Summary: The new study maps how sound and/or electrical stimulation of the body changes the somatosensory cortex. That is the brain’s touch and pain map. The results suggest that bimodal stimulation (two kinds at once) can excite or tune firing in a targeted group of nerve cells there. That offers a way to treat chronic pain without surgery or needles (non-invasive).
Chronic pain is a complex condition with many sides, and it is often hard to treat. One main challenge is that it often has several causes at once. These include physical injury, nerve damage, and emotional and mental stress. These conditions are often hard to diagnose and treat, so chronic pain is hard to manage. Also, usual pain treatments, such as medicine and physical therapy, may not work for everyone and can have side effects.
Chronic pain often does not respond to many treatments, so doctors often need to prescribe opioids. But long-term opioid use is not an option. So researchers are looking for safer ways to manage chronic pain. They are most interested in methods that do not use drugs, like electrical body stimulation. One example is TENS, or Transcutaneous Electrical Nerve Stimulation.
TENS devices are easy to find at most pharmacies. But in most cases they give only limited pain relief, which is far from good enough. So researchers are looking for ways to make TENS work better. And in a new study, it appears researchers have found a way to boost the pain-killing effect of TENS. They found that using sound therapy along with TENS may strengthen its pain-killing action.
In the new study, researchers looked at multisensory integration in the cortex. The idea is to switch on several sense and movement pathways at once. The goal is to treat brain disorders such as tinnitus or essential tremor. Tinnitus is a type of chronic hearing pain. It makes a person hear ringing, whistling, or buzzing in their ears. Earlier studies have shown that combined sound and body stimulation can change the hearing pathway and significantly improve tinnitus symptoms.
The team wanted to map how sound and/or electrical stimulation affects the somatosensory cortex (SC). They used guinea pigs put under with ketamine. First, the team mapped the SC’s layout. They were applying electrical stimulation to different body areas with needle electrodes under the skin, or they used broadband sound. Then they tested how parts of the SC can be switched on or suppressed through combined stimulation. The SC map in response to electrical stimulation of the body matched earlier rodent studies.
Also, broadband noise mostly switched on SC regions that respond to lower body stimulation. Sound alone excited only a few SC spots. But combining sound with other stimulation could affect every SC recording site. And noise used in conjunction with electric stimulation of one body area could target specific parts of the SC.
The study concludes that these results show that bimodal stimulation (sound and electrical) can excite or tune firing in a wide but targeted group of SC nerve cells. That gives a non-invasive way to change or break up bad firing patterns in parts of the SC. The goal is chronic pain treatment.
This study is a first step. It looks at using several sense and movement pathways at once to treat brain disorders. These include tinnitus, essential tremor and chronic pain. Now the method needs testing in a broader group of people. That means people living with chronic pain from different health problems.
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Frequently asked questions
Does a TENS unit work for chronic pain?
Only partly. TENS (transcutaneous electrical nerve stimulation) devices are sold at most pharmacies. But in most cases they give limited relief, far from good enough for someone living with chronic pain. That shortfall is why researchers are looking for ways to make electrical stimulation work harder. Pairing it with sound is one of them.
Can sound make electrical stimulation work better for pain?
Early animal research says it may. Sound alone excited only a few spots in the somatosensory cortex, the brain’s touch and pain map. Combined with electrical stimulation, it could affect every recording site. And pairing noise with stimulation of one body region targeted specific parts of that map. That offers a non-invasive way to break up the abnormal firing behind chronic pain.
Is combined sound and electrical stimulation available for patients now?
Not as a proven treatment. The mapping study was done in guinea pigs under anesthesia. It is an early step. The method now has to be tested in a broader group: people living with chronic pain from different health problems. The same combined approach has already improved tinnitus symptoms in earlier studies.
Why look for chronic pain treatments that don’t use drugs?
Chronic pain often has several causes at once. These include injury, nerve damage and emotional stress. It often fails to respond to medicine or physical therapy. Doctors then turn to opioids, but long-term opioid use is not an option. Stimulation methods like TENS treat pain without putting another substance into the body.
Medical Disclaimer: Keep in mind that the content provided is not direct medical advice for patient care, but is provided for thoughtful discussion.
Dr. Gurpreet Singh Padda, MD, MBA, MHP
