Navigation Links
Overactive nerves in head and neck may account for 'ringing in the ears'
Date:1/10/2008

Do your ears ring after a loud concert" Nerves that sense touch in your face and neck may be behind the racket in your brain, University of Michigan researchers say.

Touch-sensing nerve cells step up their activity in the brain after hearing cells are damaged, a study by U-M Kresge Hearing Research Institute scientists shows. Hyperactivity of these touch-sensing neurons likely plays an important role in tinnitus, often called ringing in the ears. The study, now online in the European Journal of Neuroscience, will appear in the journals first January issue.

The research findings were made in animals, but they suggest that available treatments such as acupuncture, if used to target nerves in the head and neck, may provide relief for some people plagued by tinnitus, says Susan E. Shore, Ph.D., lead author of the study and research professor in the Department of Otolaryngology and the Kresge Hearing Research Institute at the U-M Medical School.

People with tinnitus sense ringing or other sounds in their ears or head when there is no outside source. Whether its mild and intermittent or chronic and severe, tinnitus affects about one in 10 people. An estimated 13 million people in Western Europe and the United States seek medical advice for it. It is a growing problem for war veterans. Since 2000, the number of veterans receiving service-connected disability for tinnitus has increased by at least 18 percent each year, according to the American Tinnitus Association.

Increasing numbers of baby boomers are also finding that when they cant hear as well as they used to, tinnitus seems to move in. The condition commonly occurs with hearing loss, but also after head or neck trauma such as whiplash or dental work.

Tinnitus varies in individuals from a faint, high-pitched tone to whooshing ocean waves to annoying cricket-like chirping or screeching brakes. For some, it is constant and debilitating.

Some people, oddly enough, find that if they clench the jaw or press on the face or neck, they can temporarily stop tinnitus, or in some cases bring it on. To understand tinnitus and its strange link to touch sensations, Shore and her research team have conducted a series of studies in guinea pigs, measuring nerve activity in a part of the brain called the dorsal cochlear nucleus that processes auditory and other signals.

In normal hearing, the dorsal cochlear nucleus is the first stop in the brain for sound signals arriving from the ear via the auditory nerve. Its also a hub where multitasking neurons process sensory signals from other parts of the brain.

In this study, we showed that when there is a hearing loss, other parts of the brain that normally convey signals to the cochlear nucleus have an enhanced effect, says Shore, who is also an associate professor in the Department of Molecular and Integrative Physiology at the U-M Medical School.

When you take one source of excitation away, another source comes in to make up for it. The somatosensory system is coming in, but may overcompensate and help cause tinnitis, she says.

The somatosensory system is a nerve network in the body that provides information to the brain about touch, vibration, skin temperature and pain. The part of the system that provides sensations from the face and head, called the trigeminal system, brings signals to the cochlear nucleus that help us hear and speak.

But when people experience hearing loss or some other event, such as having a cavity filled or a tooth implanted, these neurons from the face and head can respond like overly helpful relatives in a family crisis. The resulting neuron firings in the cochlear nucleus, like too many phone calls, create the din of tinnitus, a phantom sound produced in the brain.

In the study, Shore and the papers second author Seth Koehler, a U-M Ph.D. student in the U-M departments of Otolaryngology and Biomedical Engineering measured the patterns of activity of neurons in the brains of normal and deafened guinea pigs. They used a 16-electrode array to measure signals from the trigeminal nerve and multisensory neurons in the dorsal cochlear nucleus. When they compared results in the two groups, they found clear differences in trigeminal nerve activity.

The study shows that in deafened animals, the somatosensory response is much stronger than in animals with normal hearing, Shore says.

Shores research team knew from earlier research that some neurons in the cochlear nucleus become hyperactive after hearing damage, and this hyperactivity has been linked to tinnitus in animals.

This study shows that it is only those neurons that receive somatosensory input that become hyperactive, she says, which should make the search for treatments for tinnitus in some people more straightforward.

Many people with temporomandibular joint syndrome (TMJ), a condition that causes frequent pain in the jaw, experience tinnitus. Shores research could lead to a better understanding of this link. In people with TMJ, the somatosensory system is disrupted and inflamed. Shore says that its possible that in this situation, as in hearing loss, somatosensory neurons stir excessive neuron activity in the cochlear nucleus.


'/>"/>

Contact: Anne Rueter
arueter@umich.edu
734-764-2220
University of Michigan Health System
Source:Eurekalert  

Related medicine news :

1. Protein in human hair shows promise for regenerating nerves
2. WeissComm Partners Makes 10 New Hires as It Wins New Accounts and Grows Existing Business
3. World fertility experts to meet in Montreal - IVF and IVM patients to provide first-person accounts at 14th World Congress
4. Small Army Takes on Cure for Diabetes and New Approach to Ending World Poverty with Addition of Non-Profit Accounts
5. American Academy of Dermatology Association Commends President Bush for Signing Tanning Accountability and Notification (TAN) Act
6. Sutter Moves to Reduce Public Accountability, Slash Hospital Beds
7. BancTec Showcases Accounts Payable and Healthcare Solutions at The Association for Financial Professionals (AFP) Annual Conference
8. New Study Shows Lower Costs, Increased Consumer Engagement in Account-Based Health Plans
9. Big ticket: Youll spend more thinking about your bank account than about your wallet
10. Symmetry Medical Provides Update of Previously Disclosed Accounting Review at Sheffield, UK Operating Unit
11. Better detection accounts for increase in cases of thyroid cancer
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Overactive nerves in head and neck may account for 'ringing in the ears'
(Date:2/10/2016)... ... ... It’s that time of year when most people have forgotten all about their New ... (IAAM), Hall of Fame athlete and Garrison Forest School athletic director since 2005, knows ... of her first decisions when her IAAM two-year presidency began last July was to ...
(Date:2/9/2016)... Albuquerque, NM (PRWEB) , ... February 09, 2016 , ... ... proceeds from its Heart Rate Variability scans throughout the month to the American Heart ... to spot the first signs of heart disease and Health Quest’s INSiGHT Pulse Wave ...
(Date:2/9/2016)... ... February 09, 2016 , ... ... Snowfall4pod Digital, creators of the gContentManager & Distribution Network, today announced the ... and print-on-demand network. , AVALANCHE allows enterprise customers to license and create ...
(Date:2/9/2016)... ... February 10, 2016 , ... The Journal of Pain Research ... playing field .” , As corresponding author Dr John F. Peppin says “Terminology matters, ... diagnose our chronic pain patients. ‘Chronic cancer pain’ and ‘chronic non-cancer pain’ are ...
(Date:2/9/2016)... ... 2016 , ... METTLER TOLEDO has published a new guide ... understanding of the techniques they use so they can more easily spot potential ... and rework to create a leaner overall lab experience. , The new ...
Breaking Medicine News(10 mins):
(Date:2/9/2016)... 2016  Landauer, Inc. (NYSE: LDR ), a ... monitoring, outsourced medical physics services and high quality medical ... 2016 first quarter ended December 31, 2015. ... First Quarter Highlights , Revenue of $36.5 million ... 2015 , Domestic Radiation Measurement services revenues increased 2.8% ...
(Date:2/9/2016)... , February 9, 2016 ... gab heute den Abschluss eines Kooperationsvertrags mit ... umfassender Lösungen in den Bereichen Next-Generation-Sequencing (NGS), ... QGEN ; Frankfurt Prime Standard: QIA) gab ... Genomics für die Entwicklung und Förderung umfassender ...
(Date:2/9/2016)... Mast Therapeutics, Inc. (NYSE MKT: MSTX), ... disease and heart failure, today announced that it intends to ... stock in an underwritten public offering.  The offering is subject ... assurance as to whether or when the offering may be ... the offering.   --> --> ...
Breaking Medicine Technology: