The role of the Eustachian tube

March 4, 2013 by Mathieu Telefoglou

The role of the Eustachian tube

Have your ears ever felt blocked while on a plane or driving through the mountains? This feeling is a normal reaction of the Eustachian tube following a change in atmospheric pressure.

The Eustachian tube is a tube that is about three to four centimetres long composed of a collection of muscles that link the middle ear to the roof of the mouth at the nose. Normally, the Eustachian tube is closed at rest and quickly opens with any movement of the mouth (yawning, swallowing, speaking, etc.) to allow for an air exchange between the middle ear and the exterior environment.

The Eustachian tube serves two main functions:

  • It ensures an equilibrium between the pressure in the middle ear and that of the exterior environment. The Eustachian tube equalizes air pressure on either side of the eardrum to protect the middle ear from the change in air pressure, such as during take-off in a plane. This can therefore give a normal and temporary impression that the ears are blocked.
  • It ensures mechanical protection against the introduction of infectious agents into the middle ear cavity and allows them to evacuate. The Eustachian tube acts as a broom to prevent nasal secretions and mucous produced by the nasal mucous membranes from getting into the middle ear and causing infections such as muco-serous otitis media.

Two types of atypical Eustachian tube functions can generally be distinguished: tubal dysfunction and tubal incompetence.

Tubal dysfunction is a temporary or permanent disorder characterized by an abnormal closing of the Eustachian tube. This can be the result of an obstruction due to an inflammation of the mucous membranes in the nose caused by a cold or an allergy, for example. This situation can, to a certain extent, bring on a feeling of blocked ears, a retraction of the tympanic membrane, a buzzing, a loss of hearing and pain in the ear. According to a recent study1, 28.9% of people who complain of a blocked ear sensation have problems with their Eustachian tube.

On the other hand, tubal incompetence is characterized by a permanent opening of the Eustachian tube. According to a study, this pathology affects approximately 0.3 to 6.6% of the population, and of this percentage, 10 to 20% of these individuals are bothered by their symptoms2. Tubal incompetence can give the impression of hearing yourself speaking louder and, sometimes, a buzzing in the ears that varies with breathing can be noticed.

An audiologist can contribute to detecting a problem by evaluating the tubal function, which consists of measuring the permeability of the Eustachian tube when it is active. The ENT specialist can judge the best medical treatment, if one is needed.

For more information on this subject, don’t hesitate to consult an audiologist or ENT specialist at a Lobe Santé auditive et communication multidisciplinary clinic.

References:
1. PARK, M.S., et al. (2012). “Clinical Manifestations of Aural Fullness”, Yonsei Medical Journal, 53(5), 985-991.
2. PATEL, A.A., and S.C. LEVINE (2011). “Patulous Eustachian Tube”, Online Otolaryngology chapter for emedicine.com, (republished), http://emedicine.medscape.com/article/858909-overview#a0199.