How retraining works
When we talk about TRT (Tinnitus Retraining
Therapy), this is not simply
an abstract learning exercise. In the subconscious part of the brain concerned
with hearing, beyond the inner ear, (but before conscious perception of
sound takes place), subconscious filters, or networks of nerve cells (neuronal
networks) are programmed to pick up signals on a ‘need to hear' basis.
Think again of the way we invariably detect the sound of our own name, or a
distant car horn, or a new baby stirring in sleep, whereas we may be unaware of
the sound of rain pounding on the roof or surf beating on a sea shore.
Retraining therapy involves reprogramming or resetting these networks which are
selectively picking up 'music of the brain' in the auditory
system.
Tinnitus retraining first
involves learning about what is actually causing the tinnitus.
As a result of this and other therapy including sound therapy, the
strength of the REACTION against tinnitus gradually reduces.
This reaction controls the setting of subconscious filters which are
constantly looking for threats. With strong reactions, the filters are constantly
monitoring tinnitus, but without a reaction, habituation occurs, as it does to
every meaningless sound that is constantly present. Firstly the disappearance of
the reaction means that sufferers no longer feel bad, or distracted, and normal
life activities can be resumed – sleep, recreation and work, as before.
Secondly as the auditory filters are no longer monitoring the tinnitus it
is heard less often and less loud. As
a result it can finally become a friend instead of an enemy.
Think, now, how much of this treatment depends on being able to believe
that tinnitus results from normal compensatory changes in the hearing mechanism,
rather than irreversible ear damage.
While it is important to have a proper examination by an ear specialist, those professionals who themselves
believe that tinnitus is an 'ear' phenomenon cannot help your tinnitus. We are
in a difficult situation where the classical training of tinnitus being due to
inner ear damage is still very dominant. Few have an understanding based on
the Jastreboff neurophysiological model (Jastreboff P.J. 1990).
Habituation of reaction and
perception
The presence of any continuous stimulus results in a process called habituation, whereby the individual responds
less and less to the stimulus, as long as it does not have any special
significance. Think of moving house, from the quietness of the countryside, to live by a busy road.
At first the traffic sounds are disliked, and appear very loud. As this
reaction diminishes with time (habituation of reaction) there is an automatic
reduction in the perception of traffic sounds (habituation of perception),
The final stage of habituation is when the signal is no longer detected, and
cortical neurones are unresponsive.
With tinnitus this means that it is no
longer heard, or only on a very occasional basis. The important difference is that even when it is heard, it no longer
produces any unpleasant feelings. However, maintaining tinnitus habituation is easier if tinnitus IS
heard from time to time.
This enables you to renew your beliefs that tinnitus is ‘your
friend’, and guards against relapse. Even
where people do develop new negative reactions to tinnitus (where tinnitus may
have been absent for some years), treatment with TRT is always quicker the second time. Any
learned skill is easier to practice when all you need is revision. Sadly, some
people think because tinnitus can return after TRT that ‘the treatment has
failed’. As the goal is to get
rid of tinnitus reaction, rather than tinnitus perception – provided you have
achieved this, then TRT is always successful, and permanent.
It is important to distinguish between the
role of the ear in the EMERGENCE of tinnitus (e.g. disco tinnitus, or the Heller
and Bergman effect) and the
PERSISTENCE of tinnitus with an aversive response to it. Despite the importance
of hearing change (temporary or permanent) in triggering an emergence of
tinnitus, a recent study of our tinnitus clinic patients showed there was no
significant difference in hearing between the tinnitus group and normal
population statistics.
Wearable sound generators (WSGs)
Wearable sound generators (which look
similar to hearing aids), have an important role to play. Tinnitus
masking was at one time thought to be useful in that it simply made tinnitus
inaudible. In fact, this proved to block tinnitus habituation, as it must be audible for habituation to occur.
Habituation to any signal cannot occur in the absence of its perception. Imagine
trying to habituate your response to spiders, which you hate, simply by avoiding
them. Much better long-term results
can be obtained if wide band noise is used at low intensities while the tinnitus
can be heard at the same time. WSGs contain many frequencies, and therefore
gently stimulate all the nerve cells in the auditory pathways allowing them to
be more easily reprogrammed, (increasing their plasticity). They must be fitted and
instruction given by a trained professional. Wrong use, including one-sided use,
can make sufferers worse.
Silence is not golden
Emergence of tinnitus is often dependent on
silence. Most tinnitus is first heard at night in a well soundproofed bedroom, or
a quiet living room (Heller and Bergman 1953). Persistence of tinnitus depends
not only on the meaning attached to it, but also to the contrast it creates with
the auditory environment. Contrast contributes greatly to the intensity of any
perception. Thus a small candle in the corner of a large darkened room seems to
be dazzlingly bright, until the room lights are switched on making it virtually
invisible. Everyone, especially
tinnitus patients should avoid extreme silence, and retraining programmes will
always use sound enrichment (see instructions on this website). Make
sure there is always a pleasant, non-intrusive background sound (like a large
slow fan, or an open window, and purchase a device for generating nature
sounds). Choosing what sound is right for you may take some time. Nature sounds are
always the best, as they are already habituated, and usually produce feeling of
relaxation, calm and well-being. Avoid masking tinnitus, but have some sound
present during day and night. Remember filters are working 24 hours a day, even
when asleep, and so should sound enrichment.
Many tinnitus patients have decreased
sound tolerance and for this reason often seek very
quiet environments (see 'Decreased Sound Tolerance' on this website). They are their own worst enemy! In all cases, sound enrichment
should be practiced, using unobtrusive sound sources, to break the silence.
SELECTED REFERENCES
Hazell J.W.P. (1995) Models of tinnitus:
Generation,
Hazell J.W.P. (1995) Tinnitus as the
manifestation of a
Hazell J.W.P. (1995) Support for a
neurophysiological
Jastreboff, P.J. (1990) Phantom auditory
perception
Jastreboff, P.J. and Hazell, J.W.P. (1993)
A
Sheldrake J.B., Jastreboff P.J., Hazell
J.W.P. (1995)
Heller, M.F. Bergman M. (1953) Tinnitus in
normally
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