Why Chiropractic Works: Research Explains Biology of Spinal Adjustments
Studies show that chiropractic can reduce musculoskeletal symptoms, and new research is beginning to explain why.
Musculoskeletal conditions like back pain and whiplash can affect your body's ability to sense itself and its surroundings. Sensorimotor integration describes how our brain organizes and processes information, allowing it to detect changes in the environment and in ourselves. Without proper sensorimotor integration, we wouldn't instinctively know how much effort to use when grasping or lifting an object, or where to turn when we hear a sound. In multiple studies, people with whiplash, fibromyalgia, neck pain, and back pain showed signs of sensory dysfunction, which has been linked to increased disability and pain.
Sensory dysfunction can cause a negative feedback loop in the way people process and experience pain. Joint dysfunction within the spine can alter how the central nervous system processes information, leading to poor muscle control and function, which increases disability and pain and contributes to more joint dysfunction.
Chiropractic spinal adjustments may disrupt this negative feedback loop to correct sensory dysfunction, according to a new study.(1) In the study, the authors analyzed 15 years of research investigating the effects of chiropractic spinal adjustments on sensory function.
Scientists can assess sensory function by using tests that measure sensory-evoked potential (SEP). The test involves placing small electrodes on a person's arm and legs which generate electrical signals. Electrodes are also placed on the person's head and spine that record how their central nervous system responds to these signals. This allows scientists to track how the brain transmits and processes information.
In three studies using these SEP tests in patients with neck pain, researchers found that spinal adjustments of the neck actually altered the nature of the electrical signals being fired off by the central nervous system. This suggests that that spinal adjustments do indeed impact how the central nervous system perceives and responds to pain.
In another study, patients with neck pain had reduced elbow joint positioning compared to healthy participants. Sensory dysfunction can impact your body's ability to sense the position of limbs and joints, also known as proprioception. After receiving spinal adjustments, the neck-pain patients had more accurate elbow joint positioning, suggesting improvements in proprioceptive processing.(2)
Sensory dysfunction can also affect motor control, or your body's ability to use muscles accurately. When performing a motion like throwing a ball, the central nervous system must activate several postural trunk muscles to help you maintain postural stability as you throw. Studies show that people with low-back pain have delayed reaction time when activating these muscles. In one study of people with back pain, chiropractic spinal adjustments reduced this delayed response time to improve muscle reflex and motor control.(3)
The authors suggested that chiropractic spinal manipulation may alter somasensory processing, sensorimotor integration, and motor control, which may correct sensory dysfunction in patients with musculoskeletal conditions. This could improve joint and motor function while reducing disability and pain. Although more research is needed to understand these complex biological processes, the findings suggests that changes in sensory function may be a central mechanism behind the pain-alleviating effects of chiropractic spinal adjustments.
In addition to altering the central nervous system, recent research suggests that chiropractic spinal adjustments can affect the immune system which may improve your response to inflammation and infection.
Reference
1. Haavik H, Murphy B. The role of spinal manipulation in addressing disordered sensorimotor integration and altered motor control. Journal of Electromyography and Kinesiology 2012; 22: 768-776.
2. Haavik H, Murphy B. Subclinical neck pain and the effect of cervical manipulation on elbow joint position sense. Journal of Manipulative Physiological Therapeutics 2011;34:88-97.
3. Marshall P, Murphy B. The effect of sacroiliac joint manipulation on feed-forward activation times of the deep abdominal musculature. Journal of Manipulative Physiological Therapeutics 2006;29(3):196-202.
