Sounds Are More Intense When You Have Chronic Pain

By Crystal Lindell

Throughout the day, whenever I hear something particularly high-pitched or loud, I will often turn to my fiancé and say, “Turn it down. That sound is literally causing me pain.”

He always obliges, but I know he’s skeptical. And I understand that my complaint doesn’t really make sense. 

However, new research seems to support my experience.

A study at the University of Colorado Anschutz School of Medicine, published in the Annals of Neurology, found that people with chronic pain are significantly more sensitive to sound.

For the study, researchers recruited 142 adults with chronic back pain and 51 healthy people who were pain free. While receiving MRI brain imaging, both groups had mechanical pressure put on their bodies to stimulate pain, while being subjected to annoying sounds. Participants were then asked to rate how unpleasant the experience was.

The differences in responses between chronic pain patients and healthy controls was significant. On average, back pain sufferers reacted more strongly than 84% of people without pain.

The researchers also looked at brain activity during the experiments. The MRI scans showed stronger responses in brain regions that process sound (the auditory cortex) and emotional sensations (the insula). There was lower activity in regions that normally help calm or regulate emotions, like the medial prefrontal cortex.

Interestingly, the results overlap with other studies showing how patients with fibromyalgia react to painful stimuli.

"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,” said senior author Yoni Ashar, PhD, Co-Director of the Pain Science Program at the Anschutz School of Medicine. 

“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." 

The researchers wanted to see which treatments could help reduce the brain’s response to noise. The pain patients were broken up into three groups that received either Pain Reprocessing Therapy (PRT), a placebo saline injection, or the usual care they were already getting for back pain. 

PRT is a type of mindfulness therapy, in which patients are encouraged to think differently about their pain in order to minimize it.

Out of all the treatments, PRT was the most effective. It reduced the heightened brain response to sound and increased activity in brain regions involved in regulating unpleasant experiences. But the effect was only minimal.

"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 – such as sensory signals from the back, sounds and likely other sensations as well," said Ashar.

Overall, it’s great to see research like this validating what I know is a common experience for chronic pain patients.  

However, I do think there may be some “chicken and the egg” issues with this study. Which comes first: sensitivity to sound or back pain?

Maybe people who are more sensitive to sound are more likely to develop chronic pain. In other words, does the pain cause sound hypersensitivity, or does hypersensitivity cause the pain? 

Ashar and his research team plan further studies of senses other than hearing — such as light, smell or taste — to see if chronic pain causes sensitivity to those stimuli and how brain regions respond to them.

Scientists Use Light and Sound to Reduce Pain

By Pat Anson, Editor

British researchers have found that pain can be significantly reduced if the brain if “tuned in” to a particular frequency, a discovery that could potentially lead to new visual and sound therapies to treat chronic and acute pain.

"This is very exciting because it provides a potentially new, simple and safe therapy that can now be trialed in patients,” said Professor Anthony Jones, director of the University of Manchester Pain Consortium. “The potential is for this to be another treatment for chronic pain.”

Jones and his colleagues say nerve cells in different parts of the brain communicate with each other using different frequencies.  

Nerves in the front of the brain associated with a placebo analgesic effect are tuned in at 9-12 cycles per second, and apparently use that frequency to influence how other parts of the brain process pain.

To test their theory, researchers had 64 healthy volunteers wear goggles and headphones, and exposed them to different flashing lights and sounds while heat pain was induced with a laser on the back of their arms.

The volunteers who were exposed to an alpha frequency at 9-12 cycles felt significantly less pain than those who were exposed to other light and sound levels.

“This study provides new evidence that visual and auditory entrainment in the alpha range can influence the perception of acute pain independently of arousal and negative emotional influences,” the researchers said. “Overall, visual entrainment produced a larger effect than auditory entrainment in the mid- and lower alpha frequencies. This provides further evidence that external stimulation can modulate pain perception and requires further study to ascertain its relevance to clinical pain states.”

Further studies are needed to test the effectiveness of alpha wave therapy in patients with different pain conditions. Researchers say the simplicity and low cost of the technology should facilitate more clinical studies.

"It is interesting that similar results were obtained with visual and auditory stimulation, which will provide some flexibility when taking this technology into patient studies,” said Dr. Chris Brown, a lecturer in Psychology at The University of Liverpool who was involved in the research. “This might be particularly useful for patients having difficulty sleeping because of recurrent pain at night."

The study, which was self-funded as part of a PhD project, is being published in the European Journal of Pain.