Learning Objectives: 1. Understand the relationship between PET symptoms and the transfer function of the middle ear 2. Review methods to test ET function 3. Review interventions that might be used at the middle ear level to treat symptoms of PET.

The eustachian tube can cause a variety of distortions in hearing, and the middle ear. At one end, failure of opening can result in negative middle ear pressure, which initially affects the low-frequencies, and may cause symptoms suggestive of fullness in the ear. At the other end, a ET that is open all the time can cause autophony, and also a sensation of fullness. In between are syndromes where the ET transmits sound more than normal, and if the ear is able to respond to these, then they might cause symtoms of autophony. Particularly, this is so with ears that have “floppy segments” in the TM. There is a complex interaction between which comes first, the autophony, which then causes various behavioural changes such as sniffing, to attentuate the response of the middle ear, and which then cause the eardrum to loose rigidity, or whether the eardrum loss of rigidity comes first, perhaps from childhood infections, which then causes autophony and behavioural respones such as sniffing.

We will review our experience with testing for abnormal transmission of sound through the ET, and our experiences with manipulation of the TM to reduce the symptoms of PET, as well as other middle ear interventions.