Tinnitus is the term for the sensation of hearing sound in your ears or head when no outside sound is present. Typically, sufferers describe the sound as ringing in ears, though others hear hissing, buzzing, whistling, roaring and even chirping. One in 50 million American adults suffer from Tinnitus (1 in 5). It can occur at any age and can happen suddenly or progress gradually. The most common causes of tinnitus are noise exposure, aging, head injury or side effects of medication. Tinnitus is different, which is what has made finding relief so elusive until now.