Sound can suppress pain: new research shows how
A new study has identified how sound blunts pain. Using state-of-the-art brain imaging, an international team of researchers has discovered the neural mechanism through which sound numbs pain. Interestingly, lower volumes were more effective than loud music.
We have known for years that music and other sounds can help suppress pain. In fact, medical practitioners have been using soft music as analgesia during dental and medical surgery, labor, and other chronic pain. In 1960, Wallace Gardner published a study describing how he used sound for pain relief while conducting tooth extractions. Many researchers have been studying and using the phenomenon since then.
There were hints that the brain was at play. However, the neural mechanism of how sound numbs pain was unclear—until recently.
To find out how the brain produces pain relief in the presence of sound, an international group of researchers studied mice with inflamed paws. They introduced the mice to three kinds of sounds:
- A pleasant piece of classical music
- Unpleasant rearrangement of same classical music
- White noise
Surprisingly, all kinds of sounds generated similar levels of pain relief. This is in contrast to what we thought, that only melodious sound can help suppress pain. More interestingly, the researchers discovered that intensity was key, not pleasantness. Sound worked as an analgesic only when the volume was like a whisper, and not when it was raised.
But the big question remains: what was really happening in the brain?
Using advanced techniques, the researchers identified the neural circuit through which the auditory cortex conveys sound signals to the thalamus, which also receives pain signals. Low-intensity sound reduces the activity of the receiving neurons in the thalamus, thereby numbing the sense of pain.
Other methods of treating pain by suppressing activity in this pathway resulted in the same pain-relief outcomes. Undoubtedly, this suggests the research has finally identified the neural mechanism through which sound numbs pain.
The findings more or less validate Gardner's study, which surmised that music numbed pain by hindering communication between the auditory system and thalamus.
Although the study was conducted on mice, the findings may apply to humans. This could help to develop safer treatments for pain.
The study is relevant because it opens up a world of opportunities to develop safer pain treatments. With sound treatment/therapy for pain, we will worry less about opioids and addiction.
How sound numbs pain explained at last
In summary, low-intensity sound numbs pain by disrupting signals between the auditory cortex and thalamus, thereby toning down pain processing in the thalamus. And luckily, the pain-relieving effect of sound lasts well beyond the sound itself.