An EMG, or electromyogram, is a test that’s been around for decades, but doctors have only recently started using it again on patients with back pain, thanks to new research showing its effectiveness as a diagnostic tool. Unlike an MRI that simply takes a photograph of the spine, the EMG registers electrical activity in the muscles surrounding the spine. This method can more accurately identify the source of pain, says Andrew Haig, a physician and professor of physical medicine and rehabilitation at the University of Michigan Health System. “Taking a photo of a car with a dent in it isn’t going to tell you whether the radio works, and taking a photo of an old spine isn’t going to tell you if it hurts,” Haig says.
In fact, having an MRI could even be bad for you, Haig says. Most older spines have some sort of disc degeneration or other problems, and surgeons often identify those issues as the source of the back pain and a reason to operate. But studies have found that people with disc problems aren’t necessarily in pain. And fixing disc problems isn’t a sure way to relieve pain.