Featured Research

from universities, journals, and other organizations

Tinnitus: New evidence touch-sensing nerve cells may fuel 'ringing in the ears'

Date:
February 1, 2012
Source:
University of Michigan Health System
Summary:
A new study finds new evidence that touch-sensing nerve cells may fuel tinnitus. Future treatments may target these cells.

ANWe all know that it can take a little while for our hearing to bounce back after listening to our iPods too loud or attending a raucous concert. But new research at the University of Michigan Health System suggests over-exposure to noise can actually cause more lasting changes to our auditory circuitry -- changes that may lead to tinnitus, commonly known as ringing in the ears.

U-M researchers previously demonstrated that after hearing damage, touch-sensing "somatosensory" nerves in the face and neck can become overactive, seeming to overcompensate for the loss of auditory input in a way the brain interprets -- or "hears" -- as noise that isn't really there.

The new study, which appears in the Feb. 1 issue of The Journal of Neuroscience, found that somatosensory neurons maintain a high level of activity following exposure to loud noise, even after hearing itself returns to normal.

The findings were made in guinea pigs, but mark an important step toward potential relief for people plagued by tinnitus, says lead investigator Susan E. Shore, Ph.D., of U-M's Kresge Hearing Research Institute and a professor of otolaryngology and molecular and integrative physiology at the U-M Medical School.

"The animals that developed tinnitus after a temporary loss in their hearing after loud noise exposure were the ones who had sustained increases in activity in these neural pathways," Shore says. "In the future it may be possible to treat tinnitus patients by dampening the hyperactivity by reprogramming these auditory-touch circuits in the brain."

In normal hearing, a part of the brain called the dorsal cochlear nucleus is the first stop for signals arriving from the ear via the auditory nerve. But it's also a hub where "multitasking" neurons process other sensory signals, such as touch, together with hearing information.

During hearing loss, the other sensory signals entering the dorsal cochlear nucleus are amplified, Shore's earlier research found. This overcompensation by the somatosensory neurons, which carry information about touch, vibration, skin temperature and pain, is believed to fuel tinnitus in many cases.

Tinnitus affects up to 50 million people in the United States and millions more worldwide, according to the American Tinnitus Association. It can range from intermittent and mildly annoying to chronic, severe and debilitating. There is no cure.

It especially affects baby boomers, who, as they reach an age at which hearing tends to diminish, increasingly find that tinnitus moves in. 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. Tinnitus is the number one disability afflicting members of the armed forces.

The involvement of touch sensing (or "somatosensory") nerves in the head and neck explains why many tinnitus sufferers can change the volume and pitch of the sound by clenching their jaw, or moving their head and neck, Shore explains.

While the new study builds on previous discoveries by Shore and her team, many aspects are new.

"This is the first research to show that, in the animals that developed tinnitus after hearing returned to normal, increased excitation from the somatosensory nerves in the head and neck continued. This dovetails with our previous research, which suggests this somatosensory excitation is a major component of tinnitus," says Shore, who serves on the scientific advisory committee of the American Tinnitus Association.

"The better we understand the underlying causes of tinnitus, the better we'll be able to develop new treatments," she adds.

Funding: The research was supported by grants from the National Institutes of Health, the Tinnitus Research Consortium and the Tinnitus Research Initiative.


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. S. Dehmel, S. Pradhan, S. Koehler, S. Bledsoe, S. Shore. Noise Overexposure Alters Long-Term Somatosensory-Auditory Processing in the Dorsal Cochlear Nucleus--Possible Basis for Tinnitus-Related Hyperactivity? Journal of Neuroscience, 2012; 32 (5): 1660 DOI: 10.1523/JNEUROSCI.4608-11.2012

Cite This Page:

University of Michigan Health System. "Tinnitus: New evidence touch-sensing nerve cells may fuel 'ringing in the ears'." ScienceDaily. ScienceDaily, 1 February 2012. <www.sciencedaily.com/releases/2012/02/120201092301.htm>.
University of Michigan Health System. (2012, February 1). Tinnitus: New evidence touch-sensing nerve cells may fuel 'ringing in the ears'. ScienceDaily. Retrieved July 21, 2014 from www.sciencedaily.com/releases/2012/02/120201092301.htm
University of Michigan Health System. "Tinnitus: New evidence touch-sensing nerve cells may fuel 'ringing in the ears'." ScienceDaily. www.sciencedaily.com/releases/2012/02/120201092301.htm (accessed July 21, 2014).

Share This




More Health & Medicine News

Monday, July 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

TheStreet (July 21, 2014) New research shows Gilead Science's drug Sovaldi helps in curing hepatitis C in those who suffer from HIV. In a medical study, the combination of Gilead's Hep C drug with anti-viral drug Ribavirin cured 76% of HIV-positive patients suffering from the most common hepatitis C strain. Hepatitis C and related complications have been a top cause of death in HIV-positive patients. Typical medication used to treat the disease, including interferon proteins, tended to react badly with HIV drugs. However, Sovaldi's %1,000-a-pill price tag could limit the number of patients able to access the treatment. TheStreet's Keris Lahiff reports from New York. Video provided by TheStreet
Powered by NewsLook.com
$23.6 Billion Awarded To Widow In Smoking Lawsuit

$23.6 Billion Awarded To Widow In Smoking Lawsuit

Newsy (July 20, 2014) Cynthia Robinson claims R.J. Reynolds Tobacco Company hid the health and addiction risks of its products, leading to the death of her husband in 1996. Video provided by Newsy
Powered by NewsLook.com
Tooth Plaque Provides Insight Into Diets Of Ancient People

Tooth Plaque Provides Insight Into Diets Of Ancient People

Newsy (July 19, 2014) Research on plaque from ancient teeth shows that our prehistoric ancestor's had a detailed understanding of plants long before developing agriculture. Video provided by Newsy
Powered by NewsLook.com
Contaminated Water Kills 3 Babies in South African Town

Contaminated Water Kills 3 Babies in South African Town

AFP (July 18, 2014) Contaminated water in South Africa's northwestern town of Bloemhof kills three babies and hospitalises over 500 people. The incident highlights growing fears over water safety in South Africa. Duration: 02:22 Video provided by AFP
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