CHRONIC PAIN CHANGES BRAIN STRUCTURE AND FUNCTION

From a recent seminar I gave late-April at the American University of Beirut. Full text below:

The brain may suffer serious, structural and functional damage as a result of persistent chronic pain that does not respond to traditional medicinal therapy, Dr. Carl Saab, assistant professor of neuroscience and neurosurgery at Brown University, explained April 27, 2012 during an AUB seminar titled, “Brains Suffer from Pain.”

Saab said that a collection of recent studies revealed a correlation between chronic pain and changes in brain structure in tested patients. Previously, chronic pain was treated as a secondary symptom that had no, or benign effects on neurological structures.

“Such evidence has challenged us to rethink the concept that chronic pain is a disease entity by itself,” he said.

The discovery of correlations between pain and brain function could help researchers tap into novel diagnostics, Saab explained, whereby researchers could use methods of visualization of brain activity to reach an accurate diagnosis.

One obvious method involves the use of functional magnetic resonance imaging (fMRI), which scans the brain to map neural activity.

“Based on imaging data, we can conclude that certain brain regions are consistently activated in patients with chronic pain according to a reproducible, predictable pattern,” he said. “All of these regions are shown to be overactive or hyperactive, using fMRI, and are therefore referred to as the brain’s ‘neuromatrix’ for pain.

A second method of visualization uses electrophysiology, which measures the electrical activity of neurons at the highest temporal and spatial resolutions possible. One benefit of this method for researchers is that it can be tested on both humans and animals; it is also cost-effective and practical. This type of technology has similarly revealed a reliable correlation between pain and brain function, manifesting as measurable brain rhythms that shift under pain conditions.

But despite these correlations, Saab cautioned that all evidence was circumstantial and that scientists have yet to discover a 100-percent predictable diagnostic due to inherent technical limitations and the subjective nature of pain. So far, verbal reporting by the patient remains the gold standard for evaluating pain in humans.

– Carl

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