Throbbing pain isn’t a matter of the heart
The finding could drastically change how researchers look for therapies that can ease pain, said Dr. Andrew Ahn, a neurologist at the UF College of Medicine. He and his colleagues reported their findings in the July issue of the journal Pain.
“Aristotle linked throbbing pain to heart rhythm 2,300 years ago,” Dr. Ahn said. “It took two millennia to discover that his presumption was wrong.”
People who experience a toothache or a migraine — or even just hit their shin on the coffee table — can note a throbbing quality to the pain that physicians have long associated with arterial pulsations at the location of the injury. Some medicines even constricted blood vessel walls in hopes of lessening the effect.
“Current therapies for pain do not adequately relieve pain and have serious negative side effects, so we thought that by examining this experience more closely we could find clues that would lead us to improved therapies to help people who suffer from pain,” Dr. Ahn said. “It turns out that we have been looking in the wrong place all along.”
Along with researchers Jue Mo and Mingzou Ding from the UF College of Engineering and Morris Maizels of the Blue Ridge Headache Center in Asheville, N.C., Dr. Ahn examined a patient who had a throbbing sensation that remained even after her chronic migraine headaches had resolved. They simultaneously recorded the patient’s sensation of the throbbing pain and her arterial pulse and found that they differed from one another, indicating that the pulsing of blood from the heartbeat was unrelated to the throbbing quality of pain.
Through the use of an electroencephalogram, they found that the throbbing quality was correlated with a type of brain activity called alpha waves.
“We understand very little about alpha waves, but they appear to have an important role in attention and how we experience the world,” Dr. Ahn said. “In addition, by analogy to how a radio works, alpha waves may also act as a carrier signal that allows different parts of the brain to communicate with itself.”
What scientists don’t know yet is exactly how alpha waves cause throbbing pain. But the current findings indicate that the experience of pain is linked more to how the brain works and not to the pulsations of blood at the location of the pain. Understanding this will allow researchers to design new studies to discover better treatments for pain.
This work was supported by the Facial Pain Research Foundation and in part by grants from the National Institutes of Health. ¦