Tinnitus causes and risk factors

The cause is not known; however there are several theories: 

• Damage to sensory cells. The cochlea is the part of the inner ear responsible for transforming the sound waves perceived by the sensory cells into electrical signals which are interpreted by the brain as sounds. When the sensory cells of the cochlea are damaged, there is an imbalance between the electrical signals that tell the brain "there is sound" and those that say "there is no sound". This damage causes the electrical signals that must maintain the silence not to work well and become weak; thus the auditory neurons get out of control and produce spontaneous electrical signals for no apparent reason.  

• Auditory central nervous system response. Tinnitus appears as an automatic reaction of the auditory neurons compensating for the lack of electrical signals that reach the brain.  

• Stochastic resonance. This term suggests there is a kind of "adjustment" of the auditory system to certain weak signals or those close to the hearing threshold limit. Tinnitus appears as a side effect of this stochastic resonance.  

The main risk factors for suffering tinnitus are:

Among the less common causes are: 

• Ménière's disease. Tinnitus can be an early symptom of this internal ear disorder. 

• Vestibular schwannoma or acoustic neuroma. This is a benign tumour of the cranial nerve from the brain to the inner ear and is responsible for controlling balance and hearing.  

Tinnitus activates the limbic system which also has emotional effects. It is as if the brain, constantly confronted with tinnitus, adapts and learns to relate that sound to emotions. For this reason, it is associated with other disorders, such as depression or anxiety, concentration problems, insomnia, erectile dysfunction, headache, bruxism and social isolation, which in turn can make the tinnitus worse.