Sound Data Support Wider Use of Cochlear Implants

Cochlear implants proved their mettle for various types of hearing deficits, such as loss of speech recognition, speech understanding, and sensorineural hearing loss, according to results from a trio of trials.

In a study of newly implanted Medicare beneficiaries who meet the expanded indications of an AzBio Sentence Test score of 41% to 60% in their best-aided condition, intervention with a cochlear implant was linked with improved sentence, word, and telephone recognition, reported Teresa A. Zwolan, PhD, of Michigan Medicine in Ann Arbor, and co-authors.

Then in a study done in academic and community-based cochlear implant programs, in adult hearing-aid users, with and without mild cognitive impairment (MCI) across a variety of domains, single-ear cochlear implant seemed safe and effective for restoring speech understanding in both quiet and noise, as well as boosting quality of life (QoL), reported Craig A. Buchman, MD, of the Washington University School of Medicine in St Louis, and co-authors.

Next, a secondary analysis of the trial by Buchman’s group in older adult hearing-aid users with postlingual bilateral moderate-to-profound sensorineural hearing loss (SNHL) revealed clinically meaningful audiometric and QoL benefit, along with an acceptable risk profile, suggesting that “cochlear implantation in older adults may facilitate the concept of healthy aging,” according to Cameron C. Wick, MD, also of Washington University, and co-authors.

Finally, Buchman and co-author conducted a systematic review for the development of consensus statements on “the use of unilateral cochlear implants in adults with severe, profound, or moderate sloping to profound bilateral SNHL.”

All three trials, and the review, appear in JAMA Otolaryngology – Head & Neck Surgery. Buchman and some co-authors in the various studies are part of the CI532 Study Group.

The benefits of cochlear implants to restore speech comprehension are tried and true, pointed out Anil K. Lalwani, MD, of Columbia University Irving Medical Center in New York City, in an accompanying invited commentary.

But “what is impressive about this series of articles is their design: unlike the large volume of cochlear implantation literature, 3 of the articles [Zwolan, Buchman, and Wick] are prospective clinical studies and thus contribute invaluably to cochlear implantation research specifically and to treatment of hearing loss generally,” he stated.

No matter how good the data are, cochlear implants are still underused, most often because of associated costs, Lalwani added, noting that in the U.S., the overall price-tag for cochlear implant was about $100,000 per implant in 2017.

“If 10% of the worldwide approximately 500 million individuals with disabling hearing loss are candidates for cochlear implantation, the global cost of the procedure would be $5 trillion. Even if only 5% were candidates for cochlear implantation, the cost would still be a staggering $2.5 trillion. For comparison, the 2019 U.S. budget was $4.4 trillion,” he wrote.

Lalwani blamed the current trend of treating implants as a “boutique item with a boutique price tag,” and called for manufacturing modernization to make implants more reasonable and accessible.

While clinicians can’t necessarily influence the production of cochlear implants, they can address another barrier to use: “fear of surgery and unpredictability of outcome for individual patients…While the surgeon focuses on speech perception, the patient is concerned about speech quality,” Lalwani stressed. “Real concerns include the outside world sounding unnatural or mechanical…there is a need for minimally invasive techniques and more predictable outcomes for a given patient.”

Zwolan’s group conducted a multicenter nonrandomized trial, looking at pre-operative and post-operative speech recognition, telephone communication, hearing device benefit, health utility, and QoL in 34 participants (ages ≥65 years). All had bilateral moderate-to-profound hearing loss and had a best-aided preoperative AzBio Sentence Test score in quiet of 41% to 60%. The latter test was approved in 2015 by the Centers for Medicare and Medicaid Services (CMS) to qualify candidates for the study, the authors explained.

Participants were enrolled at eight different centers and received a multichannel cochlear implant between September 2014 and July 2018. Analysis was performed on an intention-to-treat basis, and statistical analysis of the final results was done in 2019. The authors reported that 31 of 34 participants (74%; median age 73.6 years) completed testing through the 6-month evaluation, while and 29 completed testing through the 12-month evaluation.

The median preoperative AzBio Sentence Test scores were 53% for the best-aided condition and 24% for the cochlear implant-alone condition. In comparison, median scores 12 months after implantation improved to 89% for the best-aided condition and 77% for the cochlear implant–alone condition.

The outcome showed a median change of 36% for the best-aided condition (lower bound of 1-sided 95% CI 31%) and a median change of 53% for the cochlear implant-alone condition (lower bound of 1-sided 95% CI 45%), Zwolan and co-authors stated.

Study limitations included the small number of participants and the lack of generalizability to results gathered at only three centers. Still, “These findings support expansion of the [CMS] current indications for cochlear implants,” the authors stated.

Buchman’s group conducted the CI532 clinical trial, a repeated-measures investigation, at 13 U.S. centers. Eligible participants were 96 adults (median age 71 years; 65% male.) with postlinguistic onset of bilateral moderate sloping to profound or worse sensorineural hearing loss of 20 years’ duration.

All participants were fluent in English and underwent an optimized bilateral hearing-aid trial for a minimum of 30 days. MCI (Montreal Cognitive Assessment or MoCA total score 25) was observed in 48 of 81 study participants (59%) at baseline.

Individuals with aided Consonant-Vowel Nucleus-Consonant (CNC) word score in quiet of ≤40% correct in the ear to be implanted and ≤50% correct in the contralateral ear. All participants received the same cochlear implant system and contralateral hearing aid.

The study was done from 2017 to 2018 from enrollment to final follow-up. The primary outcome was speech understanding in quiet (CNC word score) using both the cochlear implant and opposite ear hearing aid. Secondary outcomes included the AzBio signal-to-noise ratio of +10 db (+10 SNR) Health Utilities Index Mark 3 (HUI3).

Buchman’s group reported the following:

• 6 months after activation: 40.5% (95% CI 35.9%-45.0%) absolute marginal mean change in CNC word score; 24.1% (95% CI 18.9% to 29.4%) absolute marginal mean change in AzBio+10 SNR.
• >15% improvement in the CNC word score in the implant ear: 96% of patients.
• Speech perception marginal mean improvements in participants with baseline MCI: 40.9% (95% CI 35.2%-46.6%) for CNC word score; 27.5% (95% CI 21.0%-33.9) for AzBio+10 SNR.
• Speech perception marginal mean improvements in participants without MCI: 39.6% (95% CI 31.8%-47.4%) for CNC word score; 17.8% (95% CI 9.0%-26.6%) for AzBio+10 SNR.

The authors also found statistically significant and clinically important improvements in the HUI3 and the Speech, Spatial, and Qualities of Hearing Questionnaire 49 (SSQ49) at 6 months.

There were three serious adverse events (AE) that required revision surgery (two cases with electrode misplacement and one with aversive symptoms), but all resolved without incident, they added.

Study limitations included the short follow-up period and the evaluation of a single implant type (CI532 implant fitted with the CP1000 sound processor). Nonetheless, “Cochlear implants are safe and effective in restoring speech understanding in both quiet and noise and improve QOL in individuals with and without MCI,” the authors stated.

Wick and co-authors did an ad hoc secondary analysis of the CI532 trial. Baseline QoL testing was performed after 1 month of optimized bilateral hearing aid use. From enrollment to follow-up to data analysis, the study years were 2017 to 2020. The authors also used a “novel sponsor-developed Device Use Questionnaire (DUQ)…designed to evaluate hearing ability, listening environments, and device connectivity…The DUQ uses a visual analog scale format ranging from 0 (very dissatisfied) to 100 (very satisfied). Satisfaction is defined as greater than 50.”

For this analysis, there were 70 participants (median age 74 years; 73% men). A “Mixed-model analysis with estimated marginal means and 95% CIs compared preimplantation baseline performance with 6-month post-implantation performance,” the authors explained.

They found a clinically important improvement in CNC words was in the bimodal condition, with a mean difference of 37.2% (95% CI 32.0% to 42.4%), and in the unilateral (cochlear implant only) condition, with a mean difference of 44.1% (95% CI 39.0% to 49.2%).

They also reported the following:

• Clinically important improvement in AzBio sentences signal-to-noise ratio of +10 dB): 21.6% mean difference (95% CI 15.7% to 27.5%) in the bimodal condition; 24.5% (95% CI 18.3% to 30.7%) in the unilateral condition.
• HUI3: 0.186 improvement (95% CI 0.136 to 0.234).
• SSQ49: 2.58 improvement (95% CI, 2.18-2.99).
• DUQ: 94% of participants were satisfied with overall hearing in the everyday listening condition.

There were no major AEs, but there were a few expected minor AEs, most commonly swelling and/or pain (35.3%), according to Wick’s group.

Study limitations included differences in pre-operative counseling, post-op rehabilitation, and availability of cochlear implant accessories among the 13 centers. Again, the 6-month follow-up may have been too short to “reflect the final hearing performance of the participants.”

But “As the population ages, the management of hearing loss should consider social, emotional, and cognitive factors to promote healthy aging,” Wick and co-authors advised. “This study reinforces that adults [≥65 years] can derive significant hearing and QoL benefit after cochlear implantation with an acceptable risk profile.”

Finally, for the systematic review, Buchman and co-authors convened a Delphi consensus panel of 30 international specialists (majority otolaryngologists) who combed through over 6,000 studies, narrowing that down to 74 articles that fulfilled all of the inclusion criteria, such as TK. Those were used to develop the 20 evidence-based consensus statements.

Statements addressed topics such as the inadequate awareness of cochlear implantation among primary and hearing healthcare clinicians; the need for better referral to cochlear implantation; the use of pure-tone audiometry screening methods in adult hearing loss; and that eligible adults should receive cochlear implants as soon as possible to boost post-implantation speech recognition.

“Further research to develop consensus statements for unilateral cochlear implants in children, bilateral cochlear implantation, combined electric-acoustic stimulation, unilateral implantation for single-sided deafness [SSD], and asymmetrical hearing loss in children and adults will be beneficial for optimizing hearing and QOL for these patients,” Buchman’s group wrote.

In an accompanying viewpoint, Jeffrey W. Yu, MD, of the University of Illinois at Chicago, noted that “Patients with SSD have multiple therapeutic options, including living with 1 hearing ear, a contralateral routing of signal (CROS) hearing aid, and an osseointegrated bone conduction device.”

But these treatment modalities have fallen short in terms of offering the optimal therapeutic outcome, he stated. On the other hand, “Cochlear implantation has been demonstrated to improve all aspects of SSD, including hearing in noise, directionality, and balance, as well as to eliminate the head shadow effect,” Wu said.

Like Lalwani, Wu also called on clinicians to “guide patients to self-identify challenges related to hearing in noise, directionality, and safety in the workplace…clinicians should be advocates and approach the clinical challenge of SSD with the concept of shared decision-making.”

Because he wears a CROS hearing aid, Wu said he felt he had understood “how my patients with hearing loss struggle in their every day lives…Clinicians evaluating patients with SSD need to walk hand-in-hand with patients. By taking the perspective of the patient, we can help identify the degree of emotional distress of and hearing disability perceived by the patient.”

1. In older adults, intervention with a cochlear implant was linked with improved sentence, word, and telephone recognition, was deemed safe and effective for restoring speech understanding in both quiet and noise, and led to clinically meaningful audiometric and quality of life benefits.

2. International hearing healthcare clinicians developed consensus statements on “the use of unilateral cochlear implants in adults with severe, profound, or moderate sloping to profound bilateral [sensorineural hearing loss].”

Shalmali Pal, Contributing Writer, BreakingMED™

Cat ID: 494

Topic ID: 398,494,282,494,730,192,60,925