Tinnitus is a sensation of hearing noise when no external sound is present. It is a ringing, buzzing, clicking, whistling, hissing, or roaring sound that can vary in pitch and can come and go or be present all the time. In many cases the sound can be so severe that it can interfere with a person’s daily activities or even sleep. Tinnitus is not a condition itself but a symptom of an underlying condition such as hearing loss, ear injury, or a circulatory disorder. It is a difficult problem to live with and can cause fatigue, stress, sleeping problems, trouble with concentration and memory, and depression, anxiety and irritability.