Bob Marley once said, "One good
thing about music, when it hits you, you feel no pain." A recent study
using a mouse model backs up Marley's musing with some scientific data.
In
the past, scientists have explored the idea of using music as a therapy in a
variety of ways.
One study revealed
that joining a choir might improve the lives of people with Parkinson's disease, for instance.
Others
still have concluded that music, in the right setting, can reduce the sensation
of pain.
For
instance, one recent meta-analysis of 14 studies concludes that
"music may be beneficial as an adjuvant for chronic pain patients, as it
reduces self-reported pain and its common comorbidities."
With
the opioid crisis in full flow, finding ways to enhance the effectiveness of
less addictive pain medication without producing side effects would be
game-changing.
A
new study reopens the investigation and retests the power of music — in
combination with four different medications — against two models of pain in
mice.
The
researchers, from the University of Utah Health in Salt Lake City, have published their findings in the journal Frontiers in Neurology.
Music vs. pain
The
researchers used two pain models: the carrageenan model, which mimics
inflammation-related pain; and plantar incision, which replicates surgical
pain.
They
split the mice into two groups of five to eight animals. They exposed the
control group to only ambient noise, while they played the experimental group
three 3-hour segments of Mozart each day for 3 weeks.
Interestingly,
the researchers did not choose the segments of music at random. As Grzegorz
Bulaj, Ph.D. — an associate professor in medicinal chemistry — explains:
"Music
is like DNA. We had musicians analyze sequences of several Mozart pieces to
optimize the playlist. This was exciting but challenging to integrate these
musical analyses into neuropharmacology."
They
ran the study four times, each time using a different drug that can reduce
pain. These drugs were ibuprofen, cannabidiol, levetiracetam, and a galanin
analog called NAX 5055.
Both
the control and the music groups received doses considered suboptimal.
The ibuprofen trials produced the most striking
results. In the group that listened to music, pain responses in the carrageenan
model dropped by 93 percent, compared with the mice that took ibuprofen but did
not listen to music.
Also,
in the carrageenan model, music and cannabidiol reduced swelling by 21 percent.
NAX 5055 plus music reduced swelling by 9 percent. In the surgical pain model,
music also significantly reduced some but not all responses to pain.
"There is emerging evidence
that music interventions can alleviate pain when administered either alone or
in combination with other therapies. I was particularly excited to see reduced
swelling in the inflammatory pain model."
First
study author Cameron S. Metcalf, Ph.D.
Metcalf
goes on to explain that standard inflammation medications
do not produce such a quick response.
Surprises and next steps
Using
animal models comes with certain difficulties, but in this case, the
scientists' use of a mouse model makes it more interesting; it removes the
complex human psychological response to music. One is almost tempted to believe
that harmony has an intrinsic healing quality.
Although
it may seem surprising that a rodent might physiologically respond to music,
this is not the first time that scientists have demonstrated this. Research
into mice and music has a long pedigree.
For
instance, the authors of a review of 42 relevant studies — published in December 2018 — found that "[m]usic
interventions seem to improve brain structure and neurochemistry; behavior;
immunology; and physiology in
rodents."
Among
other things, the authors write that "music exposure was linked with
statistically significantly improved spatial and auditory learning, reduced
anxiety-related behavior, and increased immune responses."
"The holy grail is to combine
the right drug with this new paradigm of music exposure, so we do not need as
much drug for analgesic effects."
Grzegorz
Bulaj, Ph.D.
How does music exert its effect?
The
scientists did not design this study to unpick how music might reduce pain, but
they do outline some theories.
For
instance, earlier research demonstrated that music upregulates the production
of brain-derived neurotrophic factor (BDNF). This protein supports neurons and
encourages the growth of neurons and synapses. In the long-term, BDNF inhibits pain
sensitivity.
Other
theories that the study authors consider are music's ability to impact
parasympathetic tone, cortisol levels, pro-inflammatory cytokines, the
dopaminergic system, and opioid receptors.
It
will take a great deal more work to tease apart the mechanisms involved, and
the answer is likely to involve all of the above and more.
Much more to learn
It
is important to note some of the study's limitations. Firstly, the scientists
only used small numbers of animals, so we cannot draw firm conclusions at this
stage.
Also,
the study did not address other types of pain, such as neuropathic pain, which
nerve damage causes.
Another
issue is that the scientists only used major key sections of Mozart's music,
and, of course, there is a wealth of variation in music. In fact, most studies
exploring the physiological impact of music focus on classical music.
Additionally, mice hear different frequencies to
humans, and it is unclear how this impacts the results and their relevance to
humans.
The
authors also note limitations in their choice of control group, having exposed
the control mice to ambient sound. In future studies, it would be interesting
to replace this with total silence, white noise, or a different type of music.
In
many ways, the study presents more questions than it answers. What would happen
if the mice listened to different styles of music? What if they listened for
longer each day? And what if they listened for 6 weeks or 6 months?
However, the results remain highly interesting. As
Bulaj points out, "If we could package music and other nonpharmacological
therapies into mobile apps and deliver them with drugs and it works, it will be
better than drugs alone. It is exciting to find new ways to improve pain
treatments."
No
doubt, researchers will chase this line of investigation further. Anything that
helps reduce pain without adverse effects is of great interest. Perhaps one
day, doctors will be able to prescribe a playlist to accompany our pills.
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