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Newborn Screening What is Universal Newborn Hearing Screening (UNHS)? Simple, hearing child is hearing inexpensive and safe tests are now available to check in the first days of life. It is no longer necessary to wait until a old enough to take a formal hearing test in order to check for loss. Newborn hearing tests are important for families, because much can be done if hearing loss is caught early in a baby's life. Hearing screening programs are called "universal" because the goal is to test all newborn babies. This means that babies in both the regular and intensive care nurseries are screened before they leave the hospital (or within 3 weeks of hospital discharge). Many people refer to screening programs by the name Early Hearing Detection and Intervention (EHDI). This title is popular because detecting a hearing loss is just the first step. If a hearing loss is detected, the next step is intervention. Intervention may include hearing aids or hearing devices, and services to support the family and baby in learning communication skills. It is important for all babies to be screened, but not all babies are born in hospitals. Individual states may have different requirements for babies who are born at home. Ideally, babies born at home should be tested before they are two months old. Newborn Screening Why is Universal Newborn Hearing Screening Important? You might be wondering why it's important to detect hearing loss so early. It is remarkable how quickly babies start to learn language and speech. Listening in the first few months of life prepares the baby to learn language. By the first birthday, infants are already figuring out what words mean. Before their first birthdays, they babble many of the sounds they hear spoken around them. These early steps are building blocks for communication. Babies learn language by tuning in to family talk. Now suppose a baby has a hearing loss and no one finds this out. This can lead to slow development of speech and language. It can create difficulties in family communication. Delays in speech and language can also lead to school problems, both academic and social. Finding hearing loss early helps to prevent these delays. Hospitals routinely screen babies for some specific problems, like PKU (PKU is an abbreviation for Phenylketonuria. Children born with this rare genetic disorder cannot metabolize a part of protein in food). Interestingly, hearing loss occurs more often in babies than any of the other problems that are screened for at birth. Approximately one to three babies out of 1000 will be born with permanent hearing loss. Because this represents an important public health concern, many hospitals are participating in hearing screening programs. Newborn Screening How Does Newborn Hearing Screening Testing Work? Currently there are two tests that hospitals and agencies use to screen babies for hearing loss. Both of these tests are safe and comfortable. They pose no risks for babies. One of are and a hears into the hearing the OAE test. Otoacoustic Emissions the tests is called otoacoustic emissions or OAEs. For this test, a miniature earphone and microphone placed in the ear, sounds are played response is measured. If a baby normally, an echo is reflected back ear canal and this is picked up by the microphone. When a baby has a loss, no echo can be measured on Auditory Brainstem Response The second test is called auditory brainstem response or ABR. For this test, sounds are played to the baby's ears. Band-aid like electrodes that are placed on the baby's head detect brainwaves. This test actually measures the brain responding to sounds. This test also identifies babies who have a hearing loss. The two test methods may be used individually or in combination. In some hospitals, babies are first screened using OAEs, and the babies who do not pass this test are given the ABR test. Both tests are accurate and reliable. Your hospital has selected a method based on hospital resources, available personnel, cost, and the number of babies born in the hospital. Newborn Screening What Does it Mean if a Baby Fails the Newborn Hearing Screening Test? When a baby does not pass the newborn hearing screening test, this does NOT necessarily mean the baby has a hearing loss. Across the nation, between 20 to100 babies per 1000 (two-10 percent) do not pass the screening test. Only one to three babies per 1000 (less than 1 percent) actually have hearing loss. This means that most of the babies referred for follow-up testing will be shown to have normal hearing. You may wonder why a baby with normal hearing would fail the newborn hearing-screening test. There are several common reasons: Vernix in the ear canal Fluid in the middle ear Movement and/or crying during the test Even though most babies will pass the follow-up hearing testing, it is VERY important to take your baby for follow-up testing. This is the best way to be SURE about your baby's hearing. Newborn Screening Can a Baby Pass the Test and Still Have Hearing Loss? Although it doesn't happen very often, sometimes babies can pass a hearing test and still have hearing loss. Some mild hearing losses or losses that affect only some pitches may not be picked up by the screening test. Some infants have hearing loss that is not present at birth. These babies are born with normal hearing, but develop a hearing loss after the newborn period. This condition may result from certain illnesses or from some genetic causes. Hearing loss after the newborn period might also happen because of the use of certain medications or as a result of trauma or disease. If your baby has risk factors for these types of hearing loss or if you have concerns about your child's responses to sound or speech development, you should discuss this with your baby's doctor. It is important to keep in mind that regardless of your baby's age, there are safe, effective and accurate tests that can be used to determine how well your baby hears. Newborn Screening What Should I Do If My Baby Fails the Test? You should discuss the test results with your baby's doctor. The doctor will probably refer your baby to a pediatric audiologist for further testing. The First Step In many cases, the first step will be a rescreen using techniques similar to those used in the hospital. In other hospitals and clinics, a diagnostic Auditory Brainstem Response (ABR) test will be done immediately. Recall that ABR was discussed previously, but that was a screening version of the test. A diagnostic ABR is a more thorough test of the baby's hearing. When we hear sounds, we recognize different pitches or tones. A piano keyboard has a range of tones from low to high. Speech sounds we hear are also made up of a range of tones. The last time your hearing was tested, you probably listened for soft tones that ranged from low to high pitch. A diagnostic ABR is a test that will help determine how much hearing loss is present for these different pitches of sound. The goal of this test is to find the softest sounds that produce a response for low, middle, and high pitched sounds. If your baby is tested before 2 months of age, testing usually can be done while the baby is sleeping naturally. If your baby is older or very active, a liquid medicine may be used to make your baby sleepy. This will ensure that the baby's movements do not interfere with the test. If the baby passes the ABR test, no further testing is needed. However, babies should continue to be watched for hearing loss that occurs after the newborn period. The Second Step If diagnostic testing shows that your baby has a hearing loss, a number of professionals may become involved to help your baby and your family. Some of the people you may meet include the following: Services Coordinator - this professional works with early intervention programs. He or she works closely with the family to identify needs and to ensure that providers work together and coordinate their efforts to make intervention manageable for the family Infant/Family Specialist - a teacher who specializes in working with infants who have hearing loss and their families Pediatric Audiologist - a professional who specializes in testing the hearing of infants and children and recommends hearing instruments Ear, Nose and Throat Physician - a doctor who specializes in problems of the ear, nose and throat Pediatrician or Family Practitioner - a doctor who provides primary health care for infants and children If your baby has a hearing loss, these professionals will be eager to provide support to your family. Their main goal will be to work together to limit the effects of the hearing loss on your baby's development. It is essential that appropriate services begin as soon as a diagnosis of hearing loss is made. The Joint Committee on Infant Hearing and the American Academy of Pediatrics recommend that services should begin before 6 months of age if at all possible. All About Hearing Loss How the Ear Works The Ear is made up of three parts: External Ear Middle Ear Inner Ear The picture on the right shows the three parts of the ear: External Ear Sounds travel through the external ear or ear canal and cause vibration of the eardrum (tympanic membrane). Middle Ear Eardrum movement causes the three middle ear bones (ossicles) to vibrate. This vibration creates movement of fluid in the inner ear (cochlea). Inner Ear The inner ear, or cochlea, sends nerve impulses to the brain. Once the brain receives the message, we have a sensation of hearing. The sound wave moves the eardrum and attached ossicular chain. The stapes footplate, in the round window, transfers the vibrations to the perilymphatic compartment (scala vestibuli) and to the inner ear structures. Depending on frequency, the vibration has a maximum effect (resonance) at a different point along the basilar membrane, accounting for passive tonotopy. Here on the left, a high frequency sound effects a basal portion of the cochlea. Animated drawing by S Blatrix, from "Promenade around the cochlea ' by R Pujol, S. Blatrix, T. Pujol and V. Reclar-Enjalbert, CRIC, University Montpellier 1 - INSERM All About Hearing Loss Types of Hearing Loss Hearing losses may be located in the external, middle or inner ear or both. These different types of hearing loss are described below. Conductive Hearing Loss If there is a problem in the external or middle ear, a conductive hearing loss exists. This means sound is not being conducted properly to the inner ear. Common causes of conductive hearing loss are wax (cerumen) in the external ear, fluid in the middle ear, or a hole or tear (perforation) in the eardrum. Most types of conductive hearing loss can be treated medically or surgically. Below are pictures of a normal ear drum, middle ear with fluid, and an eardrum with a perforation. Normal Eardrum Middle Ear Fluid Eardrum Perforation Michael Hawke, M.D., Diseases of the Ear, published by Manticore Communications Cross section of the middle ear showing middle ear fluid Sensorineural Hearing Loss If a problem occurs in the inner ear, the hearing loss is sensorineural. Common causes of sensorineural hearing loss in young children are certain pre-natal infections, lack of oxygen during birth, or genetic factors. Sensorineural hearing loss usually cannot be cured medically or surgically, but the use of hearing aids or other amplifying systems can help children hear and develop speech and language. Mixed Hearing Loss Children with sensorineural hearing loss also can develop middle ear problems (such as fluid in the middle ear) This can make the infant's hearing loss worse. When there is a combination of two problems (sensorineural and conductive hearing loss), this is known as a mixed hearing loss. All About Hearing Loss What Is An Audiogram? shaded region shows the level and frequency of average speech When your baby is a bit older, the pediatric audiologist will measure his or her hearing and plot a graph called an audiogram. An audiogram is a graph used to show the softest sounds that a person can hear at different pitches. The graph shows this range of sounds included in typical speech. Different sounds in our language vary in their pitch and loudness. For example, the "s" sound you use in the word "cats" is high in pitch and fairly soft. In contrast, the "o" sound in "bow" is low in pitch and fairly loud. The frequency and loudness of individual speech sounds are also shown on the audiogram. Hearing is tested using earphones or loudspeakers. These send sounds to the ear canal and through the middle ear to reach the inner ear. This is known as air conduction testing. If air conduction testing shows a hearing loss, another device, a bone vibrator, is placed behind the ear to send sounds directly to the inner ear. The sound bypasses the ear canal and middle ear. With conductive hearing loss, sounds can be heard at softer levels with the bone vibrator than with the earphone. With sensorineural hearing loss, sounds will be heard at similar levels through both devices. Now, you can experience what hearing loss sounds like in comparison to normal hearing. The audiogram to the right shows normal hearing. Click for an example of normal hearing file type This audiogram shows a mild highfrequency hearing loss. A child with this degree of hearing loss will have trouble hearing and understanding soft speech, speech from a distance or speech in a background of noise. Click for an example of mild hearing loss file type The audiogram here shows a moderate high-frequency hearing loss. A child with this degree of hearing loss will have difficulty hearing conversational speech even at close distances. Click for an example of moderate hearing loss file type The audiogram here shows a severe hearing loss. A child with this hearing loss may only hear very loud speech or loud environmental sounds. Click for an example of severe hearing loss file type All About Hearing Loss Hearing Tests to Expect As Your Child Grows As your child grows, a variety of hearing tests will be conducted by the Audiologist. Birth to 6 Months of Age Currently, a diagnostic auditory brainstem response (ABR) test is the only method available for testing hearing in newborns and infants up to 6 months of age. While this test is similar to the ABR screening that is often performed in newborn nurseries, the diagnostic ABR gives more detailed information about the degree of hearing loss across frequencies in both ears. This is also known as a frequencyspecific ABR. Under two months of age, this test can be performed while a baby is sleeping naturally. If a baby is older or very active, a liquid medicine may be used to help your baby sleep. For this test, small bandaid-type electrodes are placed behind each ear and on your baby's head. Sounds are then presented to the ears using miniature earphones. The electrodes pick up responses from the hearing nerve and are displayed on a computer screen. This test usually lasts about 2 hours. Infants and Toddlers (6 mos. - 24 mos.) Children older than 6 months can be tested using a behavioral technique known as Visual Reinforcement Audiometry (VRA). With this test, a sound is presented either through miniature earphones or a loudspeaker. The child is trained to turn to the sound by the use of an animated toy. By using this technique, it is possible to obtain detailed information about the child's hearing loss across frequencies in both ears. Test results are graphed on an audiogram. Young Children and Preschoolers (24 months - 5 years) Children in this age range are tested using Conditioned Play Audiometry (CPA). This is a game-like activity where the child is asked to do a specific task, such as dropping a block in a bucket, every time a sound is heard. Typically, sounds are presented through miniature earphones and results are graphed on an audiogram. As with VRA, it is possible to obtain detailed information about the child's hearing loss across frequencies in both ears. Other tests may be conducted in addition to the standard tests that are run at specific ages. Tympanometry Tympanometry is used to determine if the baby's middle ear is functioning normally. This test is important because fluid in the middle ear or other abnormalities can affect hearing responses. This test is performed by placing a small earphone in the baby's ear canal and gently changing the air pressure in the ear. This test is helpful in identifying the presence of an ear infection and/or fluid in the middle ear. A normal tympanogram shows a definite peak at normal room pressure (0) An ear with fluid will show a flat tympanogram Other patterns are found with various middle ear problems, including eardrum perforations, eustachian tube problems, etc. If the tympanogram shows a tracing that is not normal, your baby may be referred to his/her physician. Tympanogram testing also may be used to evaluate if pressure equalization (tympanostomy) tubes are present and working correctly. Your child's physician and audiologist use both the tympanogram and ear examination results to see if the tube is open. The picture to the right shows an ear drum with a tympanostomy tube in place. Tympanostomy Tube in Place Diagnostic Otoacoustic Emissions (OAEs) Diagnostic otoacoustic emissions generally are used in combination with ABR and behavioral audiometric results. A miniature earphone is placed in the ear canal and a series of tones are presented. The sensitive microphone measures an echo from the inner ear. This information helps define your child's type of hearing loss. Causes of Hearing Loss Parents who have just received word that their child has a hearing loss can display a wide range of reactions. A common feeling that most parents experience is wondering what caused their child's hearing loss. This section will help parents begin to answer that question. We will walk you through the process that medical professionals use to discover the cause of a hearing loss and determine the appropriate treatment. The emphasis will be on some of the more common causes of hearing loss. Trying to come up with an answer to the question of what caused a hearing loss is somewhat like putting together a jigsaw puzzle. Unfortunately, we do not always have all the pieces to that puzzle and there is not a final picture to guide us. Each physical finding, medical test result, and piece of family medical history provides a piece of the puzzle. Sometimes, one of those pieces can "fill in" a big enough section of the puzzle that the medical professionals feel confident that they know the cause of the hearing loss. It is also possible that after all the testing, after all the questioning, and after all the examinations, the answer remains unclear. You may be told that the cause of the hearing loss is still unknown. Causes of Hearing Loss Non-Genetic Hearing Loss In about 25% of cases of hearing loss there is a non-genetic cause that can be identified. Nongenetic hearing loss is most often caused by illness or trauma before birth or during the birth process. Older infants and young children can also develop non-genetic hearing loss due to illness or trauma. Some viral infections are known to be associated with hearing loss. These infections carry the highest risk of causing hearing loss if the mother has the illness during pregnancy or passes the infection to her baby during the birth process. The primary infections are Toxoplasmosis (Catscratch disease), Syphilis, Rubella (German Measles), Cytomegalovirus (also known by the initials CMV) and Herpes. The amount of hearing loss that can result varies widely and some babies show no hearing loss at all, even if they have one of these infections. These infections can affect other systems in the body as well and medical professionals will need extensive birth history and test information to identify these infections as a cause for hearing loss. Low birth weight has also been identified as a risk factor for hearing loss. Newborn specialists identify 1500 grams (approx. 3.3 lbs.) as a cut-off point, with children weighing less than 1500 grams having an increased likelihood of hearing loss. Hyperbilirubinemia (jaundice) that is severe enough to require a blood transfusion can also result in hearing loss. This is related to the potential damage that high levels of bilirubin can cause to the nerves of hearing. Sometimes medications that are known to be ototoxic (damaging to hearing) are prescribed to babies, usually to treat serious infections or birth complications. The most common otoxic medications used at this time include a family of antibiotics called aminoglycosides with names such as gentamycin, tobramycin, kanamycin. and streptomycin. Hearing loss resulting from the use of these antibiotics may also have a genetic component. They present more of a risk to hearing when they are used multiple times or in combination with other medications, such as diuretics. Although cancer in infants and young children is rare, there are some chemotherapy drugs that are used which are also ototoxic, especially when used to treat tumors that are in the skull. All babies are evaluated at birth on a 10-point scale, called an APGAR score, for A: Activity (muscle tone); P: Pulse; G: Grimace (reflex irritability); A: Appearance (skin color); and R: Respiration. Newborns are given APGAR scores at 1 minute and 5 minutes after birth. The higher the score, the healthier the baby is. When babies have scores of 0-4 at one minute or 0-6 at five minutes, their risk for having hearing loss increases. Also, prolonged mechanical ventilation for a duration of five days or longer due to persistent pulmonary hypertension increases the risk for hearing loss. These conditions of breathing problems and other distress at birth do not mean that a baby will always have a hearing loss, but do indicate the need to monitor hearing closely. One illness that carries a high risk of causing hearing loss and/or balance problems is bacterial or viral meningitis. Because of improvements in immunizations, the cases of bacterial meningitis have declined sharply in recent years, but immunizations are not available for the viral type of this infection. Because meningitis is an infection of the lining of the brain and spinal cord, the sense organs of hearing and balance are especially sensitive to this infection. It is clear that non-genetic hearing loss can result from a wide variety of illnesses and problems at birth. Medical professionals depend on a careful review of birth information to help them identify non-genetic hearing loss. Causes of Hearing Loss How do genetic professionals view hearing loss? Most genetic professionals working with hearing loss are in general agreement that the cause of hearing loss in about one-quarter of cases is Unknown, one-quarter Non-genetic, and about one-half Genetic. For the purposes of this section, we will only focus on the genetic causes. Within the genetic half, about 70% of cases are generally thought to be recessive in nature, about 15% dominant and the remainder include all other inheritance types. The next section will explain these genetic terms in more detail. Genetic 50% Non-genetic Unknown 25% 25% Understanding genetics and inheritance Many parents are unfamiliar with how hearing loss could be caused by genetic factors. As you work through the process of identifying the cause of your child's hearing loss, it will be helpful to have a basic understanding of genetics and the major categories of inheritance. If you are already familiar with genetic concepts, this list briefly summarizes the important points of genetic inheritance: Genes code for messages. Genes are found on chromosomes. Chromosomes come in pairs called homologs. The messages on each of the chromosomes in a pair may be different; those differences determine dominant or recessive expression of the gene message. The major forms of inheritance are Dominant, Recessive and Sex-linked. There are other types of inheritance. Causes of Hearing Loss Basic Genetics What Are the Most Common Forms of Genetic Hearing Loss? Of the 50% of the genetic forms of hearing loss, an estimated 70% are due to recessive causes, about 15% have a dominant cause; and the remaining 15% include all the other forms of inheritance. GENETIC RECESSIVE 70% DOMINANT 15% OTHER GENETIC 15% NON-GENETIC AND UNKNOWN Genetic scientists subdivide genetic hearing loss into two general categories: "Non-Syndromic" (meaning hearing loss and nothing else) and "Syndromic" (meaning hearing loss with other clinical findings). By far, the more common is Non-syndromic hearing loss which includes 2/3 of all genetic hearing losses. SYNDROMIC NONSYNDROMIC RECESSIVE RECESSIVE DOMINANT DOMINANT OTHER OTHER GENETIC GENETIC NON-GENETIC AND UNKNOWN What is the Most Common form of genetic hearing loss? One gene, known as Connexin 26 (abbreviated CX26), is estimated to be responsible for half of all the recessive cases of hearing loss. There are over 400 known genetic causes involving hearing loss. CX26 alone is responsible for about 1/3 of all the cases of genetic hearing loss! SYNDROMIC NONSYNDROMIC CONNEXIN26 RECESSIVE DOMINANT OTHER GENETIC RECESSIVE DOMINANT OTHER GENETIC NON-GENETIC AND UNKNOWN What are the Next Most Common Forms of Genetic Hearing Loss? Since CX26 accounts for about 1/3 of all cases of genetic hearing loss, that leaves about 1/3 of all cases as non-syndromic (this includes all types of inheritance) with the remaining 1/3 as syndromic. Among the remaining 1/3 of non-syndromic cases of genetic hearing loss, 13 dominant and 8 other recessive genes have been described. What are the Common Dominant Syndromic Hearing Loss Types? The following descriptions are only a brief review. Medical professionals can guide you for further information. About 5% of all hearing loss is dominant syndromic in nature. http://www.familyvillage.wisc.edu/index.htmlx Waardenburg Syndrome - The hearing loss in Waardenburg Syndrome may be present in one or both ears and is a sensorineural type of loss. The striking features of Waardenburg syndrome may include: premature graying hair, white forelock, fused eyebrows (synophrys), two different-colored eyes (heterochromia irides, usually bright blue and brown), widely-spaced eyes (hypertelorism), high nasal bridge, under-developed nose tip (hypoplastic alae nasia) and partial albinism. http://www.boystownhospital.org/parents/info/genetics/waardenburg.asp http://www.nidcd.nih.gov/health/pubs_hb/waard.htm Branchio-Oto-Renal (BOR) Syndrome - The hearing loss in BOR Syndrome is conductive, sensorineural or mixed. Cysts (or pits) can be found on the neck (branchial cleft) or in front of the outer ear (prearicular). The outer ear (pinna) may be malformed and stapes fixation, inner ear malformations and/or enlarged vestibular aqueducts may be present. A major medical concern with BOR are the associated renal (kidney) problems, which could be life threatening. http://www.boystownhospital.org/parents/info/genetics/bor.asp Neurofibromatosis Type II (NFII) - The hearing loss in NFII is progressive sensorineural leading to possible deafness. Café-au-lait (coffee with cream-colored) spots may appear on the skin, with freckling and cataracts. Acoustic tumors may grow on the VIIth cranial nerve, causing hearing loss. Tumors may also grow on other nerves. http://www.nfinc.org/ http://neurofibromatosis.org/ http://www.vh.org/Providers/TeachingFiles/RCW/080495/NeuroFibroHome.html Stickler Syndrome - The hearing loss in Stickler Syndrome is usually conductive, although some losses may be mixed or sensorineural. Progressive hearing loss has also been reported. There are three syndrome types. All are related to altered expression of a collagen/connective tissue gene. Associated features may include: cleft palate, downward-placed tongue (glossoptosis), small jaw (micrognathia), under-developed midface, progressive severe near-sightedness (myopia), cataracts, retinal detachment/degeneration, bone/joint disorders, early adult-onset arthritis, and middle ear bone (ossicular) malformations. http://www.sticklers.org/sip/ Treacher-Collins Syndrome - The hearing loss in Treacher-Collins is conductive. Striking facial features include cleft palate, down-slanting eye-slit openings (palpebral fissures), unusual pupil openings (coloboma), under-developed cheek bones (malar hypoplasia), absent/malformed outer ears, absent (atresia) or narrow (stenosis) ear canals, skin tags in front of the ear (prearicular), teeth alignment problems (malocclusion) and possible balance (vestibular) problems. http://www.treachercollinsfnd.org/ What are the Common Recessive Syndromic Hearing Loss Types? Recessive Syndromic hearing loss accounts for about 20% of all types of genetic hearing loss. Usher Syndrome - There are three (3) types of Usher syndrome with different types of hearing loss. Type I has congenital, profound, sensorineural hearing loss. Type II has a downwardsloping, sensorineural hearing loss. Type III has a progressive sensorineural hearing loss. All types have balance (vestibular) problems and progressive vision loss due to retinal degeneration (retinitis pigmentosa). http://www.nidcd.nih.gov/health/pubs_hb/usher.htm Alport Syndrome - Hearing loss in Alport syndrome may be sensorineural, conductive or mixed and may be progressive. Alport syndrome may also be X-linked (linked to sex-chromosome inheritance). Other features include kidney problems (nephritis), near-sightedness (myopia) or cataracts, and palate abnormalities. http://www.cc.utah.edu/~cla6202/ASHP.htm Jervell and Lange-Nielson Syndrome - The hearing loss in JL-N syndrome is sensorineural. The other major finding in JL-N is an abnormal heart rhythm (long Q-T), which could lead to fainting spells and possible sudden death. These might be mistaken for seizures. These abnormal heart rhythms are successfully treated with medication (beta blockers). Pendred Syndrome - The hearing loss in Pendred syndrome may be mixed or sensorineural and may be progressive. Pendred Syndrome may have an associated goiter,and variable inner ear malformations (Mondini malformation with or without enlarged vestibular aqueduct). http://www.medicinenet.com/Script/Main/Art.asp?li=MNI&ArticleKey=9460 What are Some Less-Common Syndromic Hearing Loss Types? CHARGE Syndrome - The letters in CHARGE stand for Coloboma, Heart, Atresia of the choanae, Retardation of growth and development, Genital and urinary abnormalities, and Ear abnormalities. CHARGE is thought to be multifactorial. The hearing loss may be conductive, sensorineural or mixed and range from mild to profound. In addition to the features in the name, there may be partial facial paralysis, cleft palate, cleft lip, kidney problems, and feeding problems due to an opening between the windpipe and the feeding tube. http://www.chargesyndrome.org/ X-Linked Congenital Stapes Fixation with Perilymph Gusher - For boys with this syndrome, the hearing loss is mixed and may be progressive. Females who carry this gene may have mild, mixed or sensorineural hearing loss. Boys with this gene have a further risk of increased hearing loss if middle ear surgery is performed to correct the stapes fixation because the surgery may result in massive and sudden loss of inner ear fluid (perilymph). Mitochondrial Conditions Mitochondria are structures in the cell that produce the energy that cells need to survive. Neither the mitochondria nor the cell can exist without the other. Interestingly, mitochondria have a separate set of genes that are not part of the cell's genes. This is because mitochondria originally came from energy-producing bacteria that merged with the cell. Anything that affects bacteria could also affect the function of the cell's mitochondria, which might eventually affect the cell's energy source. Changes in the mitochondrial genes can also result in syndromes involving hearing loss. Mitochondrial Encephalopathy, Lactic Acidosis and Stroke-like Episodes (MELAS) - About 30% have sensorineural hearing loss. The findings are highly variable and may include: intermittent vomiting, limb weakness, stroke-like episodes, partial paralysis, partial blindness, seizures, migraine-like headaches, diabetes, short stature, heart problems and kidney problems. Maternally Inherited Diabetes and Deafness (MIDD) - The hearing loss is sensorineural. The only other finding is diabetes. Kearns-Sayre Syndrome (KSS) - The hearing loss is sensorineural. Other findings include: unsteady gait (ataxia), short stature, delayed puberty, progressive paralysis of the eye muscles (ophthalmoplegia) and progressive blindness (retinopathy). Myoclonic Epilepsy and Ragged Red Fibers (MERRF) - The hearing loss is sensorineural. Other findings include unsteady gait (ataxia), epilepsy, and possible blindness (optic atrophy). 1555DELG - The hearing loss is sensorineural and may be progressive. Those who have this condition may have sudden hearing loss when exposed to aminoglycoside antibiotics (e.g., neomycin, gentamycin, streptomycin, kanamycin, tobramycin, or amikacin). Causes of Hearing Loss asked Answers to some frequently questions Why did this happen to my child? Hearing science professionals estimate that 1 in 300 babies are born with some degree of hearing loss. Human genetic professionals estimate that half of those cases of hearing loss are due to the genes that the baby inherited. About 12 babies per 10,000 have a recessive cause of their hearing loss. Congenital hearing loss (hearing loss present at birth) that is due to one of the many recessive genes is about twice as common as Cystic Fibrosis, another recessive genetic condition. To answer the question, "Why did this happen to my child?" there could be at least one of three answers. 1. Unknown (the cause of the hearing loss cannot be discovered) 2. Non-genetic (illness or trauma before, during or after birth) 3. Genetic (the hearing loss will depend on the type of inheritance present) In 70% of cases of genetic hearing loss, the cause is autosomal recessive; therefore, Both parents are "carriers" of a gene that causes recessive hearing loss. There are many different genes in many different locations that may cause genetic hearing loss. At one of these locations, a parent my carry one of the recessive genes that can cause deafness and one of the dominant genes that is responsible for normal hearing. Because each parent has only one recessive gene that can cause hearing loss, both parents can hear. If each parent passed on one recessive gene, then the child would receive two recessive genes (one from each parent) and that is the cause of the recessive hearing loss. In 15% of cases of genetic hearing loss the cause is autosomal dominant. In this case only one parent may have the dominant gene for hearing loss. That parent will have some degree of hearing loss. If the autosomal dominant gene also has other physical findings (i.e., it is syndromic), the parent who has the dominant gene also may have some of these other physical findings. The parent with the dominant gene may pass that gene for hearing loss on to the child. For the final and remaining 15% of genetic hearing loss cases, the answer to the question, "Why did this happen to my child?" is specific to the particular type of genetic inheritance. Why is my child being referred for Genetic Testing? Genetic testing may determine whether your child's hearing loss is due to non-genetic causes or to a gene that causes hearing loss. From this information, professionals can calculate the likelihood that other children in your family may also have a hearing loss due to the same cause. A full genetic evaluation will also determine if there are other health conditions that also need to be addressed. What does this mean for my child? In general, why your child has a hearing loss does not affect how your child will be educated. Management of your child's hearing loss will be based upon the specific characteristics of your child and his or her communication needs. The findings from a genetic evaluation may be relevant for your child's medical care What is the likelihood that this will happen again with any other children in my family? If the cause of your child's hearing loss is an autosomal recessive gene, then the likelihood that this will happen in another child (assuming the same partner) is 1 in 4 (25%). If the cause of your child's hearing loss is an autosomal dominant gene, then the likelihood that this will happen in another child (assuming the same partner) is 1 in 2 (50%). Should I have my other children tested? If it is determined that you and your partner carry the silent (recessive) gene which causes a hearing loss, then each of the children resulting with that partner have a 2 in 3 (66%) chance of also carrying that same gene. Whether or not your hearing children should be tested to determine if they also carry the deafness gene is a matter of choice. Your hearing children may want to know their own gene carrier status so they would know whether to have their partners tested to determine if their children (your grandchildren) have a chance of having hearing loss due to this gene. There is a 2 in 3 chance that hearing siblings (brothers and sisters) of a child with recessive hearing loss carry the hearing loss gene (like you and your partner). If this is the case, then their life partner could be tested to determine if they are also a carrier. If that partner is also a carrier of the same gene, then each of their children would have a 1 in 4 (25%) chance of having the same genetic hearing loss. If that partner does not carry the same gene, then all of their children would be hearing, although each child would have a 50% chance of carrying the hearing loss gene. There is a 1 in 3 chance that hearing siblings do not carry the recessive hearing loss gene. If this is the case, there is virtually no chance of having a child with a hearing loss due to this gene, as the gene is not passed on. Is this something that I need to be concerned about in my other relatives? If you and your partner carry a recessive gene, then at least one of your parents and one of your partner's parents also carry the gene. This means that each of your brothers and sisters has a 1 in 2 (50%) chance of carrying the same gene. What will all this cost? The monetary costs of a genetic evaluation and medical tests are generally covered by your health insurance. Families should always check with their health insurance carrier to determine if genetic and medical tests are covered under their particular plan. Some people experience the psychological cost of guilt that they were responsible for this condition in their child. Be assured that everyone carries some recessive genes that, if present in a double dose, would cause some sort of genetic condition. Guilt feelings are natural during the stages of grieving and acceptance of your child's hearing loss. However, if those feelings persist or if they affect your ability to function day-to-day, please seek out someone who can help. Causes of Hearing Loss Glossary Autosomes - The 22 pairs of chromosomes that contain genes that do not determine your sex. These are numbered from the largest (#1) to the smallest (#22) pairs. Chromosome - A collection of many hundreds or thousands of genes strung together like beads on a string. There is no rhyme or reason for the order of the genes on a chromosome. Humans usually have 46 chromosomes (23 pairs) and they are found in the nucleus of each cell in your body (with the exception of the cells responsible for reproduction). One pair of chromosomes determines your sex (Sex Chromosomes); all the other chromosomes are called Autosomes. Think of a chromosome as one of a volume of books, each containing many sentences (genes). Since chromosomes come in pairs, then genes also come in pairs. This is the basis for the different types of inheritance: Dominant and Recessive. Dominant gene (inheritance) - Since genes come in pairs, a dominant gene is always expressed (message is read) regardless of the message on the other gene. Gene - A coded message that tells the body how to make a chemical substance that the body needs. For example, the gene that codes for the molecule hemoglobin, which carries oxygen in the red blood cells, is found in humans on chromosome #9. Think of a gene as a sentence in a book. Hearing Loss - The condition of less than full hearing capacity. The degree of hearing loss can have different terms; hard of hearing, hearing impaired and deaf are three of the more common terms. Unless otherwise specified, hearing loss includes all of these sub-classifications. Recessive gene (inheritance) - If paired with a Dominant gene, the message of the recessive gene will not be expressed. However, if paired with another recessive gene, then the message will be expressed. Sex Chromosomes - The one pair of chromosomes that determine your sex. In humans, females have two "X" chromosomes, while males have one "X" and one "Y" chromosome. Therefore, human males determine the sex of the children (whether the sperm contains the "X" or "Y" chromosome). Cochlear Implants Cochlear implants are devices that can provide sound for people who receive little or no benefit from hearing aids. Hearing aids make sounds louder. However, for children and adults who have severe to profound hearing loss, making sounds louder may not be enough to allow the ear to process sound. A cochlear implant may be more successful than hearing aids in some cases, because it bypasses the damaged sense organ of hearing (cochlea) and directly stimulates the hearing (auditory) nerve. Part of the cochlear implant includes tiny electrodes that are surgically inserted into the cochlea. The cochlear implant converts sound into electrical signals that go to the auditory nerve. This section includes information on how the cochlear implant works, who is a candidate, and how to help children learn to listen with this device. Cochlear Implants What Is a Cochlear Implant and How Does it Work? Cochlear implants are implantible devices designed with the goal of providing sound detection and speech recognition for people who receive little or no benefit from hearing aids. There are several manufacturers of cochlear implants such as Advanced Bionics Corporation, Cochlear Americas, and Med-El. The cochlear implant-regardless of the manufacturer-is comprised of both internal and external components. The internal portion, which is implanted surgically, has a receiver and tiny electrodes. The receiver is imbedded under the skin behind the ear and the electrodes are surgically inserted into the cochlea. The external portion, shown in the picture below includes a speech processor that is connected to a headpiece by a cord. The headpiece has a transmitting coil that sends the signal from the speech processor to the internal part of the device. It magnetically attaches to the surface of the head behind the ear at the spot where the internal portion of the implant is located. Platinum Series Auria Processor Sprint Processor Esprit Processor There are additional speech processors and configuration options available other than those shown above The internal and external portions work together to change sound into electrical signals that are sent to the hearing nerve. First, the microphone picks up the sound energy, and transmits the signal through the cord to the speech processor. The speech processor filters, analyzes, and converts the sound energy into a digital code that is then sent back through the cord to the headpiece where it is transmitted across the skin, via radio frequencies, to the internal receiver. Then, the internal receiver delivers the signal to the electrodes that have been placed inside the cochlea. The electrodes bypass the damaged parts of the cochlea and send a tiny electrical charge directly to the auditory nerve. Finally, the auditory nerve carries these electrical signals to the brain where they are interpreted as sound. This process occurs so rapidly that the listener will hear speech and other sounds without any noticeable delay. Cochlear Implants Is My Baby a Candidate for a Cochlear Implant? The criteria for determining who can benefit from cochlear implants have changed a great deal since the devices were first introduced. Currently, cochlear implants are approved by the Food and Drug Administration (FDA) for children 12 months of age and older. Criteria for Cochlear Implantation in Children: In general, it is recommended that a child be appropriately fit with hearing aids and use them for 3-6 months before determining implant candidacy. In cases of meningitis, a shorter hearing aid trial may be recommended or the trial may be waived as bony growth in the cochlea following meningitis may create problems for implantation. In a few cases of meningitis, the physician may proceed with implantation prior to the child reaching 12 months of age. This is to insure adequate insertion of the electrodes into the cochlea, before the bony growth fills the cochlea. Degree of hearing loss Children between 12 months and 18 months of age: Profound, sensorineural hearing loss of 90 decibels or greater in both ears Children 18 months of age and older:Severe-to-profound sensorineural hearing loss of 70 decibels or greater in both ears To learn more: What is an Audiogram? Lack of benefit from appropriately set hearing aids Examples of this would include: —Inconsistent response to his/her name in quiet —Failure to alert to environmental sounds while wearing amplification No medical contraindications Included in the list of contraindications are things such as an absence of the auditory nerve; medical conditions or developmental delays that would severely limit participation in aural habilitation; and active middle ear infections. Children should be in a rehabilitative or educational setting where the development of auditory (listening and speaking) skills is emphasized. Rehabilitative or educational environments that encourage auditory skill development are likely to have a positive effect on the speech and language progress in children. High motivation, positive family environment, and realistic expectations are all important factors in a child's performance with the cochlear implant. Cochlear Implants Follow-up and Rehabilitation Cochlear implant surgery requires general anesthesia and lasts about 2 to 3 hours. Surgery is usually completed as an outpatient procedure, and may include a one-night stay in the hospital. It generally takes 3 to 5 weeks for the surgical incision to heal, but most children resume normal activities within days after the surgery. Between 4 to 6 weeks after surgery, the child will return to the clinic to have the device activated for the first time. During the time between surgery and implant activation, the child will not be able to wear a hearing aid in the implanted ear and so will not be able to hear in that ear. If a hearing aid is worn in the non-implanted ear, the child should continue to wear this aid during the time between surgery and activation. Some children will continue to wear a hearing aid in their nonimplanted ear to improve localization and listening in noise. Device activation may be either a one or two-day process. Up to 20 return visits may be needed within the first year for both fine-tuning of the speech processor and auditory training or aural rehabilitation. Cochlear Implants Expectations What exactly is meant by "benefit" or "success" with a cochlear implant? It is important to keep several important facts in mind: The benefit from cochlear implants is not often immediate. Improvements occur over a period of months or even years. The amount of benefit seen is linked to the age of a child at the time of implantation, the cause of the hearing loss, and family support and involvement. Reasonable expectations may include improved detection of environmental sounds and speech, improved speechreading ability, and improved clarity of the child's speech. How much speech understanding a child with a cochlear implant will obtain and how clear his or her speech will be is difficult to predict. Cochlear implant surgery should be viewed as the first step in a long process. Parents should understand that their participation is crucial in their child's educational process so that the most benefit can be achieved. Children with cochlear implants need support services from a number of professionals for educational and speech language development. The amount of support needed is variable from one child to the next. A child's performance with a cochlear implant cannot be predicted. Each child will have varied performance with the cochlear implant. Each child will have varied performance with the cochlear implant. However, providing the right support services and environment can optimize learning and development. It is important to remember that it can take up to one year after the implant is activated for distinct changes to show in a child's ability to communicate. In a small number of cases, a child may show only limited benefit from the cochlear implant or seemingly no benefit at all. This can generally be linked to a significant malformation of the cochlea or to a hearing nerve that has a very limited number of nerve fibers. In other words, the cochlear implant is sending a signal, but the structures needed to pass the signal on to the brain are not there. A variety of school placements are possible for children with cochlear implants.. To make the most of a cochlear implant, a child needs be in a program that clearly states and supports listening and speaking goals. Children in auditory oral, simultaneous communication, or manual communication programs can all benefit from listening therapy or auditory training. All programs regardless of communication modality can emphasize listening and speaking goals. The types of communication modalities most commonly used are described on the Getting Started page. It is important to keep in mind that a child's individual communication goals, strengths, and abilities should be used to determine the educational setting. Placement should not be based solely on the fact that a cochlear implant is in use, and educational and support service needs must be assessed for each child. Hearing Aid Choices Fitting appropriate hearing aids or other sensory devices is one of the first steps in helping an infant with hearing loss. Today's advanced technology allows for the successful fitting of hearing aids on very young babies. Because language skills begin to develop within the first few months of life, it is important to have your baby fitted with hearing aids as soon as possible. However, hearing aids are complex. There is much to learn about these devices and there are many decisions to make. The next section answers questions about the many different types of hearing aids and how they work. You will also find practical ideas for hearing aid use. Hearing Aid Choices What are the different styles of hearing aids? There are two basic kinds of hearing aids typically recommended for children: Behind-the-ear (BTE) hearing aids In-the-ear (ITE) or in-the-canal (ITC) hearing aids The most commonly used and most appropriate style for infants and young children is the behind-the-ear (BTE) hearing aid. Although there are many different types of in-the-ear (ITE) hearing aids, these devices are best suited for adults. Generally, they are not appropriate for children under 6-7 years of age. Why? Because young children's ear canals are small and they grow rapidly during the first few years of life. This means that they would quickly outgrow their hearing aid cases. Also, ITE hearing aids are made from a hard plastic that can cause severe injury to a child's ear canal if the hearing aid becomes damaged. Many years ago, children used body hearing aids. Because these aids are heavy, cumbersome, and the cord can pose a strangulation risk, body aids are rarely used today and only under special circumstances. Hearing Aid Choices How does a hearing aid work? All hearing aids, regardless of style, are made with the same basic parts. In the behind-the-ear (BTE) hearing aid, shown below, you can see the microphone, tone hook, volume control, on/off switch, and battery compartment. The microphone picks up sounds from the environment and sends them to a processor that amplifies the signal (makes it louder). The hearing aid will amplify some pitches of the incoming sound more than others depending upon your child's hearing loss. Your audiologist uses the hearing aid's tone controls (located on the reverse side of the instrument) to make the amplified sound appropriate for your child's hearing loss. After the sound is amplified, it is routed through the hearing aid tone hook to an earmold which is custom made for each child. The tone hook is a small plastic piece that hooks over and behind the child's outer ear (pinna). The earmold holds the hearing aid in the child's ear and directs sound from the hearing aid into the ear canal. Earmolds are made from soft materials after an impression is taken of your child's ear. They are made individually for each child and fit snuggly in the ear canal. As a baby grows, earmolds need to be replaced on a regular basis. Hearing Aid Gain The graph below shows how much the hearing aid increases the level of sound at different pitches (frequencies). This is known as hearing aid gain. For mild hearing losses, small amounts of gain are needed. A severe hearing loss requires more gain. When a hearing loss is different at each frequency, the audiologist also has to adjust the gain of the hearing aid appropriately. Hearing Aid Choices How is a hearing aid fitted and evaluated on an infant or young child? The process of fitting hearing aids to children is very different than it is for adults. Adults can tell their audiologist how well a hearing aid seems to work, if certain sounds are too loud, or if speech sounds garbled or unclear. Young children cannot do this. For this reason, it is important to find a pediatric audiologist with extensive experience in fitting hearing aids to children. Because a child's early years are particularly important for speech and language development, finding the best hearing aids for each child is very important. Hearing aids must be fit individually for each child. No one hearing aid is appropriate for everyone. Some important factors that a pediatric audiologist will consider when selecting hearing aids are: Degree and shape of the hearing loss Durability and service of hearing aid models Compatibility with special amplification systems used in schools Adult hearing aid users may sometimes choose to wear only one hearing aid. When fitting hearing aids on infants and children, pediatric audiologists will almost always recommend hearing aids for both ears. Two hearing aids are needed to support the child's learning of language and speech. Even if a child has different degrees of hearing loss in each ear, hearing aids for both ears usually will be recommended. The best method of testing hearing aid benefit for young children is called probe microphone testing. During this test, a small, soft microphone is placed in the child's ear next to the earmold. This approach allows the audiologist to determine how much sound is being delivered to the child's ear. Because infants and young children have much smaller ear canals than adults, it is important to make these measures to avoid loudness discomfort and/or further damage to the child's hearing. For very young children, a special probe microphone technique called Real-Ear-to-Coupler-Difference (RECD) measurement can be used. The audiologist combines this information with the response of the hearing aid measured in a test box to find the best hearing aid and hearing aid settings without having to do repeated hearing aid testing on the child. If an audiologist uses RECD measures before fitting the hearing aid directly on the child, she/he can avoid the problem of too much sound from the hearing aid or inaccurate volume settings. RECD testing is one of the most recent developments in hearing aid evaluation for infants and young children. It is considered state-of-the-art for pediatric audiologists. Research studies have shown that this type of testing is safe even with babies younger than 6 months. The most important goal for infants and young children who wear hearing aids is making speech loud enough for the child to hear. Probe microphone measures enable the audiologist to determine how much of speech will be heard with different types of hearing aids. Audibility of speech can be used to compare aided and unaided hearing, different hearing aid settings, and different listening conditions. The graphs above show how audible speech is for a child with a mild to severe sloping hearing loss without a hearing aid (top panel) and with a hearing aid (bottom panel). The circles show the child's hearing levels. The crosshatched areas show how much of speech is loud enough to hear at a distance of 1 meter. The asterisks (*) on the lower panel show the loudest level that this hearing aid can produce. Click on the loudspeakers to hear how speech would sound to this child under these two conditions