Audiological Management of Children with Single-Sided Deafness

Transcription

1 Audiological Management of Children with Single-Sided Deafness Sarah McKay, Au.D. 1 ABSTRACT The difficulties school-aged children with unilateral hearing loss (UHL) experience have been documented. Children with singlesided deafness (SSD), however, face unique obstacles. These children are more likely to experience difficulties than their peers with lesser degrees of UHL and are not candidates for conventional hearing aids. Newer hearing technology options are emerging for individuals with SSD, but the efficacy of these new devices has not been extensively studied in young children. This article will review the current evidence concerning amplification options for children with SSD, discuss factors the audiologist should take into consideration when contemplating amplification, and review other recommendations the audiologist can make in the best interest of the child. KEYWORDS: Unilateral hearing loss, single-sided deafness (SSD), transcranial, bone-anchored hearing aid (Baha), TransEar, contralateral routing of signal (CROS) Learning Outcomes: As a result of this activity, the participant will be able to (1) list current amplification options available to children with single-sided deafness (SSD) and (2) list recommendations the audiologist can make for a child with SSD. In this article, the reader will learn about the impact of single-sided deafness (SSD) on children and about amplification options currently available for these children. For the purposes of this article, SSD is defined as severe to profound hearing loss in one ear with normal hearing in the better ear. SSD is sometimes compared to unilateral hearing loss (UHL) that is considered unaidable or, if bilateral, would fit audiological candidacy criteria for cochlear implantation. As audiologists develop guidelines for the care and management of different populations of patients, evidencebased practice (EBP) should help guide these The Center for Childhood Communication, The Children s Hospital of Philadelphia, Philadelphia, Pennsylvania. Address for correspondence and reprint requests: Sarah McKay, Au.D., The Center for Childhood Communication, The Children s Hospital of Philadelphia, 3405 Civic Center Blvd., Philadelphia, PA ( mckay@ .chop.edu). Fitting Options for Children and Adults with Single- Sided-Deafness; Guest Editors, Michael Valente, Ph.D., and Kristi Oeding, M.S. Semin Hear 2010;31: Copyright # 2010 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel: +1(212) DOI: ISSN

2 AUDIOLOGICAL MANAGEMENT OF CHILDREN WITH SSD/MCKAY 291 decisions. A common EBP triad includes incorporating best available clinical evidence, individual clinical expertise, and patient s preferences to achieve the best possible patient outcome. There is ample evidence documenting the difficulties children with SSD experience 1 6 and the advantages of binaural hearing. In addition, clinicians have published guidelines to support medical and nonmedical recommendations for these children. 7 Unfortunately, when audiologists explore the efficacy of providing amplification (conventional and nonconventional) to this population, they are often left with more questions than answers. How does one make evidence-based decisions when there is a lack of evidence? This article will present information from the clinician s perspective. This article also will review the current evidence on amplification options for children with SSD, examine factors that should be taken into consideration in the clinician s decision-making process, and review other recommendations for children with SSD. As a nonconventional introduction to this article, the reader is asked to place him- or herself in a scenario experienced by many audiologists working with young children. The clinician is performing a follow-up diagnostic auditory brain stem response test on a 3- month-old infant who has failed his or her newborn hearing screening in one ear. The results indicate a unilateral profound sensorineural hearing loss. If honest, the initial reaction may be one of relief that the hearing loss is not bilateral. If the loss were bilateral, the clinician would make ear mold impressions and discuss immediate amplification options with the child s family. Although devastating to the parent, these decisions provide an action plan (e.g., how to best help their child). It is known from existing evidence that approximately one-third of children with SSD will experience educational difficulties, and, in addition, it is known that some children will experience speech/language delays and socialemotional difficulties. 1 It is still unknown why certain children experience difficulties and others do not. However, children with SSD have greater academic difficulties than those with lesser degrees of UHL. Clinicians know that a child with bilateral hearing loss (BHL) will likely benefit from amplification, and if he or she does not, cochlear implantation is an option. Conventional amplification options that may be available to young children with lesser degrees of UHL, however, may not be viable options for this child with SSD as they will not likely be able to provide usable access to speech sounds, improved localization, or a more balanced sense of hearing between the two ears. Nonconventional amplification options such as bone-anchored devices or the TransEar (Ear Technology Corporation, Johnson City, TN) that may be available to an older child with SSD are either not available to this infant or have not been sufficiently studied in the infant/toddler population to determine if these options are beneficial or detrimental. The parent is looking for answers or at least guidance. How does the audiologist proceed with counseling? BINAURAL ADVANTAGES To understand the impact of SSD, it is imperative to review the importance of binaural advantages such as the head shadow effect, localization, binaural summation, and the binaural squelch effect. The loss of these advantages due to SSD may be detrimental in many listening situations. It will be beneficial for parents and other caregivers (i.e., teachers) of a child with SSD to have a greater understanding of these concepts to help them understand later recommendations for amplification, hearing assistive technology including frequency modulation (FM) systems, and preferential positioning. Localization (the ability to determine from which direction sound is arriving) is affected because individuals with SSD do not have the benefit of interaural time and intensity cues due to the presence of only one functioning cochlea. These differences are due in part to the head shadow effect (diffraction effect of the head). Children with SSD experience difficulty with localization on the horizontal plane Typically, when sound arrives from one direction, the interaural time difference and ongoing phase differences at the two ears allow the individual to determine from which direction the sound is arriving. Phase (i.e., time) differences provide

3 292 SEMINARS IN HEARING/VOLUME 31, NUMBER cues for low-frequency information (below 800 Hz), and the head shadow effect (diffraction effect of the head) for frequencies above 1500 Hz. 11 Because the head shadow effect affects high frequencies, the greatest impact will be on the recognition of consonant sounds. Localization is important for safety such as quickly reacting to a horn when riding a bike or learning to drive. There are more subtle advantages associated with localization. Localization provides a person a sense of security within their environment (knowing where others are in relation to oneself). Additionally, localization is important in group interactions when an individual has to react to quick changes in talkers. If a child with SSD is delayed in attending to a talker, he or she may miss some of the intended message. Binaural summation is the increased perception of loudness when sound is heard by two normal-hearing ears rather than one. For a speech signal near threshold, the advantage is 3 db, and at suprathreshold levels (conversational speech), the advantage is 6 to 10 db. 12 The listening difficulties resulting from a lack of binaural summation may have a significant impact on speech recognition abilities of children with SSD. The difficulties experienced with speech recognition in noise may be because children with SSD do not have the benefit of binaural squelch. 8,13,14 Normal bilateral hearing allows a person to filter out noise to enhance the audibility of the speech signal. Research has found that children with SSD exhibit greater difficulty recognizing nonsense syllables in noise than do children with normal hearing. 9 AMPLIFICATION OPTIONS FOR CHILDREN WITH SSD The American Academy of Audiology Pediatric Amplification Protocol addressed the fitting of amplification on children with UHL in its Special Consideration section. 15 This protocol states: Use of hearing aid amplification is indicated for some children with unilateral hearing losses. The decision to fit a child with unilateral hearing loss should be made on an individual basis, taking into consideration the child s or family s preference as well as audiologic, developmental, communication, and educational factors (p. 3). Audiologists may first view this statement as vague, but its ambiguity is likely deliberate and based on the existing evidence. In 2005, the Centers for Disease Control and Prevention in alliance with the Marion Downs Hearing Center held a National Workshop on Mild and Unilateral Hearing Loss. At this workshop, 50 experts convened to review the current literature and develop future research needs in the areas of screening, diagnostics, hearing aid technology, and early intervention. Some of the future research needs pertained specifically to amplification options for children with SSD. 16 Conventional Hearing Aids There is evidence to suggest that some children with mild to moderately severe SSD benefit from a hearing aid fit on the poorer ear. 6,17,18 The evidence is limited and subjective in nature (e.g., questionnaires, functional auditory measures). Although providing amplification to a child with this range of SSD may partially compensate for the loss of binaural advantage, the extent to which amplification improves localization and speech recognition in noise is unclear. Goals of fitting a conventional hearing aid to a child with UHL may include: (1) providing amplification that allows access to speech sounds in the poorer ear using a validated prescriptive method such as desired sensation level input/output 19 in conjunction with real-ear measures, (2) providing improved localization abilities, and (3) providing a more subjectively balanced sense of hearing between the ears. Unfortunately, none of these goals can be adequately achieved by providing a conventional hearing aid to a child with SSD. Hearing Assistive Technology FM SYSTEMS The benefit of FM technology for school-aged children with SSD has been documented

4 AUDIOLOGICAL MANAGEMENT OF CHILDREN WITH SSD/MCKAY 293 Figure 1 Ear-level frequency modulation (FM) devices. In the case of the child with single-sided deafness, only one device would be fit and the FM device would be placed in the better ear. FM technology helps to overcome the negative effects of background noise, distance, and reverberation and is typically used in classrooms. For many children with SSD, FM technology has been their only amplification option. In studies comparing performance in noise using an FM system versus contralateral routing of signal (CROS) hearing aids, children with SSD obtained greater benefit from FM. 21,24 The benefit of an increased signal-to-noise ratio (SNR), particularly in noisy listening environments, cannot be disputed. Several FM options exist for children with hearing loss, but choices are more limited for children with SSD. Children who use conventional hearing aids can use an integrated ear-level FM receiver. This technology continues to become more sophisticated, adapting to a child s changing listening environment. Children with SSD are typically provided the following FM options: (1) an ear-level FM device to the normal hearing ear (Fig. 1), (2) a personal desktop unit, or (3) a classroom FM or infrared sound field system (Figs. 2A and 2B). Research is limited on the most optimal FM configuration for children with SSD. 16 Ear-level technology can provide the best SNR as compared to personal desktop and Figure 2 (A) In this case, the teacher is wearing a wireless microphone that transmits the signal to a wireless frequency modulation (FM) receiver. The signal is then wirelessly transmitted to the amplifier, and the amplified signal is heard from the loudspeaker to the left. (B) This is an example of one commercially available FM sound field system sending the amplified signal to two or more loudspeakers that would be suspended within the classroom.

5 294 SEMINARS IN HEARING/VOLUME 31, NUMBER classroom sound field systems, 22 but this option may not always be the best choice based on the individual needs of the child. For example, a young child will likely require some form of open ear mold to retain an ear-level FM device, and such a fitting could partially occlude the better ear, impacting his or her ability to adequately hear classmates. If ear-level FM is not considered to be the best option for a young child with SSD, desktop technology may be considered. Conversely, older children change classes frequently and may find a desktop unit cumbersome. A clear benefit of a classroom sound field FM or infrared system is its advantage to improve the SNR for all students within the classroom. Studies such as those conducted by the Mainstream Amplification Resource Room Study Project have demonstrated that classroom sound field amplification systems benefit all children in the classroom, not just those with hearing loss, attention difficulties, or auditory-processing disorders. 23 Improvements have been observed in attentiveness, behavior, and, most notably, academic performance. Possible negative consequences of the installation or preexistence of a classroom sound field amplification system is the belief that this system satisfies the recommendation for FM and will be sufficient for all children with hearing loss and that ear-level FM devices are no longer warranted. Clinical audiologists are urged to communicate with educational audiologists and hearing support teachers before making a decision about what type of FM or infrared system is best for the child. These professionals have the ability to observe students, conduct trials using different devices, and perform functional listening evaluations in the child s classroom environment. Parents may want to consider supplemental assistive listening technology for their child to use at home. Amplified/modified alarming devices (e.g., alarm clock, fire/smoke alarm) should be considered for children with SSD because the ability to adequately hear an alarm depends on the orientation of the better ear while in bed. An amplified phone will likely not be needed for a child with SSD as he or she would never elect to place the phone receiver to the poorer ear. Parents also may want to choose closed captioning as a supplement to conventional audio on the television for their child. This choice will likely depend on room configuration, existing noise levels, and other considerations. CROS HEARING AIDS Until recently, CROS hearing aids have been considered the primary amplification option for patients with SSD. In a CROS configuration, a microphone on the poorer ear transmits the signal via hard wire or wireless technology to a receiver on the better ear. For retention, a behind-the-ear (BTE) hearing aid is often coupled to an open ear mold or may be in the form of an in-the-ear (ITE) hearing aid. In most CROS configurations, there is at least partial occlusion of the better ear that must be considered. Some CROS configurations use a hearing aid on the better ear as the receiver. Caution is advised when fitting this type of CROS system to a child with SSD. Obtaining real-ear measures using a pediatric prescriptive target such as desired sensation level input/ output is critical to ensure appropriate gain and output to the better ear. Research in adults has revealed improvements in localization using CROS amplification, but this improvement is thought to be the result of perceived subjective differences in sound quality between ears. 25 When the signal was perceived as sounding natural, it was thought to be arriving on the better side, and when the signal was judged as sounding tinny, it was thought to arrive from the poorer side. These improvements in localization were not present in high levels of ambient noise. In a study 24 comparing the CROS, an unaided condition, and an FM for children, the CROS system was found to be beneficial in some listening situations, particularly in situations when the speech signal originated on the side of the poorer ear. CROS, however, was found to be detrimental in listening situations where noise originated on the poorer side and was transmitted to the better ear. 24 Young children are often in fluctuating listening situations where the signal source simply cannot be controlled. Additionally, young children may not be able to manipulate their listening environment or positioning and/or determine

6 AUDIOLOGICAL MANAGEMENT OF CHILDREN WITH SSD/MCKAY 295 when device use is beneficial or detrimental. For this reason, CROS amplification is not typically recommended for young children. The authors of this study suggest that older children may be better candidates for CROS because they are better able to monitor their listening environment, make accommodations to head placement and physical placement within a room, or control settings/programs that may improve the listening situation. An older child also may be more likely to determine in which listening situations a CROS may or may not be appropriate. 24 Factors such as a child s age and maturity and typical listening environments should be taken into consideration when recommending CROS. For more information about CROS, please see the article by Taylor in this issue. TRANSCRANIAL AMPLIFICATION Transcranial amplification devices are fit to the poorer ear and transmit the signal via bone conduction to the cochlea of the better ear. The purpose of transcranial amplification is to minimize the head shadow effect. Three technologies that provide transcranial amplification are bone-anchored devices (e.g., Baha, Cochlear Americas, Centennial, CO; Oticon Medical Ponto, Oticon Medical, Somerset, NJ), Trans- Ear, and a transcranial CROS that is a high-gain/high-output BTE hearing aid, a deep-seated ITE power hearing aid, or a completely in-the-canal hearing aid. BONE-ANCHORED HEARING DEVICES Two bone-anchored devices currently available for individuals with SSD are the bone-anchored hearing aid (Baha) BP100 by Cochlear Americas and the more recently released Ponto and Ponto Pro by Oticon Medical. The Baha provides a surgical and nonsurgical option for children with UHL (please see comprehensive review of Baha by Flynn in this issue). Initially, the Baha was intended for patients with conductive or mixed hearing loss, but the Baha has more recently been approved for patients with SSD. Due to issues of anatomic maturation, surgical implantation of the Baha is only approved for children 5 years or older. Prior to the age of 5 or if surgery is contraindicated, a child can use a Baha processor fit to a soft band (Fig. 3). Few studies are available using the Baha on children with SSD. Priwin et al 26 studied the Baha on 22 children with bilateral and unilateral conductive hearing loss. Children with conductive SSD performed better in speechin-noise (0 db SNR), but no statistically significant improvements were observed using easier listening conditions (þ4 db and þ6 db SNR). Additionally, no improvements were observed in sound localization. Children also were asked to rate overall satisfaction with the Baha using the Swedish version of the International Outcome Inventory for Hearing Aids. 26 Results suggested general satisfaction with the Baha and an improved quality of life after being Figure 3 Baha soft band fitted over the left mastoid.

7 296 SEMINARS IN HEARING/VOLUME 31, NUMBER fit with the Baha. Although these results are promising, the delivery mode of sound to a patient with conductive SSD is different from that of transcranial delivery of sound in patients with sensorineural SSD, and thus results cannot be compared. There have been several studies of adults with SSD using the Baha Although results have varied, common threads have emerged. Many adult studies have reported improved speech-in-noise abilities when compared to CROS amplification. Additionally, there seems to be a subjective preference for the Baha over CROS. Although objective test measures have shown little benefit with the Baha for localization, there have been subjective reports of improved localization in everyday life. There are two published studies on the use of the Baha for children with SSD. Christensen and Dornhoffer 32 retrospectively reviewed the results of three teenagers (ages 16 to 18 years) with SSD who were surgically implanted with the Baha Divino at Arkansas Children s Hospital. In this study, speech-in-noise abilities and subjective benefit were assessed pre- and postfitting. Speech-in-noise abilities were evaluated using the Hearing in Noise Test (HINT) to obtain a percentage correct at 0 db SNR and þ10 db SNR. Results reported improved speech-in-noise performance with the Baha. The Children s Home Inventory for Listening Difficulties (CHILD) also was completed by both patients and parents. Results of the CHILD showed improved listening abilities using the Baha. Christensen et al 33 recently completed a follow-up study to their previous study. In this 3-year retrospective chart review of 23 children (average age 12.6 years) with SSD who were using either the Baha Divino or the Baha Intenso, speech-in-noise results and CHILD results pre- and postimplant were obtained using a similar protocol as the previous study. Preimplant HINT scores obtained at 0 db, þ5 db, and þ10 db SNR yielded scores of 42%, 76%, and 95%, respectively. Postimplant scores with the Baha were reported to be 82%, 97%, and 99%, respectively. The CHILD was administered to both patients and parents. Mean preimplant ratings were reported to be 4.5 and Figure 4 Frequency modulation receiver coupled to a bone-anchored hearing aid processor. 4.6 for patients and parents, respectively, with postimplant ratings improving to 6.9 and 7.1. The greatest improvements for HINT and CHILD ratings were observed in the teenage group (children over 13 years). The authors noted that 17% of children had complications (failed osseointegration, skin reactions, lost abutment). New bone-anchored processors (BP100 and Ponto/Ponto Pro) have recently been introduced to provide a cleaner signal. This is achieved by providing position compensation, environmental detectors, automatic multichannel directional microphones, and noise reduction. In addition, bone-anchored processors allow for connection of FM receivers and other audio inputs (i.e., MP3 player, TV, CD, etc.) through its Europin connector (see Fig. 4). 34 TRANSEAR The TransEar is a transcranial amplification device (see Fig. 5). With this device, a digital BTE hearing aid is coupled to a bone conduction vibrator encapsulated in a hard ear mold worn in the poorer ear. Sound is sent via bone conduction from the poorer ear to the cochlea of the better ear. This device was first described in adults with SSD by Valente et al, 25 and at that time, the three adults using the device were not able to achieve appropriate gain without feedback. The TransEar has recently been modified to provide more gain in the high frequencies using a newly developed high-frequency vibrator with peak energy from 2100 to 2300 Hz. The goal of this modification is to provide better speech recognition, specifically for high-frequency consonant sounds. The TransEar has two program options: one for a quiet listening environment and the other with an adaptive noise reduction setting. 35 Although the TransEar is reportedly being fit in pediatric

8 AUDIOLOGICAL MANAGEMENT OF CHILDREN WITH SSD/MCKAY 297 Figure 5 TransEar (Ear Technology Corporation, Johnson City, TN) hearing aid with the behind-the-ear on top and the bone conduction vibrator embedded in a custom ear mold at the bottom. populations, no studies have been published on the efficacy of TransEar fittings for children with SSD. Information about the TransEar is available at TRANSCRANIAL CROS The transcranial CROS is a high-gain/highoutput BTE, ITE, or completely in-the-canal hearing aid fit to the poorer ear, which generates enough output to stimulate via bone conduction to the cochlea of the better ear. Although some subjective benefit has been reported from this fitting in adults, 25 no studies have been completed on children with SSD. Valente et al 36 studied eight adults with SSD as a result of acoustic neuroma. In this study, a wireless CROS was compared to a transcranial CROS for each subject. After a 60-day trial, three of the subjects preferred the transcranial CROS, four preferred the wireless CROS, and one did not benefit from either system. The subjects in this study were homogeneous in that they had the same hearing loss, yet still did not report the same device preference. Although this study only included adults, the authors conclusion that no single recommendation could be made for this population likely applies to children with SSD as well and is in keeping with the American Academy of Audiology Pediatric Amplification Protocol, which suggests making decisions about amplification for children with UHL on an individual basis. For a more detailed review of the transcranial CROS, please see the article by Valente and Oeding in this issue. New developments and continuing advances in the transcranial devices described above are exciting and may prove to be options that children with SSD and their parents have been waiting for. However, several questions must be addressed: 1. Will the detrimental effects experienced with CROS when noise originates on the poorer aided side also be experienced when using transcranial amplification, or can the introduction of features such as noise reduction minimize this detrimental effect? 2. Are audiologists confident that the benefit experienced in adults also can be extended to the pediatric population? 3. Considering differences in age, maturity, and the ability to competently report benefit/detriment between adults and the pediatric population, what pediatric age group would be considered candidates for these types of devices? 4. Should these devices be used in place of or in conjunction with FM technology? If these devices are used in conjunction with FM, what configuration will be most appropriate?

9 298 SEMINARS IN HEARING/VOLUME 31, NUMBER ASSESSMENT OF BENEFIT Validation of Children s Functional Auditory Performance Many factors may contribute to the decision to obtain amplification. The use of functional auditory measures may help families and audiologists through this decision-making process. Functional auditory measures allow the audiologist to determine which listening situations may provide a child more difficulty and may subsequently help the audiologist determine which device is most appropriate (e.g., amplification and/or FM system). These measures also can serve to facilitate counseling and open discussions between the parent, audiologist, and child. When a child completes these questionnaires, the answers may help give his or her parent insight into difficulties being experienced by the child. In an informational booklet entitled Incorporating Functional Auditory Measures into Pediatric Practice, specific functional auditory assessment measures are recommended based on age and degree of hearing loss. 37 SSD falls under the umbrella term of minimal hearing loss, which is a specific category in this booklet. The booklet also describes each measure that can be completed by the parent, child, or teacher. Difficulties reported by teachers on these measures may not only serve to facilitate communication with the parents but also justify the need for obtaining hearing assistive technology. Functional auditory measures allow the audiologist to view each child beyond the confines of the clinic environment. Assessment of Speech-in-Noise Performance Speech-in-noise performance may be of particular interest when assessing a child with SSD. A child with SSD should perform better in a monaural direct condition in which speech is originating on the better side and noise is delivered to the poorer side due to the head shadow effect. Conversely, a child with SSD will have difficulty in a monaural indirect condition, where speech is originating on the side of the poorer ear and noise is delivered to the side of the better ear again, due to the head shadow effect (see Fig. 6). CROS amplification has a negative impact on children when noise originates on the poorer aided ear and is sent to the better ear. 24 Would the same affect be expected with transcranial amplification? As stated earlier, adults have shown improved performance for speech-in-noise when using the Baha compared with CROS. There are limited data to suggest the same with children. Although there is no single recommended speech-in-noise battery for children with SSD, clinicians should make decisions based on the age of the child, his or her abilities, and, in some cases, sound booth/loudspeaker configuration. Not all loudspeaker arrays allow for specific azimuth test conditions (e.g., 90 degrees, 180 degrees), whereas most sound suites allow for speech and noise to be presented simultaneously from 0 degrees azimuth, or speech from 0 degrees and noise from 90 degrees. One may choose to select a test with an adaptive procedure, such as the HINT, 38 in which HINT speech-shaped noise is varied to determine a reception threshold for sentences in noise or obtain a percentage correct score using word or sentence lists presented in varying SNR conditions. Although unaided and aided speech scores and warble tones can be obtained by plugging and muffing the better ear, aided speech-in-noise testing should be completed with the better ear unoccluded to best approximate a real-life listening situation. Recorded speech materials will provide the most reliable results, and it is important for the purposes of individual pre- and postdevice comparison to remain consistent with test materials and presentation protocols. The clinician also must be aware of what differences in performance are considered to be significant. Tables provided by Thornton and Raffin 39 may assist audiologists in determining when differences in speech recognition scores reach statistical significance. ADDITIONAL MANAGEMENT CONSIDERATIONS Most parents will know if their child has SSD soon after birth. The results of newborn

10 AUDIOLOGICAL MANAGEMENT OF CHILDREN WITH SSD/MCKAY 299 Figure 6 (A) Monaural direct condition where speech arrives to the side of the better ear and noise to the side of the poorer ear. (B) Monaural indirect condition where speech arrives to the side of the poorer ear and noise to the side of the better ear. hearing screening and subsequent electrophysiological diagnostic testing will help diagnose the degree, type, and configuration of the hearing loss. In some respects, this concrete diagnosis of SSD may be a relief. These parents do not face the same decision-making process that other parents of newly diagnosed infants with BHL do. Unlike BHL, there is no solid evidence to support the early fitting of amplification to infants with SSD, even those children with hearing loss that would be considered aidable. Some parents of children with these lesser degrees of UHL may elect to pursue a hearing aid for their child. What about the infantwithssd?itisatthesemomentsthat clinicians should take a moment to consider EBP. Although some of the transcranial amplification devices discussed earlier may be an option for this child as he or she becomes older, there is limited evidence to support these fittings for infants. There is also no evidence available yet to determine which children will benefit the most from amplification. Audiologists may not yet have the clinical tools to fit infants with transcranial devices, and in most fitting scenarios, it is simply not possible. Finally, clinicians need to ask, how is it possible to accommodate parents expectations when as professionals, we do not know what to expect? COUNSELING Pediatric audiologists are very familiar with the confusion and anger that parents experience after learning their child has permanent hearing loss, including SSD. Margolis reported that parents could not recall 40 to 80% of what was counseled immediately after the initial session. 40 Additionally, of the information that is remembered, half was remembered incorrectly. Williams et al 41 reported that 84% of parents did not understand the information that was given following initial diagnosis. The development and

11 300 SEMINARS IN HEARING/VOLUME 31, NUMBER provision of written informational materials about SSD to parents were cited as a future need at the National Workshop for Children with Mild and Unilateral Hearing Loss. 16 It is critical that parents leave the initial and subsequent appointments with written information to which they can refer. 42 Many clinics provide general information about hearing loss, but SSD presents different challenges than BHL. Many of the recommendations that audiologists can make to these parents revert back to the binaural advantages discussed earlier. Information should include the difficulties that children with SSD can encounter and suggestions to help ameliorate these difficulties. Educating parents about proximity and placement to obtain the optimal signal input will be critical. During the first year of life, babies are likely to be in very close proximity to their caregiver. It is important to explain how decreasing the distance between speaker and listener (e.g., mother feeding, cuddling baby) will provide an improved SNR. This ideal SNR will soon degrade as a toddler begins to walk and parents call their child from a distance. This child may hear their name being called but miss some of the intended message. The difference between audibility and recognition should be conveyed to parents. Informational materials about SSD in children are available in Appendices A and B. Healthy People 2010 includes hearing conservation as a published objective as follows: Reduce noise-induced hearing loss in children and adolescents 17 years and under. 43 Information should be provided to parents about safety and hearing conservation issues. As mentioned earlier, children with SSD will have poorer localization skills, which may impact their ability to react quickly to a car horn or other sound alerting devices. Hearing conservation practices will be critical because this child has hearing in only one ear. Published informational flyers as well as websites provide strategies on protecting hearing, including recommended safe listening levels/time limits for personal listening devices such as an ipod. Websites that include information about hearing conservation are: dangerousdecibels.org; nidcd.nih.gov; org; and hearing/noise.asp. Although amplification may not be an option for an infant newly diagnosed with SSD, there are things parents can do to help their child. Clinicians must think beyond amplification. The Joint Committee on Infant Hearing (JCIH) 2007 Position Statement 7 provides the following medical and nonmedical recommendations for children with hearing loss (including children with SSD): 1. For infants with confirmed hearing loss, a genetics consultation should be offered to their families. 2. Every infant with confirmed hearing loss should be evaluated by an otolaryngologist who has knowledge of pediatric hearing loss and have at least one examination to assess visual acuity by an ophthalmologist who is experienced in evaluating infants. 3. All families of infants with any degree of bilateral or unilateral permanent hearing loss should be considered eligible for early intervention services. 4. There should be recognized central referral points of entry that ensure specialty services for infants with confirmed hearing loss (page 3). These recommendations should be made in conjunction with the child s primary care physician. Perhaps the most important recommendation and most reassuring to the parent will be the referral to an otolaryngologist. In addition to evaluating outer and middle ear status, the otolaryngologist can order imaging (computerized tomography or magnetic resonance imaging) to evaluate inner ear structures. Such results may provide the structural cause of the hearing loss. Although the diagnosis of an absent cochlear nerve may be perplexing, it may also be of some relief to parents. This diagnosis may alleviateanyfearofasyndromewithother associated abnormalities, and it also provides a concrete explanation for the SSD. This diagnosis also may rule out bilateral anatomic anomalies of the cochlea associated with progressive hearing loss. Another argument for performing imaging is that children with

12 AUDIOLOGICAL MANAGEMENT OF CHILDREN WITH SSD/MCKAY 301 absent cochlear nerves may be initially misdiagnosed as having auditory neuropathy (present otoacoustic emissions and/or cochlear microphonic in conjunction with elevated or absent auditory brain stem response waves). Laury et al 47 completed a study of 11 children identified at the Children s Hospital of Philadelphia with this retrocochlear pattern. Magnetic resonance imaging findings verified that 73% (8 of 11) had absent cochlear nerves, 18% (2 of 11) had tumors, and only one was idiopathic. Progression of hearing loss in the poorer ear of a child with SSD is clearly not of concern, but progression of hearing loss in the better ear is of great concern to many parents and clinicians. In a study of children with sensorineural SSD (n ¼ 83), Germiller 48 found that only 20.5% of children had normal imaging. The remaining children had abnormalities of the vestibular aqueduct, cochlear hypoplasia, and vestibular hypoplasia. 48 Neault 49 also reported on the computerized tomography results of children with SSD. Of 18 children, 8 (45%) had abnormal findings. Five of the eight had abnormal cochlear anatomy bilaterally. An evaluation and subsequent imaging by an otolaryngologist may serve many purposes. Either results will either rule out anatomic anomalies known to be associated with progressive hearing loss or, if such an abnormality is identified, results allow for a structured audiological monitoring schedule to be established. An additional benefit to establishing a relationship with an otolaryngologist is for the expeditious treatment of otitis media with effusion. The JCIH 2007 position statement addresses otitis media with effusion as follows 7 : The effect of otitis media with effusion (OME) is greater for infants with sensorineural hearing loss than for those with normal cochlear function... OME further reduces access to auditory cues necessary for the development of spoken English.... Prompt referral to either the primary care physician or an otolaryngologist for treatment of persistent OME is indicated in infants with sensorineural hearing loss (page 15). The JCIH 2007 Position Statement recommends that any child with bilateral or UHL be considered eligible for early intervention services. 7 One may wonder why this recommendation was included for children with SSD when it is not yet known if children with SSD benefit from early intervention to the same degree as children with BHL. Although the author would not presume to know the specific rationale behind this recommendation, one could speculate that until evidence is gathered, the Committee was acting in the best interest of children with SSD. This are children who, prior to the advent of universal newborn hearing screening, were typically not diagnosed until school age. Children with SSD are known to be at higher risk for academic and speech/ language difficulties than their normal-hearing peers. Can clinicians surmise that these children will obtain the same benefit from early intervention as children with BHL? This is still an unknown, but until the answer is known, the provision of early intervention to children with SSD may be beneficial. As many know, the provision of early intervention services for children with SSD is different from state to state. One state may consider any child with any degree of UHL a candidate for early intervention services, and another state may provide periodic monitoring for these children. A comprehensive list of eligibility criteria can be viewed at 50 CONCLUSION Audiologists are now faced with the early identification (in infancy) of children with SSD, with no evidence yet available to support amplification. Clinics and centers currently fitting hearing aid technology to children with SSD are encouraged to report their findings. Audiologists should move forward at a cautious pace and develop protocols that allow the components of EBP to guide their decisions. Ongoing advances in hearing aid technology in conjunction with reports of aided benefit in adults with SSD elicit optimism for children with SSD. Audiologists must continue to make management choices in the best interest of their patient, allowing a child with SSD every chance for success.

13 302 SEMINARS IN HEARING/VOLUME 31, NUMBER REFERENCES 1. Bess FH, Dodd-Murphy JD, Parker RA. Children with minimal sensorineural hearing loss: prevalence, educational performance, and functional status. Ear Hear 1998;19(5): Bess FH, Tharpe AM. Case history data on unilaterally hearing-impaired children. Ear Hear 1986;7(1): Oyler RF, Oyler AL, Matkin ND. Unilateral hearing loss: demographics and educational impact. Lang Speech Hear Serv Sch 1988;19: Bovo R, Martini A, Agnoletto M, et al. Auditory and academic performance of children with unilateral hearing loss. Scand Audiol Suppl 1988; 30: English K, Church G. Unilateral hearing loss in children: an update for the 1990s. Lang Speech Hear Serv Sch 1999;30: Kiese-Himmel C. Unilateral sensorineural hearing impairment in childhood: analysis of 31 consecutive cases. Int J Audiol 2002;41(1): ; American Academy of Pediatrics, Joint Committee on Infant Hearing. Year 2007 position statement: principles and guidelines for early hearing detection and intervention programs. Pediatrics 2007;120(4): Penn TO, Grantham DW, Gravel JS. Simulated conductive hearing loss in children. J Am Acad Audiol 2004;15(4): ; quiz Bess FH, Tharpe AM. Unilateral hearing impairment in children. Pediatrics 1984;74(2): Morrongiello BA. Infants monaural localization of sounds: effects of unilateral ear infection. J Acoust Soc Am 1989;86(2): Auslander MC, Lewis DE, Schulte L, Stelmachowicz PG. Localization ability in infants with simulated unilateral hearing loss. Ear Hear 1991; 12(6): Lieu JE. Speech-language and educational consequences of unilateral hearing loss in children. Arch Otolaryngol Head Neck Surg 2004;130(5): Ricketts TA, Tharpe AM. Directional microphone technology for children. In: Seewald RC, Bamford J, eds. A Sound Foundation Through Early Amplification 2004: Proceedings of the Third International Conference. United Kingdom: Cambrian Printers; 2005: Moore DR, Hutchings ME, Meyer SE. Binaural masking level differences in children with a history of otitis media. Audiology 1991;30(2): American Academy of Audiology Pediatric Amplification Protocol Available at: Accessed November 18, Proceedings of The National Workshop on Mild and Unilateral Hearing Loss Available at: Accessed December 12, Davis AC, Reeve C, Hind S, Bamford J. Children with mild and unilateral hearing impairment. In: Seewald R, Gravel J, eds. Proceedings of the Second International Conference, A Sound Foundation Through Early Amplification. Chicago, IL: Phonak; 2001: McKay S. To aid or not to aid: children with unilateral hearing loss. Poster presented at the American Academy of Audiology Annual Convention; April 17 20, 2002; Philadelphia, PA 19. Seewald RC, Scollie SD. An approach for ensuring accuracy in pediatric hearing instrument fitting. Trends Amplif 2003;7(1): Flexer C. Classroom management of children with minimal hearing loss. The Hearing Journal 1995;9: Updike CD. Comparison of FM auditory trainers, CROS aids, and personal amplification in unilaterally hearing impaired children. J Am Acad Audiol 1994;5(3): Anderson KL, Goldstein H. Speech perception benefits of FM and infrared devices to children with hearing aids in a typical classroom. Lang Speech Hear Serv Sch 2004;35(2): MARRS. MARRS Project. Available at: Accessed October 4, Kenworthy OT, Klee T, Tharpe AM. Speech recognition ability of children with unilateral sensorineural hearing loss as a function of amplification, speech stimuli and listening condition. Ear Hear 1990;11(4): Valente M, Valente M, Mispagel K. Fitting options for adult patients with single sided deafness Available at: com. Accessed October 14, Priwin C, Jönsson R, Hultcrantz M, Granström G. BAHA in children and adolescents with unilateral or bilateral conductive hearing loss: a study of outcome. Int J Pediatr Otorhinolaryngol 2007;71(1): Wazen JJ, Ghossaini SN, Spitzer JB, Kuller M. Localization by unilateral BAHA users. Otolaryngol Head Neck Surg 2005;132(6): Lin LM, Bowditch S, Anderson MJ, May B, Cox KM, Niparko JK. Amplification in the rehabilitation of unilateral deafness: speech in noise and directional hearing effects with boneanchored hearing and contralateral routing of signal amplification. Otol Neurotol 2006;27(2): Hol MK, Bosman AJ, Snik AF, Mylanus EA, Cremers CW. Bone-anchored hearing aid in unilateral inner ear deafness: a study of

14 AUDIOLOGICAL MANAGEMENT OF CHILDREN WITH SSD/MCKAY patients. Audiol Neurootol 2004;9(5): Hol MK, Kunst SJ, Snik AF, Cremers CW. Pilot study on the effectiveness of the conventional CROS, the transcranial CROS and the BAHA transcranial CROS in adults with unilateral inner ear deafness. Eur Arch Otorhinolaryngol 2010; 267(6): Niparko JK, Cox KM, Lustig LR. Comparison of the bone anchored hearing aid implantable hearing device with contralateral routing of offside signal amplification in the rehabilitation of unilateral deafness. Otol Neurotol 2003;24(1): Christensen L, Dornhoffer JL. Bone-anchored hearing aids for unilateral hearing loss in teenagers. Otol Neurotol 2008;29(8): Christensen L, Richter GT, Dornhoffer JL, Dornhoffer JL. Update on bone-anchored hearing aids in pediatric patients with profound unilateral sensorineural hearing loss. Arch Otolaryngol Head Neck Surg 2010;136(2): Cochlear Limited. Available at: cochlearamericas.com/baha. Accessed December 27, TransEar, Ear Technology Corporation. Available at: Accessed December 27, Valente M, Valente M, Goebel J. Wireless CROS versus transcranial CROS for unilateral hearing loss. Am J Audiol 1995;4(1): Tharpe AM, Flynn T. Incorporating functional auditory measures into pediatric practice Available at: Accessed October 14, Nilsson M, Soli SD, Sullivan JA. Development of the Hearing in Noise Test for the measurement of speech reception thresholds in quiet and in noise. J Acoust Soc Am 1994;95(2): Thornton AR, Raffin MJ. Speech-discrimination scores modeled as a binomial variable. J Speech Hear Res 1978;21(3): Margolis RH. In one ear and out the other-what patients remember. Available at: audiologyonline.com. Accessed December 20, Williams DM, Darbyshire JO, Brown B. Families of young, hearing-impaired children: the impact of diagnosis. J Otolaryngol 1978;7(6): Roush J. What happens after screening? The Hearing Journal 2000;53(11): Healthy People Available at: vision.htm#_Toc Accessed April 2, Dangerous Decibels. Available at: Accessed December 27, Noisy Planet. Available at: nidcd.nih.gov. Accessed December 27, Noise induced hearing loss printable brochure. Available at: hearing/noise.asp. Accessed December 27, Laury AM, Casey S, McKay S, Germiller JA. Etiology of unilateral neural hearing loss in children. Int J Pediatr Otorhinolaryngol 2009; 73(3): Germiller JA. Medical evaluation and management of unilateral hearing loss. Pediatric audiology pediatric evaluation: unilateral and mild bilateral hearing loss. Paper presented at Children s Hospital of Philadelphia Pediatric Audiology Conference; March 13, 2009; Philadelphia, PA 49. Neault M. Progression from unilateral to bilateral hearing loss. Paper presented at the National Workshop on Mild and Unilateral Hearing Loss; July 2005; Available at: ncbddd/ehdi/documents/unilateralhl/mild_uni_ 2005%20Workshop_Proceedings.pdf. Accessed November 16, National Center for Hearing Assessment and Management (NCHAM). Available at: Accessed December 27, 2009