Twenty-nine years have passed since the first American child received a cochlear implant – a single-electrode system and the first to undergo U.S. FDA adult clinical trials. Since its introduction, this hearing device has single-handedly transformed the field for therapists working with communication disorders – and fanned a firestorm of controversy still raging in some communities today.

Since cochlear implants (CIs) for congenitally deaf children are often considered to be most effective when implanted at a young age – while the brain is still learning to interpret sound – many recipients are implanted before they are able to decide for themselves if they want the implant. Critics, many of whom reside within the deaf community, not only question the ethics of such an invasive elective surgery on children, but also speculate about the rights of the individual citizens, language, ethics, and the effects of the device on deaf culture.

For some of the more extreme opponents of the surgery, CIs in children represent the first wave of “cultural genocide” for the deaf community, seen as a minority group threatened by the hearing majority. Rather than perceiving deafness as a disability to be “fixed”, individuals who are deaf instead celebrate their diverse culture – a model of deafness that clashes with many individuals who feel that refusing to implant deaf children is unethical, comparable to refusal to treat any other handicap.

Treading into this debate between parents of deaf children and the deaf community, audiologists, speech-language pathologists, and communication therapists are working in unison with the patient to assist in the communicative rehabilitation and the challenges that arise for children emerging from a silent world.

Divergent Sounds

Medical science has long recognized that hearing is critical to speech and language development, communication, and learning. Children with listening difficulties, whether due to hearing loss or auditory processing problems, are predisposed to serious hurdles in their formative development – a “fork in the road” that begins even before a child’s first words.

“During the first eight months of life, hearing and hearing-impaired babies produce the same type of vocalizations – they coo, squeal, grunt, blow raspberries, and produce sounds that adult listeners describe as vowel-like or consonant-like,” says Emily Tobey, PhD, Nelle C. Johnston Chair in Early Childhood Communication Disorders at the Callier Center for Communication Disorders University of Texas - Dallas.

She continues, “At around nine months, the vocalization behavior of hearing and hearing-impaired children begins to differ. Normal hearing babies begin to babble by producing syllables composed of consonant-vowel combinations. These early babbling behaviors form the syllable foundations associated with English. Hearing impaired babies, however, do not enter this babbling stage. Instead, they continue to produce the non-speech vocalizations associated with the behaviors observed in the first six months of life. Babbling behaviors may occur very late for hearing-impaired children, sometimes as late as four years – or never at all.”

As the majority of children with hearing loss have no other abnormalities or distinguishing features, many children in the past were diagnosed late, resulting in significant delays in language acquisition. However, universal tests that require little to no direct child response have been developed and utilized in maternity wards of hospitals, allowing physicians to diagnose hearing loss and begin early intervention therapy.

“Candidacy for a cochlear implant has changed significantly over the years,” says Christy Miller-Gardner, AuD, manager of clinical education at Sylmar, Calif.-based Advanced Bionics. “Today’s FDA pediatric criteria include children 12 months through 17 years of age with profound, bilateral sensorineural hearing loss. Symptoms or behaviors that may suggest the need for a cochlear implant include: delayed or lack of speech and language development; lack of recognition to normal sound stimuli, such as not responding to one’s name; lack of social interaction with children and adults; lack of response to speech and hearing emphasis in the child’s education or therapy environment.”

Despite the benefit of early diagnosis, audiologists and speech therapists continue to struggle with parents whose children have hearing disabilities, yet are not eligible for a cochlear implant. A relatively common reason for an ineligible status is that the child’s hearing is actually “too good” – meaning that the child can hear some sounds with the aid of non-implant hearing device. Other ineligibility factors may include a damaged hearing nerve or prolonged exposure to deafness, at which point, the brain may begin using the hearing area of the brain for other functions. 

“We take a team approach to our cochlear implant candidates, from the candidacy evaluations and then transitioning them to aural (re)habilitation,” says Jennifer Kolb, MEd, CCC-A, an audiologist and program specialist in the Bill Daniels Center for Children’s Hearing at The Children’s Hospital in Denver. “Our cochlear implant team includes surgeons, audiologists, speech-language pathologists, a family consultant, a social worker, and a deaf educator, in addition to our surgeons. We have regular team meetings to discuss our candidates and if needed, to address any issues with programming or therapy.”

Marcia Taber, MS, CCC-SLP, a colleague of Kolb’s and manager of Deaf and Hard of Hearing Services at The Children’s Hospital, points out: “Each of the team members is scheduled time with the patient to assess their current level of functioning in their area of expertise. Then, the team comes together and discusses results, impact, eligibility, or concerns. If there are any major concerns, brainstorming occurs to try to assist the family in resolution of any barriers to the success of the child with the CI.”

Where Patient and Technology Meet

For pediatric CI recipients, therapy in the form of aural habilitation begins before implantation and continues throughout the assessment process. More importantly, the family and support system of the patient become the focus of the team of therapists, as the team works to prepare them for a multitude of possible outcomes after the implant is activated.

“The approach pre-operatively is to educate the child’s family members on their role as a language facilitator, reinforce the purpose and use of consistent amplification, and highlight listening and language opportunities that occur naturally in the child’s home,” says Carissa Moeggenberg, MA, CCC-A, manager of Rehab Programs at Advanced Bionics. “During this pre-operative timeframe, the parents should work with their child’s educational team to ensure that all academic and therapy services are implemented and that the child is actively enrolled and receiving these services.”

Compared to the hearing aids that many patients are accustomed to by the time of their surgery, CIs can provide a number of advantages to hearing-impaired patients. While avoiding problems of acoustic feedback, as well as earmold issues, CIs can provide greater ease in high-frequency consonant perception and offer an opportunity for a natural-sounding voice.

“Hearing aid technology has drastically changed in the last 10 years or so. Digital signal processing is now standard, and this allows the audiologist to provide more flexibility in the fittings,” says Sue Dreith, AuD, CCC-A, manager of audiology services at The Children’s Hospital. “Hearing aids are much smaller, which is important when fitting on little ears. [Frequency modulated] (FM) systems are routinely used with hearing aids, and we have seen many changes in the compatibility of FM systems with hearing aids, including some integrated receivers.” 

She continues, “Despite the improvements in hearing aid technology, some children are still not able to access the full range of conversational speech, as in the case of severe-to-profound hearing loss. After an adequate trial with hearing aids and appropriate aural habilitation therapy, cochlear implantation becomes an option.”

However, for children whose hearing status make them ineligible for CIs, new alternatives are becoming available. For example, patients with “cochlear dead regions” – locations where the cochlear inner hair cells and/or neurons are not functioning adequately to send the sensory information to the brain – are typically plagued by an inability to understand speech, due to many of its high frequency components, such as soft voiceless consonants.

While today’s hearing aid technology can provide sufficient amplification to reach this hearing threshold, if the speech sounds cannot be detected or accurately transmitted by the high frequency regions of the cochlea, why waste energy pumping out the amplified high frequency sounds that do not help the patient understand speech, and often serve to increase issues with acoustic feedback?

According to Tabitha Parent Buck, AuD, chair of Chair of Audiology at the A.T. Still University - Arizona School of Health Sciences in Mesa, Ariz., frequency compression is an available alternative to providing “wasted amplification” in the high frequencies.

“Frequency compression can give the patient access to speech cues that were missed or unusable with standard amplification,” she says. “This is because the frequency compressed sounds are delivered to frequency regions where the patient has better thresholds with viable inner hair cells and neurons to encode and transmit the information. The frequency-compressed signal will sound different than the original signal, but, if the spectral features of the speech are maintained, the auditory system can utilize the speech information.”

A Gauntlet of Sound

“After the cochlear implant is switched on, the child will attend therapy sessions one to two times weekly, in addition to early intervention or school services,” says Kolb. “Parents are heavily involved in the intervention process and are taught ways of implementing listening activities into their daily routines. Collaboration with school personnel can also be an important part of the aural (re)habilitation process, as well.”

Given the importance and complexity of rehabilitation for a CI recipient, it’s crucial that their program be uniquely tailored to meet the individual needs of the child, focusing the development of listening, oral speech, and language skills.

“As with most intervention with children, play is their primary means of learning,” says Taber. “Therapists must create play-based, age-appropriate activities that incorporate the variety of skills needed to help the child progress through the auditory hierarchy that leads to comprehension and learning. As mentioned, parental training is critical to the success of a program for very young children.”

In an effort to target this demographic in need, Advanced Bionics has created an online rehabilitation resource – The Listening Room – that provides free activities and resources that foster the development of listening and oral language skills for children with hearing loss. The Listening Room provides parents and other caregivers with tools for perpetuating effective rehabilitation in the home setting, and eases them into a sense of familiarity with possible challenges.

“A whole host of impacts are possible for families of individuals with cochlear implants,” says Tobey. “You just need to simply imagine how many different sounds are generated in a typical house that will now be heard – alarm clocks, shower water, toilets flushing, phones ringing, doorbells ringing, people talking, pets barking. Learning what all of these sounds are can be both exciting and challenging for a cochlear implant user.”

Bringing a new CI user into the hearing world can be quite an ordeal for the entire team of therapists, as they attempt to manage expectations – both their own and those of the parents – regarding the activation and progress of the implant. Just like a child with normal hearing sensitivity, CI recipients must spend several months listening and learning what sounds are before they can start to talk. The team is often challenged by subtle childhood behaviors that are actually cochlear responses – for example, the child may be more or less vocal, may be more tired, or may have a “listening” expression on their face.

“When a child is initially stimulated, and for subsequent mappings, the protocols put into use with adults are often ineffective and frustrating when working with children,” says Rebekah Cunningham, PhD, clinical coordinator at the A.T. Still University - Arizona School of Health Sciences.

She continues, “Instead, audiologists rely on standard pediatric behavioral techniques  – ‘Put the block in the bucket when you hear a sound’ – if the child is old enough and has enough language. If they are too young or have limited language, or both, these techniques are useless and the audiologist relies on the child’s reaction to the sound of the CI, which can include crying, eye widening, turning away, hugging a parent, and cessation of an activity.”

Unlike working with adult CI recipients, a young child has limited speech and language, as well as limited experience with sound, so the audiologist should be looking for subtle responses when activating the cochlear implant. The devices have telemetry, which allow audiologists to measure responses from individual electrodes and the hearing nerve, which can be of great assistance in building a listening program.

Nearly three decades into this controversial and groundbreaking field, audiology, speech-language therapists, and those specializing in communication disorders continue to find themselves walking a tenuous line on the subject of CIs. Neither a replacement human ear nor a “miracle cure” for deafness, cochlear implantation remains simply one option among many for caregivers looking to bring their hearing-impaired children into a world of sound.

— Bob Stott is senior editor at Therapy Times. Questions and comments can be directed to bstott@therapytimes.com.