalborg University (Denmark), Riphah International University (Pakistan), University of Hertfordshire (UK), Radboud University Medical Center (The Netherlands), King’s College (UK), and the University of Aberdeen (UK). This study cites 169 references.
“This study evaluated the underlying neurophysiological mechanisms of chiropractic care using a multifaceted approach, recording behavioral, subjective, and neurophysiological data.”
The objectives of this study were to “elucidate the mechanisms of chiropractic care using resting electroencephalography (EEG), somatosensory evoked potentials (SEPs), clinical health assessments (Fitbit), and Patient-Reported Outcomes Measurement Information System (PROMIS-29 [attached at end of review]).”
- EEG and SEPs were collected pre and post the first intervention and post 4 weeks of intervention.
- PROMIS-29 (Patient-Reported Outcomes Measurement Information System) was measured pre and post 4 weeks to measure health-related quality of life (QOL).
- PROMIS-29 assesses pain intensity using a single 0–10 numeric rating item and seven health domains (physical function, fatigue, pain interference, depressive symptoms, anxiety, ability to participate in social roles and activities, and sleep disturbance), using four items per domain.
- The PROMIS-29 is a reliable and valid instrument to assess the impacts of health care and track changes in health over time. [attached at end of review]
- Fitbit data was recorded continuously for four weeks.
76 people with chronic low back pain (CLBP) were randomized to a chiropractic group (n=38) and a control group (n=38).
The chiropractic care included 4 weeks (approximately 3 times per week) of manual high-velocity low-amplitude (HVLA) adjustments to the spine or pelvis identified as being subluxated.
- “These HVLA directed at vertebral subluxations rapidly stretch the surrounding paraspinal tissues and, in particular, the deep small paraspinal muscles.”
- “This results in a ‘bombardment’ of proprioceptive input to the CNS that elicits the changes in central neural excitability and motor control changes.”
The clinical indicators of vertebral subluxations included “tenderness to palpation of the relevant joints, manual palpation for restricted intersegmental range of movement, palpable asymmetric intervertebral muscle tension, and any unusual or blocked joint play and end feel of the joints.”
The control group had usual care which was any care recommended or prescribed by non-chiropractic health providers for CLBP, including self-management advice, pain drugs, physical therapy, or referral to a pain clinic.
EEG = electroencephalography:
delta waves (1-4 cycles per second):
very slow brain waves
seen mostly during sleep
theta waves (5-7 cycles per second):
slow brain waves
seen during daydreaming and twilight states and meditation
alpha waves (8-12 cycles per second):
seen during relaxed states; the brain is active but relaxed
beta waves (13-20 cycles per second):
fast brain waves
seen during concentration mental work, in conscious thought and logical thinking
KEY POINTS FROM THIS ARTICLE:
1) “Chiropractic care is based on the premise that correcting vertebral subluxations improves central neural function, improving human performance and clinical outcomes.”
2) “Vertebral subluxation is recognized by the World Health Organization as a biomechanical lesion within the vertebral column.”
- “[Vertebral subluxation] is characterized by abnormal movement or function of spinal segments which is identified by clinical markers such as restricted intersegmental range of motion, tenderness upon palpation, palpable asymmetric intervertebral muscle tension, and altered joint play and end feel.”
3) “Vertebral subluxation involves altered afferent input from muscle spindles in the paraspinal muscles at the subluxated levels.”
- “This disruption in sensory input can cause maladaptive central neural plastic changes, resulting in impaired sensorimotor integration and control.”
- “These maladaptive central plastic changes in the central nervous system (CNS) can worsen over time, which is thought to contribute to dysfunction, pain, and other symptoms by disrupting normal sensorimotor control.”
- “These maladaptive central plastic changes are thought to be reversed or improved through chiropractic care.”
4) “Over the past decade, multiple studies have shown that chiropractic adjustments alter central neural function and improve the ability of peripheral muscles to produce force.”
5) “Chiropractic adjustments have been shown to influence various aspects of neurophysiology, including somatosensory processing, sensorimotor integration, and motor control, all crucial for executing motor tasks accurately and recovering from central nervous system injuries.”
- Chiropractic care drives neuroplastic brain changes in “structures such as the primary somatosensory cortex, primary motor cortex, prefrontal cortex [PFC], and cerebellum.” [Important]
- “Improvements in either prefrontal cortex or cerebellar function could explain many of the clinically relevant changes that have been documented following chiropractic care, such as improved joint position sense error, cortical processing, reflex excitability, reaction time, cortical sensorimotor integration, motor control, upper and lower limb muscle functions, and pain changes.”
- Both the PFC and cerebellum influence emotional control and mental health, as well as neuroendocrine responses, autonomic nervous system function, and immune function. [Very Important]
6) Findings:
- “Resting EEG showed a significant increase in Theta, Alpha and Beta, and a significant decrease in Delta in the chiropractic group post intervention.”
- “Significant improvements in light sleep stage were observed in the chiropractic group along with enhanced overall quality of life post 4 weeks, including significant reductions in anxiety, depression, fatigue, and pain.”
- Fitbit data showed “significant differences between the control and chiropractic groups, with the chiropractic group showing significantly increased light sleep stage duration.”
- “Fitbit data revealed that the light sleep stage significantly increased in duration in the chiropractic group over the four weeks of this study. Improved sleep length is consistent with existing research indicating that chiropractic adjustments help to alleviate tension from within the body, encouraging blood flow, enabling the muscles to relax and making it easier to also mentally relax and fall asleep.”
- “As the participants in this study reported improvements in CLBP over the four weeks of the study, the chiropractic adjustments appear to have positively influenced pain processing, another factor known to improve sleep quality.”
- “The current study supports this finding and suggests that chiropractic care does have an impact on sleep quality.”
- The PROMIS-29 showed an overall improvement in quality of life in the chiropractic care group compared to the control group.
- “Chiropractic care had a significant effect on the PROMIS-29 domains of anxiety, depression, fatigue, pain intensity, and pain interference.”
7) Alpha rhythms are lower in individuals with chronic pain, compared with healthy controls.
- “In the current study, there were clear increases in Alpha power connectivity involving the frontal lobes.”
- “The Alpha power frequency changes found in this study likely reflect changes in pain perception in the chiropractic patients.”
8) The prefrontal cortex (PFC) plays a crucial role in executive functions.
- “Any alteration in prefrontal activity after chiropractic care could potentially elucidate or establish connections with the diverse enhancements in neural function.” [Very Important]
- Chiropractic adjustments altered proprioceptive input from the paraspinal tissues which may be powerful enough to alter processing within the PFC.
- Chiropractic adjustments may activate the descending pain inhibitory pathway.
- “It is well known that the descending modulatory pain pathway is malfunctional in chronic pain patients.”
9) “[This study supports] the notion that part of the mechanisms of chiropractic care is that it might improve the descending modulatory pain pathway in CLBP patients, and this may be why it has been found to be clinically effective for both acute and CLBP problems and is a recommended option in relevant clinical guidelines.”
- The HVLA adjustments of vertebral subluxations over the four weeks has likely altered the sensory stimuli coming from the spine.
- “Their internal narrative sense of self appears to have been altered over the four weeks of care, with changes in the emotional processing associated with internal and external stimuli which are influencing how they perceive themselves and the world around them, reflected by the reported decrease in fatigue, depression, anxiety, and pain.”
10) “Numerous previous studies have also reported enhanced quality of life and well-being following chiropractic care, possibly linked to reduced pain and improved mobility.”
- “Several studies have found quality of life improvements beyond just improvements in pain or pain related disability, similar to what has been documented in the current study.” [Important]
11) “Pain and pain-related diseases are considered to be the leading causes of disability and the greatest disease burden worldwide.”
- There is an association between depression and anxiety, and chronic pain.
- “Chiropractic care not only improved symptoms of pain and unpleasantness, but also resulted in improvements in fatigue, anxiety, and depression.”
- “Chiropractic care may potentially prevent pain from becoming chronic and the current study provides some insight into the mechanisms of this.” [Important]
- “Having ongoing maintenance chiropractic care (i.e., after the initial care period improves symptoms) results in less days of pain and improved QOL on an ongoing basis.”
- Long-term chiropractic care for CLBP may “significantly lower rates of hospitalisations, emergency department visits, advanced diagnostic imaging, specialist visits, lumbosacral surgery, interventional pain medicine techniques, i.e., a reduced escalation of care.”
- “Ongoing chiropractic care, even after the initial pain symptoms improve, will likely continue to impact somatosensory networks, …. thus maintaining positive neuroplastic changes that prevent such escalations of care, worsening of symptoms, and decreases in QOL.” [Very Important]
12) Possible Mechanisms:
- The contemporary model of the vertebral subluxation suggest that it can lead to abnormal multisensory processing and lead to poor motor control of the vertebral column and other muscles in the body.
- “The current findings provide compelling evidence for why chiropractic care, that includes the HVLA adjustments directed towards subluxated segments, can impact not only chronic pain symptoms, but also influence anxiety and depression symptoms.”
- There is evidence that proprioceptive input from the deep paraspinal muscles is essential for intervertebral motor control.
- “[A] change in proprioceptive input to the CNS may ultimately be responsible for the development and maintenance of musculoskeletal pain syndromes.” [Important]
- Over time, abnormal or reduced proprioceptive input from dysfunctional spinal regions (i.e., vertebral subluxations) would be capable of causing ongoing central maladaptive changes. [Very Important]
- “With ongoing poor motor control, as the CNS is less accurately aware of what is occurring at the vertebral column level (due to the reduced/abnormal proprioceptive inputs from that paraspinal region); this would likely lead to repeated microtraumas at the subluxated spinal levels as well as other areas of the body that require accurate sensory input from the spine, such as accurate upper and lower limb motor control.”
- “Over time, it makes sense that this could explain the development of chronic musculoskeletal pain problems.”
- “This contemporary model also explains how spinal adjustments, i.e., HVLA thrusts delivered to subluxated spinal segments, can improve vertebral column motor control by bombarding the CNS with mechanoreceptive input from the segments that are dysfunctional.” [Very Important]
- “Once the CNS is more accurately aware of the vertebral column, and it changes the body and world schemas, and therefore controls spinal movement better this will also naturally improve whole body perception and functions as well.”
- “This research contributes significantly to the scientific discourse on the mechanisms of chiropractic care, paving the way for further investigations into its holistic impacts on health and well-being.” [Key Point]
13) Conclusions:
- “Many health benefits of chiropractic care are due to altered brain activity.” [Key Point]
- “These results further our understanding of the multifaceted impacts of chiropractic care on various health parameters, as well as improving our understanding about the mechanisms for these changes.”
- “These results provide support for the contemporary model of the vertebral subluxation and help to explain how chiropractic HVLA adjustments impact the way the brain integrates both interoceptive and exteroceptive sensory information in a multimodal fashion, including the consideration of past memories and future expectations.” [Key Point]
- This study suggests that “chiropractic care alters a person’s narrative sense of self, that can enable that person to think, feel and function better.” [Key]
Comments From Dan Murphy:
Heidi Haavik and her team of researchers are publishing the most important neurophysiological research for the chiropractic profession, and I believe that all chiropractors should financially support their efforts:
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We have reviewed these other studies by Dr. Haavik:
Article Review 25-07:
Cervical Spine Manipulation Alters Sensorimotor Integration
Article Review 26-22:
The Potential Mechanisms of High-Velocity, Low-Amplitude, Controlled Vertebral Thrusts on Neuroimmune Function
