Scientists get to the heart of that throbbing pain

It’s actually brainwaves you’re feeling, Florida researchers say

Florida scientists believe they have disproven a common belief about throbbing pain: That’s not your heart pounding, after all. You’re actually feeling brainwaves.

The throbbing feeling can come with virtually any type of pain, the University of Florida team found — toothache, headache, a sprained ankle. And both physicians and patients have long associated this with the pulsating nature of blood flow through the arteries. Their conclusion: Pumping blood through a sore spot makes the pain throb.

Some pain medicines even constrict blood vessel walls in hopes of lessening the effect. The belief even goes back to Aristotle, more than 2,300 years ago.

But Dr. Andrew Ahn, a neurologist at the university, was doing research on why pain therapies often don’t work very well. While investigating the throbbing type of pain, he ran into a case that made him wonder.

The patient was a woman who had a history of chronic migraines. But after each migraine passed, she still had a throbbing feeling in her head — not a typical migraine pounding, but a steady beat of some kind.

Ahn and his colleagues had previously monitored the heart rate of patients and found out that it wasn’t associated with their throbbing pain, because the timing was all wrong. He says anyone who checks his or her pulse during an episode of pain can find the same thing.

“It turns out that we have been looking in the wrong place all along,” he concluded.

But their migraine patient volunteered for an electroencephalogram (or EEG), which measures and records the electrical activity of the brain. It showed that her throbbing was closely related to a type of brainwave called an alpha wave.

Alpha waves increased during the throbbing episode, and their rhythm closely paralleled the throbs. By contrast, her heart rate was 68 beats per minute while the throbbing rate was 48 times per minute.

“We understand very little about alpha waves, but they appear to have an important role in attention and how we experience the world,” 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 links the alpha wave to the throbbing isn’t known yet. But Ahn says the throbbing is linked to how the brain works, not how the heart pumps blood.

That, he says, is a step toward designing better pain treatment.

Ahn’s team published in the journal Pain.