Featured Research

from universities, journals, and other organizations

Tinnitus treatment: Rebooting the brain helps stop the ring of tinnitus in rats

Date:
January 13, 2011
Source:
University of Texas at Dallas
Summary:
Targeted nerve stimulation could yield a long-term reversal of tinnitus, a debilitating hearing impairment affecting at least 10 percent of senior citizens and up to 40 percent of military veterans, according to a new article.

New research suggests that targeted nerve stimulation could yield a long-term reversal of tinnitus, a debilitating hearing impairment affecting at least 10 percent of senior citizens and up to 40 percent of military veterans.
Credit: iStockphoto/Lev Dolgatshjov

Targeted nerve stimulation could yield a long-term reversal of tinnitus, a debilitating hearing impairment affecting at least 10 percent of senior citizens and up to 40 percent of military veterans, according to an article posted in the Jan. 12 online edition of Nature.

Researchers Dr. Michael Kilgard and Dr. Navzer Engineer from The University of Texas at Dallas and University-affiliated biotechnology firm MicroTransponder report that stimulation of the vagus nerve paired with sounds eliminated tinnitus in rats. A clinical trial in humans is due to begin in the next few months.

Described as a ringing in the ears, tinnitus causes mild irritation for some people but is disabling and painful for many others. The U.S. Veterans Administration spends about $1 billion a year on disability payments for tinnitus, said Kilgard, associate professor in the School of Behavioral and Brain Sciences at UT Dallas and co-author of the journal article.

Tinnitus is a symptom some people experience as a result of hearing loss. When sensory cells in the inner ear are damaged, such as from loud noise, the resulting hearing loss changes some of the signals sent from the ear to the brain. For reasons that are not fully understood, some people will develop tinnitus as a result.

"We believe the part of the brain that processes sounds—the auditory cortex—delegates too many neurons to some frequencies, and things begin to go awry," said Michael Kilgard, Ph.D., associate professor of behavior and brain sciences at UT-Dallas, and a co-principal investigator on the study. "Because there are too many neurons processing the same frequencies, they are firing much stronger than they should be."

In addition, the neurons fire in sync with one another and they also fire more frequently when it is quiet. According to Dr. Kilgard, it's these changing brain patterns that produce tinnitus, which is usually a high-pitched tone in one or both ears, but it may also be heard as clicking, roaring, or a whooshing sound.

"Brain changes in response to nerve damage or cochlear trauma cause irregular neural activity believed to be responsible for many types of chronic pain and tinnitus," he said. "But when we paired tones with brief pulses of vagus nerve stimulation, we eliminated the physiological and behavioral symptoms of tinnitus in noise-exposed rats."

The researchers are, in essence, retraining the brain to ignore the nerve signals that simulate ringing. They monitored the laboratory rats for several weeks after therapy, and the improvements persisted.

"This minimally invasive method of generating neural plasticity allows us to precisely manipulate brain circuits, which cannot be achieved with drugs," said Dr. Navzer Engineer, vice president of preclinical affairs at MicroTransponder and lead author on the study. "Pairing sounds with VNS provides that precision by rewiring damaged circuits and reversing the abnormal activity that generates the phantom sound."

The research team is developing parameters for a clinical trial in humans. Vagus nerve stimulation (VNS) is currently used in humans for treatment of epilepsy and depression. "The translation from basic science to the clinic has been quite rapid," Engineer said. "It's exciting that the National Institutes for Health has been so supportive of our efforts to move this work along faster, in hopes of providing effective treatments to tinnitus patients."

The National Institutes of Health (NIH) early in 2010 granted Kilgard and MicroTransponder $1.7 million to further investigate whether nerve stimulation offers a long-term cure for tinnitus.

The first patient could be treated in Europe by early 2011, Engineer said. The initial set of human participants will have the electrodes attached to the left vagus nerve in their neck during a short outpatient procedure. They will come to the clinic Monday through Friday for a few weeks of treatment. At each daily session, they will experience VNS paired with sounds.

MicroTransponder, a neuroscience based medical device company, was founded by UT Dallas PhD candidate Will Rosellini and sponsored by the school's Institute for Innovation and Entrepreneurship. MicroTransponder is developing a less invasive wireless medical device to stimulate the vagus nerve. The UT Dallas/MicroTransponder team also is studying how best to optimize the paired therapy for tinnitus patients.

Past research has shown that the severity of chronic pain and tinnitus is tied to the degree of plasticity in the brain's cortex. A previous study showed that repeatedly pairing sensory stimuli with electrical stimulation of a brain structure called nucleus basalis generates powerful and long-lasting changes in cortical organization. Since the vagus nerve is easier to access for clinical use, and is known to trigger the release of molecules in the brain that promote neural changes, follow-up studies were performed on the vagus nerve.

For the VNS study, the research team used a "gap detection model" to document tinnitus in rats that were exposed to loud noise for one hour while under anesthesia. Each of the noise-exposed rats used in this study exhibited a significant impairment in the ability to detect a quiet gap in a tone near their tinnitus frequency, but exhibited no impairment when the gap was placed in a higher or lower tone.

"Previous research showed that a frequency-specific impairment in gap detection is a likely sign that noise-exposed rats experience a mid-frequency tinnitus 'ringing' that fills the silent gaps," Kilgard said. "Though it isn't possible to evaluate the subjective experience of rats, this gap impairment has been taken as an indicator of tinnitus."

When the rats were exposed to VNS paired with sounds, the gap impairment was eliminated -- indicating that the tinnitus was gone.

Today's therapies for tinnitus have limited success and frequently must be modified over time because they become ineffective. "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 said.

Additional sponsors of the work include the James S. McDonnell Foundation, the Norman Hackerman Advanced Research Program and the Texas Emerging Technology Fund.

The paper's other authors were: UT Dallas neuroscientists Drs. Jonathan Riley, Jonathan Seale, Will Vrana, Jai Shetake, Sindhu Sudanagunta and Michael Borland. The article will be published in the Jan. 27 print edition of the journal.


Story Source:

The above story is based on materials provided by University of Texas at Dallas. Note: Materials may be edited for content and length.


Journal Reference:

  1. Navzer D. Engineer, Jonathan R. Riley, Jonathan D. Seale, Will A. Vrana, Jai A. Shetake, Sindhu P. Sudanagunta, Michael S. Borland, Michael P. Kilgard. Reversing pathological neural activity using targeted plasticity. Nature, 2011; DOI: 10.1038/nature09656

Cite This Page:

University of Texas at Dallas. "Tinnitus treatment: Rebooting the brain helps stop the ring of tinnitus in rats." ScienceDaily. ScienceDaily, 13 January 2011. <www.sciencedaily.com/releases/2011/01/110112132130.htm>.
University of Texas at Dallas. (2011, January 13). Tinnitus treatment: Rebooting the brain helps stop the ring of tinnitus in rats. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2011/01/110112132130.htm
University of Texas at Dallas. "Tinnitus treatment: Rebooting the brain helps stop the ring of tinnitus in rats." ScienceDaily. www.sciencedaily.com/releases/2011/01/110112132130.htm (accessed October 21, 2014).

Share This



More Mind & Brain News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Your Birth Season Might Determine Your Temperament

Your Birth Season Might Determine Your Temperament

Newsy (Oct. 20, 2014) A new study says the season you're born in can determine your temperament — and one season has a surprising outcome. Video provided by Newsy
Powered by NewsLook.com
Court Ruling Means Kids' Online Activity Could Be On Parents

Court Ruling Means Kids' Online Activity Could Be On Parents

Newsy (Oct. 17, 2014) In a ruling attorneys for both sides agreed was a first of its kind, a Georgia appeals court said parents can be held liable for what kids put online. Video provided by Newsy
Powered by NewsLook.com
The Best Foods To Boost Your Mood

The Best Foods To Boost Your Mood

Buzz60 (Oct. 17, 2014) Feeling down? Reach for the refrigerator, not the medicine cabinet! TC Newman (@PurpleTCNewman) shares some of the best foods to boost your mood. Video provided by Buzz60
Powered by NewsLook.com
You Can Get Addicted To Google Glass, Apparently

You Can Get Addicted To Google Glass, Apparently

Newsy (Oct. 15, 2014) Researchers claim they’ve diagnosed the first example of the disorder in a 31-year-old U.S. Navy serviceman. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins