Featured Research

from universities, journals, and other organizations

Tinnitus discovery opens door to possible new treatment avenues

Date:
December 16, 2013
Source:
University of Michigan Health System
Summary:
For tens of millions of Americans, a condition called tinnitus means there’s no such thing as the sound of silence. Now, new scientific findings that help explain what is going on inside their unquiet brains

For tens of millions of Americans, there's no such thing as the sound of silence. Instead, even in a quiet room, they hear a constant ringing, buzzing, hissing, humming or other noise in their ears that isn't real. Called tinnitus, it can be debilitating and life-altering.

Now, University of Michigan Medical School researchers report new scientific findings that help explain what is going on inside their unquiet brains.

The discovery reveals an important new target for treating the condition. Already, the U-M team has a patent pending and device in development based on the approach.

The critical findings are published online in the Journal of Neuroscience. Though the work was done in animals, it provides a science-based, novel approach to treating tinnitus in humans.

Susan Shore, Ph.D., the senior author of the paper, explains that her team has confirmed that a process called stimulus-timing dependent multisensory plasticity is altered in animals with tinnitus -- and that this plasticity is "exquisitely sensitive" to the timing of signals coming in to a key area of the brain.

That area, called the dorsal cochlear nucleus, is the first station for signals arriving in the brain from the ear via the auditory nerve. But it's also a center where "multitasking" neurons integrate other sensory signals, such as touch, together with the hearing information.

Shore, who leads a lab in U-M's Kresge Hearing Research Institute, is a Professor of Otolaryngology and Molecular and Integrative Physiology at the U-M Medical School, and also Professor of Biomedical Engineering, which spans the Medical School and College of Engineering.

She explains that in tinnitus, some of the input to the brain from the ear's cochlea is reduced, while signals from the somatosensory nerves of the face and neck, related to touch, are excessively amplified.

"It's as if the signals are compensating for the lost auditory input, but they overcompensate and end up making everything noisy," says Shore.

The new findings illuminate the relationship between tinnitus, hearing loss and sensory input and help explain why many tinnitus sufferers can change the volume and pitch of their tinnitus's sound by clenching their jaw, or moving their head and neck.

But it's not just the combination of loud noise and overactive somatosensory signals that are involved in tinnitus, the researchers report.

It's the precise timing of these signals in relation to one another that prompt the changes in the nervous system's plasticity mechanisms, which may lead to the symptoms known to tinnitus sufferers.

Shore and her colleagues, including former U-M biomedical engineering graduate student and first author Seth Koehler, Ph.D., hope their findings will eventually help many of the 50 million people in the United States and millions more worldwide who have the condition, according to the American Tinnitus Association. They hope to bring science-based approaches to the treatment of a condition for which there is no cure -- and for which many unproven would-be therapies exist.

Tinnitus especially affects baby boomers, who, as they reach an age at which hearing tends to diminish, increasingly experience tinnitus. The condition most commonly occurs with hearing loss, but can also follow head and neck trauma, such as after an auto accident, or dental work.

Loud noises and blast forces experienced by members of the military in war zones also can trigger the condition. Tinnitus is a top cause of disability among members and veterans of the armed forces.

Researchers still don't understand what protective factors might keep some people from developing tinnitus, while others exposed to the same conditions experience tinnitus.

In this study, only half of the animals receiving a noise-overexposure developed tinnitus. This is similarly the case with humans -- not everyone with hearing damage ends up with tinnitus. An important finding in the new paper is that animals that did not get tinnitus showed fewer changes in their multisensory plasticity than those with evidence of tinnitus. In other words, their neurons were not hyperactive.

Shore is now working with other students and postdoctoral fellows to develop a device that uses the new knowledge about the importance of signal timing to alleviate tinnitus. The device will combine sound and electrical stimulation of the face and neck in order to return to normal the neural activity in the auditory pathway.

"If we get the timing right, we believe we can decrease the firing rates of neurons at the tinnitus frequency, and target those with hyperactivity," says Shore. She and her colleagues are also working to develop pharmacological manipulations that could enhance stimulus timed plasticity by changing specific molecular targets.

But, she notes, any treatment will likely have to be customized to each patient, and delivered on a regular basis. And some patients may be more likely to derive benefit than others.


Story Source:

The above story is based on materials provided by University of Michigan Health System. Note: Materials may be edited for content and length.


Journal Reference:

  1. Seth D. Koehler And Susan E. Shore. Stimulus Timing-Dependent Plasticity in Dorsal Cochlear Nucleus Is Altered in Tinnitus. Journal of Neuroscience, December 2013

Cite This Page:

University of Michigan Health System. "Tinnitus discovery opens door to possible new treatment avenues." ScienceDaily. ScienceDaily, 16 December 2013. <www.sciencedaily.com/releases/2013/12/131216154334.htm>.
University of Michigan Health System. (2013, December 16). Tinnitus discovery opens door to possible new treatment avenues. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2013/12/131216154334.htm
University of Michigan Health System. "Tinnitus discovery opens door to possible new treatment avenues." ScienceDaily. www.sciencedaily.com/releases/2013/12/131216154334.htm (accessed September 1, 2014).

Share This




More Mind & Brain News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Coffee Then Napping: The (New) Key To Alertness

Coffee Then Napping: The (New) Key To Alertness

Newsy (Aug. 30, 2014) Researchers say having a cup of coffee then taking a nap is more effective than a nap or coffee alone. Video provided by Newsy
Powered by NewsLook.com
Young Entrepreneurs Get $100,000, If They Quit School

Young Entrepreneurs Get $100,000, If They Quit School

AFP (Aug. 29, 2014) Twenty college-age students are getting 100,000 dollars from a Silicon Valley leader and a chance to live in San Francisco in order to work on the start-up project of their dreams, but they have to quit school first. Duration: 02:20 Video provided by AFP
Powered by NewsLook.com
Baby Babbling Might Lead To Faster Language Development

Baby Babbling Might Lead To Faster Language Development

Newsy (Aug. 29, 2014) A new study suggests babies develop language skills more quickly if their parents imitate the babies' sounds and expressions and talk to them often. Video provided by Newsy
Powered by NewsLook.com
Electrical Stimulation Boosts Brain Function, Study Says

Electrical Stimulation Boosts Brain Function, Study Says

Newsy (Aug. 29, 2014) Researchers found an improvement in memory and learning function in subjects who received electric pulses to their brains. 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:
from the past week

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