Tinnitus is the perception of sound within the human ear in the absence of corresponding external sound. Tinnitus is not a disease, but a condition that can result from a wide range of underlying causes: neurological damage (multiple sclerosis), ear infections, oxidative stress, foreign objects in the ear, nasal allergies that prevent (or induce) fluid drain, wax build-up and exposure to loud sounds. Withdrawal from benzodiazepines may cause tinnitus as well. In-ear earphones, whose sound enters directly into the ear canal without any opportunity to be deflected or absorbed elsewhere, are a common cause of tinnitus when volume is set beyond moderate levels. Tinnitus may be an accompaniment of sensorineural hearing loss or congenital hearing loss, or it may be observed as a side effect of certain medications. However, the most common cause is noise-induced hearing loss.
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