It is very well accepted that tinnitus often is "centralized" -- while it is usually initiated with an inner ear event, persistent tinnitus is associated with changes in central auditory processing (Adjamian et al, 2009). Sometimes this idea is used to put forth a "therapeutic nihilism" -- suggesting that fixing the "cause" -- i.e. inner ear disorder -- will not make the tinnitus go away. This to us seems overly simplistic -- while it is clear that the central nervous system participates in perception of sounds, and thus must be a participant in the "tinnitus" process, we think that it is implausible that in most cases that there is not an underlying "driver" for persistent tinnitus.
Prolonged exposure to loud sounds is the most common cause of tinnitus. Up to 90% of people with tinnitus have some level of noise-induced hearing loss. The noise causes permanent damage to the sound-sensitive cells of the cochlea, a spiral-shaped organ in the inner ear. Carpenters, pilots, rock musicians, street-repair workers, and landscapers are among those whose jobs put them at risk, as are people who work with chain saws, guns, or other loud devices or who repeatedly listen to loud music. A single exposure to a sudden extremely loud noise can also cause tinnitus.
Millions of Americans experience tinnitus, often to a debilitating degree, making it one of the most common health conditions in the country. The U.S. Centers for Disease Control estimates that nearly 15% of the general public — over 50 million Americans — experience some form of tinnitus. Roughly 20 million people struggle with burdensome chronic tinnitus, while 2 million have extreme and debilitating cases.1