What Did You Say?
Understanding Hearing and Vestibular Function
September 30, 2003

Statistics from the Centers for Disease Control indicate that 34 million people in the U.S. (about one in ten) suffer from hearing loss. Of these 34 million people, ap-proximately 86 percent are considered hard of hearing and 14 percent are considered deaf. Poor hearing can be caused by numerous factors, among them aging, heredity, noise exposure, injury, and disease.

Hearing loss is particularly prevalent among seniors, affecting about one in three of all people 65 and older. In fact, it trails only arthritis and hypertension among treatable but disabling conditions in this age group. As the baby boom generation approaches retirement, the number of people who are hard of hearing is expected to increase rapidly, mostly likely doubling by the year 2030.

The ear is composed of three major regions, each of which serves a distinct and important function and is vulnerable to its own diseases and disorders. The outer ear consists of the ear canal and the visible parts of the ear; the middle ear is composed of the eardrum and three tiny bones that transmit sound; and the inner ear contains organs important for both hearing and balance.

There are two basic kinds of hearing loss, conductive and sensorineural. Conductive hearing loss normally involves a problem with the outer or middle ear. When a hearing impairment is caused by the interruption of sound transmission to the inner ear, it is classified as a conductive loss. This abnormality may be due to a variety of causes ranging from wax blockage to infection to a punctured eardrum.

Sensorineural (nerve-related) hearing loss involves problems or damage in the inner ear. While it can also, like conductive loss, be caused by deep infection or trauma, sensorineural hearing loss is most frequently caused by aging and/or noise exposure. Tumors can also cause sensorineural hearing loss by damaging either the organs of the inner ear or the nerves that carry their messages to the brain.

In addition to its role in the hearing process, the inner ear is also home to the vestibular system, a collection of small organs with an integral role in maintaining balance. Problems with the vestibular system can be caused by infection, disease, or trauma and can cause dizziness, unsteadiness, and nausea.

Tonight, Drs. Barry E. Hirsch and Yael Raz will take us on a tour of the ear as they explain the dynamics of hearing and balance. They will also discuss types of hearing loss, ways of testing hearing and vestibular function, and the latest diagnostic and treatment techniques for a wide range of ear-related disorders and diseases.

Barry E. Hirsch received his M.D. degree at the University of Pennsylvania and completed his otolaryngology residency at the University of Pittsburgh School of Medicine. He also received a subspecialty fellowships in neurotologic surgery at the School of Medicine and at the University of Zurich in Switzerland. He joined the Department of Otolaryngology in 1985 and was named director of the Division of Otology in 1999.

Dr. Hirsch's fields of clinical and research interest are otology, neurotology, cranial base surgery, cochlear implants, and acoustic neuromas. Dr. Hirsch is also an active educator and is involved with the university's otology fellowship training program and resident education.

Yael Raz, M.D.
Assistant Professor of Otolaryngology, School of Medicine

Yael Raz received her M.D. degree from the University of California Los Angeles School of Medicine. Dr. Raz completed residency training in otolaryngology-head and neck surgery as well as fellowship training in otology, neurotology, and skull base surgery at Johns Hopkins University.
Dr. Raz's clinical interests include the management of chronic ear disease, conductive and sensorineural hearing loss, skull base tumors, and vestibular disorders. Her research focuses on cochlear development with an emphasis on the molecular mechanisms that guide connections between the nervous system and the developing inner ear.

The Encyclopedia of Deafness and Hearing Disorders. Allen E. Sussman, Ph.D., Carol Turkington. Facts on File, 2000.

Fundamentals of Hearing: An Introduction. William A. Yost. Academic Press, 2000.

Hearing Better: Understanding Your Hearing and Ear Care Options.
John M. Burkey, William H. Lippy, Arnold G. Schuring, Franklin M. Rizer. Upublish.com, 1999.

Mayo Clinic on Hearing: Strategies for Managing Hearing Loss, Dizziness, and Other Ear Problems. Wayne Olsen. Mayo Clinic, 2003.

A Quiet World: Living With Hearing Loss. David G. Myers. Yale University Press, 2000.

Tinnitus: Questions and Answers. Barbara Tabachnick Sanders, Jack A. Vernon. Pearson Allyn & Bacon, 2001.

When the Brain Can't Hear: Unraveling the Mystery of Auditory Processing Disorder. Teri James Bellis. Atria Books, 2003.

Auditory Sound Transmission: An Autobiographical Perspective.
Jozef J. Zwislocki. Lawrence Erlbaum Association, 2002.

webdb.nidcd.nih.gov/resdir/resourc.html
The National Institute of Deafness and Other Hearing Disorders Directory lists national organizations that focus on health issues relating to hearing, balance, smell, taste, voice, speech, and language.

www.earfoundation.org
The EAR Foundation is a national non-profit association of physicians, educators, and concerned citizens. Through its Web site, it provides the general public with support services through its website including a network for people suffering from Meniere's Disease, online support groups, and ear health information tailored to seniors and children.

www.vestibular.org
The Vestibular Disorders Association (VEDA) is a nonprofit organization that provides information to health professionals and to the general public about inner ear balance disorders like Meniere's disease, benign paroxysmal positional vertigo (BPPV), and labyrinthitis. VEDA offers education and support through its books, videos, resource lists, short publications, and membership services.

www.entnet.org
The American Academy of Otolaryngology-Head and Neck Surgery is the world's largest organization representing specialists who treat the ear, nose, throat, and related structures of the head and neck. The academy's Web site provides a clearinghouse of information on the medical disorders treated by otolaryngologists.

www.ata.org/
The Web site of the American Tinnitus Association (ATA) offers unbiased information about tinnitus and other hearing disorders, listings of medical professionals who treat the condition, and answers to frequently asked questions.

www.agbell.org/
The Alexander Graham Bell Association offers a wealth of information about hearing loss, including links to advocacy groups and brochures about detecting hearing loss, advice for parents, hearing technology, and more.