Eustachian tube
Patulous Eustachian tube (PET) is the name of a physical disorder where the Eustachian tube, which is normally closed, instead stays intermittently open. When this occurs, the person experiences autophony, the hearing of self-generated sounds. These sounds, such as one's own breathing, voice, and heartbeat, vibrate directly onto the ear drum and can create a "bucket on the head" effect. PET is a form of eustachian tube dysfunction (ETD), which is said to be present in about 1 percent of the general population.