XML Feed for RxPG News   Add RxPG News Headlines to My Yahoo!   Javascript Syndication for RxPG News

Research Health World General
 
  Home
 
 Latest Research
 Cancer
 Psychiatry
 Genetics
 Surgery
 Aging
 Ophthalmology
 Gynaecology
 Neurosciences
 Pharmacology
 Cardiology
 Obstetrics
 Infectious Diseases
 Respiratory Medicine
 Pathology
 Endocrinology
 Immunology
 Nephrology
 Gastroenterology
 Biotechnology
 Radiology
 Dermatology
 Microbiology
 Haematology
 Dental
 ENT
  Hearing Imapirment
 Environment
 Embryology
 Orthopedics
 Metabolism
 Anaethesia
 Paediatrics
 Public Health
 Urology
 Musculoskeletal
 Clinical Trials
 Physiology
 Biochemistry
 Cytology
 Traumatology
 Rheumatology
 
 Medical News
 Health
 Opinion
 Healthcare
 Professionals
 Launch
 Awards & Prizes
 
 Careers
 Medical
 Nursing
 Dental
 
 Special Topics
 Euthanasia
 Ethics
 Evolution
 Odd Medical News
 Feature
 
 World News
 Tsunami
 Epidemics
 Climate
 Business
Search

Last Updated: Aug 19th, 2006 - 22:18:38

Hearing Imapirment Channel
subscribe to Hearing Imapirment newsletter

Latest Research : ENT : Hearing Imapirment

   DISCUSS   |   EMAIL   |   PRINT
Aldosterone linked to good hearing as we age
Feb 12, 2006, 18:38, Reviewed by: Dr. Priya Saxena

"We found a direct link between blood levels of aldosterone and the ability of people to hear normally as they age. Depressed hormone levels may hurt hearing both in the inner ear and the part of the brain used for hearing. More research is needed, however, to understand the precise role that aldosterone plays – for instance, whether it's a cause of failed hearing, or whether it's symptomatic. Before we understand the issue more fully, people should not worry about their aldosterone levels or look to boost the amount in their bloodstream."

 
Researchers have linked a hormone known to adjust levels of key brain chemicals to the quality of our hearing as we age. The more of the hormone that older people have in their bloodstream, the better their hearing is, and the less of the hormone, the worse their hearing is.

The hormone, aldosterone, is known to regulate kidney function and also plays a role in controlling levels of two crucial signaling chemicals in the nervous system, potassium and sodium. For nerves to send signals crisply and work properly, potassium and sodium must be in precise proportion, without any disruption in the molecular channels or gates through which they move. Levels of potassium are particularly crucial in the sensitive inner ear, where fluid rich in potassium plays a central role in converting sounds into signals that the nervous system recognizes.

The team of scientists in Rochester, N.Y., put 47 healthy men and women between the ages of 58 and 84 through a battery of sophisticated hearing tests. Scientists also measured their blood levels of aldosterone, which is known to drop as people age. They found that people with severe hearing loss had on average about half as much aldosterone in their bloodstream as their counterparts with normal hearing. The researchers noted, however, that the levels of aldosterone found in all the participants is considered normal, and that no patients or physicians should consider altering aldosterone levels without more research.

The findings come from researchers at the International Center for Hearing and Speech Research (ICHSR), a group funded by the National Institute on Aging that is recognized as a leader in research on age-related hearing loss. The center includes scientists from the National Technical Institute for the Deaf at Rochester Institute of Technology and neuroscientists from the University of Rochester.

"The inner ear is especially sensitive to any disruption in potassium levels," said Robert D. Frisina, Ph.D., professor of Otolaryngology at the University of Rochester Medical Center and an adjunct professor at Rochester Institute of Technology. "We know that potassium levels in the inner ear seem to decrease as we age and that these falling levels play a role in age-related hearing loss, and we also know that blood levels of aldosterone generally decrease with age.

"We found a direct link between blood levels of aldosterone and the ability of people to hear normally as they age. Depressed hormone levels may hurt hearing both in the inner ear and the part of the brain used for hearing. More research is needed, however, to understand the precise role that aldosterone plays – for instance, whether it's a cause of failed hearing, or whether it's symptomatic. Before we understand the issue more fully, people should not worry about their aldosterone levels or look to boost the amount in their bloodstream."

The team led by Frisina published its results in the November issue of the journal Hearing Research. This week at the annual international meeting of the Association for Research in Otolaryngology in Baltimore, the team presented its latest results showing just how important potassium regulation is to age-related hearing loss.

In Baltimore, Otolaryngology medical resident Jared Spencer, M.D., presented results from "knockout" mice whose genes controlling the potassium channels in the inner ear don't function properly, and confirmed that malfunctioning potassium channels are central to age-related hearing loss, or presbycusis. The channels are highly concentrated in a part of the brain that plays an important role providing feedback from the brain to the ears. Frisina's team previously discovered that the feedback system is one of the first things to go wrong in age-related hearing loss, often declining in people who are in their 40s and 50s, usually before they even realize their hearing is declining.

"We are now working out some of the underlying biology about how the decline occurs," said Frisina. "We have evidence that these potassium channels may play an important role in the failure of the feedback system, which is a big part of age-related hearing loss."

Nearly everyone wrestles with failing hearing at some point. While some people suffer from hearing damage as a result of exposure to loud noise, or from other causes such as the side effects of some medications, for many people hearing problems occur with no known cause. Some people notice problems in their 40s and 50s, but the process becomes very noticeable for most people in their 60s and older.

Frisina said that until the biology of the problem is better understood, the best advice for people concerned about hearing loss is to limit exposure to loud, damaging noise and to medications that are toxic to the ears. He also counsels people to eat healthy and to exercise – "all those things you know you should be doing to stay healthy with age," he said.

Meanwhile, his team is looking at the possibility of using gene therapy to try to correct the problem. It may be possible some day to modify a person's inner ear to correct the potassium imbalance that is central to hearing loss. Such an approach might also address the biggest cause of congenital deafness, which involves a genetic mutation that mucks up the potassium balance in the inner ear.
 

- November issue of the journal Hearing Research
 

www.urmc.rochester.edu

 
Subscribe to Hearing Imapirment Newsletter
E-mail Address:

 

The new findings come from a research group founded by Robert Frisina's father, D. Robert Frisina, Ph.D., founding director of NTID, who heads one of the largest research groups in the world studying age-related hearing loss. The group has attracted top researchers from around the world to come together to study the problem. Members of the group, which numbers more than two dozen, hail from Egypt, Brazil, Russia, China, Korea, India, and the United States.

In addition to Frisina, Frisina and Spencer, the team includes post-doctoral research associate Sherif Tadros, M.D., of both the University and NTID, who is first author of the Hearing Research paper; research nurse Susan Frisina of both NTID and the University; audiologist Frances Mapes of NTID; and otolaryngologist Xiaozia Zhu, M.D., of the University.


Related Hearing Imapirment News

UK researcher identifies brain region responsible for spatial hearing
Beta-actin mutations linked to deafness and dystonia
Aldosterone linked to good hearing as we age
Salicylate causes tympanic membranes to rupture more easily
Amount of hearing in an ear prior to surgery is unrelated to a patient's ability to interpret speech using an implant
Spatial Hearing Aid Can Provide Direction of Sound
Stem Cells to Help Hearing Impaired


For any corrections of factual information, to contact the editors or to send any medical news or health news press releases, use feedback form

Top of Page

 

© Copyright 2004 onwards by RxPG Medical Solutions Private Limited
Contact Us