 A group of adults aged 18 and above, and children aged 5-17 years with normal ears, and a similar group of people that are already known to have Eustachian tube dysfunction, will both take six different tests and complete four different questionnaires. The differences in the results between the group with ETD and the healthy group will be compared. The results for each test or questionnaire will be compared to see which is best at telling the healthy and Eustachian tube function groups apart, and therefore at diagnosing Eustachian tube dysfunction. The investigators will also look to see if a combination of one or more of the tests or questionnaires is best at diagnosing the disease. 