Tinnitus is a perception of sound in the absence of an external source. While if placed in a sound-proof environment almost everyone will hear something, to the tinnitus sufferer the tones are perceptible even in normal life, and may in fact be loud enough to interfere with normal hearing.
The reported causes of tinnitus are so diverse that one wonders whether the attributions are meaningful. War veterans report tinnitus as the most common injury. Others feel it was started by a course of antibiotics. Exposure to loud sounds is also cited, as is long-term stress. The last, of course, is about as big a catch-all cause as one could cite.
Considering the auditory system, it seems that tinnitus shouldn’t be hard to trigger. With an external sound, pitch (frequency) is identified – for sounds higher than 1000 Hz – from the place in the cochlea where the hairs vibrate in response to the sound. The loudness is known from the amount of energy transferred to those same hairs. Exposure to loud sounds causes damage to the little hairs, leading to deafness at that frequency.
But as regards high-frequency tinnitus, all that needs to happen is for the neurons reporting the cochlear signal to either:
- Become sensitized so that they fire too easily, or
- Be stimulated by another process in the brain.
Both of these are natural because the brain is plastic – it is constantly seeking to make connections and circuits to do more with the information it is processing.
When a signal is irritating (such as an itch) the brain also provides mechanisms to shut off the over-active neurons. Conversely, if we assign high priority to the input (such as when we can’t see the itchy skin under a cast), the brain can amplify the signal. Both of these capabilities are located in the prefrontal lobe, the part of the brain that allows the “I” to control its experience.
Sometimes that high priority isn’t assigned because the information is significant to us – sometimes its given high priority because it distracts us from problems that we don’t know how to solve. Finally, a subconscious that’s got deep survival concerns can raise all kinds of random signals to let the conscious mind know that it’s unhappy. In that case, tinnitus might be preferable to intense neurogenic pain.
With all these mechanisms available to generate tinnitus, we can see why the reported causes are so variable.
But how to control it?
Note that as tinnitus can have medical causes, therapy should be undertaken only under the consent of the client’s doctor.
Hypnotherapists sometimes cite a 70% success rate with tinnitus. That number is a little wobbly – it actually reflects self-assessment (after all, only the sufferer can hear the sound) that the condition has improved.
The best bet is to try to activate the suppression circuitry in the prefrontal cortex. That’s usually contrary to the default process: because we find the sound to be irritating, the sympathetic nervous system is activated, causing us to focus attention on the irritation, thereby amplifying it. To achieve suppression, we want to create an association of comfort and calm with the sound, activating the parasympathetic nervous system and prompting the prefrontal cortex to suppress the input.
One method is to have the client hum or imagine the sound while undergoing relaxation therapy, followed by suggestions that the sound is an anchor to relaxation. Another way to do this, perhaps more natural to the auditory processing system, is to sing in harmony with the sound. This was successful for me when tinnitus woke me up in the middle of the night, and is similar to discomfort management techniques that associate pain with a shape and then change the properties of the shape to something that we can control. Universally in each case, however: we’re moving the response from sympathetic to parasympathetic control.
These therapies are less likely to be successful if the tinnitus is a defense against anxiety or an alarm signal from the subconscious. In that case, the Therapeutic Imagery Journey of Discovery may help to reveal the subconscious association with the sound. Once understood, the therapeutic plan can suggest a substitute signal or address the underlying cause.
For example, someone anxious in social settings might find tinnitus a convenient reason to avoid socializing. If we address the anxiety, the tinnitus would be susceptible to moderation using relaxation therapy.
Currently my most severe trigger for tinnitus is thinking about tinnitus. Mine has been off the charts since I started doing research for this post. In most cases I notice it and then turn my attention to things that are more important and pleasing to me. As described above, my prefrontal cortex swings into action and dampens the signal. That’s common among others afflicted with the condition: it tends to fade into the background when something more interesting grabs our attention.
And I apologize for the terrible pun in the title.