Tinnitus is the phantom perception of noise in the ears that occurs in the absence of an external sound source. It is estimated that about one in five people experience tinnitus. Tinnitus by itself is not a disease but may be a symptom of another condition. In addition to a ringing sound, the noise may be perceived as buzzing, roaring, crickets, the ocean or even music. A special variant of tinnitus, pulsatile tinnitus, is hearing one’s heartbeat in one or both ears. Both pulsatile and non-pulsatile tinnitus may be constant or intermittent. The source of the tinnitus can be the ear itself; however, tinnitus is far more commonly of central origin (from the brain).
The inciting event for tinnitus may be a change in inner ear function; however, the tinnitus generator is likely to be somewhere in the brain’s auditory circuitry (central auditory pathways). Some of the most common causes include age-related hearing loss, exposure to loud noises, earwax impaction, certain medications or a stiffening of the middle ear bones as in otosclerosis. Often, a precise cause is never identified. Tinnitus may also be related to other conditions such as Meniere’s disease, acoustic neuroma, head trauma, TMJ, depression, anxiety and sleep irregularities. Current theories suggest that the brain’s “re-tuning” of central auditory pathways in response to hearing loss (even in non-speech frequencies) is the most common cause of non-pulsatile tinnitus. It must be remembered that sound is common and does not typically incite an emotional response. Tinnitus, however, is often experienced in a negative context due to the development of conditioned reflexes caused by abnormal connections between our auditory pathways and primitive centers of the brain that control emotion.
Pulsatile tinnitus, the perception of blood blow in the skull base, is often benign but can be due to unusual causes such as narrowed blood vessels (carotid or vertebral arteries), glomus tumors, arterio-venous fistulas and arterio-venous malformations. Other unusual conditions such as increased intracranial pressure resulting from obesity or superior semicircular canal dehiscence syndrome can also cause pulsatile tinnitus.
A thorough medical history, examination of the ears and a comprehensive hearing test make up the initial/minimum workup for idiopathic tinnitus (with an unknown cause). Unilateral tinnitus, tinnitus associated with new onset asymmetric hearing loss (hearing loss that is worse in one ear) or tinnitus with new balance complaints requires skull base imaging (MRI Brain with Internal Auditory Canal Protocol). Pulsatile tinnitus is often worked up using either MR or CT angiography. Suspected superior semicircular canal dehiscence is diagnosed with non-contrast temporal bone CT scan and increased intracranial hypertension is worked up/treated by neurologists. New sensorineural hearing loss and non-pulsatile tinnitus diagnosed within 30 days of onset may be treated with oral or injectable steroids.
If there is no source identified for tinnitus or if the cause is unable to be treated, there are several management options to consider. Often, the tinnitus never goes away completely, so finding strategies for coping with symptoms is critical. Cutting down or stopping smoking/consumption of alcohol along with regular exercise and relaxation may improve the tinnitus. Consultation with an audiologist to consider hearing aids or use of a tinnitus-masking device (hearing aid-like device that produces white noise) is reasonable. A trial of melatonin is sometimes effective. Additionally, cognitive behavioral strategies with or without sound treatments (tinnitus retraining) may be recommended.