Crouzon syndrome is a genetic condition that causes the plates of the skull to become fused, preventing growth of the brain and causing deformities of the face. It is associated with deformity of the inner ear, or even complete absence of ear canals.
A genetic cause of hearing loss not associated with a syndrome is the connexin 26 gene. Connexin genes are important in the development of hair cells in the cochlea, and a mutation in this gene is the most common non-syndromic genetic cause of deafness.
Deafness caused by connexin 26 is characterized by profound loss of hearing from birth, and not accompanied by other symptoms such as blindness. Newborn infants with confirmed deafness can be tested for connexin 26 (also known as GJB2). If both parents carry the connexin 26 gene, their baby will have a 25% chance of being born deaf.
Complications During Pregnancy
Some illnesses contracted during pregnancy are associated with hearing problems in infants. German measles, syphilis and diabetes all show a high risk to the unborn baby. Some medications are also dangerous for the unborn child. Ototoxic medicines, that is, medicines that cause damage to the ear, could be a major source of hearing loss in new-born children.
It is not always clear which drugs are ototoxic – the same drug can have varying ototoxic properties in different people. Always be very careful about taking medication while pregnant, and if you become sick during pregnancy, make sure that the consulting doctor knows that you are pregnant.
Premature babies are often at risk for developmental problems including hearing loss. The myriad of problems that a premature baby faces puts a strain on the baby’s immune system. Often the lungs are undeveloped, necessitating the use of a ventilator. Excessive ventilator use is associated with lung infections that can spread to the ear canal.
A premature baby may also need to the receive nourishment intravenously or through a tube that passes through the nose and into the stomach. All these procedures place the baby at an increased risk for infection which may ultimately affect the hearing.
Trauma during birth may also play a factor in infant hearing loss. Large babies, babies with an oversized cranium or a breeched fetus can indicate a difficult delivery that may injure the baby. Such trauma, especially to the head, may cause hearing loss.
Conductive Hearing Loss
Conductive hearing loss refers to a blockage in the ear canal, preventing sound from passing from the outer ear to the inner ear. This usually causes temporary hearing loss, and when the cause is removed, the hearing usually returns to normal.
Temporary hearing loss is very common throughout childhood, and the most common cause is upper respiratory infection. This causes an accumulation of fluid in the middle ear, which, if it cannot drain, will affect the ability of the ear drum to vibrate, reducing the ability to hear.
Common colds can be another cause for hearing loss. A heavy cold can cause the pressure on the ear drum to become imbalanced, preventing it from vibrating.
Another common cause of conductive hearing loss is the build-up of wax in the ear. A doctor can remove the excess wax by flushing it out with water, using a special suction vacuum, or removing it with forceps.
Congenital conductive hearing loss in children can be caused by anatomic abnormalities of the outer and middle ear including congenitally fixed stapes, aural atresia (lack of an ear canal), stenosis (constricted ear canal), and microtia (missing or deformed outer ear). All of these conditions have the potential of surgical correction once the child reaches at least three years of age.
Acquired Hearing Loss - Permanent
Permanent hearing loss can happen at any time of life. Although we associate hearing loss with aging, children can also lose their hearing through a number of causes.
Diseases like chicken pox and measles, if severe enough and not properly attended to, have been connected with permanent hearing loss. Encephalitis is another disease with a very strong link to hearing loss. Head injury or noise trauma can be another cause.
Common ear infections, if left untreated, can lead to permanent hearing loss. Otitis media is an extremely common childhood condition. This is an inflammation of the inner ear that may cause fluid build-up. Usually the condition will clear up with no permanent affect on hearing, but repeated episodes of otitis media may cause damage to the ear drum and hearing nerves.
Enlarged Vestibular Aqueducts
One possible cause for progressive hearing loss in children is enlarged vestibular aqueducts. The vestibular aqueducts are narrow passages that connect the inner ear with the cranium. In normal adults, the vestibular aqueducts are narrow, “J” shaped tubes, but in new born babies they are straight and much wider. As the child grows, the tube becomes thinner and takes on the “J” shape found in adults.
In some children, however, the tube remains wide, and this condition is known as Enlarged Vestibular Aqueducts Syndrome (EVAS). The cause is unknown, but does occasionally appear to be genetic and run in families.
If your child is experiencing progressive hearing loss, he can be tested for EVAS by a CT scan. This will give your doctor detailed information about the anatomical structure of your child’s inner ear. If diagnosed with EVAS, the doctor may suggest avoiding sports, as head trauma could lead to an increase in hearing loss.
Ear infections and other ear-related injuries can lead to permanent hearing loss . Any change in your child’s hearing should be immediately attended to. Untreated hearing loss is associated with:
Always consult a doctor as quickly as possible. Your best choice would be to seek out an otologist (an ENT who specializes in only ear related disorders) with a strong pediatric practice. State of the art diagnostics, combined with the selection of appropriate hearing aids and skilled, professional programming and fitting, like that provided by the audiologists at the Hearing Device Center of the California Ear Institute, combined with assistive listening devices and acoustical modifications may also necessary to creating the optimal listening environment for a hearing impaired child. Click here to make an appointment to improve your hearing today !
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