Diagnosis
Smith and Tysome reviewed Tests of the ET in 2015 (Smith and Tysome, 2015). They concluded that "Currently, no single test could be considered a 'gold standard' for the diagnosis of ET dysfunction".
Practically, ETD is diagnosed by talking to the patient, and identifying symptoms that clear with manipulation of the ET, such as by "popping" the ear.
A ETD questionnaire was developed in 2014 called the EDTQ-7 (Schroder et al, 2014). We are dubious that a questionnaire is needed for this simple diagnosis. Van Roeyen et al (2015) reported that the ETDQ-7 was unable to distriminate between obstructive ET dysfunction and patulous ET. The questionnaire had good discriminant validity for ETD vs. healthy controls.
Formal measurement of ET function
Eustachian tube function can be evaluated formally by the process of measuring pressure in the ear using
tympanometry, documenting that it is different than 0, then having the person attempt to open up their ET, and then measuring it again. If pressure changes, then the ET opened. If it didn't, either the pressure was normal to start with, or the tube didn't open.