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  • About 20% of all adults around the world live with chronic pain.
  • Researchers from the University of Minnesota discovered via an animal model that the combination of electrical and sound stimulation has the potential to treat chronic pain.
  • Scientists hope their model will provide a noninvasive, non-drug treatment for chronic pain symptoms.

Researchers estimate about 20% of all adults around the world live with chronic pain — a condition that can impact a person’s everyday life physically, mentally, and emotionally.

Treatment for chronic pain can include different types of medications, lifestyle changes, and different types of therapies, both traditional and alternative.

Now, from findings via an animal model, a team of researchers from the University of Minnesota Twin Cities says a combination of sound and electrical body stimulation has the potential to treat chronic pain.

This study was recently published in the Journal of Neural Engineering.

When you injure yourself, nerves notify the central nervous system of what has happened. The brain then interprets what has occurred as pain.

Normally, the amount of pain a person feels lessens as the injury heals.

However, sometimes a person’s nerves do not stop sending pain signals to the central nervous system, making the brain think they are still in pain, resulting in chronic pain.

Certain types of injuries have a higher rate of developing chronic pain, including:

And chronic pain may also occur after a person experiences a very painful disease, such as:

In addition to pain, people with chronic pain may also experience:

Doctors normally treat chronic pain with a combination of pain medications. These include over-the-counter pain medications, opioids, anti-inflammatory medications, and antidepressants that help block pain signals in the body. Additionally, doctors may suggest lifestyle changes to help alleviate pain, including physical therapy, massage, and meditation.

Researchers have also looked at alternative therapies for treating chronic pain, including acupuncture and electrical stimulation.

For the new study, the researchers wanted to use a mouse model to investigate how bimodal sensory stimulation — both sound and electrical — would affect or alter neural activity in the somatosensory cortex. The somatosensory complex is the area of the brain responsible for receiving sensory information, such as pain.

“We wanted to determine if combining sound and body stimulation repeatedly would change the coding patterns in somatosensory cortical neurons,” Dr. Cory Gloeckner, PhD, assistant professor at John Carroll University and lead author of the study, explained to MNT.

“Some sensory disorders, such as chronic pain and tinnitus, are linked to abnormal coding patterns of sensory cortex neurons, so the ability to noninvasively modulate or shift coding patterns in these neurons could potentially help treat such sensory disorders.”

To investigate their hypothesis, Dr. Gloeckner and his team applied electrical stimulation and broadband sound to a guinea pig model.

During the study, researchers found the combination of stimulations activated neurons in the brain’s somatosensory cortex.

“From previous studies, we know there are also overlayed brain regions for auditory and somatosensory perception maps,” Dr. Gloeckner said. “And we already know that somatosensory signals can induce long-term changes to neurons in the auditory system; so, we hypothesized and investigated how well sound stimuli could modulate activity in the somatosensory cortex.”

“We found that while sound stimulation alone only affects a small subset of somatosensory cortex neurons, sound stimuli affected almost every neuron we recorded from in the somatosensory cortex when combining it with body electrical stimulation. That was unexpected and impressive that a sound stimulus could affect so much of the somatosensory cortex.”

– Dr. Cory Gloeckner, PhD, assistant professor at John Carroll University and lead author of the study

Dr. Gloeckner continued: “In a practical sense, this means we can use sound stimuli to potentially modulate neurons across the somatosensory cortex relevant for treating chronic pain, which has been linked to coding patterns in the somatosensory cortex.”

Dr. Gloeckner pointed out that the study does not directly show that bimodal stimulation treats chronic pain in humans.

“This is an initial study in animals that investigates a potential mechanism with promising results, but it would need to be tested in humans to determine its efficacy for treating pain,” he added. “Since our treatment would be noninvasive, the next step would be to try it directly in humans to see if it can make a significant impact on chronic pain symptoms.”

Dr. Gloeckner said it is important for medical professionals to have non-drug options available for treating chronic pain.

“Drugs, including opioids, are common treatments used to reduce symptoms but are not sufficiently effective for many individuals, and opioid addiction has become a massive problem in America,” he explained.

“Our potential treatment, on the other hand, is a noninvasive approach that could be easy to use that doesn’t involve any drugs. It can be implemented with simple, inexpensive equipment that can be accessible to patients and also may even be more acceptable than drugs or surgery.”

MNT also spoke with Dr. Medhat Mikhael, a pain management specialist and medical director of the non-operative program at the Spine Health Center at MemorialCare Orange Coast Medical Center in Fountain Valley, CA, who was not involved in this study.

He stated he has been using electric stimulation via a transcutaneous electrical nerve stimulation (TENS) unit or implantable device, and meditation through music to assist chronic pain patients for some time.

“In the old days, we relied on medications to help. A lot of medication that helps with pain … do have side effects and risk of addiction, risk of dependency and tolerance, and … could make the patient have weird feelings, feel dizzy, [and] feel nauseous all the time. If you can use something that does not adversely affect the central nervous system or give you side effects or give you risks, like dependency, tolerance, addiction, that’s a blessing.”

– Dr. Medhat Mikhael, pain management specialist and a medical director at MemorialCare Orange Coast Medical Center

For the next steps in this research, Dr. Mikhael said he would like researchers to examine neuromodulation through central nervous system stimulation, as well as look at the difference between older technologies and the new technology doctors now have used to deliver electrical stimulation to the central nervous system.

“Researchers like this would encourage insurance companies to approve things like this because short-term cost might be a concern,” Dr. Mikhael said.

“But if you look at the long term, that these patients with these implantable devices are not getting hospitalized anymore, are not getting surgeries anymore, are not visiting the ER anymore, are not using oral medications anymore, that makes a huge difference. The short-term upfront costs prevent a lot of the long-term very high costs over the years.”