Aural atresia is an underdeveloped external ear (auditory) canal, eardrum, and middle ear bones, causing hearing loss.
1. OUTER EAR: the external auditory canal
2. MIDDLE EAR: the eardrum and ear bones (“ossicles”): incus, malleus and stapes
3. INNER EAR: the cochlea, semi-circular canals, and auricular nerve
The illustration below explains how sound is normally processed:
Although the outer and middle ear anatomy is affected in aural atresia, most children have a normally functioning inner ear (cochlea and auditory nerve).
Aural atresia is often associated with microtia, a congenital condition in which the outer ear is small, malformed, or missing. The majority of patients born with microtia are affected only on one side (unilateral microtia and aural atresia), although approximately 10% are affected on both sides (bilateral microtia and aural atresia).
While some children may have an ear canal, there is no eardrum and the middle ear is not properly formed. Others may have a very small ear canal with associated hearing loss, called aural stenosis.
A baby born with aural atresia or aural stenosis needs to see an Audiologist for specialized hearing testing and be closely monitored by an Otolaryngologist (Ear, Nose and Throat Surgeon).