Treating Tinnitus

Hearing is a series of events in which sound waves in the air produce electrical signals and cause nerve impulses to be sent to the brain where they are interpreted as sound. The ear has three main parts: the outer, middle and inner ear. Sound waves enter through the outer ear and reach the middle ear where they cause the ear drum to vibrate. The vibrations are transmitted through three tiny bones in the middle ear, called the ossicles. These three bones are named the malleus, incus and stapes (and are also known as the hammer, anvil and stirrup). The ear drum and ossicles amplify the vibrations and carry them to the inner ear. The stirrup transmits the amplified vibrations through the oval window and into the fluid that fills the inner ear. The vibrations move through fluid in the snail-shaped hearing part of the inner ear (cochlea) that contains the hair cells. The fluid in the cochlea moves the top portion of the hair cells, called the hair bundle, which initiates the changes that lead to the production of the nerve impulses. These nerve impulses are carried to the brain where they are interpreted as sound. Different sounds move to the population of hair cells in different ways, thus allowing the brain to distinguish among various sounds.

For the first time, scientists (Alan H. Lockwood, M.D., of the State University of New York in Buffalo) have located an area in the brain involved in the production of tinnitus. Tinnitus is a ringing, roaring, buzzing, or clicking sound that occurs inside the head, it is often referred to as "ringing in the ears." The noise can be intermittent or constant, with single or multiple tones; it can be subtle or at a life-shattering level. It can strike people of all ages and, for most, it is difficult to treat.

There are currently over 50 million Americans who are affected by tinnitus to some degree. Of these, about 12 million suffer severely enough to seek medical attention. And, about one million sufferers are so seriously debilitated that they cannot function on a "normal," day-to-day basis.

Using positron-emission tomography (PET), Dr. Lockwood's group was able to map brain regions of individuals who had tinnitus in only one ear. These individuals also had the ability to change the loudness of their tinnitus by performing special movements of their face and mouth. Cerebral blood flow, an indication of increased brain activity, was measured while these individuals were at rest, and performed the movements that affected their tinnitus, and while listening to loud beeps or pure tones that were presented using ear phones. The PET scan detected changes in the auditory cortex, that part of the brain that processes sounds, on the side of the brain opposite the tinnitus. In contrast, the auditory cortex on both sides of the brain reacted to pure tones presented to one ear at a time. Since external tones presented to one ear affect both sides of the brain, the fact that the internal tones of tinnitus affect only one side of brain indicate that tinnitus may be initiated by brain activity rather than by the ear.

Having the ability to image brain activity patterns during various communication events involving stuttering, aphasia, tinnitus, and American Sign Language is revolutionizing our understanding of normal and disordered processes of human communication. In one of many remarkable advances this year, NIDCD scientists are able to visualize brain activity occurring with tinnitus, or ringing in the ears. Tinnitus has been extremely difficult to study without an objective model as it is associated with virtually every kind of hearing loss. These studies provide ground-breaking information about the nature of tinnitus, which will hopefully lead to improved strategies for diagnosis and treatment for the millions of Americans challenged with the incessant or intermittent audiotory sensation that is tinnitus.

While not every case of tinnitus has an apparent source, there are a variety of causes. Exposure to loud noise, either over an extended period of time or one extreme incident, is probably the most common. Other possible causes of tinnitus include: certain medical conditions; certain medications; allergies.

Exposure to harmful sounds causes damage to the sensitive hair cells of the inner ear and to the nerve of hearing. These structures can be injured by noise in two different ways: from an intense brief impulse, such as an explosion, or from continuous exposure to noise, such as that in a woodworking shop.

The effect from impulse sound can be instantaneous and can result in an immediate hearing loss that may be permanent. The structures of the inner ear may be severely damaged. This kind of hearing loss may be accompanied by tinnitus, which may subside over time. Hearing loss and tinnitus may be experienced in one or both ears, and tinnitus may continue constantly or intermittently throughout a lifetime.

There is not a cure for tinnitus. However, a variety of treatment options exist that offer varying levels of relief to many sufferers. Treatment options include:

Be sure to consult with a qualified healthcare professional who treats tinnitus for more information about these and other treatment options.

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