Tinnitus is sometimes described as “ringing in the ears”, but the sufferer may actually hear a hissing, buzzing, roaring or humming sound that does not originate from anything in the external environment. Tinnitus has two classifications: objective and subjective.

Objective tinnitus can be heard by the person examining the sufferer as well as the patient and is due to a physical abnormality that results in sounds being produced within or near to the ear. Examples include a vascular tumour, prolonged opening of the Eustachian tube, abnormal rhythmic activity of the tiny muscles within the ear, or a condition such as anaemia or thyrotoxicosis (excess levels of thyroid hormones) that increases cardiac output and hence causes a pulsing vibration. Objective tinnitus is very rare.

Subjective tinnitus comprises sounds that only the affected individual can hear and is due to an auditory system problem. The mechanism by which it occurs is not fully understood. One school of thought is that the cochlea’s usual neurological activity is a source of continuous noise but is filtered out by the central auditory system and masked by environmental noises. However, if cochlear activity changes, the noise it makes may seep through the central auditory system, or penetrate through any surrounding sounds – perhaps due to impaired hearing – and can be perceived as tinnitus. This is then exacerbated by the sufferer focusing on it, often driven by anxiety.

Hearing impairment accounts for around two-thirds of subjective tinnitus, most commonly because of sensorineural hearing loss as a result of ageing, noise damage or Ménière’s disease. In around a third of cases, no cause is identified and it is regarded as idiopathic.

Being exposed to loud noises increases the risk. This group of sufferers is diverse, ranging from heavy machinery workers and weapon-handling soldiers to those who play in bands, attend concerts or listen to loud music through headphones. 

The impact of tinnitus varies; some consider it a minor annoyance, whereas others find the condition significantly reduces their quality of life, sometimes leading to reduced social interaction, insomnia, anxiety and depression.

Everyone with tinnitus should undergo a hearing test to establish if there is any hearing loss and, if there is, whether it is sensorineural or conductive. Other tests that are conducted include a general neurological assessment to exclude an underlying condition such as MS, blood sampling to check for anaemia, diabetes and establish thyroid function, and auriscopy to examine the ear. Medical, family and noise exposure histories should also be taken.