Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Tinnitus ?
    ### Response:
    Tinnitus is often described as a ringing in the ears. It also can sound like roaring, clicking, hissing, or buzzing. It may be soft or loud, high pitched or low pitched. You might hear it in either one or both ears.    Millions of Americans have tinnitus. People with severe tinnitus may have trouble hearing, working or even sleeping.
    