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24 Remote Microphone Technologies

Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7), copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.

Fig. 24.4 Electromagnetic and NFMI systems.

Fig. 24.5a–d Soundeld or CAD systems.

261

III Hearing Access Technologies for Infants and Children

across the room (Fig. 24.5). These systems improve the SNR in

classrooms by 2 to 5 dB

ized test scores, literacy, and classroom behavior.

is important to note, however, that soundﬁeld/CADS provide

minimal improvements in speech recognition in classrooms with unfavorable acoustics.30 As in the other types of systems, the transmitter may be connected to electronic devices, such as the classroom smart board, television, tablet, or computer.

The loudspeaker conﬁgurations for soundﬁeld systems/CADS

may vary from a single loudspeaker or single unit that includes several loudspeakers within a tower, to systems with multiple wall- or ceiling-mounted loudspeakers. Installation of one tower is much simpler and less expensive than that of multiple-loudspeaker systems. The loudspeakers in each system may contain

dierent types of loudspeakers including line array loudspeakers, cone/piston-motion loudspeakers, and at panel/forced reso-

nance loudspeakers. For additional information about these types of loudspeakers, the reader is referred to Ostergren.

15,20,22

and may also enhance standard-

15,26,27,28,29

24.3.3 Personal Soundeld Systems

A personal or desktop soundﬁeld system consists of an RM and

transmitter that sends the signal via RF or IR transmission to one

loudspeaker that is placed on the child’s desk or nearby. Given the close proximity to the child, the personal soundﬁeld system

is designed to provide a better SNR to the child than CADS can. A

comparison of performance with a personal soundﬁeld system

to other types of systems will be discussed in the following section.

Special Consideration

Schafer and Kleineck20 conducted a meta-analysis of nine cochlear implant studies and determined the speech recognition

beneﬁt (i.e., RM system score – implant alone score) obtained

from the use of personal FM systems, CADS, and personal desktop systems. Results suggested that the personal FM system yielded

signiﬁcantly greater beneﬁt (38% improvement) than the remaining two systems; also, the desktop system (17% improvement) resulted in greater beneﬁt than the CADS (3.5% improvement).

Wolfe and colleagues13 compared speech recognition with two

types of CADS: a ﬁxed-gain IR system with four loudspeakers and

an adaptive-gain (e.g., Dynamic), digital RF, single-tower CADS in adults and children with and without hearing loss. The children with hearing loss also completed conditions with a personal, adaptive-gain FM system alone and in conjunction with the CADS.

On average, adult and pediatric participants received signiﬁcant

improvements in sentence recognition in noise with both CADS;

however, at higher noise levels (65 to 75 dBA), the single-tower

CADS with adaptive gain resulted in better performance than

the multiple-loudspeaker, ﬁxed-gain CADS. This dierence was

attributed to the adaptive gain, which increases the output of the speaker when the noise level at the transmitter increases. When the children with hearing loss used the personal adaptive FM

system, scores were signiﬁcantly higher than with either CADS,

and the addition of the CADS to the personal FM system did not

signiﬁcantly increase scores.

To summarize, compared to personal systems, CADS do not provide as much improvement in speech recognition for children with hearing aids or cochlear implants. Personal and desktop

systems provide signiﬁcant beneﬁt; however, personal systems

will provide substantially better speech recognition than desktop systems will.23 Also, personal systems will oer a more consistent improvement in SNR because there is no issue with ideal placement relative to the desktop system.

Personal RM systems provide the greatest improvement in SNR to the child.

24.4 Performance Comparisons Across Types of Systems

Several published studies have compared the beneﬁts in speech

recognition obtained with personal systems, CADS, and personal desktop FM systems. assessed speech recognition in noise in eight 9- to 12-year-old children with mild to severe hearing loss, using a personal FM system, a personal FM desktop system, and an IR CADS. Both

the personal desktop and personal FM resulted in signiﬁcant

improvements relative to the hearing aids alone; however, the CADS did not improve performance. In another study, Anderson et al10 evaluated speech recognition in noise in 28 children, 8 to

14 years old, who used hearing aids or cochlear implants coupled

to personal FM, personal FM desktop, and CADS FM systems. All systems provided better speech recognition relative to the personal hearing technology alone, but the personal FM and personal FM desktop systems resulted in higher performance than the CADS FM system.

9,10,13 ,20

First, Anderson and Goldstein9

Pitfall

Classroom audio distribution systems (CADS) do not provide adequate improvement for children with any degree of hearing loss; personal systems will provide the greatest improvements.

In addition to dierences across the major types of RM systems,

dierences may also be found between types of personal systems.

For instance, in one study, hearing aids was compared when using a digital, adaptive RM

system versus a digital FM accessory. No dierences in sentence

recognition were found in quiet or in low levels of noise, but the adaptive system resulted in better performance at higher noise levels, likely because of the automatic increases in gain, the directional microphone, and the digital noise reduction in the adaptive system. However, the digital audio streaming accessory system is substantially less expensive than most personal digital RM systems, and it does not require a separate receiver because it is built into the personal hearing device. Selection of the most appropriate type of system will depend on the child’s listening environment, with dynamic school environments requiring the adaptive feature for optimal performance.

speech recognition of 18 adults with

262

24 Remote Microphone Technologies

Another dierence between personal systems may occur for

directly coupled (i.e., direct audio input [DAI]) as compared to neckloop induction systems. One study showed better speech recognition with the DAI over the neckloop, which may be attributed to the strength of the signal to the telecoil, which is often designed for telephone use and not RM system use (i.e., orientation of telecoil designed for phones).33 However, it is important to note that only one induction neckloop is required for children with bilateral hearing aids or cochlear implants, which would be less expensive than the two directly coupled receivers.

24.5 RM Parameters and Signal

Processing That Aects

Performance

24.5.1 Fixed-Gain vs. Adaptive Systems

Receiver gain, which may be ﬁxed, adjusted, or adaptive in some

receivers, increases or decreases the output of the RM system to a child’s personal hearing device or from a CAD. Fixed- or adjustable-gain receivers provide a static output that does not change with the environmental noise level regardless of the ambient noise level. Adaptive-gain receivers (i.e., dynamic systems), on the other hand, automatically increase the receiver gain of the RM system when the ambient noise level exceeds a certain dB SPL value as measured in the transmitter microphone.

Published research has demonstrated signiﬁcantly better speech recognition in noise with adaptive systems than with ﬁxed- or

adjustable-gain systems. For example, Wolfe et al34 reported

scores that were 50 percentage points higher with adaptive than with ﬁxed systems in 25 adult and pediatric cochlear implant

recipients. Similarly, Thibodeau35 reported signiﬁcant improve-

ments with adaptive gain, ranging from 20 to 40 percentage points in ﬁve children and ﬁve adults with hearing loss, with the

majority of participants favoring the adaptive system.

24.5.3 Transmitter Characteristics

The signal processing and other technological characteristics of transmitters may substantially impact performance of children using RM technology. First, the use of directional rather than omnidirectional microphones may substantially improve speech recognition performance when worn by a single talker. Directional microphones aim to focus on the speech signal from the primary talker while attenuating background noise. However, when a transmitter is used during group work, an omnidirectional setting should be used to attempt to capture the speech of everyone in the group. Some more contemporary transmitters are able to detect the transmitter’s orientation in space and automatically select the most appropriate microphone polar plot pattern for the situation (e.g., if the transmitter is in the vertical plane, a directional response is selected to focus on the speech of the talker). Second, microphones may also come

in multiple conﬁgurations including lavalier/lapel style (placed 6 to 8 inches from mouth), boom or head-worn (3–6 inches

from mouth), pass-around, and microphones that are built into the body of the transmitter. Boom microphones have a distinct advantage over lapel microphones because the intensity at the microphone does not change with head movement.

Third, performance may also be inuenced by signal processing

characteristics and user controls including digital noise reduction, multitalker network, speech enhancement, automatic voice activation, and volume/sensitivity controls. Fourth, some transmitters also allow the older child, teacher, or parent to conduct diagnostic

assessments, which conﬁrm signal delivery from the transmitter

to the receiver. Fifth, some FM systems allow the user to switch to multiple analog transmitting channels, which is important for schools with children with hearing loss in multiple classrooms, while others only have one channel. Additionally, one transmitter is able to provide digital and analog FM radio signals. Finally, some transmitters allow the audiologist to adjust settings (e.g., receiver gain, optimization for a particular make of cochlear implant sound processor) for each child through programmable options, while others have no options or manual controls.

24.5.2 Digital vs. Analog Systems

There are a few published studies that suggest equivalent or better performance with digital over analog RM systems. First, Wolfe et al with cochlear implants while using three personal systems: a

ﬁxed-gain analog FM system; an adaptive analog FM system; and

an adaptive digital system. Overall, the adaptive-gain systems

provided better speech recognition than the ﬁxed-gain systems, and at moderate to high noise levels (65 to 80 dBA), the digital

adaptive system resulted in better speech recognition than the analog adaptive FM system. Similarly, Thibodeau36 reported that, in 11 adults with hearing loss and hearing aids, adaptive-gain

systems resulted in signiﬁcantly better speech recognition than ﬁxed-gain systems. Also, digital adaptive systems resulted in better performance than analog FM adaptive systems (i.e., 35 percentage points at 75 dBA noise).

12,16

evaluated sentence recognition in 44 individuals

There are also multiple receiver characteristics that could

inuence performance with the RM system. First, as previously

mentioned, receivers with adaptive receiver gain will result in

better performance than those with ﬁxed gain. Second, some

transmitters include LED lights to indicate that the system is functioning. Third, as discussed previously in this chapter, the way the receiver interfaces with personal hearing technology varies among options that include:

Direct electrical connections through the DAI of the personal

•

device using a special battery door, audio shoe, or adaptor Design-integrated receivers

•

Built-in receivers (i.e., RF antenna is housed within the body of

•

the hearing aid or cochlear implant sound processor) Body-worn receivers with neckloops for use with the user’s

•

telecoil

24.5.4 Receiver Characteristics

263

III Hearing Access Technologies for Infants and Children

24.6 Remote Microphone Use with Cochlear Implants

Multiple research studies report signiﬁcant beneﬁts of RM technology for individuals with cochlear implants. Given the dierences in hearing aids and implant sound processors, there are several important considerations for managing RM systems for this population. First, the default gain setting in most RM systems is designed for hearing aids; therefore, the default setting may not be appropriate for implant processors, which often have higher input impedances for DAI than hearing aids do. As a result, the audiologist will need to review guidelines or published research to determine the optimal gain setting for a particular RM system.

Second, many sound processors have adjustable audio mixing in order to control the relative strength of the signal from the RM system versus the sound processor microphone. There are several audio-mixing ratios, but the two most commonly used settings are to provide equal emphasis from the two microphones (1:1 or 50/50) or to attenuate the input from the sound processor microphone to allow emphasis of the RM system. Equal emphasis is recommended for children to allow clear access to environmental sounds, speech from classmates, and incidental hearing.

Third, the advanced signal processing in some sound processors may impact performance with the RM system. In particular, enabling the autosensitivity control (ASC) in Cochlear sound processors will greatly improve speech recognition in noise when using an RM system.34 Also, in individuals with Advanced Bionics

Naida CI Q70 processors, speech recognition was signiﬁcantly

better when the ClearVoice digital noise reduction processing was used in conjunction with a digital, adaptive RM system.

Finally, because the audiologist is not able to listen to the output of the implant while connected to the RM system, extra equipment may be necessary to verify functioning of the devices. In some cases, cochlear implant monitor earphones or a listening check device may be used to verify the signal from the processor microphone and/or from the RM system. Additionally, in some cases functioning of the RM system may be determined by connecting it to a loaner hearing aid with the appropriate audio shoe and by listening to the device with a hearing aid listening tube. Some neckloop RM systems allow the audiologist to plug in earbuds to listen to the output from the receiver.

11,12,16,18 ,20, 21,22 ,23, 33,3 4

24.7 RM System Verication and

Validation

There are three ways to verify an appropriately ﬁtted RM system:

electroacoustic test measures, real-ear measures, and behavioral testing. Although much of the advanced signal processing in RM systems cannot be veriﬁed with available test measures, electroacoustic testing may be conducted to examine the output from

an appropriately ﬁtted personal hearing aid when the test signal

is delivered to the hearing aid microphone as compared to the output when the test signal is delivered to the RM system microphone, when both microphones are active simultaneously.37 The goal of the electroacoustic testing is to obtain equal output (i.e., transparency) for the hearing aid and the RM system when

sequentially introducing equal inputs (often 65 dB SPL speech

signal) to the two microphones. If the average output (at 1,000,

2,000, and 4,000 Hz) of the RM system deviates from the average

output of the personal hearing aid by more than 2 dB, the receiver gain/volume should be adjusted and the testing repeated until a better output match has been achieved. In real use, the closer

proximity of the transmitter microphone to the mouth (i.e., 3–6

inches) relative to the proximity of the hearing aid microphone results in an approximate 10-dB advantage at the ear in a quiet environment. A step-by-step guide to conducting electroacoustic test measures with RM systems in hearing aids is provided by Auriemmo et al.

Real-ear veriﬁcation RM systems may also be done with hearing

aids and transparent FM/DM-only receivers; however, with hear-

ing aids, the electroacoustic testing is more ecient. Step-by-step real-ear veriﬁcation procedures for ﬁtting RM systems to children

with normal hearing, such as those with ADHD, ASD, or APD, are given by Schafer et al.40 Regardless of population (i.e., children with normal hearing or children with hearing loss), the goal of real-ear measures is to meet prescribed targets, avoid exceeding the child’s estimated or measured uncomfortable loudness level, and avoid occluding the ear canal and hindering the child’s ability to hear environmental sounds or peers.

When a child is able, behavioral testing may be completed with and without (e.g., hearing aid alone) the RM system by using reliable and valid speech-in-noise tests, such as the Pediatric AzBio,41 Hearing in Noise Test for Children (HINT-C),42 the Bamford-KowalBench Speech-in-Noise (BKB-SIN) test,43 or Phrases in Noise Test (PINT).44 The PINT, HINT-C and BKB-SIN yield a 50% speech-in-

noise threshold in dB SNR, while the AzBio or the HINT-C at ﬁxed intensities yield a percent-correct score. For ﬁxed-intensity tests, the authors recommend a +5 or 0 dB SNR with a ﬁxed level of 60 or 65 dBA for the speech to replicate a dicult listening situation. Given that these tests are prerecorded, a compact disc (CD) player

will be required, and the transmitter microphone will need to be placed approximately 6 inches in front of a single-cone loudspeaker to simulate the primary talker. One or more loudspeakers may be used to present the noise that is available on the CD. Care should be taken to ensure that directional microphones are facing the proper direction relative to the loudspeaker. Scores and thresholds are often substantially better with an RM system as compared to no device or the personal hearing device alone. It is important to note that behavioral testing only estimates how a child may identify speech, but identifying (i.e., repeating back) does not predict comprehension of speech (i.e., understanding

what is said), which is a more dicult auditory skill. Also, testing

in a soundbooth with recorded stimuli does not replicate visual distractions, reverberation, and acoustics in typical classrooms, nor does it take into account the multitasking required of most students (e.g., simultaneously listening and taking notes). As a result, in some cases, speech-in-noise testing will overestimate the child’s performance and comprehension in the real world.

Pearl

Speech-in-noise testing may be used to document an appropri-

ately tted RM system.

264

24 Remote Microphone Technologies

To validate the beneﬁt from the ﬁtting, several parent or teacher

questionnaires may be used to document auditory behaviors or school-based performance with and without the system. The reader is referred to the American Academy of Audiology (AAA) guidelines45 for more information about the various types of

questionnaires that may be helpful for documenting beneﬁts with RM systems. Other strategies to validate beneﬁt include inter-

views with parents, teachers, students; documenting changes

in academic performance; and observing on-task versus o-task

behaviors with and without the system.

25,46

24.8 Parent or Teacher Orientation to RM Systems

Learning to use an RM system may be challenging for parents, teachers, or guardians, especially when they are used in conjunction with personal hearing devices. As a result, it is imperative to provide an orientation. According to the AAA practice guidelines,45 this orientation should include the implications of the child’s hearing loss, device function, device features and

beneﬁts, and limitations of the device including when to use it,

care and maintenance, troubleshooting and listening checks, self-monitoring of function, and advocacy. A demonstration and

a simpliﬁed user guide are also beneﬁcial to teachers and parents

because they can review the most critical information about the system quickly. Also, a daily listening check followed by simple troubleshooting (e.g., dead battery), if necessary, should be recommended at home and at school from the teacher, school nurse, special educator, or speech-language pathologist.

Sampling of Manufacturer Websites

Advanced Bionics (Santa Clarita, CA): https://www.advancedbionics.com/us/en/home.html

Cochlear Ltd. (Sydney, Australia): http://www.cochlear.com/wps/wcm/connect/intl/home

N ReSound A/S (Ballerup, Denmark):

https://www.resound.com/en-us

ED-EL (Innsbruck, Austria): http://www.medel.com/us/

Oticon (Gothenburg, Sweden): https://www.oticon.com

Phonak (Warrenville, IL): https://www.phonak.com/us/en.html/ Starkey Hearing Technologies (Eden Prairie, MN):

https://www.starkey.com W

idex (Lynge, Denmark): https://www.widex.com

Discussion Questions

1. Name three types of transmission for RM systems.

2. Identify the three broad types of RM systems, and provide an

advantage and disadvantage for each type.

3. What is the most appropriate type of system for a child with hearing aids or a cochlear implant?

4. Name and describe two ways to verify the appropriateness of

the RM system tting.

5. What are two ways to validate the RM system tting?

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266

25 Red Flags: Identifying and Managing Barriers to the Child’s Optimal Auditory Development

25 Red Flags: Identifying and Managing Barriers to the

Child’s Optimal Auditory Development

Jane R. Madell, Joan G. Hewitt, and Sylvia Roteisch

Summary

The audiologist’s responsibility is greater than simply evaluating hearing,

tting, and evaluating hearing technology. Audiologists have the responsibility for studying the whole child, identifying concerns, and making the appropriate recommendations for management. Some children are tted with technology and seem to do very well. Others seem to struggle. When a child is struggling, it is incumbent on the audiologist to determine why. An audiologic evaluation that does not include speech perception testing using lang uage-appropriate materials in different listening conditions will provide an incomplete picture of the child’s abilities and the child’s auditor y access to spoken language, which will make it difcult to come up with an appropriate habilitation plan. By attending to a child’s progress in speech, language, and auditory development, we can plan appropriate inter vention. This chapter will identify “red ags” that indicate when the problem is with technology settings, speech production, language development, or voice and discuss how to improve performance.

Keywords

red ags to auditory/neural development, hypersensitivity, behavioral control issues, vision as primary, insucient progress,

auditory support, interventionist support, hearing aids, cochlear implants, BAHA

Key Points

The audiologist’s responsibility is greater than simply tting

•

and evaluating hearing aid technology; audiologists also have the responsibility of studying the whole child and making appropriate recommendations. All professionals are responsible for fully understanding the

•

child’s abilities within their areas of specialization and for collaborating with other professionals to provide a comprehensive picture of the child and the child’s abilities. If an audiologic evaluation does not include assessment of

•

aided speech perception at normal and soft conversational levels, in quiet, and with competing noise using age-appropriate testing materials, professionals and parents will have an incomplete picture of the child’s auditory access to spoken language, which will limit their ability to plan appropriately for the child. It is not enough for an audiologist to pay attention only to

•

audiologic issues. An audiologist must attend to speech and language development because it provides direct information about what a child is hearing and what the audiologist might need to do to modify technology. A child’s phoneme perception and production, voice quality,

•

and language development can provide signicant data concerning the child’s auditory access and the appropriateness of technology settings. When a child has appropriate parental and interventional

•

support and does not have a signicant cognitive/neurologic

disability, red ags (areas of signicant concern) point to the

type of technology or the technology settings as the source of the child’s lack of progress. Variability or delay in a child’s progress in audition, speech,

•

or language should merit investigation into all aspects of the child’s intervention.

25.1 The Audiologist’s Responsibility When a Child Is Not Attaining Expected Outcomes

Many children with hearing loss who are ﬁtted with optimal

technology do well and attain the listening and spoken language outcomes expected by family and professionals. Most children are ﬁtted with technology and do well. They are able to hear suciently well to develop speech and language and learn. However, not every child with hearing loss is a superstar. Why is there a huge variation in performance among children who seem to be equal? We know that not all children achieve the same level of

listening, spoken language, literacy, and academic proﬁciency,

but why? Certain factors are clearly a problem that will explain

some dierences in performance. For example, some children do

not hear well with technology, some are not receiving appropriate therapy, some have parents and family who are not involved and not providing speech and language stimulation, and some have other developmental issues that interfere with progress. However, sometimes all variables seem to be managed in a positive fashion, yet the child still does not make the expected progress.

The audiologist has a larger responsibility than simply evalu-

ating hearing and ﬁtting hearing aid (HA) and cochlear implant

(CI) technology. As audiologists, we have the responsibility for monitoring performance with technology and for working with other professionals to study the whole child. All professionals are responsible for fully understanding the child’s abilities within their areas of specialization. Each professional who works with a child with hearing loss needs to evaluate the child’s use of auditory information. Audiologists need to obtain threshold information and assess speech perception with technology, while speech-language pathologists (SLPs) and Listening and Spoken Language Specialists (LSLSs) need to monitor how well the child functions daily while wearing and using auditory technologies in all environments. Teachers of the Deaf (TODs) need to monitor the child’s use of hearing in the classroom, and parents are responsible for monitoring the child’s performance at home and in social settings. The audiologist may need to teach parents and other professionals how to monitor the child’s hearing and use of technology accurately.

We must accept and understand that a child’s ability to hear is

the fundamental basis for all speech and language development

267

III Hearing Access Technologies for Infants and Children

and that the success of our audiologic intervention is reected in the success of the child. “Success” should be deﬁned as reaching

the family’s desired outcomes so that the child’s spoken language, literacy, and academic skills are consistent with hearing peers. The audiologist has the responsibility to understand not only the audiologic data as it pertains to the child, but also the child’s development in the critical areas of speech, language, and functional listening skills. To be successful, we need to obtain relevant information from evaluations administered by other team members to make a determination about the child’s progress. If a child is not making one year’s progress in one year’s time, all team members are responsible and should be concerned. Clinicians must look at the overall progress of the child, beyond their own area of specialization (see Chapter 26 about collaborative team management). If clinicians look only to their own area of specialization

and report that the problem is “not in their area,” then the child’s

development is compartmentalized and the potential of one area

of the child’s development to aect others, positively or adversely,

is ignored. All professionals must make the commitment to hold themselves accountable and take responsibility to recognize and

examine issues in their own areas. To address red ags (a warning

to address areas of concern) and improve the child’s progress, we must each collaborate with other team members, understand

the signiﬁcance of the measures collected by colleagues in their

areas of expertise, and evaluate how these data can contribute to analyzing test results in our own area of expertise. It is critical that the child’s lack of progress be discussed with the entire team: all the professionals who work with the child and the family. Only by evaluating all aspects of the child’s performance and being willing to accept that some of the responsibility might be ours can we determine what needs to be done to improve a child’s outcomes.

Hypersensitivity

A red ag that should raise immediate concern is hypersensitivity to auditory stimuli. A child demonstrating eye blinks or facial nerve stimulation in response to stimulation from the cochlear implant should provoke serious concern and prompt immediate professional action.

Behavioral Control Issues

Occasionally, children refuse to wear technology because of their behavioral control issues; however, in the authors’ experience, this is unusual. Other factors should be eliminated before reaching the conclusion that the child’s own behavior is the source of the problem.

Poor Responses to Auditory Stimuli

Poor responses to auditory stimuli are a red ag. A child who has

no responses or poor responses to sound (even as an infant) is a focus of serious concern.

Failure to Make One Year’s Progress in One Year’s Time

Children who are not making 1 year’s progress toward desired

outcomes in 1 year’s time are demonstrating another signiﬁcant red ag. Audiologists need to inquire about speech-language and

academic progress. SLPs, LSLSs, and TODs need to ask about technology thresholds and speech perception in quiet and in noise to be sure the child is performing as well as possible.

Pearl

All clinicians must look at the overall progress of the child beyond their own area of specialization.

25.2 Red Flags That Might Signal a Barrier to the Child’s Optimal Auditory/Neural Development

25.2.1 Red Flag: Basic Behavioral

Observations

Children Not Wanting to Wear Technology

If children hear well with their technology, they should want to wear their technology all day, every day. A child who does not want to wear technology is demonstrating the most basic red

ag. A child may not tolerate technology because it is too loud

and uncomfortable or because it is too soft and the child cannot hear with it.

25.2.2 Red Flag: Ineective Audiologic Intervention

All professionals need to ensure that they are providing eective

intervention, while parents need to ensure that their children

are receiving eective intervention. Audiology services are ineective if they fail to evaluate regularly how a child hears

and understands speech with each piece of technology. Testing should include unaided thresholds and aided thresholds with the right and left ear technology individually and with the technology worn binaurally. Speech perception testing should be performed at normal and soft conversational levels in quiet and in competing noise (see Chapter 9 for more detail on performing speech perception testing and selecting appropriate tests).

Audiologic red ags are indicated when audiologists obtain

aided thresholds that are too soft (≤ 15 dB hearing level [HL]), aided thresholds that are not soft enough (35 dB HL or poorer), poor speech perception scores (poorer than 80%) in any of the test

conditions (normal and soft conversation in quiet, and normal conversation in competing noise), or speech perception results completed with inappropriate test materials (such as using a picture-pointing test for a mainstreamed child in third grade) (see Chapters 9 and 16).

268

25 Red Flags: Identifying and Managing Barriers to the Child’s Optimal Auditory Development

Audiologists can support eective intervention by doing the

following:

Understanding normal auditory skill development and the

•

eect of hearing loss on auditory skills development Ensuring that technology is appropriately ﬁtted through regu-

•

lar audiologic evaluations and programming visits

Recognizing that only appropriately ﬁtted technology can

•

provide optimal auditory access to the brain Collecting data about auditory perception from other profes-

•

sionals who work with the child and from parents

Evaluating comprehensively any signs of diculty noted by

•

any of the professionals or parents

25.2.3 Red Flag: Ineective Speech, Language, and Listening Intervention

In addition to the diagnostic and the technology aspects, audiologists must examine the speech-language and listening

intervention being provided to the child. Red ags indicative of ineective intervention would be noted in the delay of initial and

basic auditory skill development. The clinician would primarily note a lack of clinical behaviors expected early in the auditory hierarchy when a child responds to fewer sounds with his HAs on than with them o, responds to fewer sounds with his CI than previously with his HAs, or when skills acquired with his HAs do not transfer to his CI.

respond to his or her own name, a lack of “listening attitude,” a

poor voice quality, no evidence of improvement in speech production, an inability to discriminate or identify suprasegmentals, vowels, and consonant features (see Chapter 19, The Acoustic Speech Signal), and limited comprehension of familiar phrases based only on suprasegmentals or key words.

(Table 25.1). All interventionists should be concerned

Red ags include, but are not limited to, the child failing to

25.2.4 Red Flag: Vision as Primary Modality

When a child’s intervention does not primarily focus on audition and instead uses vision as the primary input modality for receiving spoken language, problems in the child’s speech production often are observed. These speech errors are a consequence of the limited visual availability of acoustic speech features.

Table 25.1 Professional expectations for a baby aided by 3 months or implanted by 12 months

Preliminary-level skills Hearing age (months) Skill 1 3 6 9 12 > 12

Responds to Ling sounds HA, CI Responds to name HA, CI Discriminates suprasegmentals CI HA Babbles ve vowels HA, CI Discriminates nasal from plosive HA, CI Produces nasal HA, CI Produces plosive HA, CI Discriminates fricative CI HA Comprehends ve words CI HA Produces fricative HA, CI Babbles ve consonants HA, CI Comprehends 2–3 stereotypic phrases HA, CI

Expressive vocabulary of 5–10 words HA, CI Babbles ve voiceless consonants HA, CI

Higher-level skills Hearing age (months) Skill 12 18 24 30

Comprehends 50 words HA, CI Comprehends 100 words HA, CI Comprehends simple sentences HA, CI Produces 10 words HA, CI Produces 50 words HA, CI Produces 2-word phrases HA, CI Produces 2-word combinations HA, CI

Abbreviations: HA, hearing aid; CI, cochlear implant.

Note: This table shows the results of a survey of professionals who work with infants and children with hearing loss.

269

III Hearing Access Technologies for Infants and Children

Indications of speech acquisition through vision and the resulting error patterns would include confusions of phonemes produced in the same place, voicing errors for cognate pairs, pitch-dependent vowels, and poor control of suprasegmentals. Utilizing even minimal auditory cues would typically prevent most of these error patterns. To address and/or prevent visual speech errors, the intervention must focus on the child’s use of audition and eliminate the child’s reliance on vision for the reception of speech, phonemes, and spoken communication.

The child with hearing loss who is provided with optimal hearing technology that is appropriately set and receives appropriate intervention should develop auditory, speech, and language skills in the typical sequence and at an appropriate rate in a given time interval.

2,3,4,5

25.2.5 Red Flag: Child Making

Insucient Progress toward

Attaining Desired Outcomes

When a child is not developing skills at the appropriate rate, weak areas of development and the rate of progress must be examined

to detect the red ags revealing issues possibly aecting the child.

Interventionists should be alert to any signs of deterioration of skills in the areas of comprehension, vocabulary, and language development (e.g., loss of ability in speech discrimination, iden-

tiﬁcation, or production). These can be evidenced by the child’s

inability to demonstrate a previously emerging or mastered skill after regression or a plateau in a child’s development. Regression or plateau in a child’s auditory development is never acceptable and merits troubleshooting for cause.

25.2.6 Red Flag: Speech Production

Listening to the child’s speech will indicate what he is hearing. Children speak what and how they hear. If a child is not producing a particular phoneme, it is as likely as not the child is not hearing that speech sound well enough or often enough to cement appropriate connections in the auditory centers of the brain. A

red ag is indicated by children exhibiting poor voice quality,

such as a gravelly quality or glottal fry, or by the inappropriate use of intensity demonstrated by the child who always whispers, is always too loud, or is unable to simulate a whisper in his

productions. Additional red ags are noted in speech production

with issues of oral/nasal balance (hyper- or hyponasality), lack of pitch control, and vocalizations that occur on inhalation rather than on exhalation of the breath stream.

Red ags are raised when development of phonemes is atypical

or does not follow the normal rate or sequence. When monitoring speech production, interventionists must be aware when the variety of manner of production or place of production is too limited. An inappropriate developmental sequence would be indicated when the child utilizes more advanced phonemes but demonstrates gaps in phoneme repertoire for earlier-acquired

phonemes. Another red ag would appear when a child is unable

to produce phonemes with particular speech features, such as unvoiced consonants or bilabials.

25.2.7 Red Flag: Language Development

Interventionists must monitor the child for indications of appropriate emergence of language skills even prior to the initial expressive use of words. An overall lack of development of

“conversational” babbling/jargoning is a concern. A child without

intelligible vocabulary or language development who produces only canonical babble and jargoning is not developing the next level of language abilities. Interventionists must be concerned when they observe receptive language development, but no parallel development of expressive language or speech production abilities by the child.

25.3 Recognizing Eective Auditory Intervention

If the family has chosen listening and spoken language, the child’s use of audition is fundamental. Intervention requires a

deﬁned auditory component such that the focus of therapy is

auditory skill development in the appropriate sequence through the auditory modality. auditory goals is determined through the knowledge of the normal progression of audition. The LSLS or SLP must assess the child to determine baseline auditory abilities and then progress

through skills beginning at the appropriate level of diculty.

Intervention then moves through the sequence by incorporating auditory goals in every activity in every session. Eective intervention provides guidance and coaching to parents, enabling auditory goals to be incorporated throughout the child’s daily life and in all settings (Table 25.1).

6,7

In this auditory model, a sequence of

25.4 Supporting Intervention through Auditory Demand

25.4.1 Auditory Support

All clinicians working with a child must determine whether the demand for the child to use audition extends across all environments—therapy, home, and school. Is the child wearing technology during all waking hours in every setting? Is there a consistent way to respond if the child removes her technology? Is the child expected to report age-appropriate issues with her equipment? Do adults interacting with the child have an expectation that the child will respond to sound, and have a clear understanding of what the child can and cannot hear in each

speciﬁc environment?

270

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