A muscle spasm could mean more than pain in your back — it could also hurt your ears.
Despite being the leading cause of disability worldwide, many people with lower back pain suffer in silence, unable to find relief.
And those with chronic back pain experience noise discomfort in different ways than those without pain.
They aren’t just annoyed by a car door slamming or a loud stereo; they actually feel sensory overload, according to a study from the University of Colorado Anschutz.
Published last week in the journal Annals of Neurology, the research is the first to understand how those with everyday pain process sound differently and more intensely, as well as an effective treatment.
Researchers compared self-reported and neural responses and MRI brain imaging in 142 adults with chronic back pain to 51 patients without pain.
While undergoing the MRIs, the participants were asked how unpleasant different everyday sounds felt and measured how strongly key brain regions responded.
The chronic pain patients had much stronger reactions to the sounds than 84% of those without pain.
The brain scans also showed stronger responses in the auditory cortex and insula, which process sound and emotional sensations, respectively, while seeing lower activity in the medial prefrontal cortex region that helps calm and regulate reactions.
Essentially, when someone is in pain, the brain is on high alert and “turns up the volume” on all sensory inputs, not just signals from the spine, so as not to miss anything.
“Their brains are responding differently, in regions that process both the loudness of sound and its emotional impact,” said senior author Yoni Ashar. “There’s a broader sensory amplification happening in the brain, and that opens the door for treatments that can help turn that volume down.”
The researchers then assigned those with back pain to one of three different treatments: pain reprocessing therapy (PRT) that teaches the brain to recategorize signals, placebo treatment of a saline injection or whatever current treatments they were using.
PRT was the most effective as it not only reduced heightened brain response to sound but also reduced activity in the regions that regulate unpleasant experiences.
Previous research has also found that PRT was successful in completely or nearly eliminating pain in two-thirds of participants with chronic back pain.
Evidence from the other groups also caused researchers to believe that those who are sensitive to light, sound or smell may be more susceptible to developing chronic pain after an injury.
“These findings add to growing evidence that chronic back pain is not just a problem in the back,” Ashar said. “The brain plays a central role in driving chronic pain, by amplifying a range of sensations — sensory signals from the back, sounds and likely other sensations as well.”
This research also raised the question of which came first, whether the increased sensitivity is a cause of chronic back pain or a pre‑existing vulnerability to develop chronic pain.
