Two recent studies provide hope for those afflicted with tinnitus, an annoying and sometimes debilitating ringing in the ears.
One study shed light on a possible cause of the troubling disorder. The researchers, led by Josef Rauschecker of Georgetown University Medical Center in Washington, used high-tech MRI scans to zero in on areas of the brain linked to the phantom ringing.
Dr. Rauschecker noted that tinnitus tends to occur in people who have suffered a loss of hearing in certain frequencies as a result of normal aging, loud-noise exposure or an accident. The brain, he said, tries to compensate for the partial hearing loss. "The neighbouring frequencies sort of expand into the gap," he said, which results in the ringing sound.
Anyone who has been to a rock concert or listened to music at an extremely high volume, will have noticed a ringing in the ears for a day or so. Eventually, though, the ringing disappears. But for people with tinnitus, the ringing persists. The MRI scans revealed that part of the brain (the ventromedial prefrontal cortex) that would normally turn off or cancel out the ringing is unusually small in people with tinnitus. "Hopefully, we can find some therapies [to treat tinnitus]that are based on this new knowledge," said Dr. Rauschecker, whose study was published in the journal Neuron.
In the second study, researchers at the University of Texas and MicroTransponder Inc. in Dallas, report they were able to eliminate tinnitus in rats by stimulating the vagus nerve in the neck while simultaneously playing a variety of sound tones over an extended period of time.
They compared their novel therapy to hitting a "reset button" that basically retrains a part of the brain that interprets sounds. Their findings were published in the journal Nature.
Dr. Rauschecker said, in some respects, the two research papers are "highly" complementary. "The vagus nerve stimulation they used could well exert its effects … [through]the same structures we found to be involved in tinnitus."