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Tinnitus: Ringing in the Ears
How many people have tinnitus?
Where does tinnitus come from?
Conditions related to non-pulsatile tinnitus
Conditions related to pulsatile tinnitus
Can tinnitus occur without a hearing loss?
Can a single exposure of loud sound cause tinnitus?
The word tinnitus is derived from the Latin word tinnire, meaning "to ring". Tinnitus is often defined as the perception or sensation of sound in the ear or head when no external sound is present. It may be described as ringing, buzzing, hissing, roaring, crickets, clicking, fluttering, or any number of other sounds (including music), alone or in combination. It can be intermittent or continuous and can fluctuate in character and intensity. It can be subjective or objective and pulsating (pulsatile) or non-pulsating. Sometimes it is only in one ear, but often it is in both ears. It is correctly pronounced either “ti-NIGHT-us” or “TIN-i-tus”.
How many people have tinnitus?
- It is estimated that over 50 million Americans experience some degree of tinnitus
- Of these, about 12 million have severe enough tinnitus to seek medical attention
- The severity of tinnitus varies from an occasional awareness of a noise in one or both ears, to an unbearable sound that prevents some people from functioning normally in their lives. Most people who have tinnitus tolerate it well. However, about 4-8% have difficulty coping with the sound and are so seriously debilitated that they cannot function on a "normal," day-to-day basis.
- It is most prevalent between 40 and 70 years of age, more common in men, and occasionally can occur in children.
Subjective tinnitus
Subjective tinnitus is the most common type and is heard only by the patient. This is usually perceived as a non-pulsatile continuous sound. It is usually associated with a sensorineural hearing loss (i.e., hair cell loss). It is commonly more apparent when environmental (ambient) sounds are at low levels or when it is quiet. People also note it more often when they have not slept well, are tired, under stress, or upset. It is less apparent generally when the ambient noise level is high, such as in a movie, or in a relaxed environment, like a vacation.
Objective tinnitus
Objective tinnitus can be heard through a stethoscope placed over the head or base of the skull near the patient's ear. This type of tinnitus is less common and usually pulsatile.
Where does tinnitus come from?
Tinnitus may originate at any location along the auditory pathway from the hair cells to the auditory cortex. Some leading theories include injured cochlear hair cells that discharge repetitively and in a different manner than normal hair cells with respect to the timing and amplitude of the discharge. Abnormal auditory nerve fibers may also fire differently with respect to amplitude and timing as compared to the normal nerve signal. There may also be hyperactivity of the auditory nuclei in the brainstem or a reduction in the usual suppressive activity of the central auditory cortex on peripheral auditory nerve activity. It is important to remember that tinnitus is usually a symptom of other underlying pathology. Your physician needs a thorough case history to help make the diagnosis and recommend appropriate treatment.
Conditions related to non-pulsatile tinnitus
Most cases of tinnitus result from the same conditions that cause hearing loss. There are two main types of hearing loss: conductive and sensorineural.
A conductive hearing loss is caused by the inhibition of sound transmission to the inner ear. This inhibition may be caused by outer ear problems (such as cerumen impaction, debris in the canal, or swelling arising from otitis externa), or middle ear abnormalities (such as tympanic membrane perforations, middle ear fluid, chronic ear disease, or abnormalities of the ossicular chain such as otosclerosis).
A sensorineural hearing loss indicates a disease or abnormality in the inner ear,(usually to the cochlear hair cells) causes. Causes of a sensorineural hearing loss are noise exposure and hereditary factors.
Other tinnitus related ear problems are Ménière’s disease, tumors on the hearing nerve or any neurological problems of the head, trauma and teeth clenching. Additionally, numerous medications list tinnitus as a side-effects.
Ménière’s disease (excessive accumulation of endolymph in the membranous labyrinth) is characterized by recurrent episodes of vertigo, aural fullness, tinnitus, and a sensorineural hearing loss.
Acoustic neuroma, a benign tumor, arises from the Schwann cells of the vestibular nerve. The first symptom is usually unilateral tinnitus. Tinnitus may be present for months or years before the sensorineural hearing loss or vertigo is noticed.
Neurological disorders, head, neck, and ear trauma are implicated in some patients reporting tinnitus. These conditions include skull fracture, injury to the inner ear, closed head injury, whiplash injury, and multiple sclerosis.
Clenching teeth can elevate the tinnitus level. When this occurs there is a reflex in the base of the skull, involving the pterygoid musculature, which causes the tensor tympani tendon in the middle ear to tighten, amplifying the perceived level of tinnitus.
Medications can also cause bilateral tinnitus as well as affecting the hair cells in the inner ear. The presence of tinnitus usually heralds a cochlear hearing loss. Ideally, simultaneous administration of several ototoxic agents (drugs that damage the cochlea) or prolonged treatment with high dosages of an ototoxic medication should be avoided when possible. Audiological monitoring for possible ototoxicity is helpful when prolonged use of ototoxic agents is needed.
Below are some medications and substances that can cause or increase tinnitus:
AnalgesicsAspirin
Nonsteroidal anti-inflammatory drugs
Antibiotics
Aminoglycosides
Erythromycin
Chemotherapeutics
Bleomycin (Blenoxane)
Cisplatin (Platinol)
Mechlorethamine (Mustargen)
Methotrexate (Rheumatrex)
Vincristine (Oncovin)
Loop diuretics
Bumetanide (Bumex)
Ethacrynic acid (Edecrin)
Furosemide (Lasix)
Others
Chloroquine (Aralen)
Heavy metals: mercury, lead
Quinine
Caffeine
Nicotine
Conditions related to pulsatile tinnitus
Other physical problems can also lead to complaints of tinnitus. These include vascular abnormalities, congential heart malformations, middle ear tumors, head trauma and surgery.
Patients with vascular abnormalities complain of pulsatile tinnitus. Arterial bruits may be transmitted to the ear from arterial vessels near the temporal bone. The carotid artery is the most common source.
Venous hums may be heard in patients with hypertension or abnormally high placement of the jugular bulb. This type of tinnitus is a soft, low-pitched venous hum, which can be altered by head position, activity, or pressure over the jugular vein.
Congenital arteriovenous malformations are usually asymptomatic, while the acquired type often is associated with pulsatile tinnitus.
Glomus tumors are vascular neoplasms arising from the paraganglia cells around the carotid bifurcation, the jugular bulb, or the tympanic arteries. These tumors usually cause a loud pulsating tinnitus.
A severe blow to the head may cause pulsatile tinnitus. Additionally, pulsatile tinnitus can result from surgery,.
Pulsatile tinnitus (i.e. like that of the heart beat) is more worrisome, particularly if it is unilateral, as it may represent a vascular abnormality, a vascular tumor or a vascular malformation in the skull base. If the pulsatile tinnitus is bilateral, it may indicate intracranial hypertension. It also may simply be caused by carotid pulsations being transmitted through the temporal bone.
Can tinnitus occur without a hearing loss?
Tinnitus may or may not be associated with a hearing impairment. However, up to 90 percent of all tinnitus patients have some level of hearing loss.
Can a single exposure of loud sound cause tinnitus?
A one-time exposure can cause tinnitus as well as a noise-induced hearing loss. Usually this is an impact type of sound, such as a gunshot.
Can tinnitus be treated?
Treatment options are dependent on the cause of the tinnitus and how much it affects the individual. Beginning with the most conservative options, the treatment includes:
- Using masking techniques, such as a fan, radio, or sound generator, which make the tinnitus less noticeable
- Tinnitus maskers, which generate sounds to mask the tinnitus
- Hearing Aids, when indicated for a hearing loss, which provide amplification and also make tinnitus less noticeable
- Biofeedback therapy, which help with coping strategy techniques
- Habituation therapy / Tinnitus Retraining Therapy, which includes extensive counseling and the use sound generators
- Medications that decrease the level of tinnitus. All generally have GABA activity (GABA is a general inhibitor of the nervous system). At the present time however, there is no single drug, which can be given that will eliminate the tinnitus completely.