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National Institute on Deafness and
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For Immediate Release
Wednesday, February 13, 2008


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News Advisory

NIDCD-Supported Research on Stem Cells and Hearing Loss, Music through the Cochlear Implant and a Virtual Grocery Store for People with Balance Disorders Featured at ARO Conference in Phoenix
What: Current research supported by the National Institute on Deafness and Other Communication Disorders (NIDCD), one of the National Institutes of Health, will be featured at the 2008 Midwinter Meeting of the Association for Research in Otolaryngology (ARO).
When: February 16-21, 2008
Where: Phoenix Convention Center, Phoenix, Ariz.

Additional Information: Research topics to be presented by NIDCD-funded scientists will include:

State of the Science: Will Stem Cells Cure Hearing Loss Some Day?
Every time you cut your finger or burn your tongue, new cells are produced that are able to restore things to normal. So why can't the same happen for the tiny sensory cells in our inner ear, called hair cells, that translate sound into electrical signals? If they are damaged in humans — through disease, too much noise or certain medicines — they can't be regenerated. In this presentation, NIDCD-funded scientist Stefan Heller, Ph.D., Stanford University, describes two areas of exploration in which researchers are trying to grow new hair cells. He'll report on where the science currently stands in the differentiation of mouse and human stem cells into hair cells and the development of drug treatments that could one day be used to stimulate hair cell growth. The symposium presentation "Cochlear Hair Cell and Neuronal Regeneration — from the Culture Dish into the Animal" takes place Monday, February 18, 8:40 a.m. MST, West 101 A-C.

Beyond Words — Helping Cochlear Implant Wearers Listen to the Music
Cochlear implants have brought a sense of sound to more than 100,000 deaf and hard-of-hearing people worldwide, yet music perception remains a source of frustration for many implant users. To better understand the problem, researcher Jay Rubinstein, M.D., Ph.D., and others from the University of Washington have developed the Clinical Assessment of Music Perception (CAMP) test, an easy-to-use computer tool designed to help clinicians assess a cochlear implant wearer's ability to discriminate pitch progression, melody and the source of the musical tones, whether it's a guitar, harmonica or flute. In this presentation, Dr. Rubinstein's research team present data from one commercially funded multicenter study, plus results from additional research in his laboratory, in which CAMP is used to assess music perception in people who wear cochlear implants. In this same workshop, rock-and-roll and R&B musician and cochlear implant wearer Richard Reed conducts a first-hand demonstration of what music sounds like through a cochlear implant.  The workshop session "Music Lost and Found" (Reed)  takes place Sunday, February 17, 7:50 p.m. MST, West 301 A. The session "Music Perception with Cochlear Implants" (Rubinstein et al)  takes place at 8:20 p.m. in the same location.

How Background Noise Affects Language-Learning Skills in Kids with Cochlear Implants
Understanding what someone is saying in a roomful of talkers is difficult enough for a person with normal hearing. Researchers at the University of Wisconsin wanted to find out how such an environment might affect toddlers fitted with cochlear implants who are developing their language skills. Comparing children with normal hearing to children with one or two cochlear implants, the researchers tested the children's ability to identify spoken words in quiet environments and environments in which people were talking in the background. Children with normal hearing performed very well in the quiet environment, though their ability declined when there was background noise. Children with cochlear implants were not as accurate as the children with normal hearing in recognizing speech in both quiet and noisy environments. In addition, children with cochlear implants took much longer at identifying speech, regardless of the presence of background noise. These data may provide insight into how young children who use cochlear implants develop their language skills. The podium session "The Effect of Competing Noise on Spoken Word Recognition in Toddlers Who Use Unilateral or Bilateral Cochlear Implants" takes place Wednesday, February 20, 3:15 p.m. MST, West 101 A-C.

Researchers Use Common Hearing Test to Explore Link Between Iron Deficiency and Cognitive Impairments
Iron deficiency is the most common nutritional disorder, affecting more than two billion people worldwide. It is especially prevalent in young children and women during their childbearing years. Infants who are iron-deficient often experience learning problems and other cognitive impairments, yet the underlying mechanism is unclear.

Researchers at the University of Rochester Medical Center have found that rat embryos that were deficient in iron very early in their development exhibited a significant loss of myelin, a protein that surrounds nerve fibers of the central nervous system and helps speed the rate by which electrical signals travel along a nerve fiber. This loss of myelin is associated with slower auditory brainstem responses (ABRs), a non-invasive measure of the time it takes for sounds played into the ear to travel along the auditory nerve to the brain. The researchers find that ABR technology is a useful tool for diagnosing the loss of myelin along the auditory nerve and for pinpointing the window of time when iron deficiency is most damaging to the developing brain.  Based on this animal model, the researchers propose that cognitive impairments found in iron-deficient children could in part be due to defects in auditory processing and consequently language acquisition. The poster session "Non-Invasive Strategy to Characterize the Impact of Gestational Iron Deficiency on Auditory Nerve Myelination" takes place Tuesday, February 19, 1:00 p.m. MST (48 hours), West 301 B-D.

Virtual Grocery Store Could Help People with Balance Problems
To someone with a balance disorder, a trip to the grocery can be a dizzying experience. Walking the aisles can be difficult when scanning store shelves for one product amidst an array of fruit roll-ups, frozen waffles and fabric softeners. Researchers from the University of Pittsburgh are using virtual reality to learn more about the issue. In this clinical study, they asked volunteers with and without balance problems to shop for two products in a simulated grocery aisle while walking on a treadmill. The purpose was to determine if their ability to complete the task correlated with other clinical measures of balance. The researchers found a moderate to strong relationship between the volunteers' performance in the simulated store compared with other measures. The researchers hope to determine if virtual reality can be used as a therapeutic tool to help people recover from dizziness and balance problems. The poster session "Relationship Between Clinical Measures and Performance in a Virtual Grocery Store Environment in Persons with Vestibular Dysfunction" takes place Sunday, February 17, 1:00 p.m. MST  (48 hours), West 301 B-D.

Combination Hormone Replacement Therapy Increases Risk of Hearing Loss
As we age, our hormone levels decline, often resulting in hormonal imbalances. This is especially true in women who are going through menopause. To counter these occurrences, some women use hormone replacement therapy (HRT), a type of drug therapy taken orally to restore levels of either estrogen alone or both estrogen and progestin. Recent studies have shown that HRT can increase a person's risk of breast cancer, heart disease and stroke. In this presentation, Robert Frisina, Ph.D., University of Rochester Medical Center, describes research performed in his laboratory that, among other things, compared the hearing abilities of older women who had taken HRT with those who hadn't. They found that the women who had taken combination HRT had significantly worse hearing than those taking estrogen HRT alone or those who had never taken HRT. The results indicate that combination HRT involving progestin appears to have a negative effect on hearing when compared to estrogen alone. Understanding the effects of changes in hormone levels on sensory systems is critical for improving hearing and balance function in older people. The symposium presentation "Hormone Replacement Therapy Can Negatively Affect Hearing in Aged Women and Female Mice" takes place Wednesday, February 20, 2:25 p.m. MST, West 301 A.

Seeing Is Believing — How the Eyes May Help Reveal Hearing Loss
Can an eye exam reveal hearing loss? Researchers at the University of Oregon believe it can. In previous studies, they have demonstrated that the pupils of barn owls dilate in a reliable and distinctive way in response to a sound's loudness, pitch or location, enabling researchers to assess the detection and discrimination of sounds. In this study, the researchers evaluated whether this same response — called the pupillary dilation response (PDR) — may be an effective tool for measuring hearing loss in people. The researchers had volunteers listen to sounds of varying loudness and frequency and compared PDR measurements with traditional measurements in which subjects indicated detection by voluntarily responding with a yes or no. They found that the values were similar to one another, indicating that the PDR approaches the sensitivity of traditional audiometric tests. The researchers suggest that the PDR is a non-invasive way of evaluating people's hearing that does not require the person to speak or otherwise indicate whether or not he or she heard a sound. This may be useful for patients who are too young or are physically unable to participate actively in their evaluation. The poster session "The Pupillary Dilation Response: A Tool for Assessing Sensory Performance in Humans" takes place Tuesday, February 19, 1:00 p.m. MST (48 hours), West 301 B-D.

Stem Cells Grow in Inner Ears of Novel ‘Humanized' Mice
Age-related hearing loss is a common problem affecting older adults. A possible contributing factor is the gradual depletion of fibrocytes, cells found in the inner ear that play an important role in the recycling of key electrolytes and that are essential for normal hearing and balance. Although fibrocytes are able to replenish themselves after injury, this ability seems to decline with age. Knowing the source of these fibrocytes and the mechanisms regulating their replenishment and differentiation may lead to new strategies for treating age-related hearing loss. Researchers at the Medical University of South Carolina and the Tokai University School of Medicine, Tokyo, have shown that fibrocytes in the adult mouse's inner ear can be derived from hematopoietic stem cells (HSCs), the blood-forming stem cells that originate from such sources as bone marrow and umbilical cord blood. In this study, the research team wanted to learn if fibrocytes in the human inner ear are also derived from HSCs. They injected human HSCs into mouse models that are genetically engineered to accept human cells and tissues. After four months, the percentage of human cells in the mouse's bone marrow ranged from roughly 26-60 percent. In addition, HSCs were present in the inner ears of all the recipient mice, including those regions where fibrocytes are typically located. The poster session "Engraftment of Human Hematopoietic Stem Cells in the Inner Ear of a Humanized Mouse Model" takes place Tuesday, February 19, 1:00 p.m. MST (48 hours), West 301 B-D.

Can Cutting Calories Save Your Hearing?
Calorie-restricted diets have been known to fend off many age-related illnesses and disorders, not to mention death. So could it also protect against age-related hearing loss? Hearing loss from aging, also called presbycusis, is one of the most common disorders in older adults. Not only does it affect hearing, but it is associated with age-related changes to the brain that can impair a person's ability to process speech.

Researchers at Southern Illinois University School of Medicine wanted to find out if cutting calories or feeding animals every other day, both of which have been found to extend lifespan, could postpone presbycusis and, if so, whether gender plays a role. Female and male mice were reared for two years on one of three diets: a diet of 30 percent fewer calories; a diet in which the mice ate every other day; or a diet in which the mice ate whenever they pleased. After two years, when both male and female mice began showing signs of presbycusis, the researchers conducted behavioral tests to assess hearing. They found that the diets affected the two sexes very differently. In the males, the calorie-restricted and every-other-day diets appeared to hasten presbycusis. However, in females the opposite was true: both calorie-restricted and every-other-day diets resulted in improved hearing when compared to the eat-as-they-please diet. The poster session "Effects of Caloric Restriction and Every Other Day Feeding on Presbyacusis in a Mouse Model" takes place Sunday, February 17, 1:00 p.m. MST (48 hours), West 301 B-D.

A Miniaturized Drug-Delivery System for the Inner Ear
When researchers discuss the possibility of drug therapies that can treat hearing loss and balance disorders, one of the first hurdles is the development of drugs that are safe and effective in treating these disorders. Developing drug treatments is a long and costly process. The second hurdle is getting the drugs  to where they need to go, deep inside the skull to the inner ear. Development of a safe and efficient route for delivery of drugs to the inner ear represents a significant technical challenge. Scientists in the Massachusetts Eye and Ear Infirmary, a part of Harvard Medical School, and the Draper Laboratory, a research and development laboratory in Cambridge, Mass., are tackling the second hurdle. Using microfluidic and microelectromechanical systems (MEMS) technologies, they have developed a miniaturized pump system that, in animal studies, is able to safely and effectively deliver drugs to the inner ear for several hours to several months. Because the device is able to precisely target the fluid of the inner ear, the researchers suggest that the device will serve as a useful tool for investigating the molecular mechanisms associated with inner ear diseases and for testing new drug treatments. Their goal is to make the micropump and its electronic components so small that the entire system will one day be able to be implanted in the mastoid cavity, an opening in the bone behind a person's ear, allowing for programmable, automated, long-term delivery of therapeutic compounds to the inner ear. The symposium presentation "Microfluidic Drug Delivery to the Cochlea" takes place Monday, February 18, 10:55 a.m. MST, West 101 A-C.

For more information about the Association for Research in Otolaryngology, visit their Web site at www.aro.org

NIDCD supports and conducts research and research training on the normal and disordered processes of hearing, balance, smell, taste, voice, speech and language and provides health information, based upon scientific discovery, to the public. For more information about NIDCD programs, see the Web site at www.nidcd.nih.gov.

The National Institutes of Health (NIH) — The Nation's Medical Research Agency — includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.


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