The pediatrician’s guide to hearing loss identification and management

December 2004

An estimated three out of every 1,000 children in the United States are born with a moderate or greater hearing loss in one or both ears. Children with late identified hearing loss or mild hearing loss experience a variety of educational and psychosocial complications. Importantly, early intervention prior to 6 months of age has been demonstrated to minimize deficiency in language acquisition. This article will provide an overview of common technologies used to screen hearing sensitivity and common myths associated with hearing loss and intervention. Here are steps for in-office audiometric testing.

Step 1: Establish the protocol

First, the history and physical should document the newborn hearing screening results. If a child is not meeting age-appropriate milestones for speech-language development or if the child’s hearing has not been tested, a hearing screening is recommended. As part of the physical exam, a thorough head and neck examination should also be completed. Since there is a high incidence of otitis media with effusion in infants and toddlers, the protocol should also include an examination of the middle ear. Due to the rising incidence of noise-induced hearing loss in older children from such activities as booming loud music in cars and at rock concerts, an inquiry about noise exposure from recreational activities is advisable.

Step 2: Select equipment and testing instruments

Screening for auditory function should be conducted in a fairly quiet room. There are three common tests used to screen auditory function in young children: otoacoustic emissions, pure tone audiometry and tympanometry. Each test has its own set of advantages and limitations.

Otoacoustic emissions (OAE), a relatively new screening test, is an effective tool for screening for inner and middle ear dysfunctions. By placing a probe in a child’s ear and presenting a stimulus, measurements are obtained based on the response of the acoustic signals generated by the outer hair cells. The child is not an active participant in this test; thus, any age child can be tested using this technology. The child, however, must remain relatively still for the few seconds that it takes to obtain the measurement. Generally, if OAEs are absent, then the child is at risk for a hearing loss that is 30 dB hearing level (HL) or greater. OAEs can also be absent in the presence of middle ear pathology. Pneumatic otoscopy and/or tympanometry should be performed to examine the middle ear status if OAEs are absent. Once the middle ear pathology is resolved, then the OAE test should be readministered. A daily equipment check is recommended to ensure that the equipment is functioning properly. Visually examine the equipment and then test a person with normal hearing. Sometimes administering the OAE test to the parent or a stuffed toy first can ease the child’s anxiety.

For children older than 2.5 years, a hearing screening can be completed using a portable audiometer. Play audiometry is recommended for cooperative children between the ages of 2.5 years and 5 years. For this procedure, the child is conditioned to respond to the sounds through the earphones using a play task such as dropping a block in a bucket. For children 5 years and older, standard audiometric testing can be completed — the child simply raises his or her hand to indicate if the signal was heard.

Each ear is tested individually. The recommended protocol for a hearing screening is to test 500, 1,000, 2,000 and 4,000 Hz at 20 dB HL in each ear. Young children typically respond better to a warble tone than a pure tone. The child should respond at least twice at 20 dB HL at each frequency for it to be considered a pass. If a child does not respond at 20 dB HL, the child should be rescreened. For a hearing rescreen, the earphones should be removed, the child should be reinstructed, and if possible, a different person should administer the hearing screening. Table 1 offers some tips for testing children. If the child does not hear the pure tone at 20 dB HL at any one of the test frequencies and no middle ear pathology exists, then the child should be referred to a pediatric audiologist for a comprehensive audiological evaluation.

By law, audiometers must meet specific standards and should be calibrated once a year (American National Standards Institute S3.6, 1996). Each day the audiometer is used, a daily listening check should be performed to ensure no distortion, cross-talk or intermittency. To conduct a listening check, the examiner should have normal hearing sensitivity. First, the examiner should listen to the pure tone at 20 dB HL at 1,000 Hz in each ear to verify equipment function. Next, the examiner should place the tone on continuous (or interrupt), increase the volume to a comfortable listening level, and check for intermittency or distortion by rubbing the examiner’s fingers along the earphone wires. Finally, verify that the test frequencies increase and decrease in pitch as the frequency dial is rotated. Documentation of the listening check is recommended.

Due to the high incidence of otitis media, the use of tympanometry can be helpful to the pediatrician. Although tympanometry does not provide a direct measure of hearing sensitivity, it can afford an objective measure of middle ear status including, but not limited to, perforated tympanic membrane, patent tympanostomy tube and blockage of the external auditory meatus. Tympanometry only takes a few seconds to administer in a cooperative child. This test is also not affected by the noise in the environment; however, if the child is crying, the examiner may not be able to complete the test. As with audiometry, it does take some time to learn how to administer and interpret the test results. A daily equipment check is also recommended with this equipment. For a thorough review of tympanometry, please refer to “Objective diagnosis of middle ear effusion by acoustic reflectometry” by Richard Schwartz, MD, in the August 2004 issue of Infectious Diseases in Children.

Equipment suggestions

Table 2 proffers a review of audiometric equipment that can be used with children. For each audiological measure, information is provided regarding age appropriateness, test measurements, CPT codes, advantages, limitations and a representative sample of manufacturers. The technology selected for the hearing screening program should be age appropriate.

Three commonly used portable OAE screeners are the EuroScan by Maico, the GSI 70 Automated OAE Screener by Grason-Stadler Inc. and the AuDx by Bio-Logic Systems Corp. Two other companies that make automated OAE screeners are Madsen Electronics and Otodynamics Ltd.

Three commonly used portable audiometers are the MA 27 or MA 25 by Maico, the GSI 17 by Grason-Stadler Inc. or the AM 232 Manual Audiometer by Welch Allyn. When purchasing the equipment, order a pediatric headset to use with the earphones. Take caution if using a hand-held audiometer. It is important to obtain a good acoustic seal to ensure unwanted noise does not interfere with the testing. Combination audiometers and tympanometers are also not recommended for the busy pediatrician’s office due to the lack of portability of the equipment. These systems also usually come with additional diagnostic tests that would not be typically performed in a pediatrician’s office and would probably not be worth the extra expense.

Two common screening tympanometers are the Quick Tymp (Maico) and the MicroTymp 2 Portable Tympanometric Instrument (Welch Allyn). The MicroTymp 2 may be more desirable in the busy pediatrician’s office due to the portability of the equipment. Children like the Quick Tymp due to the visual racecar driving by on the liquid crystal display screen while the test is being performed. For infants younger than 6 months, office tympanometry equipment is usually unreliable.

Step 3: Connect with hearing professionals

The third step of in-office audiometric testing is to establish relationships with your local pediatric audiologists, pediatric otolaryngologists, early interventionists and speech-language pathologists.

If a child does not pass the hearing screening, a referral to a pediatric audiologist is recommended. Once the test is complete, the pediatric audiologist will forward the test results with recommendations. To find an audiologist in your area, check the American Academy of Audiology (www.audiology.org) and the American Speech-Language-Hearing Association (www.asha.org) Web sites. If the child presents with a hearing loss, then the child should be referred to the state early intervention program and pediatric otolaryngologist. The medical evaluation should inform the parents about specific treatment options and provide clearance for hearing aids. The pediatric audiologist should continue with monitoring hearing sensitivity and proceed with fitting hearing aids. The family should be counseled on technologies available and communication options if appropriate. Ongoing communication among the professionals working with the family is essential to ensure appropriate care of the child with hearing loss.

Common myths

Myth 1: You can only evaluate hearing sensitivity in children older than 3 years.

Hearing sensitivity can be tested at any age, but testing for hearing in the primary care pediatric office is difficult unless OAE equipment is used. From the time an infant is born, there are tests available to assess the auditory system that can help determine the degree and type of hearing loss present. Pediatricians are urged to familiarize themselves with their state protocols for newborn hearing screening to determine what their appropriate referral action would be. This information can also help with fitting appropriate technologies and guiding the professionals in making management recommendations.

Myth 2: Children with a sensorineural hearing loss cannot benefit from hearing aids.

Children who present with a permanent sensorineural hearing loss can benefit from appropriately fitting hearing aids. With the VIII cranial nerve still intact, the hearing aid provides the needed amplification to stimulate the nerve to allow for sounds to be processed and understood. In the case of a profound sensorineural hearing loss, a child may be a candidate for a cochlear implant, a surgical procedure that allows the nerve to be directly stimulated so that a child can hear sounds and speech.

Myth 3: Hearing aids restore hearing to normal.

Hearing aids provide the infant/child access to sounds in his/her environment but do not, unfortunately, restore hearing to normal. With today’s advanced technologies, however, children are able to hear more sounds and make use of those sounds due to the early intervention services that they receive.

Myth 4: It doesn’t matter when intervention starts.

Hearing loss has been associated with lifelong deficits in speech and language skills, poor academic performance and emotional difficulties. There is significantly better language development in children when remediation is started early.

Myth 5: You don’t need to monitor or be concerned about a child with a unilateral sensorineural hearing loss.

Children who present with unilateral hearing loss still need to have their hearing monitored for any changes in hearing sensitivity in both ears. Approximately 50% of children identified with a persistent unilateral hearing loss either repeat at least one grade and/or need resource assistance in school. These children also need a hearing conservation plan to ensure preservation of their hearing in the better ear.

Conclusion

The pediatrician plays an important role in ensuring that children receive appropriate management of their hearing status. If there are any concerns regarding hearing sensitivity, then the pediatrician should screen the child’s hearing or refer to a pediatric audiologist for a comprehensive audiological evaluation. There are several ways to screen the auditory system that are cost-effective, not time intensive and reimbursable. Collaboration with the professionals in the field of hearing loss is essential to ensuring optimal care to the family with a newly identified child with hearing loss.

For more information:

• ANSI S3.6 (1996). American National Standard Specification for Audiometers. Acoustical Society of America. New York: American National Standards Institute Inc.
• Bachmann KR, Arvedson JC. Early identification and intervention for children who are hearing impaired. Pediatric Review. 1998;19(5):155-156.
• Bess FH, Tharpe AM. Unilateral hearing impairment in children. Pediatrics. 1984;74(2):206-216.
• Bush JS. Practice guidelines: AAP issues screening recommendations to identify hearing loss in children. Am Fam Physician. 2003;67(11):2409-2413.
• Cunningham M, Cox EO. Hearing assessment in infants and children: recommendations beyond neonatal screening. Pediatrics. 2003;111(2):436-440.
• Joint Committee on Infant Hearing. Year 2000 position statement: principles and guidelines for early hearing detection and intervention. Pediatrics. 2000;106(4):798-817.
• Newman CW, Sandridge SA. Hearing loss is often undiscovered, but screening is easy. Cleveland Clinic J Med. 2004;71(3):225-232.
• Yoshinaga-Itano C, Sedey AL, Coulter DK, et al. Language of early- and later-identified children with hearing loss. Pediatrics. 1998;102(5):1161-1171.

• Tamala S. Bradham, PhD, fellow in infectious diseases, Children’s Hospital.
• Fred H. Bess, PhD, resident in pediatrics, Boston Combined Residency Program.