What is Tinnitus?
Tinnitus is an illusion of sounds in the absence of a physical stimulus. Tinnitus can be graded using the tinnitus handicap inventory score. Tinnitus can be subjective or objective. Subjective tinnitus is the perception of sound in the absence of a stimulus and is typically associated with hearing loss in the high frequencies. This is the most common form of tinnitus. Objective tinnitus is the detection of sound caused by the body or sound vibrations and can be exaggerated by conductive hearing loss (this is hearing loss due a problem with the ear canal, ear drum or bones behind the ear drum). There are two theories behind its cause. The first is that during quiet periods the nerve of hearing sends off sporadic signals and this activity is detected as a sound which is detected by the brain. The other theory is that it’s a failure to adapt to background noise which leads to increased stress and more noticeable tinnitus. Tinnitus affects 1 in 3 people aged over 50 with over half of them having episodes of tinnitus every day. An example of different causes of hearing loss that can present with tinnitus are shown in figure 1 ( A Pure Tone Audiogram) and figure 2 (Tympanogram).
Figure 1: A Pure Tone Audiogram showing right ear sensorineural hearing loss. This is the red line and is due to a reduction in the ability of the nerve of hearing to detect sound. The left ear (blue line) shows a mixed hearing loss which is a combination of conductive and sensorineural hearing loss. Conductive hearing loss is where there is a problem with sound getting to the nerve of hearing and can be due to blockages in the ear canal or problems with the ear drum or bones of hearing.
Figure 2: Showing right sided (red line) eustachian tube dysfunction causing negative pressure. This is where the tube from the back of the nose connecting to the middle ear is not functioning properly allowing equalisation of pressures in the ear and reduced pressures. The flat blue line representing the left ear shows fluid behind the ear drum and this reduces the ability of the drum to transfer sound to the nerve. A flat line can also represent a perforated ear drum.
Whilst hearing loss is the most common cause of tinnitus, there are many other rare causes which can include the following:
- Tumours on the vestibulocochlear nerve (nerve of hearing)
- Meniere’s disease
- Trauma (including excessive loud sound exposure)
- Neurological problems
- Cardiovascular diseases
- Metabolic conditions (such as changes in thyroid levels)
Treatment is focused on the cause but where no cause is found, then treatment options vary. Common simple strategies include avoiding exacerbating factors, reducing stress and tinnitus therapy. Hearing aids help reduce tinnitus by amplifying background noise and can be helpful for patients who suffer with hearing loss. For those patients whose tinnitus fails to resolve using simple measures, “Maskers” can be used to produce a sound at a similar frequency of the tinnitus which aims to hide the patient’s actual tinnitus.
There are numerous causes for somatosounds (sounds produced by the body) which are identified as objective tinnitus once detected. The most common causes of objective tinnitus are vascular problems such as:
- Turbulent blood flow
- High blood pressure
- Raised pressures in the brain
- Malformations of blood vessels
These typically present with the tinnitus sounding in time with your heartbeat. Other causes of objective tinnitus are mechanical problems such as:
- Eustachian tube problems
- Detectable movement or
- Muscles in the throat
Please get in contact with our Practice Management team if you would like further information or to book a consultation.