Service provision for children with PCHL begins soon after the diagnosis is made and is comprised of audiologic re/habilitation including the selection, fitting and evaluation of technology and a comprehensive early intervention program that is family-centered and interdisciplinary. See ASHA's evidence map on Treatment for pertinent evidence, clinical expertise and patient perspectives.
Attempts should be made to fit hearing aids within one month of diagnosis. See ASHA's evidence map on Hearing Aids for pertinent evidence, clinical expertise and patient perspectives.
A child with any degree of hearing loss that has the potential to impede access to speech is a potential candidate. Specific considerations include:
- chronic hearing loss due to otitis media may have detrimental long-term effects (ref); often, however, short-term hearing loss can more readily be ameliorated and/or managed by medical intervention;
- permanent bilateral hearing loss; and
- unilateral hearing loss has also been shown to impact speech and language, psychosocial, and academic success. Children with unilateral hearing loss that is within a range where speech audibility can be improved should be considered candidates for amplification.
The behind-the-ear (BTE) style is most commonly recommended for infants and young children for the following reasons:
- earmolds will need frequent replacement to account for rapid ear growth through age 7 or 8;
- vinyl or silicone earmold materials that are not easily cracked or broken and that are easy to modify;
- binaural amplification should always be provided to young children with bilateral hearing loss unless there is a clear contraindication;
- connectivity considerations, depending upon the age and involvement of the child; and
- Direct Audio Input (DAI), or built in FM receiver to allow compatibility with Hearing Assistive Techology (HAT) as required;
- flexible electroacoustic characteristics to accommodate changes in hearing over time;
- multiple memories to allow the parent to adjust the hearing aid for different listening conditions; and
- safety-related features such as tamper resistant battery doors.
A wide range of signal processing strategies are available in hearing aids. Selection of these features should be based on the child's listening needs and existing evidence.
Feedback management: Acoustic feedback can result in limited high-frequency gain and parent or caregiver frustration. Feedback management is recommended for children as long as the processing does not impose significant limitations on the bandwidth of the device or aided audibility of speech.
Digital noise reduction: Limited evidence with school-age children suggests that DNR does not negatively impact speech understanding or complex learning tasks. DNR is recommended for school-age children as long as the DNR strategy does not result in significant reduction in audibility for speech.
Directional microphones: Directional microphones can improve the signal-to-noise ratio in situations where speech and noise are spatially separated and the child is able to orient towards the signal of interest. Directional microphones may be appropriate for school-age children with hearing loss.
Frequency-lowering: Limitations in hearing-aid bandwidth can impact speech perception and communication development. Frequency-lowering signal processing strategies alter the spectrum of the signal to increase the audibility of sounds that occur beyond the audible bandwidth of the hearing aid. Frequency lowering should be used in cases where verification demonstrates that this type of signal processing can provide greater bandwidth than conventional processing.
In order to quantity the audibility of the speech signal, probe microphone measures of real-ear performance should be obtained on children whenever possible. Aided functional gain measured in a sound field for the purpose of setting devices is not sufficient and may result in less than optimal hearing aid fittings ( Seewald et al, 1999).
Primary goals of probe microphone measures for verifying a hearing aid fitting are: to optimize the audibility of speech across frequencies ; to protect the child from loudness discomfort or potential damage to hearing from amplified sound; to provide quick, repeatable and valid measures of "goodness of fit"; and to estimate the impact of signal processing strategies on audibility.
A prescriptive approach can aid the clinician in optimizing the fit to ensure important speech cues are sufficiently amplified. For infants, the most appropriate prescriptive approach is one that is audibility based and accounts for the physical differences between children and adults. The DSL [i/o] and NAL-NL (National Acoustics Laboratories-Non-Linear) fitting procedures can provide this information.
Sound pressure levels and ear canal resonance measured in young ears typically exceeds adult values due to the smaller residual volume between the earmold and tympanic membrane (Stelmachowicz et al ). The real-ear-to-coupler difference (RECD) is the difference between the acoustics measured in the 2cc coupler and the acoustics measured in the child's own ear with the earmold inserted. The hearing aid, using the infant's own earmold, can easily be set in the test box using the RECD combination with test-box measures to estimate the real ear responses.
RECD measurements should be completed
- during or after first fit,
- during monitoring visits, and/or
- with all new earmold fittings.
The hearing aid settings should be verified in the child's ear (when possible) or simulated test box measures for soft, average, and loud speech stimuli, and maximum output limits.
Validation of the aided auditory function is a critical component of the pediatric amplification fitting process. The purpose of validating aided auditory function is to demonstrate the benefits and limitations of a child's aided listening. Validation typically takes the form of parent-reports.
In the audiology clinic, hearing aids are often validated using developmentally appropriate speech perception materials in an aided sound field condition. Hearing aids should also be validated in the home/ daycare or school setting by parents/teachers/EI providers using questionnaires that measure functional auditory performance based on age.
Follow-up for Children with Hearing Aids
All family members and any professionals who will be working with the child should receive hearing aid orientation. Counseling and orientation should include routine troubleshooting and realistic expectations for the child's performance with the devices.
Fitting of personal amplification in an infant or young child is an on-going process. Minimally, an audiologist should see the child every three months during the first two years of using amplification and every 4-6 months thereafter if there are no concerns. Children with fluctuating or progressive hearing loss may need more frequent monitoring. (The Pediatric Working Group, 1996).
Follow-up appointments should include:
- audiologic evaluation to monitor hearing status;
- periodic assessment of functional measures to document auditory skills;
- electroacoustic evaluation and listening checks of the hearing aids/s;
- re-evaluation of the RECD* and other probe-microphone measures as appropriate
*RECD should be remeasured whenever earmolds are replaced.
See the available scientific evidence, expert opinion and client/caregiver perspectives pertaining toCochlear Implants in ASHA's evidence map. t http://www.ncepmaps.org/PCHL-Treatment-Cochlear-Implants.php The following are expert recommendations, based on the work of the ASHA working group responsible for the development of the technical report on Cochlear Implants.
Specific considerations for cochlear implant candidacy include:
- bilateral severe to profound SNHL with a pure-tone average of 90 dB in the better ear;
- auditory neuropathy/dyssynchrony;
- 12 months of age or older (exceptions dependent on etiology);
- limited or no benefit from binaural hearing aids coupled with intensive auditory training;
- no medical contraindications;
- realistic expectations for cochlear implant use;
- family commitment to habilitation/rehabilitation process;
Steps in the pre-implant process include;
- audiologic evaluation;
- medical evaluation/radiologic studies;
- vestibular evaluation;
- psycho-social evaluation;
- discussion regarding expectations
There are three manufacturers of cochlear implants in the US: Cochlear Corporation, Advanced Bionics Corporation, and MED-EL Corporation. The selection of the device will depend on a number of factors including:
- FDA indications for the device;
- age of the patient;
- family preference;
- availability of devices at the CI center the family selects
Research continues to assess the efficacy of bilateral cochlear implantation. Binaural cochlear implantation can be performed simultaneously or sequentially. Suggested advantages to binaural CI are better sound localization and marginally improved speech understanding scores.
Activation of the device
Device activation occurs 2-6 weeks after the surgery. After a listening check of the microphone, the impedances of each electrode are checked through telemetry.
Programming (mapping) the speech processor
The speech processor is programmed to provide sufficient stimulation of the internal electrodes so that speech is audible but below a threshold of discomfort. Objective measures for mapping include electrically evoked auditory brainstem response testing (EABR) and neural response telemetry (NRT). These measures, available through the programming software, are noninvasive and do not require a response from the patient.
Behavioral measures for mapping can be employed as children become older and are able to respond appropriately. Additionally, sound field testing will assist in verifying the appropriateness of the map for functional detection of sound.
Validation is a critical component of the CI programming process. The purpose of validating auditory function is to demonstrate the benefits and limitations of a child's listening abilities for perception of speech.
Cochlear implants are validated using developmentally appropriate speech perception materials in an aided sound field condition. Speech perception testing should include a hierarchy of listening skills that range from detection, discrimination through recognition of speech.
Validation should also be accomplished in the home/ daycare or school setting using questionnaires that measure functional auditory performance.
Follow-up for Children with Cochlear Implants
All family members and any professionals who will be working with the child should receive orientation to the cochlear implant. Counseling and orientation should include routine troubleshooting and realistic expectations for the child's performance.
Children return often for programming during the first year (e.g. 2, 4, 8 and 12 weeks, 6 months then 12 months). During this time the sensitivity of the electrodes is refined. Over time, children are taught to provide feedback on soft, comfortable and loud sounds.
Follow-up appointments should include:
- equipment check;
- continued programming of electrodes;
- behavioral evaluation including threshold and speech perception tests;
- feedback from parents and providers regarding functional listening skills in the home or daycare environment; and
- discussion regarding progress made in auditory and communication development
In many situations, distance, background noise and reverberation effects may interfere with optimal audibility. Hearing Assistive Technology (HAT) can help a listener overcome the negative consequences of these variables. Remote microphone technology HATs overcome the effects of noise, distance, and reverberation by placing a microphone close to a talker's mouth or sound source. Thus, they can improve communication access for children in adverse listening environments.
While many remote microphone HAT options exist, the focus of this discussion is personal FM (frequency-modulated) systems. Personal FM systems consist of two parts: a wireless transmitter and a small wireless receiver. The transmitter sends a low power FM radio signal. This signal is picked up by the receiver, which may be connected to a hearing aid or cochlear implant processor or worn as an earlevel FM-only receiver.
See ASHA's evidence map on Hearing Assistive Technology Systems (HATS) Permanent Childhood Hearing Loss: Treatment - Hearing Assistive Techonology Systems (HATS)), showing the available scientific evidence, expert opinion and client/caregiver perspectives.
Children who may be candidates for personal FM use include those with the following audiologic, listening and/or learning concerns:
- hearing loss (including current or potential hearing aid and cochlear implant users);
- auditory neuropathy spectrum disorder;
- auditory processing deficits;
- learning disability;
- language deficit;
- attention deficit; and
- English Language Learner
Selection of FM technology for this age group may take the following into consideration:
- degree and configuration of hearing loss;
- current use of hearing technology;
- chronological and developmental age;
- listening environments (home, daycare, car, school, etc.);
- problems such as attention, hyperactivity, sensory integration, behavior, cognition, mobility, auditory processing, learning, vision, and fine motor issues;
- technology issues (convenience, wearability, reliability, maintenance, compatibility with existing amplification, etc.);
- parental/child/caregiver/educational motivation and ability to use the device; and
- financial resources.
Careful verification of the performance of the system is necessary when fitting a child with an FM system. Specific procedures will vary based on the unique characteristics of the listener and the device configuration, but typically include one or more of the following:
- electroacoustic analysis;
- real-ear probe microphone measures; and
- behavioral measures such as sound-field aided speech recognition
Validation is an ongoing process with the purpose of demonstrating the benefits and limitations of a child's listening abilities for perception of speech. Objective validation for FM systems should be conducted with developmentally appropriate speech perception materials in conditions that reflect the typical listening environment of the listener. Subjective validation may also be completed using observation questionnaires completed by parents/teachers/caregivers. In addition, IDEA requires that use of assistive technology include a functional evaluation of the listener in their customary environment.
Daily checks of the FM system are typically performed by the parent, teacher, speech-language pathologist, or anyone who has received appropriate training by the audiologist. A daily check consists of visual inspection of the device and its coupling, followed by listening to the sound quality. If possible, the listening check should be performed in the room(s) where the FM system will be used so that any interference will be detected.
Periodic comprehensive monitoring of the FM system by the audiologist may include electroacoustic analysis, probe microphone measurements, and other in-depth troubleshooting measures. These comprehensive procedures should be performed at least annually. Monitoring procedures should be completed more frequently if there is a change in hearing status and/or hearing technology or an unresolved problem is identified during the daily check.
Periodic evaluations of hearing status and a child's performance with the FM device are necessary to monitor stability of hearing, appropriate device settings, function, and degree of benefit with the FM. These assessments may include, but are not limited to, audiologic evaluations, real-ear probe microphone measurements, behavioral assessment of speech recognition, and observations of performance in normal-use settings.
Osseointegrated device, egbone-anchored hearing aids, are considered for children with permanent bilateral conductive or mixed hearing loss or single-sided deafness. The FDA has not approved surgical implantation of bone-anchored hearing aids for children less than five years of age; however, children under five can wear the external processor in a soft band until they are old enough for implantation.
Auditory Brainstem Implants (ABI) provide electrical stimulation of the cochlear nucleus in the brainstem for patients who do not have a cochlea or auditory nerve. Clinical trials are currently in process and now include children who are not candidates for cochlear implantation. Research is needed to better describe the candidacy requirements and long-term outcomes for communication development with ABIs.