Head noise, or tinnitus, is common. It may be intermittent or constant, mild or severe, and vary from a low roar to a high pitched type of sound. It may be subjective (audible only to the patient) or objective (audible to others). It may or may not be associated with hearing impairment.
Tinnitus must always be thought of as a symptom and not a disease, just as pain in an arm or leg is a symptom and not a disease. Because the function of the auditory (hearing) nerve is to carry sound,when it is irritated from any cause, the brain interprets this impulse as noise. This phenomenon is similar to sensation nerves elsewhere. If one pinches the skin, it hurts because the nerves stimulated carry pain sensation.
Tinnitus may or may not be accompanied by a hearing impairment. Hearing is measured in decibels (dB). A hearing level of 0 to 25 dB is considered normal for conversational speech.
Conversion to Degree of Handicap
- 25dB 0%
- 30dB (Mild) 8%
- 35dB (Mild) 15%
- 45dB (Moderate) 30%
- 55dB (Moderate) 45%
- 65dB (Severe) 60%
- 75dB (Severe) 75%
- 85dB (Severe) 90%
In order to understand the possible causes of tinnitus, one must have some knowledge of the hearing mechanism. This mechanism is made up of five main divisions: the external ear, the middle ear, the inner ear, the nerve pathways, and the brain.
The external ear consists of the auricle and the external ear canal. These structures collect the sound waves and transmit them to the ear drum.
The middle ear lies between the eardrum and the inner ear. This chamber contains three ossicles: the malleus, the incus and the stapes (hammer, anvil and stirrup). Vibrations of the eardrum are transmitted across the middle ear space by these three small ear bones. Movement of the third bone (stapes or stirrup) results in fluid waves in the inner ear.
The middle ear chamber is lined by a membrane similar to the lining of the nose and contains secreting glands and blood vessels. This chamber is connected to the back of the nose by a small channel called the eustachian tube.
The eustachian tube serves to maintain equalization of pressure between the middle ear chamber and the outside atmosphere, as evidenced by the popping sensation noted in the ear during altitude changes.
The inner ear is enclosed in dense bone and contains fluid and tiny hearing cells. It is lined by a delicate, transparent membrane supplied by microscopic blood vessels. In this small chamber, fluid waves resulting from movement of the stapes are transformed into electrical impulses in the nerve.
The electrical impulses created in the inner ear chamber are transmitted to the brain by the hearing nerve. The nerve pathways leading to the brain are enclosed in a small bony canal along with the balance nerve and the nerve which stimulates movement of the facial muscles.
As the hearing nerve pathways reach the brain, they divide into an intercommunicating system far more complex than the most extensive telephone exchange. Nerve impulses are then transformed into recognizable sound.
Most tinnitus is audible only to the patient; this is called subjective tinnitus. Tinnitus audible to both the patient and others is called objective tinnitus.
Objective Tinnitus may be due to muscle spasms in the middle ear or eustachian tube, or to abnormalities in the blood vessels surrounding the ear.
Tinnitus may result from spasm of one of the two muscles attached to the middle ear bones, or from spasm of muscles attached to the eustachian tube, the channel which connects the middle ear to the back of the nose.
There are two muscles in the middle ear: the stapedius, attached to the stapes bone (stirrup) and the tensor tympani, attached to the malleus bone (hammer). These muscles normally contract briefly in response to very loud noise, or as a result of a startle reaction.
On occasion, one or both of these muscles may begin to contract rhythmically for no apparent reason, for brief periods of time. Because the muscles are attached to one of the middle ear (hearing) bones, these contractions may result in a repetitious sound in the ear. The clicking, although annoying, is harmless and usually subsides without treatment.
Should the muscle spasm continue, medical treatment (muscle relaxants) or surgery (cutting the spastic muscle) may be necessary.
Muscular tinnitus resulting from spasm of one of the various throat muscles attached to the eustachian tube is uncommon, but can also result in episodes of rhythmic clicking in the ear. This is called palatal myoclonus and usually responds to muscle relaxants.
There are two large blood vessels intimately associated with the middle and inner ear: the jugular vein and the carotid artery. These are the major blood vessels supplying the brain.
It is not uncommon to hear one's heart beat or to hear the blood circulating through these large vessels. This may be particularly noticeable when an individual has a fever or a middle ear infection, or after engaging in strenuous exercise. The circulation sound in these instances is temporary and is not audible to others.
On occasion, the sounds of blood circulating will become audible to others. This can be due to a thickening of the blood vessel wall (a normal occurrence as one grows older), a kink in the vessel, or an abnormal growth on the vessel wall. Further testing may be necessary to determine the cause and treatment indicated in these uncommon cases.
External Ear Tinnitus
Obstruction of the external ear canal by wax, foreign bodies, or swelling may produce a hearing impairment or pressure on the eardrum. This frequently results in a pulsating type of tinnitus.
Middle Ear Tinnitus
Disturbances of function of the middle ear may result from allergy, infection, injury, scar tissue, or impaired motion of the three middle ear bones. These disturbances often result in hearing impairment and may lead to head noise. But there is no relationship between the degree of hearing loss and the intensity of the tinnitus.
Inner Ear Tinnitus
Any condition which disturbs the fluid pressure in the inner ear chamber may produce head noises. This may be due to infection, allergy, or circulatory disturbances which produce changes not only in the fluid, but also in the encasing membranes of the inner ear.
Nerve Pathway Tinnitus
The nerve pathways are the most delicate structures of the hearing mechanism. The small hair cells which serve to transform fluid waves into nerve impulses are analogous to the cells of the eye's retina which transform light waves into nerve impulses. The slightest swelling of or interference with these delicate cells from any cause readily produces impairment of function and irritation. This may occur from a variety of causes: infection; allergic swelling; systemic diseases, either acute or chronic, with resultant toxic effects; sudden exposure to a blast of sound or prolonged exposure to high noise levels in susceptible persons; certain drugs to which the patient may be sensitive; and minute changes in the blood supply with resultant changes in nutrition.
Pressure changes may produce swelling both from outside and from within the nerve as it transverses the bony tunnel to the brain. In these instances, the tinnitus occurs on one side of the head and, because the bony tunnel cannot expand with the pressure phenomenon, not only the function of the hearing nerve, but also that of the balance and facial nerves, may become disturbed as they pass through this bony tunnel.
Rupture or spasm of one of the small blood vessels in the auditory pathway produces pressure and interference with circulation. Consequently, sudden tinnitus, with or without partial or total loss of hearing function, may occur. If the blood clot is small, it may absorb with little or no permanent damage. This condition, like the pressure phenomenon, occurs only on one side and, because it has occurred once, that doesn't mean it would necessarily occur again either on the same or the opposite side.
Any disturbance, whether due to swelling, pressure, or interference with circulation, may occasionally involve one or more of the complex hearing pathways as they enter and terminate in the brain. In most of these instances, the symptoms are localized to one ear and other symptoms and signs develop which aid the doctor in determining the cause and location of the disturbance.
Head noise or tinnitus may or may not be associated with hearing impairment. After reviewing the many causes of this symptom, it is easy to understand why the hearing may, at times, be affected when tinnitus is present. If a hearing loss coexists with tinnitus, the severity of the head noise is not an index as to the future course of the hearing impairment. Many persons with tinnitus have the erroneous fear that they are going to lose their hearing. This is an unnecessary fear.
If the examination reveals a local or general cause of the head noise, correction of the problem may alleviate the tinnitus. In most cases, however, there is no medical or surgical treatment which will eliminate tinnitus.
- Make every effort to avoid nervous anxiety, for this only stimulates an already tense auditory system.
- Make every attempt to obtain adequate rest and avoid over fatigue.
- The use of nerve stimulants is to be avoided. Therefore, excessive amounts of coffee (caffeine) and smoking (nicotine) should be avoided.
- Learn as quickly as possible to accept the existence of the head noise as an annoying reality, and then promptly and completely ignore it as much as possible.
- Tinnitus will not cause you to go deaf, will not result in your losing your mind, or cause your death, so immediately forget such distracting and terrifying thoughts.
- Tinnitus is usually more marked after one goes to bed and surroundings become quiet. Any noise in the room, such as a loud ticking clock or a radio, will serve to mask the irritating head noises and make them much less noticeable. Sears has available a bedside noise masker that can be adjusted to various tones and intensities. This instrument is known as a "Sleep Mate". Sleep A Tone, a device available from hearing aid dealers, is a good tinnitus masker. The natural sounds of surf, rain, or wind may be selected at the desired intensity.
- If one sleeps in an elevated position with one or two pillows, less congestion to the head will result and the tinnitus may be less noticeable.
- Sedatives of various types may be used occasionally for temporary relief.
Biofeedback training is effective in reducing the intensity of tinnitus in some patients. Treatment consists of biofeedback exercises, in hourly sessions, in which the patient learns to control circulation to various parts of the body and relax muscles attached to the head. When a patient is able to accomplish this type of relaxation, tinnitus often subsides.
Biofeedback exercises are not for all patients with tinnitus. Results of treatment have been good, however, in those individuals whose tinnitus is severe and interferes with daily activities or with sleep. Should you be interested in this treatment, your otologist will refer you to a nearby office.
The tinnitus masker is a small electronic instrument built into a postauricular (over the ear) hearing aid case. It generates a noise which prevents the wearer from hearing his own head noise.
The tinnitus masker is based on the principle that most individuals with tinnitus can better tolerate outside noise than they can their inner head noise. An attempt is made to identify the frequency (pitch) of the tinnitus. We then recommend a tinnitus masker which produces a noise matching this frequency as closely as possible, and refer the patient to a hearing aid dealer who stocks this type of device.
The auditory (hearing) pathway is one of the most delicate and sensitive mechanisms of the human body. Since it is directly associated with the general nervous system, its responses are in direct proportion to the anxiety state of the person involved.
In order for any treatment of tinnitus or head noise to be successful, it is imperative that the patient have a thorough understanding of this distressing and complex symptom.