What is Aural Atresia/Microtia?Home
Aural atresia refers to the absence or incomplete formation of an external ear canal. Both the external and middle ear may be malformed, but the inner ear and auditory nerve are often normal. In our son's case, when you look in his ears, you just see a wall of skin; no hole at all. Based on his ABR test and how well he hears with his hearing aid, we know that at least one of his inner ears (cochlea) works normally. Atresia most commonly effects just one ear (unilateral), but can effect both ears (bilateral).
What is Aural Atresia? - http://www.microtia.com/whatis.html
The Microtia And Aural Atresia Division of the IRPS - http://www.irps.net/microtiainfo.html
EMedicine � Aural Atresia -http://author.emedicine.com/ped/topic167.htm
Microtia refers to a small, abnormally shaped or absent outer ear. This is the cosmetic part. Microtia is almost always accompanied by aural atresia. Our son has small, somewhat underdeveloped outer ears; they are about 1/3 normal size. Jesse�s ears are considered as Grade II Microtia. His left ear is more developed, and borderlines on Grade I Microtia.
What is Microtia? -http://www.nyee.edu/faqlist.html?tablename=faq&key=60
The Microtia And Aural Atresia Division of the IRPS -http://www.irps.net/microtiainfo.html
eMedicine � Microtia � includes pictures of Grade I,II, and III Microtia -http://www.emedicine.com/ped/topic3003.htm#target1
A Guide to understanding Microtia -http://www.ccakids.com/Syndrome/Microtia.PDF
The effect of Atresia on hearing depends on whether just one ear (unilateral) or both ears (bilateral) are effected. If only one ear is effected, the hearing in the other ear is quite likely normal, and hearing will be adequate for normal speech and language development. It is very important to have this assessed early, however, and information should be obtained regarding unilateral hearing loss.
When the atresia is bilateral, the result is usually a moderately severe conductive hearing loss (approximately 50-60 dB). This is similar to having really good ear plugs in your ears at all times. 60 decibels (dB) is the loudness of a loud conversation; so a loud conversation sounds like a very quiet whisper to our son without his hearing aid on.
Bone Conduction Hearing Aid
When a child is born with bilateral Atresia, he or she should be fitted with a bone conduction hearing aid as soon as possible (our son got his hearing aid at 2 months old). A normal hearing aid sends amplified (loud) sounds through the ear canal. This does not work for people with Atresia, because there is no ear canal. Instead, a hearing aid is modified to send the sound out through an oscillator, or vibrator, which is connected to the main part of the hearing aid by a wire.
When this oscillator is placed on the skull (usually on the mastoid bone behind the ear), it actually vibrates the entire skull which in turn shakes the fluid in the inner ears (cochlea�s) and stimulates hearing. Because of this, only one hearing aid is required.
When the child is older (~5-7 years old), they may be candidates for the BAHA� (Bone Anchored Hearing Aid). This requires some surgery to implant a titanium abutment, and then the BAHA� "clips" on. It is much more comfortable, no headband, and most importantly, has better sound quality.
For more information on hearing aids, see our Hearing Aids page -http://www.stevesplace.ca/AtresiaMicrotia/HearingAids.htm
Atresia and microtia may be associated with syndromes such as Treacher Collins, Crouzon's, Apert's, Preiffer, Klippel-Feil, BOR�s as well as hemifacial microsomia.
http://littleear.com - Microtia and Aural Atresia Care
http://www.med.nyu.edu/PlasticSurg/Divs/micro.htm - The Microtia and Aural Atresia Division of the Institute of Reconstructive Plastic Surgery
http://www.geocities.com/microtia_and_aural_atresia/index.html - Selina�s Microtia and Aural Atresia web page