Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Patulous Eustachian Tube ?
    ### Response:
    Patulous eustachian tube is a benign condition in which the eustachian tube stays open most of the time. The eustachian tube is the tube that runs between the middle ear and throat and regulates the ear pressure around the ear drum. Under normal circumstances, it remains closed most of the time, opening only on occasion to equalize air pressure between the middle ear and the exterior environment.
    