Hearing loss represents an extremely common malady affecting families within the United States. It affects approximately 10% of the United States population and currently is more common than AIDS, cancer or heart disease. Approximately 1% of the United States population would be considered deaf, experiencing a profound hearing loss.
Symptoms of Hearing Loss
The symptoms of hearing loss may, at times be subtle and difficult for the affected individual to identify. Family members may notice the television volume increasing or notice that words have to be repeated. Communication within the family may suffer as a result. The affected individual may become isolated and may be fearful of communicating. We think of individuals as being affected by hearing loss they age and certainly hearing loss is more common in individuals as they age. However, more frequently younger adults and even children are being identified with hearing loss. A child affected by hearing loss is much more likely to experience difficulty in school and is more likely to be held back to repeat a grade.
The Miracle of Hearing
Hearing represents nothing short of a miracle. God faced a problem in getting a sound wave from the air filling the ear canal into the fluid that fills up the inner ear. God designed the ear in a special way to transmit the sound wave into the fluids. When we hear, a sound wave will come in the outer part of the ear and travel down the ear canal. The sound wave will strike the eardrum causing it to vibrate. The vibrations are then transmitted through the three hearing bones (ossicles) into the fluid that fills the inner ear (cochlea). The fluid is then set into vibratory motion stimulating delicate nerve endings within the snail-shaped cochlea. These hair-like nerve endings transmit this signal along the hearing nerve to the brain. The sound is then processed within the brain allowing the sound to be identified as a word or a phrase.
Causes of Hearing Loss
Hearing loss may occur within several different areas of the ear. The most common type of hearing loss is a problem with the hearing nerve called a sensorineural hearing loss. In this type of hearing loss, the hair-like nerve endings within the cochlea are affected. Recent studies have shown that sensorineural hearing loss is frequently related to our genetic makeup. It is now possible to identify the genetic abnormality in over 50% of children who are born deaf. This is extremely helpful in counseling the parents of these children, regarding the potential for future children being affected by hearing loss.
Over 100 different genetic defects have been identified in adults, which lead to sensorineural hearing loss including the genetic abnormalities that result in age-related hearing loss (presbycusis). It is likely that multiple factors acting upon this genetic makeup result in the hearing loss of the affected individual. These factors include noise exposure, diet and likely other environmental factors, such as middle ear infections. In the future, a blood test will allow the genetic makeup of the ear to be identified and will help in determining which individuals may develop hearing loss.
Some forms of hearing loss may be progressive, starting with a mild hearing loss and losing more hearing as time goes by. Other types of sensorineural hearing loss may be more of a sudden nature. When an individual has hearing loss affecting one ear, it is important that he or she be evaluated by a healthcare professional.
A second form of hearing loss is called a conductive hearing loss. This results when the sound cannot be conducted properly from the ear canal into the hearing nerve. Several areas of the ear may cause a conductive hearing loss. The most common form of conductive hearing loss is due to an accumulation of wax within the ear canal, which is easily remedied by cleaning the wax. Another common problem is fluid within the middle ear space behind the eardrum. This can cause the sound wave to be blocked or reduced. The resulting hearing loss can be treated by one of the most common procedures performed, insertion of tympanostomy tubes.
A tympanostomy tube is like a small piece of tubing, which has an opening down the middle allowing the fluid to be removed and permitting air to get into the space behind the eardrum. Approximately a million sets of tubes are placed in the United States annually. The tubes are also helpful in preventing middle ear infections, which occur in most children.
A conductive hearing loss may also occur with a problem with the hearing bones or ossicles. The ossicles may be damaged by chronic infections of the middle ear space. There may also be a problem with a perforation or hole in the eardrum causing a conductive hearing loss. In another common cause of a conductive hearing loss, the third hearing bone, the stirrup, becomes stuck or fixed due to growth of the bone surrounding it. This genetically transmitted problem is stimulated by a virus, which causes the bone to grow. At times, both the hearing nerve and the conduction of sound may be affected resulting in what is called a mixed hearing loss.
Prevention of Hearing Loss
Treatment of hearing loss is of obvious importance to all family members. It is important for individuals to protect their hearing by the use of earplugs when exposed to loud noises. Dangerous noise exposure is any noise over 85 dB. Any sound louder than the sound of a lawn mower, should result in protection from the sound, by the use of earplugs. Common household equipment, such as power tools, a blower or a lawnmower should routinely be accompanied by protection of the ears.
Hearing Loss and the Family
It is important for family members of individuals affected by hearing loss to understand the importance of face to face communication. Many individuals who are affected with hearing loss get visual clues as to what the individual is saying to the. They may miss out on a portion of a word or be uncertain as to what they have heard. Visual, face to face communication can help in allowing not only reading of the lips but also reading of the facial expression. The amount of background noise can also be important in communication. Muting the television sound or turning down the volume on a radio can be extremely helpful in communicating with an individual affected by hearing loss. The acoustics of the room in which the conversation is taking place is also an important factor.
Hearing Aid Devices
Many individual that are affected by hearing loss can benefit from amplification through the use of hearing aids. Hearing aids come in a variety of sizes and shapes from the very tiny hearing aids that go deep into the ear canal to the larger types that are worn behind the ear. What is most important in a hearing aid is not so much the shape of the hearing aid but the electronics within it.
There are three different basic types of hearing aids available. An analog hearing aid is a hearing aid that amplifies all sounds equally. This very basic form of hearing aid is generally the one that is advertised in the newspaper or on television at a discount. These hearing aids are a benefit for people in which the hearing loss affects all the frequencies equally. While these hearing aids are very economical, many individuals will not be pleased with the sound that is obtained through this hearing aid and will end up placing the hearing aid into the drawer and not wearing it. This leads to many people to say that a hearing aid does not work for them.
A digitally programmed hearing aid is a hearing aid in which the hearing testing information is placed into a computer and the hearing aid is adjusted in this way. This second generation hearing aid represents a significant improvement over traditional, analog type hearing aids. We generally recommend this type of hearing aid for most individuals. It can be adjusted if the hearing loss changes in some way and represents a significantly better acoustical signal presented to the ear.
In recent years, fully digital hearing aids have been introduced. A fully digital hearing aid is a hearing aid, which can be programmed like a graphic equalizer on a stereo by adjusting the low frequencies, mid frequencies and high frequencies. While the price of these hearing aids has been coming down significantly, they do represent a higher priced hearing aid, but do have extremely good acoustics.
In the last few years, a new type of device has been introduced for individuals affected with a sensorineural hearing loss. This is a partially implantable hearing aid called the Soundtec Direct System. This system uses a small magnet, which is surgically placed on the hearing bones. A device, which looks like a hearing aid is placed into the ear and creates an electromagnetic field. The electromagnetic field moves the magnet in perfect synchrony with sound, allowing the sound to be transmitted very effectively to the ear. The acoustical transmission is extremely clear, clearer than any type of traditional hearing aid.
Another recently introduced, partially implantable hearing aid is called the BAHA. This device has been introduced by a company called Entific and is useful for people who have a severe hearing loss in one ear with good hearing in the opposite ear. It is also useful for individuals who have a conductive hearing loss, which is not amendable to surgical correction. The BAHA device can also be used on individuals who are unable to wear a hearing aid for some reason within the ear canal.
Cochlear implants have been introduced over the last 15 years for individuals who are unable to benefit from traditional hearing aids. These devices are quite different from a hearing aid in that they take a sound wave and convert it into an electrical signal. The electrical signal is then delivered directly to the remaining hearing nerves within the cochlea allowing the individual to hear. Cochlear implants have improved significantly over the last few years and will undoubtedly continue to improve in the future. What seem to be the limiting factors with cochlear implants is the number of functioning nerve cells still within the cochlea for the implant to stimulate.
Many patients with a conductive or mixed hearing loss are able to benefit from surgical intervention for their hearing loss. These individuals include individuals with chronic infections of the ear and individuals who have damage to the hearing bones. Individuals with otosclerosis may be able to benefit by a procedure called a stapedectomy in which the stirrup bone is replaced by a prosthesis. Individuals with a perforation of the tympanic membrane may be able to benefit by repair of the eardrum and possibly even replacement of the hearing bones. Individuals with fluid in the middle ear space may be able to benefit from the insertion of a tympanostomy tube.
God has given us some exciting new treatment options for individual affected with hearing loss. The Bible states, "The hearing ear and the seeing eye, the Lord hath made even both of them." Proverbs 20:12. As you think about hearing, give thanks to God for how He has fearfully and wonderfully created you and for the miracle of hearing.
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