Understanding and Treating Tinnitus
By Dr Alastair MacKendrick, ENT Surgeon

Tinnitus occurs in 17% of the Australian population. Of these, 4% will approach their doctor looking for an explanation and treatment.

Tinnitus - the symptom of noise in the ears or head - is extremely variable in character, pitch and volume.

The sufferer's response to the symptoms is extremely varied and is not related to the type of tinnitus or the personality type. It is due to abnormal electrical activity anywhere along the auditory pathway, from the cochlea, the acoustic nerve, brain stem to cerebral cortex.

By far, the commonest lesion is in the outer hair cell region of the cochlea related to noise damage or 'industrial deafness'

Hyperacusis or abnormal sensitivity to normal environmental sound is often associated with tinnitus and hearing loss. However any of these three symptoms can occur in isolation, or with one or both of the others.

Management consists of making a diagnosis as to the cause and giving a plausible explanation to the patient. It involves taking a history of noise exposure, previous ear problems and head trauma, serious illness and drugs used in the past, examination of the head, neck and ears and an accurate audiogram.

If asymmetrical hearing loss is found and there is no obvious reason (eg. wax in the ear or perforated eardrum), a CT scan or MRI scan to exclude an acoustic neuroma may be required.

Treatment of Tinnitus

The sufferer must never be told 'Nothing can be done', or 'Go and live with it'. This could drive a near suicidal patient over the brink. It also creates a huge negative barrier to any future therapies.

In the vast majority of people with tinnitus natural 'habituation' occurs - the brain 'learns' to ignore it (in the same way we do not hear the fridge running or the air conditioner going after a short time).

In some tinnitus sufferers a 'feedback loop' is set up - with awareness of the tinnitus initiating activity in the limbic system and the autonomic nervous system of the brain which then reinforces or amplifies the tinnitus. Thus, associated emotional responses and physiological changes eg. dry mouth, sweating, tachycardia etc. are triggered.

In these sufferers, we attempt to stop the loop by fitting a sound generator in one or both ears. This is used to partially cover the tinnitus so that if the tinnitus is only just audible, the brain soon 'habituates' to the sound. Gradually, over six months or a year, the annoyance caused by the tinnitus is diminished as the brain habituates.

Nearly all patients will learn to ignore the tinnitus by this method - called 'Tinnitus Retraining Therapy'.