Hearing Basics

Prior to learning about the options to correct the hearing, please click on the “Ear Anatomy” image to understand how sound works.

Is a child with microtia deaf? In almost all cases, the answer is no. Why? During in-utero development the outer ear and middle ear form at about the same time. When there is a severe congenital malformation of the outer ear, such as a microtia, then there is usually a malformation of the middle ear as well. Most of the time, the middle ear malformation consists of fused or malformed middle ear bones, a smaller middle ear cavity and an abnormal course of the facial nerve.

Luckily, the inner ear (the location of the hearing and balance organs) forms at a different time as the outer and middle ears. As a result, the inner ear functions at a normal level, even in a child with a microtia. So when someone asks whether your child is deaf, the answer almost always is usually no.

When hearing loss occurs because of an outer or middle ear problem, this is called conductive hearing loss. When hearing loss occurs because of an inner ear problem, this is called sensorineural hearing loss.

In conclusion, a child with a microtia will usually have normal sensorineural hearing and moderate to severe conductive hearing loss. All this means is that the child’s inner ear is normal (normal sensorineural status), but because there is no ear canal, there is no way for sound to “conduct” to the inner ear via the ear canal. As a result, there will be conductive hearing loss.

Hearing Video Lecture

Dr. Bonilla presents a video lecture over basic facts about “Hearing” in children with microtia and atresia.

 

The Beauty of Sound

Although it is argued that children with one-sided microtia do not need any hearing assisted on the microtic side, others feel that it is important to stimulate the hearing nerve on both sides.

The video below demonstrates a 6-month old boy with right-sided microtia and atresia hearing clear sound in his right ear for the first time. The change in his demeanor shows the second that he begins to hear clear sound in his right ear.