Tinnitus refers to any auditory perception not directly produced by an external stimulus. It is commonly described as a hissing, roaring, ringing or whooshing sound in one or both ears, called tinnitus aurium, or in the head, called tinnitus cranii. The sound ranges from high to low pitch and can be a single tone, multi-tonal, or noise-like, having no tonal quality. Tinnitus may be constant, pulsing or intermittent. It may begin suddenly or progress gradually.
Although the exact mechanism underlying tinnitus is unknown, it is likely that there are many related factors. Tinnitus usually, but not always, has to do with an abnormality of the hearing or neural system.
There are a number of causes linked with tinnitus including:
Tinnitus also can temporarily result from certain medications, such as:
Current research suggests that even though tinnitus may initially be caused by an injury to the ear, ultimately an auditory pattern is established in the brain. Therefore, many treatment approaches are directed at the brain, not the ear. Although the majority of tinnitus sufferers also have hearing loss, the presence of tinnitus does not indicate that one is losing hearing.
Tinnitus can be broadly classified into two categories: objective and subjective.
This form is audible to an observer either with a stethoscope or simply by listening in close proximity to the ear. Objective tinnitus accounts for less than 5% of overall tinnitus cases and is often associated with vascular or muscular disorders. The tinnitus is frequently described as synchronous with the patient's heartbeat. In many instances, the cause of objective tinnitus can be determined and treatment, either medical or surgical, may be prescribed.
This form is audible only to the patient and is much more common, accounting for 95% of tinnitus cases. Subjective tinnitus is a symptom that is associated with practically every known ear disorder and is reported to be present in over 80% of individuals with sensorineural hearing loss, which is caused by nerve and/or hair cell damage.
Because tinnitus, like pain, is subjective, two individuals may demonstrate identical tinnitus loudness and pitch matches yet be affected in significantly different ways. The severity of the tinnitus is largely a function of the individual's reaction to the condition. That said, many tinnitus sufferers: