Why does chronic back pain make everyday sounds feel harsher? Brain imaging study points to a treatable cause

(Press-News.org) People with chronic back pain process everyday sounds differently, and more intensely, than people without pain, according to new research from the University of Colorado Anschutz.

Published today in Annals of Neurology, the study is one of the first to tie this sound hypersensitivity to specific, measurable changes in the brain, indicating that chronic back pain affects far more than the back. The research also shows there’s an effective treatment that can help.

“Our findings validate what many patients have been saying for years that everyday sounds genuinely feel harsher and more intense. Their brains are responding differently, in regions that process both the loudness of sound and its emotional impact. This tells us chronic back pain isn’t just about the back. There’s a broader sensory amplification happening in the brain, and that opens the door for treatments that can help turn that volume down,” said the paper’s senior author Yoni Ashar, PhD, assistant professor of internal medicine and co-director of the Pain Science Program at the University of Colorado Anschutz School of Medicine. 

The researchers compared self-reported and neural responses in 142 adults with chronic back pain relative to 51 pain-free controls. All participants, including controls, underwent brain imaging. During the MRI session, the researchers had participants do several tasks, such as listen to sounds while the researchers asked participants how unpleasant the sounds felt and measured how strongly key brain regions responded.

The differences between chronic pain patients and healthy controls were large. The researchers found on average, they reacted more strongly than 84% of people without pain.

The also found in the scans that changes were not happening in the initial auditory processing areas but were happening higher up in the brain. In particular, the scans showed stronger responses in regions that process sound (the auditory cortex) and emotional sensations (the insula). At the same time, they saw lower activity in brain regions that normally help calm or regulate reactions, like the medial prefrontal cortex.

The researchers also looked at treatment options and assigned participants with chronic back pain to one of three groups:

Pain Reprocessing Therapy (PRT) – therapy sessions designed to help people reinterpret pain as due to brain amplification rather than just back problems. Placebo treatment – a saline injection delivered within a supportive, clinical setting. Usual care – participants continued whatever treatments they were already using. They found that out of all the treatments, Pain Reprocessing Therapy was the most effective. It not only reduced the heightened brain response to sound but also increased activity in brain regions involved in regulating unpleasant experiences.  

“This shows that the brain’s exaggerated sensory response can improve with psychological treatment so instead of being something patients are stuck with, this sensitivity is treatable,” said Ashar. “These findings add to growing evidence that chronic back pain is not just a problem in the back, 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.”

Past research from Ashar found that Pain Reprocessing Therapy led two thirds of participants with chronic back pain to become pain‑free or nearly so after treatment, far outperforming the roughly 20% improvement seen in the placebo group.

The research also raises several important questions, including whether this heightened sensitivity is a cause of chronic back pain or a pre‑existing vulnerability to develop chronic pain. Early evidence from other groups suggests that people who are naturally more sensitive to sensory input may be more likely to develop chronic pain after an injury. It also remains unclear whether the amplification extends to other senses, such as light, smell or taste, or whether this happens with other chronic pain conditions. They say their next study will test sensitivity across additional senses to determine how widespread this amplification truly is, and whether one central brain regions may be responsible for this amplification across the senses.

About the University of Colorado Anschutz
The University of Colorado Anschutz is a world-class academic medical campus leading transformative advances in science, medicine, education and patient care. The campus includes the University of Colorado’s health professional schools, more than 60 centers and institutes, and two nationally ranked independent hospitals - UCHealth University of Colorado Hospital and Children's Hospital Colorado - which see nearly three million adult and pediatric patient visits each year. Innovative, interconnected and highly collaborative, CU Anschutz delivers life-changing treatments, exceptional patient care and top-tier professional training. The campus conducts world-renowned research supported by $890 million in funding, including $762 million in sponsored awards and $128 million in philanthropic gifts for research.

 

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