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Tinnitus ( TIN-it-tuss ) means hearing noises which have no external source. The noises can appear to be coming from
It can be hard to tell where they are coming from.
Hear what tinnitus can sound like
(953kB download from the British Tinnitus Association)
The pitch of tinnitus can be
Tinnitus can be
Tinnitus can last
Tinnitus can
Hearing voices is not tinnitus. Hearing voices is usually a symptom of mental illness.
Nearly everyone will get tinnitus in a completely quiet, sound-proofed room, or if you hold a sea shell to the ear.
The commononest cause of persistent tinnitus - noises that don't go away by themselves - is loss of hearing. The loss of hearing may be very slight, not enough to notice, but it is enough to cause tinnitus.
There are two kinds of tinnitus - objective and subjective.
Objective tinnitus is a noise, coming from inside you, that can be heard by someone else. Examples include
If you have some disturbed blood flow in an artery near the ear, you might hear the noise of the blood flowing through the constriction. The noise would be similar to that you get from a kink in a hose pipe. A doctor who puts a stethoscope over the artery will hear the same noise you hear. That is objective tinnitus.
Subjective tinnitus is a noise, seeming to come from inside you, that only you can hear. Until recently, doctors thought people imagined these noises. But they aren't imaginary. The noise is there. It is made inside the sound processing pathway, from the ear to the brain. Tinnitus can come from the cochlea of the inner ear, inside the microphone. It is extremely quiet - not audible - to anyone outside, but to the person whose cochlea is making tinnitus, it is all too audible, because it is produced inside the microphone.
If we were able put a tiny, miniaturised microphone inside your cochlea, and feed the signal to an external amplifier and speakers, we could probably hear exactly the same tinnitus that you hear. That would make it objective. Most cases of what we thought were subjective tinnitus are objective. We just don't have the means of listening to it. We can't put a microphone inside your cochlea to find out, because that would deafen the ear.
There are various theories of how tinnitus is produced. A theory is an idea of what might be true. Scientific theories evolve over time. They are judged by how well they fit the observed facts, and whether they can generate tests - experiments. A theory that cannot be disproved by experiment is not a scientific theory. Good scientists welcome challenges to their theories. Theories are placed in the public domain only to be knocked down, tested to destruction. A strong scientific theory is one which has withstood many attempts to prove it false. The following is based on modern ideas of how the cochlea works, and how sound signals are processed in the brain.
But it's not quite as simple as that.
Recordings from the nerve of hearing show there is two way traffic. Electrical signals are downloaded, from the brain to the ear, as well uploaded, from the ear to the brain. This is because the cochlea is not just a simple passive microphone. It is an active microphone. And its performance is software controlled, by the sound processing area of the brain.
Sound engineers use different microphones for different environments, such as
We humans only have one kind of microphone - the cochlea. But the microphone can be adjusted to listen in different environments. The adjustments are made for you, automatically, by nerve signals from the sound processing area of the brain. These signals travel backwards, down the nerve of hearing. They are received and acted on by the outer hair cells of the cochlea.
This ability to control the cochlea makes us very adaptable. We can hear the quietest crack of a twig when a predator approaches, but also make out a familiar voice in a noisy crowd. This gives us a survival advantage. But it is probably also why we get tinnitus.
The brain processes sound in lots of of complex pathways. This electrical activity can sometimes be heard. Like the faint hum you might hear from your stereo amplifier, it just means it is working. This processing can be heard if conditions are right - for example, in a completely sound proof room, with no external sounds, nearly everyone will hear something. They are hearing the normal sound processing that goes on in the brain. It is when these sounds become amplified that we call it tinnitus.
Tinnitus is a symptom, not a disease. Most patients with tinnitus do not have any serious medical condition. However, some do. It is the doctor's job to look for the causes of tinnitus. The search will focus on the ear and the brain.
Medical investigation of tinnitus can be divided into three stages:
The nature, onset and time course of the tinnitus can help diagose the cause. For example:
When tinnitus has been investigated, and serious disease excluded, there remains the question of what to do about it. The options include
In at least 4 out of 5 cases, tinnitus will fade into the background. Tbe noise may not nessarily go away, and, if you listen out for it, you will be able to hear it. But it won't continue in the forefront of your attention. Like an air conditioner sound that you hear when you first enter a room, it will be noticeable for a while, but then disappears into the background, especially if something else occupies your attention.
One of the best ways to deal with tinnitus is to occupy the brain with some other sounds. The sounds should be acoustically complex, and pleasant to listen to. Suitable sounds include:
Recordings of these sounds can be obtained from the RNID (Royal National Institute for the Deaf). Their range of tinnitus relaxers is available to order at www.rnid.org.uk
Sometimes, correcting the loss of hearing with a hearing aid can relieve tinnitus. It is important to use an open fit mould, as blocking the ear canal will probably make tinnitus worse.
This option may be useful in severe tinnitus. Combined with cognitive behavioural therapy, it is part of tinnitus retraining therapy (TRT).
It is important to prevent further damage to the delicate hair cells of the inner ear from excessive noise. Industrial hearing loss can result from continued exposure to noise levels in excess of 85 dB. Very loud machinery, such as a petrol chainsaw, can produce sound levels well in excess of 85dB and even short exposure can cause noise damage. Ear defenders should always be worn when using noisy equipment.
Severe tinnitus is due to the emotional reaction of the sufferer to the sound. That does not mean it is all in the mind. We all get emotional reactions to sounds. Think of the different reactions to
It is normal to have emotional reactions to some sounds. The severity of tinnitus is largely due to the emotional reaction of the sufferer. The tinnitus is perceived as more annoying and intrusive, not necessarily louder.
We have no objective way of measuring tinnitus severity. Like pain and suffering, we rely on the patient telling us what it feels like.
When tinnitus becomes severe, it is probably because the sound is perceived as a threat. This causes the brain to focus in on the sound. It becomes amplified. There are good evolutionary survival reasons why this should happen. If you are in the jungle and vulnerable, you need to focus attention on the quietest sounds of a predator approaching. Such sounds induce fear. Hormones are released into the bloodstream. The nervous system is on high alert, preparing the body to fight, or run away. The sound processing areas of the brain are switched to threat detection mode.
If you have an electronic threat detection system fitted to your home, such as an intruder alarm, there will be some means of adjusting its sensitivity. An alarm that works on a vibration or motion sensor, if set too low, could be triggered by harmless things like the wind blowing against the window. An alarm that is extremely sensitive, on a hair trigger, will give far too many false alarms. It will be going off all the time, causing a nuisance. This is probably what happens in severe tinnitus. The home intruder alarm has a simple dial, to turn down its sensitivity. Unfortunately, our brains don't come fitted with simple dials. But there are ways of adusting them. The aim is to reduce the sensitivity of the brain, so that it is only triggered by real threats, not the harmless noise of tinnitus.
The sound processing areas of the brain, below the conscious level, are quite capable of suppressing some signals and enhancing others. They forward up to the conscious level a filtered, selected version of the soundscape.
We all have selective hearing. For example, when you first walk into a room with an air conditioner, you will consciously hear the sound of the air conditioner. After a few minutes, you don't hear it any more. The sound coming from the air conditioner has stayed exactly the same. But the sound processing area of your brain has filtered it out. The emotional areas of the brain, which direct your attention, have decided the air conditioner noise is not a threat. It is not important, and can be suppresssed. You have become habituated to the sound and no longer hear it. But if someone draws your attention to it, you will hear it again.
Can tinnitus drive you mad? Can it lead to suicide? The answer is no - not on its own. But if you are clinically depressed, tinnitus can be the final straw. If you are depressed, then whatever is wrong with you - your back pain, your irritable bowel, your tinnitus - will feel ten times worse. Clinical depression is common - at least one in four will get it at some point in life. Tinnitus is also very common - nearly everyone will experience it. So, having both tinnitus and clinical depression is not unusual.
Nearly all reports of extreme tinnitus are in depressed patients. In severe clinical depression, no explanations, no rational arguments, will work. The mind is closed. The black dog is in the manger. Cognitive behavioural therapy is useless because the rational part of the mind is not accessible. Explaining tinnitus to a depressive is like explaining population control to a mother who has just seen her children murdered. Before any progress with tinnitus can be made, the depression must be treated.
Any doctor can diagnose depression. Treating depression is not something that most ENT specialists would undertake. Most cases of extreme tinnitus are due to depression. Usually, antidepressant drugs will be prescribed by a general practitioner or psychiatrist.
Tinnitus can make depression worse - negative thoughts feed off negative experiences. Depressed patients tend to wake in the early hours, when tinnitus will be at its worst. It is easy for a depressed patient to become convinced that tinnitus is the cause of all their problems. Combined ENT and psychiatric treatment may be needed.
top of pageAll information and advice on this website is of a general nature and may not apply to you. There is no substitute for an individual consultation. We recommend that you see your General Practitioner if you would like to be referred.
© 2006 - 2008 All rights reserved
Mr James W. Fairley BSc MBBS FRCS MS (Lond)
GMC No. 2719566
Enquires: Mrs Sylvia Fairley RGN RCNT Dip Nurs (Lond)
tel 01233 642244 fax 01233 662840
Sandyhurst House Sandyhurst Lane Ashford Kent TN25 4NX
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