Causes

By Mayo Clinic staff

A number of health conditions can cause or worsen tinnitus. In many cases, an exact cause is never found.

A common cause of tinnitus is inner ear cell damage. Tiny, delicate hairs in your inner ear move in relation to the pressure of sound waves. This triggers ear cells to release an electrical signal through a nerve from your ear (auditory nerve) to your brain. Your brain interprets these signals as sound. If the hairs inside your inner ear are bent or broken, they can "leak" random electrical impulses to your brain, causing tinnitus.

Other causes of tinnitus include other ear problems, chronic health conditions, and injuries or conditions that affect your auditory nerves or the hearing center in your brain.

Common causes of tinnitus
In many people, tinnitus is caused by one of these conditions:

• Age-related hearing loss. For many people hearing begins to worsen with age, usually starting around age 60. Loss of hearing can cause tinnitus. The medical term for this type of hearing loss is presbycusis.
• Exposure to loud noise. Loud noises can damage your ability to hear. Heavy equipment, chain saws and firearms are common sources of noise-related hearing loss. Portable music devices, such as MP3 players or iPods, also can cause noise-related hearing loss if played loudly for long periods. While short-term exposure, such as attending a loud concert, usually causes tinnitus that goes away, long-term exposure to loud sound can cause permanent damage.
• Earwax blockage. Earwax protects your ear canal by trapping dirt and slowing the growth of bacteria. However, when too much earwax accumulates it becomes too hard to wash away naturally (cerumenal impaction), causing tinnitus or problems with hearing.
• Changes in ear bones. Stiffening of the bones in your middle ear (otosclerosis) may affect your hearing and cause tinnitus. This condition, caused by abnormal bone growth, runs in families.

Other causes of tinnitus
Some causes of tinnitus are less common. These include:

• Meniere's disease, an inner ear disorder. Doctors think it's caused by abnormal inner ear fluid pressure or composition.
• Stress and depression. This is an especially common diagnosis when hearing tests are normal and no other cause of tinnitus can be identified.
• Head injuries or neck injuries. These neurological disorders affect nerves or brain function linked to hearing. Head or neck injuries generally cause tinnitus in only one ear.
• Acoustic neuroma, a noncancerous (benign) tumor. Acoustic neuromas develop on the cranial nerve, which runs from your brain to your inner ear and controls balance and hearing. This condition is also called vestibular schwannoma. It generally causes tinnitus in only one ear.

Blood vessel disorders linked to tinnitus
In rare cases, tinnitus is caused by a blood vessel disorder. This type of tinnitus is called pulsatile tinnitus. Causes include:

• Head and neck tumors. A tumor that presses on blood vessels in your head or neck (vascular neoplasm) can cause tinnitus and other symptoms.
• Atherosclerosis. With age and buildup of cholesterol and other fatty deposits, major blood vessels close to your middle and inner ear lose some of their elasticity — the ability to flex or expand slightly with each heartbeat. That causes blood flow to become more forceful and sometimes more turbulent, making it easier for your ear to detect the beats. You can generally hear this type of tinnitus in both ears.
• High blood pressure. Hypertension and factors that increase blood pressure, such as stress, alcohol and caffeine, can make tinnitus more noticeable. Repositioning your head usually causes the sound to disappear.
• Turbulent blood flow. Narrowing or kinking in a neck artery (carotid artery) or vein in your neck (jugular vein) can cause turbulent blood flow, leading to tinnitus.
• Malformation of capillaries. A condition called arteriovenous malformation (AVM), which occurs in the connections between arteries and veins, can result in tinnitus. This type of tinnitus generally occurs in only one ear.

Medications that can cause tinnitus
A number of medications may cause or worsen tinnitus. Generally, the higher the dose of medication you take, the worse tinnitus becomes. Often the unwanted noise disappears when you stop using these drugs. Medications known to cause or worsen tinnitus include:

• Antibiotics, including chloramphenicol, erythromycin, tetracycline, vancomycin and bleomycin.
• Cancer medications, including mechlorethamine and vincristine.
• Diuretics — water pills — such as bumetanide, ethacrynic acid, furosemide.
• Quinine medications used for malaria or other health conditions.
• Chloroquine, a malaria medication.
• Aspirin taken in uncommonly high doses (12 or more per day) may cause tinnitus.

http://www.mayoclinic.com/health/tinnitus/DS00365/DSECTION=causes

Tinnitus Causes

The most common cause of tinnitus is damage to the hearing nerves in the ear (cochlea or inner ear). We hear things through a stream of nerve impulses going from the cochlea to the auditory system in the brain. If the tiny nerves in the ear are damaged or destroyed, this produces an abnormal stream of impulses, which the brain interprets as a sound. This causes the noise associated with tinnitus.

Tinnitus in older people is usually caused by natural hearing loss (presbyacusis), which lessens the sensitivity of hearing nerves. In younger people, it is most often caused by damage to hearing as a result of excessive noise.

However, there are a number of other causes of tinnitus. It is not always possible to identify the exact cause even after examination by a specialist.

Other common causes include:

• excessive wax in the ear causing it to become blocked,
• middle ear infection (otitis media) or otitis media with effusion (serous otitis media),
• otosclerosis (stiffening of the tiny bones which transmit sound from the eardrum to the sound-detecting organ, the cochlea),
• Ménière's disease (a condition causing problems with balance),
• anemia (in which the thinner blood circulates so rapidly it produces sound), and
• pierced eardrum.

Less commonly, tinnitus may also develop as a result of:

• exposure to sudden or very loud noise (for example, gunfire, explosion),
• a head injury,
• the presence of an acoustic neuroma (a rare, benign growth that affects the hearing nerve in the inner ear),
• impacted wisdom teeth (when wisdom teeth have not completely moved into the normal position),
• adverse reactions to certain drugs such as antibiotics, diuretics, aminoglycosides, quinine and aspirin (this is more likely when the dosage is exceeded), and also allergic reactions,
• solvent abuse, alcohol abuse and other drug abuse,
• high blood pressure and narrowing of the arteries (atherosclerosis), and
• overactive thyroid gland.

Tinnitus is rarely a symptom of a more serious problem but there can be other causes such as tumors, spasm, and abnormal blood flow.

Some people relate their tinnitus to stressful events in their life, such as bereavement.

What Causes Tinnitus?

Tinnitus may be a symptom of a variety of ear disorders or other medical conditions. Usually it is difficult for doctors to determine the exact cause of tinnitus.

Many disorders of the ear, including a problem with one or more of the five parts of the hearing mechanism, may cause tinnitus. Tinnitus may also be a symptom associated with:

• Blocked ear canal
• Blockedeustachian tube
• Ear infection

For further information about ear infection, go to Middle Ear Infection.

• Otosclerosis: a common ear disorder characterized by unusual stiffness or lack of flexibility of the tine bones of the middle ear. This condition frequently causes tinnitus.
• Meniere's disease: a disorder of the inner ear characterized by recurrent dizziness, deafness, and tinnitus. In 80 to 85 percent of cases, only one ear is affected.
• Damage caused by certain drugs, including aspirin and certain antibiotics
• Hearing loss

For further information about hearing loss, go to Hearing Loss.

• Trauma or injury resulting from a blast or explosion
• Temporomandibular joint syndrome orTMJ: pain and other symptoms affecting the head, jaw, and face. TMJ is believed to be caused when the jaw joints and muscles and ligaments that support them are not working properly.

Tinnitus may also occur along with certain other medical conditions, such as:

• Anemia, or a condition in which blood levels of hemoglobin, the part of red blood cells that carries oxygen to nourish the tissues of the body, are below normal

For further information about anemia, go to Anemai.

• Hypertension, or high blood pressure

For further information about high blood pressure, go to High Blood Pressure (Hypertension).

• Arteriosclerosis, orhardening of the arteries
• Hypothyroidism, or low levels of thyroid hormone production

For further information about hypothyroidism, go to Hypothyroidism.

• Presbycusis: hearing loss and other hearing problems related to advanced age.
• Head injury

Is Tinnitus Hereditary?

There are a few rare inherited inner ear disorders, such as neurofibromatosis in which tinnitus may be a feature. However, in the vast majority of cases, this condition does not seem to run in families or be inherited as a genetic trait.

Ototoxic Medications That Cause Tinnitus

by Barry Keate

Ototoxic medications are those that are toxic to the cochlea or vestibular (balance) structures in the ear. These medications have the potential to cause hearing loss, tinnitus and/or dysequilibrium such as dizziness and vertigo.

Ototoxicity came to the forefront of clinical attention with the discovery of streptomycin in 1944. Streptomycin was successfully used in the treatment of tuberculosis; however, a large number of patients were found to develop irreversible cochlear and vestibular dysfunction. Ototoxicity was also shown with the later development of other aminoglycoside antibiotics. Today, many well known pharmaceutical agents have been shown to have toxic effects on the cochleovestibular system. The list includes aminoglycosides and other antibiotics, platinum-based chemotherapy medications, salicylates, quinine and loop diuretics.

The method of action of ototoxic medications differs somewhat among the various drugs. Aminoglycosides seem to potentiate glutamate receptors in the cochlea that promote degeneration of hair cells and cochlear neurons.1 This, in turn, generates a cascade of free radical damage which leads to the destruction of hair cells and neurons.2

The damage typically begins with the inner row of outer hair cells and progresses through the other rows, then to the inner hair cells. Patients frequently develop symptoms following the cessation of therapy. Ototoxicity-induced hearing loss tends to first manifest in the high frequencies and often causes tinnitus. It then progressively involves the lower frequencies and eventually affects speech recognition.3

Since free radical damage is central to lost hearing and vestibular disturbances, it makes sense that taking antioxidants before being exposed to ototoxic medications will reduce the potential damage. A related article on antioxidants and tinnitus can be seen in ourTinnitusInformationCenter.

Ototoxicity may be reversible or may be permanent, depending on the type of medication used, dosage and duration of treatment. There are many other medications that have been listed as potentially ototoxic.

In his excellent article, “What you should know about ototoxic medications,” published inTinnitus Today, September 1996, Stephen Epstein, MD, lists the six categories of medications that can be ototoxic and the signs of ototoxicity:

"1 – Salicylates – Aspirin and aspirin containing products
Toxic effects usually appear after consuming an average of 6-8 pills per day. Toxic effects are almost always reversible once medications are discontinued.

2 – Non-Steroidal Anti-Inflammatory Drugs (NSAIDS) – Advil, Aleve, Anaprox, Clinoril, Feldene, Indocin, Lodine, Motrin, Nalfon, Naprosyn, Nuprin, Poradol, Voltarin. Toxic effects usually appear after consuming an average of 6-8 pills per day. Toxic effects are usually reversible once medications are discontinued.

3 – Antibiotics – Aminoglycosides, Erythromycin, Vancomycin
a. Aminoglycosides – Streptomycin, Kanamycin, Neomycin, Gantamycin, Tobramysin, Amikacin, Netilmicin. These medications are ototoxic when used intravenously in serious life-threatening situations. The blood levels of these medications are usually monitored to prevent ototoxicity. Topical preparations and eardrops containing Neomycin and Gentamycin have not been demonstrated to be ototoxic in humans.
b. Erythromycin – EES, Eryc, E-mycin, Ilosone, Pediazole and new derivatives of Erythromycin, Biaxin, Zithromax. Erythromycin is usually ototoxic when given intravenously in dosages of 2-4 grams per 24 hours, especially if there is underlying kidney insufficiency. The usual oral dosage of Erythromycin averaging one gram per 24 hours is not ototoxic. There are no significant reports of ototoxicity with the new Erythromycin derivatives since they are given orally and in lower dosages.
c. Vancomycin – Vincocin. This antibiotic is used in a similar manner as the aminoglycosides; when given intravenously in serious life-threatening infections, it is potentially ototoxic. It is usually used in conjunction with the aminoglycosides, which enhances the possibility of ototoxicity.

4 – Loop Diuretics – Lasix, Endecrin, Bumex
These medications are usually ototoxic when given intravenously for acute kidney failure or acute hypertension. Rare cases of ototoxicity have been reported when these medications are taken orally in high doses in people with chronic kidney disease.

5 – Chemotherapy Agents – Cisplatin, Nitrogen Mustard, Vincristine
These medications are ototoxic when given for treatment of cancer. Maintaining blood levels of the medications and performing serial audiograms can minimize their toxic effects. The ototoxic effects of these medications are enhanced in patients who are already taking other ototoxic medications such as the aminoglycoside antibiotics or loop diuretics.

6 – Quinine – Aralen, Atabrine (for treatment of malaria), Legatrin, Q-Vel Muscle Relaxant (for treatment of night cramps)
The ototoxic effects of quinine are very similar to aspirin and the toxic effects are usually reversible once medication is discontinued.

The signs of ototoxicity, in order of frequency, are:
1 – Development of tinnitus in one or both ears.
2 – Intensification of existing tinnitus or the appearance of a new sound.
3 – Fullness or pressure in the ears other than being caused by infection.
4 – Awareness of hearing loss in an unaffected ear or the progression of an existing loss.
5 – Development of vertigo or a spinning sensation usually aggravated by motion which may or may not be accompanied by nausea."4

Dr. Epstein advises that if any of these symptoms develop while taking any medication, stop the medication immediately and call your doctor.

Just as each of us is ultimately responsible for our own health, those of us with tinnitus must be particularly careful of medications that may cause our condition to worsen. Please read all medication labels and information carefully and review possible side-effects with your doctor before using.

Antidepressants
It should also be noted that, while not strictly ototoxic, prescription antidepressants can cause or worsen tinnitus for some people. Both the older, tricyclic, and the newer, SSRI, antidepressants have this capability. Among the tricyclics, Clomipramine and Amitriptyline are among the most frequent offenders. The SSRI antidepressants include Prozac, Zoloft, Paxil, Celexa and Luvox. These are listed in the Physician’s Desk Reference as frequently causing tinnitus. One good choice for many people with both tinnitus and depression is the older medication Remeron, which has not been reported to cause tinnitus.

If you must take ototoxic medications, you should also be taking antioxidants and have your hearing monitored with periodic audiological evaluations.

List of Ototoxic Medications
Here is a complete and updated listing of allototoxic medications, derived from the 2006 Physician’s Desk Reference.

FOOTNOTES:
1-Pol Merkuriusz Lek (2001)9:713-5; Bienkowski, P; Scinsake, A; Kostowski, W; Koros, E; Kukwa, A; Ototoxic mechanism of aminoglycoside antibiotics-role of glutaminergic NMDA receptors.
2 -BaylorCollege of Medicine; August 20, 1992; Andrew T. Lyos, MD; Ototoxicity.
3 - Ear, Nose & Throat Journal; Sept. 2004; Peter S. Rowland; New developments in our understanding of ototoxicity.
4 - Tinnitus Today; Sept. 1996; Stephen Epstein, MD; What you should know about ototoxic medications

http://www.tinnitusformula.com/infocenter/articles/conditions/ototox.aspx

Tinnitus, The Annoying Sound Inside Your Head

Allan N. Schwartz, LCSW, Ph.D. Updated: Dec 2nd 2008

Do you experience a ringing, swishing or buzzing sound inside of your ears? If not, do you know anyone who complains about this problem? I am one person among 36 million people who is affected by this problem. I am happy to report that I am not among the 7 million who are so distracted by the noise that they cannot work or function.

It is important to understand that people who experience tinnitus are not crazy and are not pretending or hallucinating. This is a problem that is still not well understood and appears to have no cure. However, there are ways to either reduce its impact or prevent it from happening.

Objective and Subjective Tinnitus:

There are two types of tinnitus, objective and subjective. Objective tinnitus is caused by noise originating from inside the body. In fact, if someone was in a dark chamber with the absence of inside or outside sound, they would experience tinnitus. Anything that blocks outside noise will make a person aware of their internal body noises, the objective form of tinnitus. However, by far the most common form of tinnitus is subjective tinnitus. Subjective tinnitus is caused by abnormal activity in the nerve fibers without any actual sound being made. Mostly, this is the type of tinnitus that will be discussed here.

What Causes Tinnitus?

1. One of the most common causes of tinnitus is damage to the microscopic endings of the hearing nerve in the inner ear.

2. As people age it is common to have a certain amount of hearing nerve impairment. This impairment causes and tinnitus.

3. Exposure to loud noises is a very common cause of tinnitus, and it often damages hearing as well. Unfortunately, many people are unconcerned about the harmful effects of excessively loud noises such as from firearms, high intensity music and July fourth explosions. As we are all well aware, we live in a loud world.

4. Some medications, such as aspirin, can either cause tinnitus or exacerbate the condition. 

5. Some diseases of the inner ear, like Meniere's syndrome, can cause tinnitus.

6. Tinnitus can in very rare situations be a symptom of such serious problems as an aneurysm or a brain tumor.

7. I have known people whose tinnitus was caused by a sinus infection or other types of sinus diseases. When the infection clears, the tinnitus seems to clear.

8. Putting things in your ears, such as Q tips to clean your ears, can cause damage leading to tinnitus.

Treatment:

The first thing a person should do if they are experiencing these uncomfortable sounds in their ear is to be seen by a Medical Doctor. Obviously, it is important to rule out any serious physical problems that could be the root cause of this condition. However, after any disease process is ruled out then, there are a number of things people can do to get relief from this annoying noise in the ear.

1. Aspirin and other similar products should be used with great care as they can irritate tinnitus.

2. Avoid loud and shocking noises. Listening to music through an IPod or ear phones is all right if the volume is kept low. In fact, it is head phones and Ipods that have probably contributed to this inner ear because loud music blasting into the ears causes damage.

3. It is known that stress and anxiety can worsen the condition. While it is impossible to completely avoid stress and anxiety, it is possible to reduce its effects.

Tinnitus is annoying but is not dangerous. However, I do want to repeat a cautionary note: If you are experiencing these noises please go to the Medical Doctor, especially an Ear Nose and Throat(ENT) doctor. The purpose is to rule out and disease or organic process. However, once those are ruled out and you have been told it is tinnitus, then use some of the relaxation techniques mentioned above.

As the old television commercial said, "do not put anything in your ears...except your elbow." I have read that wax in the ears has an important role that is serves to protect the ears.

Remember, we live in a noisy world made worse by Ipods and ear phones. Turn down the levels of noise and, as they say, "chill out, man!!"

Your comments are welcome

Allan N. Schwartz, PhD

http://www.mentalhelp.net/poc/view_doc.php?type=doc&id=28982&w=5&cn=72

Tinnitus Causes

Tinnitus is the term used to describe a condition in which the person ‘hears’ sounds that are the result of changes in the auditory pathway not triggered by ‘genuine’ sounds arising in the world outside their head. The sounds certainly seem real enough and someone with tinnitus can spend hours or days looking for leaking pipes or poor electrical connections to explain the hissing or buzzing noises that suddenly develop, often heard for the first time at night when all else is quiet. Tinnitus can in turn bring on great psychological stresses, which seems strange at first sight because tinnitus is only ‘sound’ after all.
This chapter tries to explain why tinnitus can be so distressing, what causes it and how it can be managed.

WHY TINNITUS IS SO DISTRESSING

Animals have hearing as an early warning system as a first line of defence for survival, and which puts them on ‘alert’ (see box opposite). In humans, as well as the basic inbuilt ‘animal’ responses, we also have ‘thoughts, feelings and emotions’ piled on top and inter­acting with each orther.
There is a short time between the detection of sound by the cochlea and the perception of sound by the auditory cortex in the brain. Nevertheless, in this short period all sorts of interactions can occur. A quarter of a second is a long time for a fast computer and also for our brains.
Not only do we hear sound but we can also be affected by it both physically and emotionally in many ways.

There cannot be any one of us who has not felt that pleasant, exciting tingle down the spine when listening to a particularly enchanting passage of music.
We do not know all that much about the interactions and connec­tions between the auditory pathway and other parts of the brain. How they work is even less well under­stood. Suffice it to say that unusual electrical activity in the auditory pathway, anywhere from the cochlea to close to the auditory cortex, can have many and varied effects.
Changes in electrical activity in the auditory pathway, for whatever reason, are perceived by the brain as ‘sound’, even though no new sound may be present in the environment. The auditory cortex does not ‘know’ that this new activity is not external; it simply recreates it as sound. Likewise, the brain stem does not ‘know’ that the new electrical activity is not an external threat; it just responds as if it were.
Compare this to what would happen if I were to poke you in the eye: apart from the pain, you would almost certainly ‘see’ a flash of light. I have not flashed a light in your eye, but the altered electrical activity in the visual system is perceived by your visual cortex as ‘light’. In classic migraine, where the blood supply to the visual cortex is disturbed, flashes of light are a common experience.
Hearing ‘sounds’ when none is actually present can trigger quite severe additional symptoms because of the early warning effect contin­uing and the person remaining on alert (see box on page 89). Individuals can become on edge, bad tempered, irritable and unable to concentrate. If the onset of the tinnitus is associated with a bad event, such as an accident, an explosion, a whiplash injury, a family death, etc, this tends to accentuate its effect.
Other factors that raise the level of generalised brain-stem activity, such as anger, illness or tiredness when there is a need to remain alert, can all increase the awareness of the tinnitus and the distress that it is causing. Of course, thinking about the noises will tend to accentuate them.
This distress can start to affect individuals psychologically, depen­ding on their characters and personality. Some people have ordered, structured lives over which they have perfect control and they get extremely angry when they simply cannot command their tinnitus to go away. The more they concentrate on making it disappear, the worse it can get, driving them to greater anger, especially at night time in the quiet. Many individuals get up, switch on the radio, television, washing machine or tumble drier to drown out the noise, or may even go out and pace the streets.
Others despair that their world will never be quiet again and fear that they will always have this ‘noise’ with them wherever they go, and they may fall into a deep depression. Yet more will have great difficulty sleeping, and this lack of sleep and the need to function the next day leave them exhausted, which often tends to enhance the perception of the tinnitus. Many individuals are scared that they may have a brain tumour or some other terminal disease that is showing itself first by this noise. Indeed, in centuries past, noises in the head were often thought to be work of the devil. All in all, individuals can be affected in many different adverse ways depending on the impact that the tinnitus has on them personally.
Not all tinnitus is enduring; most people who go to over-loud clubs or concerts develop tinnitus but soon the noises fade into the back­ground and disappear. Some individuals have a relaxed, laid-back personality and just accept the sounds as ‘just another thing’ or ‘something to do with getting old’, and quickly come to accept their noises.

TYPES AND CAUSES OF TINNITUS

The different types of tinnitus

The vast majority of people with tinnitus have noises that can be heard only by them (subjective tinnitus). There is, however, a small group who hear sounds that are also audible to others; they have what is called objective tinnitus. These sounds are frequently the result of blood flowing through rough and narrowed arteries and causing a whooshing sound as it tumbles through the stricture. Sometimes abnormalities of veins, either malformations or benign tumours growing in or close to the ear (glomus tumours), can cause a similar whooshing, pulsatile sound, which can often be heard with a stethoscope held over the carotid artery and/or jugular vein in the neck. A woman once came to my clinic because her dog kept lifting its ears and listening to her right ear. She had, it turned out, a carotid artery narrowing and the high-pitched sounds of the blood rushing through the narrowed artery could be heard by her dog!
Clicking noises can also arise from the ear and seem to come from irregular, tic-like contractions of the muscles of the palate (palatal myoclonus) or of the middle-ear muscles. This phenomenon is similar to a facial tic when some of the facial muscles twitch, but in this case the closeness of the affected muscles to the ear makes the twitching audible. Some surgeons have attempted to cure these clicks, which can be extremely irritating to the sufferer, by cutting the muscles in the middle ear themselves, but this is rarely successful.

People whose noises are not pulsatile and cannot be heard by others describe what they hear in a huge variety of ways, including buzzing, ringing, whining and probably every possible sound that has ever been described. These sounds can also be located just outside the ear, in one ear or the other or all over the head. This type of tinnitus is called subjective and is the most common form of the condition.

CAUSES OF SUBJECTIVE TINNITUS

The ‘source’ of most forms of subjective tinnitus is not understood. It is easy to blame the hair cells by saying that they are malfunctioning, and that instead of detecting sound they are mischievously generating electrical signals that are then perceived as sounds. Scientifically, it is difficult to show that this is actually the case and, although it may be true in some people, it cannot be used as a general explanation.
However, there are some specific causes of subjective tinnitus that need to be excluded. This applies especially to tinnitus localised to one ear when, among other causes, middle-ear and mastoid disease must be ruled out. Investigations include a physical examination, audiometry and appropriate imaging by computed tomography (CT) or magnetic resonance imaging (MRI).

Tinnitus in one ear associated with some distortion of hearing is occasionally caused by an acoustic neuroma (see page 68). This is more likely if there is a sensori­neural hearing loss on the same side. The ideal way to find out whether a person has one of these benign but unpleasant tumours is to send him or her for MRI. This supplies sufficient detail to make certain that the person does not have one of the many other sorts of tumours and diseases in the head and, if this is the case, the tinnitus can be termed ‘idiopathic’ which, in effect, means without known cause – yet.
As technology improves and understanding of the mechanisms of tinnitus increases, the idiopathic group (without recognisable cause) – which is the majority at present – will probably get smaller as clear-cut causes will be found for many of those concerned. Once each clear-cut cause is defined, specific medical remedies should eventually become available.
However, at present for those people with idiopathic tinnitus without a hearing loss, all we can say is that somewhere along the line from cochlea to auditory cortex, irregular electrical signals are being generated. For people with a hearing loss, alternative mecha­nisms to explain their tinnitus have been proposed and this is how the argument goes: from the hair cell in the cochlea inwards, the hearing system is an electrical network with relays, junctions, enhancing devices, filters, etc. Any electrical system has electrical ‘noise’ in it. It is easy to demonstrate this by having a hi-fi amplifier turned to full volume with no input such as a CD or tape playing and, even if the system is extremely expensive, there will still be some noise heard through the speakers.
There will always be background electrical noise in the auditory system; normally you don’t hear this because your brain sets a threshold level that excludes it. For an incoming sound signal to be heard, it has to be greater than the background noise threshold. People have a wide range of hearing thresholds.
When a hearing loss occurs, whatever the cause, it may just be great enough to prevent normal external sounds reaching the brain. ‘Silence’ over the range of pitches represented by the deafness is therefore registered by the brain. The world is not a silent place – it may be quiet but silence is extremely difficult to achieve – and the absence of sound means that our early warning system cannot register change. The brain therefore reacts by dropping the threshold to ‘hear’ more, and by doing so strays into the internal noise levels so that the individual is hearing the workings of his or her own ear.
If placed in a totally silent space (an anechoic chamber) for experi­mental purposes, most people with normal hearing develop tinnitus, which slowly goes away when they return to a normal, noisy environ­ment. This effect will recur each time the experiment is repeated, but most people do not like the sensation of total silence because it gives them an uneasy, frightened feeling. This is presumably because they no longer have ‘hearing’ as their early warning system and they feel vulnerable at a primitive animal brain-stem level.

HOW THE BRAIN DEALS WITH CONTINUING EXTERNAL NOISES

Most of us have had the experience of sitting in a room, concentrating on something such as reading or writing, and then hearing the clock stop when we hadn’t previously noticed it ticking. Now, as the clock has stopped, there is actually nothing to hear but, previously, the brain stem filtered out the harmless repetitive noise of its ticking so that the sound did not reach the level of perception. This is more difficult to do with an irregular dripping tap, which can be a source of continued annoyance, partly because we tend to anticipate the arrival of the next drip and experience further brain­stem consternation when the sound does not occur.
Depending on the personality of the individual, he or she either learns to tolerate the irregularity or eventually gets furious and does something about it. The same thing occurs when you buy a new refrigerator. Initially the noise of it switching on and off in an irregular fashion and of the motor running can be irritating. Eventually, how­ever, almost everyone gets used to it and it stops being a problem.
The brain stem has awesome powers of processing incoming auditory signals. It can filter out those that it recognises as harmless in the light of experience. The early warning effect and all the additional emotional factors associated with unexplained and unexpected sounds do not arise, and the signal may eventually not even reach consciousness.
Humans have loaded on top of this complex survival computer an additional ‘higher level’ computer bank, which gives us sensations, feelings, thoughts and emotions that can, in turn, interact and influence the lower centres. The stage is thus set, in susceptible individuals, for an internal conflict with slightly unusual electrical activity in the auditory system awakening fear and anxiety in the ‘higher-level’ computer bank; this feeds back to promote general arousal of the brain stem and consequent distress. It is irrelevant whether the sounds are external or internal – the process remains the same.

DISRUPTION OF CONCENTRATION

Language is a very high-level skill and we use considerable brain power to understand speech. You can concentrate on only one conver­sation at a time and, although you may hear other voices going on around you, they are only sounds – you cannot understand the full sense. Almost everyone is familiar with the scene at a party when you are in deep conversation with some friends and there is a general babble around you. Someone behind your back mentions your name, which you hear, and immediately you shift the focus of your attention to this new and interesting sound. In doing so, you completely lose track of the first conversation.
Tinnitus is an attention thief. The unexplained sound tries to grab your attention. It is saying ‘Listen to me – I may be important’ and keeps distracting your brain from whatever it is doing at the time. People with tinnitus often have major difficulties in coping with complex mental tasks because of this unwelcome and persistent attention-grabber.

HELPING PEOPLE WITH TINNITUS

People who develop tinnitus can suffer serious distress and even psychiatric problems, including depression, anxiety and sometimes suicidal thoughts. Fortunately most people are not so severely affected and are referred by their GP to the ENT department of their local hospital.
At such a clinic, the ENT consultant will ask you questions to determine the nature of your problem and any associated symp­toms. If your symptoms suggest that you may have problems arising from local disease in your ear, nose and throat, your central nervous system or the major blood vessels of your neck, you will have a very thorough examination.
A pure-tone audiogram will probably be performed and, depending on the results and your symptoms, further investigations may be undertaken. In this way, the rare specific causes of tinnitus can be diagnosed and referred for appropriate treatment. For the vast majority of people, however, the tests will show that there is nothing life threatening or otherwise seriously wrong, and your doctor can be quite confident of this, whatever you may have feared. Such reassurance about the nature of the problem helps to allay inner fears, which are a potent source of the anxiety that keeps the tinnitus active. The next step is to find ways of managing the problem.
The aim of tinnitus management is to relieve the brain-stem ‘distress’ that comes with the sounds. The brain stem can be helped to ‘learn’ that the sounds are not a threat and that they can eventually be disregarded (acclimatisation), so that they no longer reach consciousness or activate the early warning effect. In many people, a careful examination, appropriate investigations and a clearly reasoned explanation are enough to set the process of acclimatisation in progress. However, the interaction between the higher centres of the brain and the brain stem are complex and poorly understood. Other people may need more help, depending on the severity and intrusiveness of their sounds and on their personality.

People with significant hearing loss

Restoration of hearing, usually with a hearing aid, often overcomes tinnitus by allowing the brain’s hearing threshold to be reset, so that the tinnitus is no longer heard. This is the best result. Sometimes, restoring hearing is not immediately effective, but the level of the tinnitus drops significantly so that the internal sounds become less important in relation to newly heard external sounds.
Most forms of acoustic manage­ment of tinnitus now work in this way. Sounds are introduced to reduce the importance of the internal sounds, so that the brain stem ‘learns’ to push the tinnitus into the background and then into insignificance. Using loud sounds to drown out the tinnitus completely is known as full masking, but this is not now thought to be the best form of management; when the masking is removed, the tinnitus may still be present at the same level.

‘Masking’ techniques: sound generators

Hearing aids can be modified to incorporate a sound generator that produces an appropriate suppres­sing sound, perhaps wide-band white noise (a ‘shushing’ sound) at half the full-masking level. This combination is very effective in people with tinnitus and hearing loss if pure amplification is not enough to reduce the tinnitus level. Once the tinnitus levels have diminished, the degree of distress associated with them also lessens and the brain stem learns to filter out the intrusive sounds.
Pure masking devices set at half-masking levels are frequently helpful for those with normal hearing. The introduction of a not-unpleasant background sound provides a distraction, so that the primary ‘warning’ effects of the tinnitus start to diminish, and eventually the tinnitus stops being an irritation and is no longer heard.

Environmental aids

Many people find that getting to sleep in a quiet environment is a real problem. For these people, quiet environmental sounds, such as having a radio playing or a cassette with their favourite music or even something like an audio-book, are sometimes a great help. Some people find the low drone of speech quite soporific, whereas others listen to the sense and so cannot get to sleep. Everyone has his or her own special way of dealing with the problem, and some experimentation may be needed. Partners may get irritated by the chosen noise (in much the same way that tinnitus irritates the sufferer), but you can get pillow loudspeakers that can be heard only when your head is on your pillow and not by anyone else. Many high street electrical shops sell these relatively cheaply but in case of difficulty the RNID has a list of suppliers (see Useful addresses).
Quiet environmental sounds can also be used to relax you during the daytime. Many people who would normally work, read or do other things, such as knitting, in the quiet find that, once they have tinnitus, they need to have music playing in the background. There are now several useful tapes that provide soothing sounds, such as the waves of the sea, to help. The RNID can advise on where to buy these if your local audiology clinic or hearing aid centre cannot help.

PSYCHOLOGICAL HELP AND COGNITIVE THERAPY

Although the techniques described above help most people to manage their tinnitus, there is a minority whose personality makes it difficult for them to tolerate this imper­fection, or who cannot accept that there is something in their lives that they are unable to control. These people need additional help, because they tend to concentrate on the tinnitus in an attempt to make it disappear. This is like trying to make yourself go to sleep – you cannot succeed in this, you simply fall asleep despite your efforts. In trying to make ‘nothing’ happen it becomes ‘something’ and this philosophy applies to tinnitus exactly.
Distraction is needed, and various relaxation techniques are useful in deflecting concentration away from the tinnitus. These techniques usually need to be taught by hearing therapists or people who are trained in the techniques. Most NHS audiology departments or hearing aid centres have hearing therapists trained in these techniques. There are many relaxation tapes and yoga-type exercises that help people who are already using sound substitution devices such as maskers, hearing aids, pillow speakers, etc. Indeed, effective relaxation therapy alone may be enough to overcome the tinnitus-related distress.
There are also some simple techniques or tricks to help at night if tinnitus either stops you falling asleep or prevents you from dropping off again when you wake during the night. First, do not look at the clock. Next, do not get up and make a cup of tea or coffee. These actions bring awareness and the stimulants in tea or coffee prolong this. Find a simple word – I like rich-sounding words such as ‘implosion’ or ‘cartridge’ – and gently repeat them again and again with different emphasis.
People become deeply entwined with their tinnitus so that it becomes a focus of their lives, taking over most minutes of every day. They find that they cannot let go of the symptom, which comes to dominate them. Cognitive therapy is a technique directed at altering the way in which people think about their symptoms.
Imagine standing in a stuffy, noisy, crowded underground train. You are packed shoulder to shoulder, you cannot move and you cannot turn your head it is so crowded. Then you start to feel someone behind you poking you in the ribs with what must be a sharpish object as it is very painful. This is an irregular but recurring event. What do you feel? Pain, of course, but also anger, resentment, and fear perhaps, but why? People give many different reasons. They may feel out of control, threatened, invaded, that the other individual is so selfish and so on – you may have other thoughts.
Eventually the train reaches the station and enough people get off to allow you to turn around and speak your mind. As you turn you see that the person behind is a blind man and that it is his white stick that has been prodding you. Now what do you feel? I am sure it is not the same as before.
The essence of the plot is that symptoms (tinnitus/pain/dizziness, etc.) engender feelings (anger/ frustration/fear) because of the way we think about them. Cognitive therapy aims to alter that link between symptoms and feelings so that the symptoms become ‘acceptable’. Once they do the symptoms tend to evaporate. Cognitive therapy for tinnitus is a specialist skill that is available within the NHS, although the provision of services is very patchy. I refer you to some excellent short books by my colleagues, which are in the reading list on page 105.

SURGERY FOR TINNITUS

Avoid surgery for tinnitus like the plague. Tinnitus is a symptom and surgery is performed for conditions that give rise to symptoms. Since virtually all forms of tinnitus are without a truly known cause, surgical procedures claiming to be curative are not logical. The emotional effect of a major operation may displace the symptoms of tinnitus. The pain of surgery may act as a ‘masker’ much as acupuncture helps relieve tinnitus while it is in use. However, performing operations to ‘cut the cochlear nerve to prevent the hair cells from sending tinnitus signals to the brain’ simply does not work and may even make individuals worse, because a dead ear cannot be helped by hearing aids, sound generators or environmental aids.
Some conditions have tinnitus as part of their presentation. Examples are otosclerosis and acoustic neuromas. Indeed the tinnitus may well improve after successful surgery to restore the hearing in otosclerosis and may become much less marked after acoustic neuroma surgery with hearing preservation. However, it is an unwise surgeon who promises that the tinnitus will get better in these specific conditions; if it does then that is an unexpected bonus.