Neuroimaging in Chronic Pain Management

Neuroimaging: Applications in Chronic Pain Management – Helen Fosam, PhD – August 30, 2016

Pain is a complex emotion with a wide spectrum of sensations spanning from extreme acute physical pain to emotional psychological pain.

Any person suffering from pain feels it as a sensation, not an emotion, so this sentence already betrays unreasonable assumptions or prejudice.

Perhaps researchers are confused on this issue because they’ve been brainwashed to believe our pain is “in our heads” like any other emotion.

Several factors contribute to the challenges of optimal pain management, including poor understanding of pain pathology, and the adoption of a ‘one size fits all’ treatment strategy. 

It has been clear for decades that all but the simplest medical problems cannot be managed with a “one size fits all” treatment because people are literally not the same, outside or inside.

The recent “Precision Medicine Initiative” is proof that this is an acknowledged fact, yet in pain research, these differences are routinely ignored, especially by the CDC and the anti-opioid lobby.

Seminal work investigating mechanisms of placebo analgesia showed the central role of the brain in pain processing.

The literature suggests that multiple brain regions play a pivotal role in pain processing

The endogenous opioid system and its activation of µ-opioid receptors are thought to mediate the observed placebo effects

Functional magnetic resonance imaging and PET studies have identified a distributed neural network in the brain involved in the sensory-discriminative aspect of pain, as well as its cognitive and affective/emotional factors

The pain matrix region -which includes the somatosensory cortices, and the anterior cingulate cortex and insula- is activated not only by a specific physical pain stimulus, but also by sensory stimuli such as flashes of light or sudden loud noise, as well as emotional experience such as social rejection and empathy for or memory of pain

This could be because they may have defined the “pain matrix” to already include sites that are activated by the same pain stimulus.

Pain sensation is only part of the body’s response to physical injury, it would be impossible to isolate a “pain matrix” to only the parts of the brain activated by a nociceptive stimulus.

See We Cannot Explain Pain with Brain Scans

An algorithm based on machine-learning techniques has been used to develop a neurological signature of pain that is sensitive enough to distinguish painful heat from non-painful heat; actual pain from anticipation or recall of pain, and physical from emotional pain

In fact, the brainstem region that processes pain when an individual is distracted has been identified; this knowledge may help distinguish acute pain from chronic pain or one’s vulnerability to transition from acute to chronic pain

Neuroimaging studies have been used to show functional and anatomical differences between the brains of individuals with chronic pain and those with acute pain, and this has led to the first longitudinal brain imaging study of chronic pain

More recent studies document cellular changes in gross brain anatomy in individuals with neuropathic and chronic pain.

Based on the current advances, is it then possible to apply neuroimaging techniques clinically to more accurately treat different pain sensations, and thus provide an alternative approach to targeted chronic pain management? In theory, yes, but with caution, according to Karen Davis, PhD, Neuroscientist at the University of Toronto.

“Using a vascular-based technology has issues that people haven’t been considering.

Getting this right will be crucial if brain imaging is going to play a part in evaluating pain.

The use of the technology is getting ahead of itself, and there are enormous legal and neuroethical implications.”

emerging data are inconsistent, especially given the fact that some drugs can change the vascular architecture and function, and thus the fMRI signal without changing brain activity.

the value of neuroimaging as a potential treatment modality, especially to improve the management of chronic pain is well recognized.

This is reflected in the task force initiated in December 2015 by the International Association for the Study of Pain, to develop guidelines on neuroimaging, determine it accuracy and reliability, and the ethical considerations surrounding its use.10

Summary and Clinical Applicability

These advances with neuroimaging are clinically valuable, particularly for personalizing the management of chronic pain, reducing the risk of misuse and abuse and managing pain in individuals who cannot feel or express their pain.

However, clinical integration of neuroimaging techniques in pain management must wait for the development of standardized techniques with proof of accuracy and reliability, guidelines, and the clarification of the ethical considerations surrounding its use.  

Because individuals can sometimes be more different than alike, determining pain by brain scan images could be based only tested and approved types of pain with known brain signatures.

Having already been a medical outlier all my life, I suspect that whatever brain pattern they decide to use to determine pain will not apply to me.

Just like spinal MRIs can show horrific misconfigurations and damage without a patient feeling pain and can be normal in a patient with terrible pain, I do not trust scans to reveal the final truth about pain.

A brain scan cannot tell them anything about my pain that I cannot tell myself, so it would  be used only if I’m being suspected of lying about it.

See Self-reported pain more reliable than fcMRI data

For more on the topic of imaging pain, see the blog tag “imaging”:
https://edsinfo.wordpress.com/tag/imaging/

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