Tinnitus
Medical experts have long grappled with a precise definition of the condition – that is, whether it is a syndrome or a disorder. A syndrome is a set of symptoms that accompanies another separate disorder while a disorder is a culmination of definitive symptoms. Whatever the technical term, it can be a debilitating condition.
Although persistent tinnitus is a common condition, it is usually benign but very annoying. It is estimated that up to 50 million American adults are bothered by it in some form or another. Sometimes the condition interferes with sleep. Tinnitus is frequently associated with most other ear disorders as well as other diseases, including cardiovascular disease, allergies, and anemia.
Tinnitus has been described since the time of the ancient Pharaohs and still remains a mystery as to how mechanisms trigger the sounds within the ear. Several theories have been proposed. One is that something happens within the central nervous system, similar to the phantom-like sensations experienced after an amputation. In similar fashion, the CNS is somehow responding to hair cells that have been lost by stimulating electric signals to the brain.
Another theory suggests that it is centered in the brain, based on evidence from PET (positron emission tomography) scans. PET scans reveal information about which part of the brain is being used to process information or to accomplish a specific task. Careful study of PET imagery of people with tinnitus suggests that tinnitus sounds stimulate a part of the brain different from that stimulated by external sounds.
Some researchers also speculate that tinnitus arises in the cochlea, specifically from disorganized activity of the hair cells. Others think the cause may lie with the activity of chemicals in the auditory nerve, which carries messages between the inner ear and the brain. Evidence also suggests that spontaneous nerve activity in the auditory pathway may be the culprit.
Turbulent blood flow through veins and arteries may also produce a sound sensation. Such blood vessels as the carotid artery and the jugular vein lie close to the inner ear. And still another thought is that tinnitus may also result from a misalignment of the jaw joint (temporomandibular joint) which can produce a clicking or grating sound.
Most scientists agree, however, that the condition most likely stems from multiple causes and mechanisms. Since a definitive cause has not been found, neither has a cure. Therfore, most people have to live with the condition and develop ways to minimize its effect on their daily lives.
Classifications of Tinnitus
Some experts have placed tinnitus into two broad categories: objective and subjective.
- Objective tinnitus is sometimes referred to as pulsatile; that is, a sound sensation that can be heard within the body as that from a turbulent blood flow. Atherosclerosis, for example, is a buildup of cholesterol and other fatty deposits that can cause the blood vessels to narrow, requiring a more forceful blood flow. This causes the heart to work harder, to a point where the ears can detect each heartbeat. The malformation of small blood vessels (capillaries) connecting the arteries and veins can also produce an audible pulse sound. Other possible sources of objective tinnitus include muscle spasms, movement of the eustachian tube, and spontaneous vibrations of the hair cells in the inner ear. About 4% of individuals with tinnitus have the objective type, and treating the vascular conditions may help reduce or even eliminate the sounds.
- Subjective tinnitus involves sounds that only the individual can detect, differing from the objective type where the doctor may also hear the sounds through a stethoscope. As a result, scientists must rely on how well people describe what they are hearing. In fact, some experts have compared the effort of defining subjective tinnitus to the popular fable of the blind mice attempting to describe an elephant. The consensus may in fact turn out to be quite different from the reality. Many believe the problem originates somewhere within the structures of the inner ear, as the cochlea and the auditory nerve, or within the auditory centers of the brain.
Although the precise nature of subjective tinnitus is unclear, several factors are known to trigger the condition or make it worse:
- Loud noises can damage hair cells in the cochlea causing a permanent condition. About 90% of people with tinnitus have some form of noise-induced hearing loss. Age-related hearing loss may also precipitate tinnitus as will a wax buildup or an ear infection.
- Medications, described as ototoxic, are associated with producing tinnitus as one of the side effects.
- Jaw disorders may result in noises in the ear. A dentist who specializes in the treatment of this joint may be able to correct the alignment and eliminate the associated noises.
Other factors associated with tinnitus include:
- Schwannomas (benign tumors that grow on nerve fibers of the brain)
- trauma or injury to the head or neck
- perilymph fistula (a rupture in the membrane covering the oval window)
- otosclerosis (stiffening of the middle ear bones)
- Meniere’s disease (causes excess fluid in the inner ear)
- excessive sodium intake
- stress (emotional or physical)
- Hyperacusis is another condition often associated with tinnitus and involves an extreme sensitivity to sound. Such everyday noise as traffic, conversation, and ringing telephone may seem uncomfortably loud. The cause of this is unclear and can be more debilitating than tinnitus. A person with severe hyperacusis may avoid social situations for fear of exposure to painful noise (phonophobia). Although some form of hyperacusis may occur in people with hearing loss, those reporting hyperacusis usually have normal hearing.
Treatments
Treatments consist only of managing the symptoms.
- Option One: Attend a program that gradually increases the tolerance of normal sounds. This may involve a white noise generator, an electronic device that generates a hissing sound similar to that when a radio is turned between stations. Initially the device is turned to barely audible levels and then gradually increased to higher levels for regularly set periods of time.
- Option Two: Using a hearing aid that will attempt to include enough background noise so as to mask the tinnitus sounds. Hearing aids can amplify external sounds so that the sounds of tinnitus are less noticeable. However, if there is no hearing loss or the tinnitus is at a different frequency from any hearing loss, a hearing aid may not be helpful.
- Option Three: In cases where option two cannot help, an alternative might be to wear a simple masking device that fits behind the ear. This device resembles a hearing aid; but, instead of amplifying sounds, it produces low-level background noise that is supposed to be easier to tolerate than tinnitus. There are controls on the masker to raise or lower the loudness. Its frequency is usually programmed by the manufacturer. An audiologist will help with the necessary choice.
- Option Four: Using a combination hearing aid and masker. This device amplifies environmental sounds and speech but can also provide background noise to mask the tinnitus.
- Option Five: Using a bedside masker or loudspeaker. Since tinnitus is often more noticeable at night because everything else is so quiet, using a bedside masker or loudspeaker allows select sounds, as ocean waves, falling rain, or white noise to override the tinnitus sounds. This type of masker can help relax and obscure the noise of tinnitus during periods of rest or sleep.
- Option Six: Others find short periods of relief in a form called residual inhibition. This is a time when perception of tinnitus is partially or completely reduced after removing the masker. These episodes may last from less than 30 seconds to two or three hours.
- Option Seven: Cochlear implants. In certain cases, as in those with total or near total hearing loss, the use of a cochlear implant may help decrease tinnitus. A cochlear implant is a hearing device implanted behind the ear that picks up external sounds and sends them to the brain as electrical signals. These signals help the wearer hear speech and environmental sounds. However, cochlear implants have also been known to induce symptoms of tinnitus. (See more information separately.)
- Other treatments include drugs to mask symptoms of depression or dizziness, cognitive therapy, biofeedback, and a retraining program where the person is taught to refocus attention from the problem to something else. Still others have found relief through acupuncture, acupressure, yoga, hypnosis, and joint and muscle manipulation. Vitamin and mineral supplements, dietary controls, and herbal medicines have also improved overall health to the point where tinnitus has disappeared.
