Case studies utilizing Dynamic sEMG and range of motion

Published: 2009-07-21 11:51:08
Author: David Marcarian | Chiropractic Economics | July 8, 2009

As a data-driven society, we have come to expect technology to be used for everything from diagnosing issues with our cars, to the use of the cardiologist’s EKG for detecting issues with the heart.

In chiropractic, we too have the technology to establish the presence or absence of spinal issues. The chiropractic tool of choice is the combined Dynamic sEMG and range of motion testing known as “DynaROM sEMG.”

According to a recent published study, (Geisser et.al. 2005, “A Meta-Analytic Review of Surface Electromyography Among Persons with Low Back Pain and Normal, Healthy Controls”, Journal of Pain, November 2005 p 711-726) combining Surface EMG and range of motion increases sensitivity and specificity significantly.

Why? Surface EMG allows us to see the “bracing and guarding” which occurs when there is limited range of motion. In addition, we’ve found clinically, that those with good range of motion can also demonstrate abnormal bracing and guarding showing that range of motion on its own is extremely limited without Surface Electromyography (sEMG).

By presenting objective, computer-based physiologic data to support your position, no longer does an MD have the upper hand in court, as the focus shifts from opinion to data, a surefire method of establishing credibility. Traditionally, the only reason attorneys give for avoiding working with DCs in soft tissue cases, is the lack of objective data typically provided. Instrumentation levels the playing field, driving attorneys to you.

Basic principle of operation
The principle is simple: A truly injured patient would most likely demonstrate limited range of motion. When experiencing pain, it is a natural defense mechanism for the muscles to brace and guard and demonstrate limited range of motion.

Surface EMG effectively measures the muscular bracing and guarding one would expect with soft tissue injury. If there is little or no muscular bracing and guarding as measured with the Surface EMG, it would lead the doctor to conclude the patient may be a symptom magnifier.

Conversely, if muscular bracing and guarding occurred concurrently with limited range of motion, this would support the claim of injury. A new case is emerging clinically which is the patient with normal range of motion, which demonstrates muscular bracing and guarding on the sEMG. This unique case is becoming seen more often clinically, and provides evidence of soft tissue injury even when range of motion is normal.

Example 1: Normal Range of Motion with Normal Dynamic sEMG
This is an example of how a patient who was not claiming pain or injury at all, bending into full flexion shows a completely normal range of motion and normal dynamic sEMG. The range of motion data is graphed in red at the bottom of the graph, with the left (blue) and right (red) lumbar DynamicsEMG graphed in the top graph. What is unique is how one can see clearly graphed, not only the end point range of motion, but precisely how the patient was moving when bending forward (you sometimes see “ratcheting” in the test results as a response to pain). Muscles are supposed to relax in flexion (known as the flexion-relaxation response) which is what you see in this study at marker 1, 3, and 5. The Flexion-Relaxation Response has been documented in a multitude of studies since the mid 1960s.
 
Example 2: Normal Range of Motion, with Abnormal Dynamic sEMG
This patient was tested six months after an automobile accident. They were seen over a six month period and received a typical protocol of chiropractic care, and some physical therapy. What is unique about this is how a patient can have what is considered a normal range of motion while still displaying abnormal dynamic sEMG data.

What does this mean? Adding Dynamic sEMG (guarding and bracing) to range of motion significantly improves the tests sensitivity and clinical relevance. It prevents a seasoned attorney from attacking you for not knowing what degree of flexion the patient was in while testing Dynamic sEMG, and at the same time, shows how muscles have responded in limited range of motion studies.

Example 3: Symptom Magnifier
This patient sought chiropractic care after a minor rear-end collision. She claimed difficulty performing both left and right lateral flexions in the cervical spine.

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