If you don’t suffer from tinnitus, you could be wondering what the fuss is all about. After all, it’s just a little bit of noise. Isn’t it?
Most people who struggle with tinnitus daily, however, would do almost anything to make the noise in their heads go away. It’s frustrating, irritating, and at its worst, debilitating. Statistics indicate that at least 10 percent of the US population and 40 percent of military veterans suffer from tinnitus.
Researchers at the University of Texas at Dallas are looking at ways to adapt an existing technology to help tinnitus sufferers. Dr. Michael Kilgard and Dr. Navzer Engineer are preparing for clinical trials of targeted stimulation of the vagus nerve to see whether or not this therapy will help the brain learn to ignore the phantom sounds of tinnitus. This same type of therapy already is used as a treatment for depression and epilepsy.
The vagus nerve is one of 12 paired cranial nerves. It’s easily accessible in the neck, which makes it a good candidate for this type of therapy. Previous research by Kilgard and Engineer has indicated that vagus nerve stimulation that was paired with frequency specific sounds eliminated tinnitus in rats.
“When we paired tones with brief pulses of vagus nerve stimulation (VNS), we eliminated the physiological and behavioral symptoms of tinnitus in noise-exposed rats,” Kilgard wrote in a paper published in the journal Nature. He said that what he and Engineer are doing is basically retraining the brain to ignore nerve impulses that the brain interprets as sound.
“Pairing sounds with VNS provides that precision by rewiring damaged circuits and reversing the abnormal activity that generates the phantom sound,” he wrote.
In the initial study, Kilgard and Engineer exposed rats to loud noise to induce tinnitus in them. They used behavioral cues to infer the frequency at which the rats experienced tinnitus, and then paired vagus nerve stimulation with simultaneous sound at that frequency. Behavioral cues indicated that over time, the tinnitus at subsided and eventually disappeared.
Now the team is preparing to try the same technique in human patients. In the first clinical trial, a group of patients will have electrodes attached to the left vagus nerve in an outpatient procedure. They’ll come back to the clinic for treatment similar to that used on the rats, where the nerve is stimulated while they hear sounds at the same frequency as their tinnitus.
If the technique works, the outcome likely will be permanent. This is a huge advantage of other current therapies for tinnitus, all of which have only limited success, and become less and less effective over time. That means they work for a while and then stop, so that the patient gets only temporary relief from tinnitus for any given therapy.
“The VNS treatment would be an improvement over current therapies involving medications or counseling because it offers a possible permanent end to the condition and doesn’t appear to cause any significant side effects,” Kilgard wrote.
You can read more about this research at University of Texas at Dallas.