National clinical trial to test new avenue for tinnitus treatment

UT Southwestern Medical Center will take part in a national clinical trial to test a device that could provide relief for people suffering from tinnitus, a persistent buzzing or ringing sound in the ears. The device uses nervous system stimuli to rewire parts of the brain, in hopes of significantly reducing or removing tinnitus.

The trial is supported by the National Institute on Deafness and Other Communication Disorders (NIDCD), which is part of the National Institutes of Health. The trial is being conducted through a cooperative agreement with Dallas-based medical device maker MicroTransponder Inc., and participants include UT Southwestern, University of Texas at Dallas, and universities in New York and Iowa.

"We are excited to be testing this new avenue for tinnitus treatment because current therapies lack the potential to significantly reduce the bothersome symptoms of tinnitus," said Dr. Teresa Chan, Assistant Professor of Otolaryngology - Head and Neck Surgery at UT Southwestern, who will perform the implant surgeries for the Dallas arm of the trial.

Roughly 10 percent of the adult population of the United States has experienced tinnitus lasting at least five minutes in the past year, with approximately 10 million of those seeking medical attention. For some, the relentless ringing causes fatigue, depression, anxiety, and problems with memory and concentration.

Most cases of chronic tinnitus are preceded by hearing loss due to damage to the inner ear, which causes false signals to the brain, creating the illusion of sound when there is none. Research suggests that tinnitus might be the result of the brain trying to regain the ability to hear lost frequencies by turning up the signals of neurons in neighboring frequencies, so the new therapy is designed to redirect brain signaling.

The new study uses a technique known as vagus nerve stimulation (VNS), which takes advantage of the brain's ability to reconfigure itself, called neuroplasticity. During the therapy, patients wear headphones and hear a series of single frequency tones, paired with stimulation to the vagus nerve, a large nerve that runs from the head and neck to the abdomen. When stimulated, the vagus nerve releases acetylcholine, norepinephrine, and other chemicals that encourage neuroplasticity.

In an earlier NIDCD-funded study using a rat model, the technique was shown to reorganize neurons to respond to their original frequencies, subdue their activity, and reduce their synchronous firing, suggesting that the ringing sensation had stopped. The scientists subsequently tested a prototype device in a small group of human volunteers in Europe and observed encouraging results.

"Tinnitus affects nearly 24 million adult Americans," said James F. Battey, Jr., M.D., Ph.D., director of the NIDCD. "It is also the number one service-connected disability for returning veterans from Iraq and Afghanistan. The kind of nervous system stimuli used in this study has already been shown to safely and effectively help people with epilepsy or depression. This therapy could offer a profoundly better way to treat tinnitus."