By guest author: Brian Taylor, Au.D.
Cochlear implants (CI) are the standard treatment for bilateral, severe to profound sensorineural hearing loss. It is estimated there are over 30,000 recipients implanted per year worldwide (Vaerenberg, et al 2014). Yet, cochlear implant audiologists remain a subspecialty within the audiology profession. In many medical centers in the United States, cochlear implant audiologists work primarily with children and adults with severe-to-profound hearing loss, participating in the identification, selection, and rehabilitation process of cochlear implantation. Survey data indicate that cochlear implants specialization is confined to a small number of audiologists, as only approximately 11% of audiologists self-identify as working with cochlear implants. This shortage of CI audiologists is likely to have an impact on access to care, but it provides an opportunity for audiologists to participate in the care of adults with severe-to-profound hearing loss, beyond fitting hearing aids.
This schism between cochlear implant audiology and other types of clinical audiology is not without merit. Historically, many of the skills required in the cochlear implant clinical realm, such as mapping of an implanted medical device, CI candidacy selection, counseling and surgical considerations are unique relative to other areas of clinical audiology. However, as cochlear implant candidacy requirements have become less restrictive, and as the programming and adjustment process (known as mapping) has become more automated, there are increasing opportunities for audiologists, who are not cochlear implant specialists, to more fully participate in the care of adults with severe hearing loss.
This blog series debunks myths that, until now, have prevented more audiologists from getting involved in the care of CI users—and makes the case for why private practice audiologists should get involved in the process of providing care to these patients.
Myth 1: Cochlear implants are suitable for individuals with profound hearing impairments only.
The opinion generally held by CI experts is that, for the motivated candidate, cochlear implants can be a life-changing experience. Figure 1 shows the hypothetical performance over time for many adult patients with a moderate, progressing-to-severe hearing loss. The Figure can be used to demonstrate how various interventions are intended to improve auditory performance for a hearing-impaired individual over time. At some point, many of these patients become hearing aid users. The hypothetical amount of improvement from bilateral hearing aid use for individuals with severe hearing loss is shown in the center of Figure 1. (Labelled as “2 HA’s”). Also depicted in Figure 1, is the presumed improvement from various interventions involving cochlear implantation and follow-up care. Notice the rather dramatic levels of improvement following intervention, compared to hearing aid use.
The three colored lines in Figure 1 illustrate three distinct types of interventions involving cochlear implants: 1.) one cochlear implant (unilateral arrangement), 2.) one cochlear implant + one hearing aid (bimodal arrangement), and 3.) either a unilateral or bimodal arrangement + auditory training. Even though each of these three lines in Figure 1 represents a hypothetical case, there is ample evidence the properly selected candidate will experience benefit in an equivalent manner (Blamey, et al 2013). In effect, Leigh et al (2013) indicated appropriate candidates can be advised that they have a greater than 75% chance of improving their speech perception with a cochlear implant over their best preoperative condition, and a 95% of chance of improvement in their implanted ear alone. Given the multiple intervention options that(bimodal arrangement), and 3.) either a unilateral or bimodal arrangement + auditory training. Even though each of these three lines in Figure 1 represents a hypothetical case, there is ample evidence the properly selected candidate will experience benefit in an equivalent manner (Blamey, et al 2013). In effect, Leigh et al (2013) indicated appropriate candidates can be advised that they have a greater than 75% chance of improving their speech perception with a cochlear implant over their best preoperative condition, and a 95% of chance of improvement in their implanted ear alone. Given the multiple intervention options that can optimize CI outcomes, audiologists who do not specialize in CI have an opportunity to participate in the management of CI users by providing some combination of care with a bimodal arrangement, auditory training, and mapping a cochlear implant.
What once was an intervention for the most profoundly hearing impaired, has expanded to include individuals with moderate-to-severe hearing loss. Driven primarily by improvements in CI technology and surgical procedures, the pool of patients considered to be viable candidates for CI has expanded. Today, an adult with unaided hearing thresholds worse than 60 dB at 500 Hz, 70 dB at 1000 Hz and 90 dB at 2000 Hz, unaided single word recognition performance worse than 45% in the better ear and documentation that hearing aid benefit is suboptimal would be within the candidacy requirements for CI (Gubbels, et al, 2017). Because the audiological candidacy requirements have expanded, it is believed a larger pool of patients, many of which might be experiencing poor hearing aid benefit, are now CI eligible. Thus, a larger number of audiologists, not directly affiliated with a cochlear implant center are needed to identify and manage these potential CI recipients.
Given the paucity of audiologists who specialize in CI, combined with the relatively poor benefit many individuals with severe-to-profound hearing loss receive from their hearing aids, it is an excellent opportunity for audiologists, who do not specialize in CI, to become directly involved in providing a full range of reimbursable CI services to adult patients. Moreover, because third party insurance and Medicare reimburse for many of the services related to CI, and because non-audiologists who dispense hearing aids are not eligible to receive third party reimbursement, providing CI services can be a differentiator in a competitive marketplace that is about to see the rise of over-the-counter hearing aids and the continued success of big-box retail.
A recent prospective study sheds light on factors that contribute to low CI uptake rates among adults with severe-profound hearing loss. Over a two-year period, Holder, et al (2018) collected data on 287 adults who presented at their clinic for a CI evaluation. The primary goal of the study was to better understand the adult population seeking a CI evaluation. A secondary goal of the study, according to the researchers, was to define the percentages of adults presenting for the CI evaluation who were bimodal (CI plus hearing aid in contralateral ear) or bilateral CI candidates.
Results of the prospective study reveal several remarkable findings: All the adults (mean age = 62.3 years) who presented to the clinic for a CI evaluation had hearing aid experience, but a whopping 62% of these individuals presented to the CI evaluation without their hearing aids. Additionally, only 32 of the 110 (29%) individuals who wore their hearing aids to the CI evaluation were successfully fitted to a standard audibility target for average level sound inputs.
Perhaps even more surprising, despite the expanded CI candidacy requirements that have occurred over the past decade-plus, nearly two-thirds of individuals who presented for the CI evaluation at Vanderbilt University Clinic had a severe-to-profound hearing loss with a mean pure tone average of 82.5 dB and very low unaided sentence recognition-in-noise scores on the AzBio of 23.3% across all 287 adults. Even though CI candidacy requirements have expanded, individuals with moderate-to-profound hearing loss, with aided speech understanding near the upper range of candidacy, are not finding their way into the CI center for an evaluation.