Editor’s note: At the 2018 World Congress on Pain in Boston, the biennial meeting of the International Association for the Study of Pain (IASP), researchers from around the world gathered from September 12-16 to discuss the latest pain research. This report, contributed by pain researcher and freelance writer Lincoln Tracy, summarizes a session that took place at the meeting on the topic of music and its potential as a treatment for pain. (RELIEF’s news coverage is editorially independent of its publisher, IASP. All editorial decisions about our reporting on IASP activities are made solely by the RELIEF editors).
People listen to music for many reasons—for the memories it evokes, to make a workout more enjoyable, perhaps for a boost of energy in the morning, the list goes on—but can music also be used to relieve pain?
Three talks during a workshop at the 2018 World Congress on Pain discussed the idea of using music to improve brain health, and particularly music’s potential as a treatment for complex conditions such as chronic pain.
The first talk, by Catherine Bushnell from the National Center for Complementary and Integrative Health, part of the US National Institutes of Health, gave an overview of how different parts of the brain respond to pain, and to relief of pain, providing the necessary background to understand how music might affect the brain during chronic pain.
The second talk, by Robert Zatorre from McGill University, discussed how the brain responds when people listen to music, and the role of the brain’s reward system in that response.
The third talk, by Joke Bradt of Drexel University, described clinical research investigating various forms of music therapy for management of chronic pain, reporting promising findings from a study she and her colleagues ran to test the effects of vocal music therapy on pain.
The workshop revealed that music activates the same reward centers in the brain that food, sex, and pain-relieving medications do. This knowledge could be used to help the millions of people throughout the world living with chronic pain.
How does the brain create an experience of pain?
To understand the potential effects of music on pain, it’s first necessary to know what happens in the brain during pain. Bushnell began her talk by describing the many neural pathways—connections between different areas of the nervous system—that control how people receive, interpret, and react to painful stimuli.
Take a hand’s accidental touch of a hot stove as an example. In this case, ascending neural pathways send information, in the form of electrical signals, from the hand, up the arm and into the spinal cord, which then relays the signals to a brain area called the thalamus. From there, the signals reach the cerebral cortex, which carries out higher brain functions and includes regions whose activity researchers have linked to chronic pain, including the insular cortex, anterior cingulate cortex, and somatosensory cortex.
Each of these brain areas is involved in a different aspect of the experience of pain. For example, the insular cortex regulates the emotional aspects of pain, whereas the somatosensory cortex is responsible for the intensity, location and duration of pain.
Descending neural pathways from the brain to the body then modulate the pain, making it better or worse. The higher cortical regions such as the anterior cingulate cortex and insula send the signal down to the brainstem, which includes structures such as the periaqueductal grey and the rostral ventromedial medulla. These structures then relay signals down the spinal cord and back to the arm and hand, where everything was originally set in motion upon touching that hot stove, enabling one to pull the hand away.
Because of their important role in modulating pain, the descending pathways are a common target for many pain relievers, including opioids, which affect different parts of those pathways.
How can psychological factors change pain perception?
Psychological factors, which Bushnell and her lab study, also affect the descending pain pathways to increase or decrease pain. Studying the effects of these factors on pain perception points the way toward understanding how music affects the brain and chronic pain.
Take attention/distraction, for instance. Many studies have shown that distraction—via movies, virtual reality, mathematical tasks, and even pleasant music—relieves pain.
And there is a strong link between attention/distraction and emotion. For instance, listening to pleasant music is not only distracting, but also makes a person feel good. Despite this overlap, though, emotion and attention control pain in different ways.
Bushnell went on to explain how, in laboratory experiments, researchers often ask people to rate their pain in two dimensions. The first dimension is the physical sensation—how strong the pain is. The second dimension is more about the emotional aspect of pain—how unpleasant the pain is. Research shows that distraction can change the intensity of the pain, but not how unpleasant the pain is. In contrast, changing one’s emotional state alters how unpleasant the pain is, with no effect on the intensity.
Why is this so? It turns out that changes in attention alter the activity of certain parts of the ascending and descending pain pathways, while changes in emotion alter different parts of those pathways.
Given music’s ability to distract—and to change a person’s emotions— music’s potential to influence pain perception seems real.
What’s different in people with chronic pain?
Numerous studies show that people with chronic pain have disruptions in regions of the brain that modulate pain. These disruptions often include changes in brain size, as well as changes in the connections between different regions of the brain.
Furthermore, chronic pain also alters the brain’s chemical signaling system. For instance, people with chronic pain show decreased levels and effectiveness of endogenous opioids—the brain and body’s natural morphine-like chemicals—and of dopamine, a key component of the brain’s reward system.
Evidence suggests that those suffering from chronic pain also have muted responses to other sensations. In a study from Bushnell’s laboratory, researchers used a paintbrush to stroke people’s hands at different speeds, and found that fibromyalgia patients were less accurate at distinguishing one speed from another. This suggests that people with fibromyalgia have a subdued response to touch, in addition to an increased sensitivity to pain.
Fibromyalgia patients also have altered emotional responses to odors, rating nice-smelling odors as less pleasant and bad-smelling odors as more intense and unpleasant, compared to people without pain. Something similar is seen regarding sound, where people with fibromyalgia rate lower-decibel sounds as more painful and unpleasant compared to pain-free individuals. This is an important finding as it implies that people with chronic pain may have different responses to listening to music compared to pain-free individuals.
Bushnell ended her talk by reminding everyone that music may modulate pain through changes in attention as well as emotion. However, she said that while researchers have learned a lot about how music affects pain perception, they know less about how pain affects enjoyment of music.
Making a sound
Zatorre started his talk by describing a part of the brain called the auditory cortex, which is located not too far from the ears, on the left and right sides of the brain. The auditory cortex encodes information about pitch—how high or low a note is—allowing for identification of different notes or sounds.
There are two neural pathways in the brain closely associated with the auditory cortex. The ventral pathway, which projects from the auditory cortex towards the front of the brain, is important in encoding features and patterns of sound. This pathway also plays an important role in predicting patterns of sound.
The dorsal pathway, which goes from the auditory cortex towards the back of the brain, engages memory and combines sensory and motor actions—like moving the hands, mouth and vocal cords—to help produce sound.
The pleasure of music
While people obtain pleasure from a range of sources, whether it be food, sex, drugs, music, or something else, the brain mechanisms underlying a pleasurable response are very similar. In each case, an area of the brain called the striatum plays a key role.
Many people report “chills” when listening to music. These “chills” provide a way to study emotional responses to music.
Zatorre uses brain imaging techniques called functional magnetic resonance imaging and positron-emission tomography—fMRI and PET, for short—to examine changes in brain activity when people listen to music. Techniques like fMRI and PET work according to the idea that the more oxygen being utilized within an area of the brain, the greater the neural activity in that area.
In studies with healthy volunteers, Zatorre had previously shown that when people listen to highly pleasurable music, the greater the “chill,” the greater the activity in the striatum. More recently, he showed that changes in activity in the striatum play a role in the anticipation of and emotional response to music in healthy individuals.
Together, his findings show that the auditory cortex and the brain’s reward system are closely linked and work together to allow pleasure to emerge from listening to music.
What about people who dislike music?
Up to 5% of people have musical anhedonia—an inability to enjoy music. People with this condition have decreased activity in the striatum when listening to music. This is a very specific deficit, as these folks have normal activity in the striatum when experiencing other rewards, such as sex or money.
However, it is possible to change what’s happening in the striatum, even in healthy persons. Transcranial magnetic stimulation (TMS), which uses a magnetic field to change nerve cell activity in the brain, as well as drugs such as risperidone and levodopa, can decrease or increase striatal activity when people listen to music. This comes about because the brain stimulation, and the drugs, change how much dopamine is available; dopamine is one of the key chemicals in the brain’s reward system.
Zatorre ended his talk by saying that music is a way in which humans have learned to enhance their emotional state, all thanks to its impact on the reward system.
Some ideas about why music could help people with chronic pain
Could music also be harnessed to help people with chronic pain? This was the topic to which Bradt then turned.
She began by highlighting aspects of Bushnell’s and Zatorre’s talks that were relevant to people with chronic pain. Those individuals have differences in brain structure and function compared to pain-free people, along with decreased levels of rewarding chemicals such as dopamine in the brain. Since listening to music boosts the chemicals that chronic pain patients tend to produce less of, this could be a reason why music could be beneficial for chronic pain conditions.
There are many other ways in which listening to music could be beneficial for chronic pain. For example, stress and anxiety are often linked to the development and maintenance of chronic pain. But listening to music lowers the activity of the hypothalamic-pituitary-adrenal (HPA) axis, a system that controls the way the body reacts to stress. Listening to music also reduces activity in a part of the brain called the amygdala, which is involved in anxiety responses. So, by controlling stress and anxiety, music could improve pain—that’s the theory.
So what does the research actually say?
Much of the research on music and pain to date has focused on the pain-relieving effects of music on acute (short-lasting) pain. These studies often involve pain-free people who are exposed to something painful, such as heat or pressure, in a research laboratory. There have also been studies examining whether music can ease pain in patients with acute pain from medical procedures such as biopsies.
But there have been fewer studies investigating how music affects people with chronic pain conditions such as fibromyalgia, though the research in pain-free people provides confidence that music could be beneficial in these cases.
There are even fewer studies that examine the effects of interactive music making—such as singing along to someone playing music or playing instruments —during chronic pain. This is an area that also holds promise since pain researchers think it is important that patients be actively engaged with their treatment in ways that allow them to bond with others who have shared similar experiences, and to express emotion.
What could using music to ease chronic pain look like? It could take many forms. Patients could self-manage their pain by listening to music that they enjoy, for instance, or musicians could perform for people with chronic pain in hospitals. More complex strategies, such as personalized music therapy with a board-certified music therapist, are also a possibility.
Bradt described an eight-week vocal music therapy program involving inner-city African Americans with chronic pain that she has tested in a research study. The program had three main components.
First, Bradt and her team asked people with chronic pain to hum or engage in toning—singing extended vocal sounds on vowels, such as ‘aaaaaaaaaaaa’—to create a sense of calm. Second, study participants engaged in vocal improvisations during group sessions, which helps promote emotional expression and bonding with others. Third, patients sang inspirational songs selected by members of the group, which also boosted emotional expression. Throughout the sessions, patients also learned music-based self-management strategies to use at home.
Almost two-thirds of the patients who participated in the study reported an improvement in their pain after eight weeks. The treatment garnered many positive comments from study participants, who said it improved their self-management of pain, promoted a feeling of being understood and supported by other group members, and helped them change their thinking and views on life, such as how music can empower and motivate people.
Bradt also spoke of other studies that focused on how anxiety, mood, and self-efficacy—the belief in one’s ability to achieve goals—influence chronic pain during music therapy. Bradt and her team have also compared the pain levels of patients with cancer who listen to music to those who take a more active role by playing music themselves.
These studies report that individual psychological and social factors contribute to the response to the music treatment, as is the case regarding other treatments for pain. For example, patients who prefer listening to music compared to playing or making music themselves had greater improvement in pain when listening to prerecorded music, rather than participating in a more active form of music therapy. In contrast, patients who enjoyed the creative act of making music benefited more from interactive music therapy sessions. This shows that what a patient prefers can influence how effective the treatment is.
Findings such as these reinforce the key message for healthcare professionals who treat people with chronic pain that it is important to individualize treatment—to find the right treatment for the right patient.
While there is still much research to do, the three talks from the World Congress session highlighted the potential for music to benefit people with chronic pain. People do indeed listen to music for many reasons—and pain treatment may soon be added to that wide-ranging list.
Lincoln Tracy is a pain researcher and freelance writer from Melbourne, Australia.