NCCIH Research Blog

The U.S. Centers for Disease Control and Prevention has recommended nonpharmacologic approaches for managing chronic pain. Manual therapies (MT) are a domain within nonpharmacologic approaches and include massage, spinal manipulation, joint/spine mobilization, and connective tissue stimulation. During the upcoming International Congress for Integrative Medicine and Health (ICIMH), NCCIH will host a symposium to examine the scientific basis for manual therapies and focus on their use in treating chronic pain conditions.

Based on prior clinical studies, it’s clear that treatment response to different manual therapies varies among individuals. Some people respond especially well to a specific type of manual therapy, while others may not respond at all or even experience negative effects. What is the scientific basis for these differences and how can clinicians select the most efficacious treatment and maximize its positive effects? These important questions are magnified given the current, national prescription opioid epidemic and the need for effective, nonpharmacologic approaches to treat underlying pain conditions. MT could be alternatives to, or reduce the need for, prescription opioids.

To help answer these questions, we must first understand how MT work to exert their effects. The mechanisms by which MT reduce pain are not well established. Historically, local and segmental responses (e.g., in tissue, structure) to MT were considered responsible for the clinical benefit. This biomechanical approach could not explain the presence of nonsegmental hypoalgesia and autonomic function changes (e.g., heart rate), bringing attention to neurophysiologic responses to MT. However, there is little consensus on the extent to which MT modulate and/or modify neurophysiologic responses in the peripheral and/or central nervous system (i.e., brain and spinal cord), nor how such responses might reciprocally affect peripheral tissues and/or immunologic processes.

What do we know about the effects of MT on the peripheral and central nervous system? There is evidence that MT affect the interaction between inflammatory mediators and peripheral nociceptors in response to injury. In addition, changes in spinal excitability following MT, as indicated by decreased nociceptive flexion reflexes and reduced temporal summation, represent evidence for reduced facilitation and increased inhibition of nociceptive input as mediated by central descending pain modulatory systems. Still, direct evidence for spinal or cortical changes are weak and whether the central nervous system plays a dominant or secondary role is unknown.

In the NCCIH-sponsored symposium at ICIMH (Friday, May 11 from 3:00 to 4:15 pm), we’ll explore theoretically-based neuroscience research that focuses on elucidating the peripheral and central neural mechanisms of MT to facilitate the development of individualized mechanism-based pain management. We have invited experts in the field to present and discuss possible theoretical frameworks and scientific findings in support of peripheral and/or central mechanisms of MT:

• Dr. Mark Bishop will introduce a theoretical and testable framework of the mechanisms of MT.
• Dr. Helene M. Langevin will discuss the evidence and importance of peripheral mechanisms of MT.
• Dr. William Reed will present evidence and the importance of central mechanisms of MT.
• Dr. Laura Case will present research related to the sensory-affective neural mechanisms of massage.

If you attend this session at ICIMH, you’ll be able to interact with the presenters after the last talk and discuss your ideas for research with fellow clinicians, physiologists, and neuroscientists.

I also welcome you to contact me (merav.sabri@nih.gov) with questions or to schedule a meeting to discuss your research ideas on this topic.