The NIH has granted a University of Texas at Dallas researcher and a university-affiliated biomedical firm $1.7 million to investigate whether nerve stimulation offers a long-term cure for tinnitus.

Described as a ringing in the ears, tinnitus affects 20 percent to 40 percent of recently returned military veterans and about 10 percent of all people over 65 years old. The U.S. Veterans Administration spends about $1 billion a year in disability payments related to tinnitus, said Dr. Michael Kilgard, associate professor in UT Dallas' School of Behavioral and Brain Sciences. The disorder causes mild irritation for some people but is disabling and painful for many others.

Kilgard will use his portion of the grant, $448,000 over two years, to continue testing whether vagus nerve stimulation (VNS) can retrain the brain to ignore the nerve signals that simulate ringing. The researchers in earlier tests found that VNS stimulation, when paired with the presentation of alternative tones, appeared to reverse the effects of tinnitus.

"We're glad to get an opportunity to further our research on tinnitus," Kilgard said. "This grant will support advances in our understanding of VNS treatment, and it will move the technological development forward so we can better deliver that therapy to patients."

The researchers plan to change the pattern for stimulation, increasing the frequency to see if more intensive therapy might reverse the effects of tinnitus faster. The primary aim of the new research is to accumulate enough data to design clinical trials using VNS to treat tinnitus in human subjects in the United States.

VNS previously translated successfully to humans for the treatment of epilepsy, depression and other neurological disorders.

The new grant resulted from the NIH's partnership with the federal government's Small Business Innovation Research program (SBIR). Part of the grant will go to Kilgard and his work in the lab, and the other portion will further research by MicroTransponder, a biomedical start-up company that works in conjunction with UT Dallas researchers and has helped bring in more than $6 million in grants in the past two years.

MicroTransponder is attempting to develop a less invasive method for delivering the electric charge that stimulates the vagus nerve in the neck. Currently, Kilgard uses wires attached to the neck to stimulate the nerve. The goal is to create a remotely controlled device similar to the technology used for toll tags on highways, Kilgard said.

Will Rosellini, a PhD student in neuroscience at UT Dallas, is CEO of MicroTransponder. Dr. Larry Cauller, associate professor of neuroscience, developed the neural interface technology that led to MicroTransponder. He is the company's chief science officer.

"For medical devices, the ultimate goal is to have the least invasive procedure possible, but this is usually accomplished in an iterative fashion, with each new version being less invasive than the past," Rosellini said. "The eventual goal is to have our SAINT System be injectable via a needle, but there are several intermediary versions of the device that must be developed and thoroughly tested before that will be possible."

Rosellini said Dr. Roger Miller, a scientific program director at the National Institute on Deafness and Other Communication Disorders, has been a champion of MicroTransponder's efforts to use VNS to combat tinnitus. Kilgard said Miller has been "extremely helpful in advancing the new therapy closer to a clinical reality."

The VNS treatment would be an improvement over current therapies involving medications or counseling because it offers a possible permanent end to the condition, an actual cure instead of just a treatment, Kilgard said. Current therapies have limited success and frequently must be modified over time because they cease to be effective.

MicroTransponder and Kilgard now are working with researchers in Belgium to set up a protocol for conducting the first round of tests in humans. Less than half of therapies that are successful in animals prove successful when tested on people, Kilgard said.

"We want to find out as much as we can about how well this works in rats. That is what this phase of the research is about," he said. "Once we have that additional data, we can try out a similar therapy on humans, and we hope to find this offers a permanent end to their tinnitus discomfort."

Dr. Bert Moore, dean of the School of Behavioral and Brain Sciences, said UT Dallas' relationship with MicroTransponder continues to yield results.

"The story behind this research is a wonderful example of how investigators such as Drs. Cauller and Kilgard, exploring basic mechanisms of how the brain adapts and learns, can collaborate with corporate partners to develop new technologies to address a variety of human problems," he said. "This is the goal of our research mission at UT Dallas, creating new knowledge so that we can impact and improve people's lives."

Source:
Emily Martinez
University of Texas at Dallas