Tinnitus

Tinnitus is the medical term for the perception of sound when no external sound is present. It is often referred to as "ringing in the ears," although some people hear hissing, roaring, whistling, chirping or clicking in one or both ears, or inside their head. Tinnitus can be intermittent or constant, with single or multiple tones, and can seem loud or soft. About 50 million Americans are believed to suffer from some form of the condition, and about 12 million of these are characterized as severe enough to require medical treatment. Currently, there is no single treatment that has proven successful, perhaps owing to the wide range of possible causes – noise-induced hearing loss, ear-damaging medications, sinus infection, etc. – and the differing degrees of disability.

The vast bulk of cases, some 90%, are caused by sensorineural hearing loss — hearing loss caused by damage to the nerves or cells of the inner ear governing the sense of hearing. This source of hearing loss includes exposure to excessively loud noise. 

More rarely, tinnitus may be caused by tumors, malformed blood vessels, diseases of the middle ear, muscle spasms, non-auditory disorders such as trauma to the head or neck, jaw joint disorders and neck misalignment. Other causes may be systemic disorders such as high or low blood pressure, anemia, diabetes, thyroid dysfunction, glucose metabolism abnormalities, vascular disorders, an abnormal growth on the jugular vein, acoustic tumors, and head or neck aneurysms.

Some cases are easily fixed by addressing the underlying temporary cause, such as adjusting to withdrawal from medication (more than 200 medicines are known to cause tinnitus when they are started or stopped), having extensive earwax buildup removed, or recovering from an ear or sinus infection.

More persistent cases associated with aging and/or hearing loss can be more challenging. Brain imaging in the 1990s suggests that subjectively experienced tinnitus is a phantom phenomenon based on hyperactivity of the auditory system.

Sudden onset of tinnitus should be evaluated right away in case its cause can be remedied or the change signals cardiovascular risks such as aneurysm, high blood pressure or stroke.

Approaches to manage tinnitus can include:

• Avoidance of possible triggers, such as smoking, caffeine, or aspirin use
• Hearing aids (when tinnitus is associated with hearing loss)
• Sound therapies to mask the noise and aid in relaxation
• Counseling
• Antidepressants or antianxiety drugs
• For severe cases, direct stimulation of auditory cortex using either transcranial magnetic stimulation, transcranial direct current stimulation, repetitive transcranial magnetic stimulation, or transcutaneous (under the skin) electrical nerve stimulation

People who experience tinnitus coupled with profound hearing loss may receive some symptom relief from auditory nerve stimulation with a cochlear implant, which aids their ability to sense sound. Research has included exploring combined sound therapy and vagus nerve stimulation.

Reviewed April 2, 2012
Jaimie M. Henderson, MD
Director-at-Large, International Neuromodulation Society, 2011 - 2014
Associate Professor of Neurosurgery, and, By Courtesy, of Neurology and Neurological Sciences; Robert and Ruth Halperin Faculty Scholar; Director, Stereotactic and Functional Neurosurgery; Co-Director, Neural Prosthetics Translational Laboratory; Stanford University School of Medicine, Stanford, California, USA

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