Breaking Down the New Guidelines on Cochlear Implants for Pediatric Single-Sided Deafness

Despite the FDA’s approval in 2019 of cochlear implants (CI) for children aged 5 years and older with single-sided deafness (SSD), not all clinicians are aware of the benefits of the procedure for these younger patients. To help attract attention to those benefits and provide guidance for CI candidacy, evaluation, and management of children with SSD, the American Cochlear Implant Alliance (ACIA) Task Force published new guidelines (Ear Hear. 2022;43:255-267).

Benefits of CI for SSD

The goal of cochlear implantation in these children is not only to achieve better speech understanding but also to provide bilateral input to encourage the development of binaural hearing, noted Lisa R. Park, AuD, a research assistant professor in the department of otolaryngology– head and neck surgery at the University of North Carolina at Chapel Hill, and lead author of the ACIA guidelines. In fact, she stressed, “Cochlear implantation, previously reserved for individuals with bilateral sensorineural hearing loss, is the only SSD treatment that provides hearing to the affected ear and encourages binaural auditory stimulation of the brain.”

The big gap within the FDA guideline is that it doesn’t address those children with congenital SSD, because if we’re implanting them at 5 years of age, many of their central neural pathways have reorganized to preclude optimal binaural hearing. —Matthew Bush, MD, PhD, MBA

According to the Centers for Disease Control and Prevention, SSD occurs in approximately 0.6 to 0.7 per 1,000 live births in the United States. By kindergarten, the incidence of SSD increases to approximately 2.5% to 6% of children. Multiple studies of SSD in adults and children have shown that CI can help to restore binaural functionality, improve quality of life, and facilitate reversal of neuroplasticity related to auditory deprivation in the pediatric population (J Neurol Surg B Skull Base. 2019;80:178-186).

One of the main challenges for children with SSD is spatial hearing in challenging listening environments, according to Matthew Bush, MD, PhD, MBA, professor and vice chair for research in the department of otolaryngology– head and neck surgery at the University of Kentucky Medical Center in Lexington. “The ability to pick out that voice of the parent, teacher, or classmate in the presence of background noise is much harder,” said Dr. Bush. “This difficulty may lead to a higher level of inattentiveness, which can lead to disruptive behaviors from the child and then, in turn, [affect] how parents interact with their child. So, there can be a downward spiral of maladaptive behavior changes that occur” (Otol Neurotol. 2017;38:1456-1462).

These deficits are often hard to recognize unless you’re really looking for them, said Nancy Young, MD, head of the section of otology/neurotology and medical director of the Audiology & Cochlear Implant Programs at the Ann & Robert H. Lurie Children’s Hospital of Chicago, the Lillian S. Wells Professor in pediatric otolaryngology at Northwestern University Feinberg School of Medicine, and a professor and fellow at the Knowles Hearing Center in the department of communication sciences and disorders at the Northwestern University School of Communication. “A young child with SSD must work so much harder to focus and understand what’s being said when background sounds are present, which is quite fatiguing. The child will start fidgeting and not pay attention,” said Dr. Young, who is also a co-author of the new ACIA guidelines. “For most teachers, this looks like just another fidgety kid who has two normal hearing ears.”

A young child with SSD must work so much harder to focus and understand what’s being said when background sounds are present, which is quite fatiguing. … For most teachers, this looks like just another fidgety kid who has two normal hearing ears. —Nancy Young, MD

Meredith A. Holcomb, AuD, CCC-A, director of the Hearing Implant Program and an associate professor in the department of otolaryngology at the University of Miami Miller School of Medicine Ear Institute, agreed that CI can yield significant improvements in speech development and socialization. “The cochlear implant not only allows patients to hear but provides them with the opportunity to understand speech and develop language and auditory skills,” she said. “Cochlear implants also positively affect a child’s academic performance, mental health, and quality of life. Additionally, cochlear implants have been found to have a positive impact on parent–child dynamics.”

Lack of Awareness of SSD Treatment

Unfortunately, these benefits can’t accrue if qualified SSD candidates are missed due a knowledge gap in the treatment community. And that gap does exist, Dr. Bush noted. “Outside of pediatric audiology, otology, neurotology, and potentially a small subset of educators and speech language pathologists, there isn’t a lot of awareness of the approval of CI for SSD, nor the existence of the data that led to the guidelines being written,” he said.

That lack of awareness can be compounded by challenges in adequately screening for SSD, Dr. Holcomb noted. “Due to the nature of SSD, some children may be missed on newborn hearing screens, particularly in those states that screen with otoacoustic emissions only,” she explained. “If the hearing loss isn’t identified at birth, the child will likely be identified later in school or during pediatrician screenings. We need to provide more education to audiologists and pediatricians on this treatment option so that timely referrals are made.”

As for which imaging modality is best for screening children, part of that calculus involves the etiology of SSD, which is often more complex than that for children with bilateral hearing loss. Therefore, screening candidates for CI is vitally important, especially to rule out cochlear nerve deficiency (CND) or eighth nerve hypoplasia. Cochlear nerve deficiency is a contraindication for CI and is reported to occur in 46% in children with SSD (Otolaryngol Head Neck Surg. 2013;149:318-325). “We want to rule out CND before we even consider children for candidacy,” Dr. Park said.

The best way to screen patients for CND is with high-resolution 3D magnetic resonance imaging (MRI), noted Dr. Young. “It’s important to know that computer tomography will not identify a significant subset of ears with CND, nor does the presence of residual hearing exclude CND,” said Dr. Young. “I felt that, as a physician on the task force, it was a very important message that high-resolution MRI be done to avoid CND-related poor outcomes. At present there is no evidence that binaural hearing benefits will occur in this SSD population.”

For patients with meningitis, “MRI is also the most sensitive modality for identifying patency problems inside the inner ear,” Dr. Young added. “If the child’s MRI shows early signs of obstruction, that’s a reason to go ahead with CI as soon as possible,” she said.

Optimal Age: The Earlier the Better

There’s another challenge: FDA approval parameters may be too narrow. Most experts agree that the optimal age of implant should be the same as the one for bilateral congenital deafness. However, the current FDA indications for SSD specify that candidates have a maximum duration of deafness of 10 years and minimum age of 5 years.

“I tip my hat to the FDA for including children in the SSD indications developed in response to an adult clinical trial,” Dr. Young said. “However, based on 30-plus years of data and experience in implantation of children with bilateral deafness, picking 5 years of age as a minimum age is arbitrary.” For children with congenital SSD, or [those] that develop SSD early in life, “reducing the period of auditory deprivation is going to improve outcomes,” Dr. Young stressed.

Dr. Bush agreed. “The big gap within the FDA guideline is that it doesn’t address those children with congenital SSD, because if we’re implanting them at 5 years of age, many of their central neural pathways have reorganized to preclude optimal binaural hearing.”

Those benefits, which are documented by years of research on CI in infants with bilateral deafness, “support implanting a child as early as possible,” Dr. Holcomb said. “In the U.S., indications are as low as 9 months of age [for children with bilateral hearing loss]; however, there is substantial literature to support implantation in children who are younger than 9 months.”

Dr. Park echoed the need for early intervention. “There is a window of time when you can rehabilitate that auditory pathway,” she said. There is evidence that SSD may impede binaural central integration perhaps as early as 2 years after onset (Trends Neurosci. 2012;35:111-122). “We have no reason to think that children with SSD would be any different than children with bilateral hearing loss. So, for now, younger is better.”

Then there’s the question of when to test very young infants with SSD who are being considered for CI. According to the guidelines, infants younger than 12 months of age should have objective measures (auditory brainstem response/ auditory steady state response testing) of sensorineural hearing loss with confirmatory audiometric results, when possible, prior to implantation.

Given all the debate over how early to intervene, it’s important to also consider the age and length of deafness at which a CI implant would not be helpful. “We aren’t ready to say that there’s a cut-off age when a patient would not benefit from CI,” Dr. Park said. “We have seen children with greater than 10 years of hearing deprivation who have benefited from CI. A teenager may not want to wear an implant, so that’s where the counseling has to come in— the teenagers have to have buy-in to have the best outcomes.”

Audiology Evaluation

One of the main features of the new guidelines is an in-depth review of the medical and audiological considerations for CI. The current FDA labeling for SSD includes a four-frequency pure tone average > 80 dB HL or > 90 dB HL, depending on which cochlear implant is being used. “These criteria may be too restrictive for children,” noted Dr. Park. According to the guidelines, “a CI evaluation is recommended for children with a unilateral 3-frequency pure tone average of > 60 dB HL and/or an aided SII < 0.65 because these children are unlikely to receive adequate benefit from traditional amplification.”

The FDA set the criteria as a profound hearing loss. “But that doesn’t always meet the needs of everyone with SSD, who may have a severe or steeply sloping hearing loss,” Dr. Park said. “Our view is that if a child can’t benefit from a hearing aid, they have an auditory nerve, and they want to hear from both ears, then they should be considered for a cochlear implant,” she said.

Trials with re-routing devices, such as a contralateral-routing-of-signal system or a bone conduction device, are not recommended for children seeking binaural hearing, “as these devices are not able to provide the brain with bilateral input, and the trial could delay a time-sensitive procedure,” noted the guidelines.

Timing aside, one of the most powerful arguments favoring CI for SSD is the striking transformations that are often observed in treated patients. Dr. Park cited, as an example, a 13-year-old who visited the office two weeks after having her implant turned on. “She came in looking completely different,” Dr. Park said. “Her mom said she was just feeling so much more confident and so much less fatigued. She just feels better, relaxed, and has less anxiety now that she can hear from both ears.”

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Nikki Kean is a freelance medical writer based in New Jersey.