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17 Articles in Volume 19, Issue #7
Analgesics of the Future: Inside the Potential of 3 Drug Delivery Systems
Balancing Pain Care - and Opioids - in the Aging Adult
Book Review: A Useful Guide for New Pain Practitioners
Correspondence: Opioid Tapering & Discontinuation
Effective Interventions for Post-Stroke Shoulder Subluxation and Pain
Family: Their Role and Impact on Pain Management
Introducing the "Phoenix Sign:" Improved Vascular Perfusion of the Dorsalis Pedis Artery after a Subanesthetic Dose of Lidocaine
Medication Management of Chronic Pain in Patients with Comorbid Cardiovascular Disease
Multisite Pain May Be Associated with Fractures in the Elderly
Reconciling the New HHS Opioid Tapering Guideline with CDC and State Policies
Research Insights: Impaired Motor Imagery in Chronic Pain Conditions
Tapentadol: A Real-World Look at Misuse, Abuse, and Diversion
Temporomandibular Disorders in Performance Artists (Part 2)
Thoracic Outlet Syndrome Presenting as an Acute Stroke Mimic
Untangling Chronic Pain and Hyperarousal with Heart Rate Variability: A Case Report
What topicals exist for post-herpetic neuralgia pain?
When to Keep Your License: Older Physicians and Boundary Issues

Research Insights: Impaired Motor Imagery in Chronic Pain Conditions

Patients with chronic pain affecting the face and limbs demonstrated impaired motor imagery, but findings are not as clear-cut for head and neck pain.
Pages 49-50

with John D. Breckenridge, PhD and Gabriel Sella, MD, PhD, MPH, MSc

In the US, individuals aged 65 years and older currently number 35 million, or approximately 13% of the population.1 Musculoskeletal (MSK) pain in this group is common, as it is estimated that 1 in 4 older adults will suffer from chronic nonmalignant MSK pain.2 These conditions may include degenerative changes related to osteoarthritis, chronic joint pain of upper and lower extremities, low back pain, fibromyalgia, and myofascial pain.

With chronic MSK pain comes impaired motor imagery, particularly in those with peripheral pain conditions affecting the face and limbs, according to research by John D. Breckenridge, PhD, an Australian physiotherapist, and his team at the University of Sydney Faculty of Medicine and Health. However, in those who suffer from axial pain conditions (such as those affecting the head and neck), the relationship is not as clear-cut. These findings come from a comprehensive systematic review and meta-analysis3 of 25 studies representing 2,266 participants with a variety of chronic pain conditions that Dr. Breckenridge and his colleagues conducted. The studies explored left/right body part judgment tasks (LRJTs).

The peripheral pain conditions represented in Dr. Breckenridge’s review included complex regional pain syndrome (CRPS), upper limb fracture, carpal tunnel syndrome, phantom limb pain, brachial plexus avulsion, osteoarthritis, inflammatory arthritis, and upper and lower limb pain from various causes. Axial pain conditions included chronic back and neck pain.

Patients with chronic pain affecting the face and/or limbs demonstrated impaired motor imagery, but findings are not as clear-cut for spine and neck pain. (Source: 123RF)

Using LRJT to Measure Motor Imagery Performance

“The LRJT has been used in neuropsychological studies for several decades, and a large body of evidence points to it being a good measure of motor imagery performance,” Dr. Breckenridge told PPM. These tasks require participants to view images of a body part and identify which side of the body each image belongs.Slower and inaccurate responses often represent signs of altered proprioception (the mental image of the body in space), which may be linked with chronic pain.

“Until now, no comprehensive systematic review has been performed to pool the findings across multiple chronic pain conditions,” Dr. Breckenridge said, adding that gleaning a better understanding of the relationship between LRJT and different types of chronic pain may help clinicians develop more effective treatment plans.

At the heart of the pain-to-LRJT relationship, he noted, is that the time it takes for a person to mentally envision moving a body part to match the image provided in LRJT corresponds with the time it takes for that person to perform the corresponding physical movement. In other words, for individuals with biomechanical constraints in their physical actions (which often includes the elderly), LRJT results reported in the literature have shown a corresponding delay in their central processing, when compared to “healthy” or “pain-free” people, he explained.

The meta-analysis showed that chronic MSK pain overall was associated with decreased motor imagery performance as measured by LRJT; individuals with chronic musculoskeletal pain were slower and less accurate at the LRJT than pain-free controls, and were slower and less accurate at recognizing images that correspond with the side of their painful body part than with their pain-free body part.

The meta-analysis also indicated important subgroups associated with peripheral and axial pain conditions:

  • The CRPS, upper limb, lower limb, and facial pain subgroups demonstrated moderate to large effects on the speed and accuracy of the LRJT compared with healthy control participants and to their nonpainful control body part.
  • The speed of LRJT performance in people with chronic neck and back pain was largely not different from the speed of healthy people, and the accuracy of LRJT performance in people with chronic neck pain was no different from that in normal people. The back pain subgroup demonstrated no effect on LRJT speed or accuracy compared with their nonpainful side.

Possible Explanations for Impaired LRJT Findings

In terms of how it works, “one theory is that when pain is persistent, otherwise pain-free stimuli becomes associated with pain—for example, moving a sore joint in a pain-free range becomes associated with pain, [moving the] joint more cautiously or slowly,” Dr. Breckenridge said. This is reflected in the LRJT because “we use similar mental processes to complete the task as we do when we move our limb to match the image.”

Gabriel Sella, MD, PhD, MPH, MSc, of the Ohio Valley Medical Center in Wheeling, WV, described another scenario. “If there is a brain injury—for example, a concussion—the proprioceptionmay be affected first, with the results that the position of the limbs or axial skeleton is reacting more slowly than in a healthy person,” he said.

Dr. Sella, who serves on PPM’s Editorial Advisory Board, also suggested that the differences in how different areas of pain affect proprioception may account for variations in the LRJT results. “Any injury that affects the capsules in the joints will affect proprioception,” he said, pointing out that the limbs have many more such “relays” than the axial skeleton.

Questions Remain Regarding Peripheral and Axial Pain Responses

“The body creates an engram [mental picture] in the brain of the limbs, trunk, face, or neck very early in life [with the right and left strongly engrained]. The more we use the movements needed to create a function, the stronger the engram gets. Obviously, we do more ‘movement’ with the limbs and the face than with the neck or trunk,” Dr. Sella noted, which could help explain why there wasn’t a clear correlation with LRJT results and axial pain conditions.

Dr. Breckenridge offered another possible explanation for the lack of consistent evidence: “Back and neck pain can be one-sided, central, affect both sides, or it can change over time. This may have made the overall pooled effect inconsistent, so it could be that chronic spinal pain does affect motor imagery, but the inconsistencies mean it is difficult to capture a clear picture.”

Another potential reason for the differences in findings among peripheral and axial pain conditions may have to do with the meta-analysis itself, which includedmany more peripheral studies than axial studies, meaning there may not be enough data available to gain meaningful insight, Dr. Breckenridge said. He pointed out, however, that the evidence may change over time as more research becomes available. “It could also be that the current LRJT tests for axial conditions are not sensitive enough,” he added.

While this leaves clinicians with inconclusive results for axial conditions, Dr. Breckenridge stressed that for practitioners treating peripheral pain, the findings may be especially helpful. Patients with peripheral conditions may benefit “from using graded motor imagery [that includes LRJT as well as mirror therapy]. This treatment aims to restore disrupted body schema [a collection of integrated body maps held in the brain that assist with movement] and has proven useful in the treatment of CRPS and chronic upper limb pain,” Dr. Breckenridge said. (More on the management of CRPS).

Dr. Sella added that, “Another possible treatment for clinicians to consider for people presenting with peripheral pain is surface electromyography (SEMG)-assistedbiofeedback [a treatment that incorporates visualization] to restore the disrupted body schema. I have found this to be a very useful restorative method for proprioception loss.”  He also stressed that the overall takeaway of thisreview for clinicians is to “pay more attention to the presence of proprioception dysfunction in any injury, especially that of the limbs. This needs to be considered both at the diagnostic time and also at the rehabilitation period.”


This article was originally published online in October 2019 and later printed in the PPM November/December 2019 issue.

Last updated on: December 9, 2019
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