Tinnitus Perception, Retraining & Habituation
How we Hear
Our conscious awareness of sound takes place near the surface of the brain when a pattern of electrical activity travelling up the nerve of hearing from the ear reaches a point just below the auditory cortex. The hearing nerve has about 10,000 different fibres, and patterns of activity in these fibres are matched with other patterns which are held in the auditory of hearing memory.
Most of what we hear is a sequence of sounds, like speech or music. There is a continuous process of matching one familiar pattern with the one coming from the ear. Each time a pattern from the ears is matched with a pattern in the auditory memory we have the experience of hearing a sound.
Putting together these matched patterns starts a process of evaluation. Another part of the brain close to the hearing centre is involved in the meaning of what we hear, and in interpreting the language. If it’s a foreign language we can hear the sound but may not understand the meaning.
The Meaning of Sound
Sound is of enormous importance. Hearing evolved in animals who were constantly in fear of their lives because of attacks from predators. The ability of animals to develop extremely acute hearing by which they could detect the very small sounds of an attacker a long way off, contributed to the survival of that species.
Warning signs are threatening and produce anxiety in an animal, prompting appropriate action to avoid attack. Some sounds can be identified as warning signals, whilst others can evoke a feeling of security or pleasure. We have this experience every day with sounds that alarm us, such as traffic horns and sounds that soothe us such as music, or the sound of nature.
In our brain the auditory cortex has a large number of connections with another centre called the limbic system which is concerned with emotion and learning. Each sound that we hear and learn the meaning of, has an “emotional label” attached to it, which may change from time to time according to how we feel in ourselves and the situations. For example the sound of a neighbour’s television set may be unpleasant and intrusive depending on whether it belongs to a well loved friend or relation, or somebody who for other reasons we dislike.
About 85% of those who experience tinnitus do not find it intrusive, disturbing or anxiety provoking. The reason for this is not so much because the quality or loudness of the tinnitus is different; in fact we have found that tinnitus is a very similar sound in those who are bothered by it and those who are not. The main difference is that those who find tinnitus troublesome, perceive it as a threat, rather than something of little or no consequence. Just as the animal alerted to danger by the sound of a predator focuses solely on that sound in order to survive, so those who consider that tinnitus is a threat or warning signal are unable to do anything but listen to it. It is part of the mechanism that humans have developed for self preservation, although clearly in this situation it is not working to our advantage!
Tinnitus as a Threat
Why is it that tinnitus should be threatening? It is an emotional link which results in tinnitus ‘sufferers’ focusing their attention on the tinnitus. Some people fear that tinnitus means they have some kind of serious illness. There are patients who worry about the possibility that it heralds a brain tumour, blood clot, or some serious mental illness (“it will drive me mad”). These anxieties are almost always unfounded. The cause of tinnitus is usually the result of very small changes of inner ear function, or the consequences of ageing, or exposure to noise.
More commonly, people fear that the tinnitus will go on for ever getting louder and continue to spoil their peace and quiet, interfere with concentration at work, quiet recreational activity and ability to sleep at night. Research shows that this is rarely the case, in the long term. Unfortunately this fear may be enhanced by professional advice. Many doctors and other professionals still advise patients that there is nothing that can be done about tinnitus and that it will go on forever. Other people fear that tinnitus may mean that their hearing is becoming impaired, although the tinnitus is the consequence of a mild hearing impairment rather than the other way around, in any event the threatening qualities of the tinnitus are enhanced.
Finally many tinnitus sufferers are angry about the treatment, or lack of treatment, or inappropriate advice that they have received. They may feel guilty for having submitted to treatment which they think is the cause of their tinnitus. Fear, anger and guilt are very powerful emotions which greatly increase attention on the tinnitus. In our experience, tinnitus improves when the patient overcome these feelings and stop dwelling on thoughts of injustice and revenge.
Retraining
Successful tinnitus management is a result of retraining and relearning. Once the tinnitus no longer presents a threat, however loud it is or however unpleasant it may seem, it can begin to diminish and in many cases may not be heard for long periods of time. Of course this is all very well to say, and very firmly held beliefs are hard to change. Retraining the auditory system to think of tinnitus as something other than a threat or warning signal can take months and sometimes even years. Such retraining should be undertaken by professionals with experience in this field. For people who also have co-existing anxiety or depression it can be difficult to change their feelings about their tinnitus.
Irish Tinnitus Association:
Head Office: 35 North Frederick Street, Dublin 1, Ireland.
Tel: +353 (0)1 817 5700
Fax: +353 (0)1 8723816
Minicom: +353 (0)1 817 5777
S.M.S. +353 (0)1 8783629
Email : ita@deafhear.ie
Think positively!
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Irish Tinnitus Association
