Cochlear Implants
by Patti Trautwein

What is Normal Hearing? Why a simple and consistent answer is needed

October 29, 2020
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By Patti Trautwein, MA, AuD, Vice President, Product Management & Marketing, Cochlear Americas

Less than 25% of people get their hearing screened annually and more than 37 million (15%) Americans have hearing loss.1-2  Less than 30% of people who can benefit from hearing aids1, 2 and approximately 8% from cochlear implants have them.3 

As an audiologist, this data can be frustrating. There have been tremendous advancements in technology in the last few decades, including more treatment options with devices that are smaller, smarter and deliver better outcomes. Despite these advances, why haven’t the growing number of people with hearing loss accessed treatment?  Recent clinical and market investigations have identified awareness, acceptance, cost and stigma as primary obstacles to adopting hearing devices.4

A recent article by Christopher Spankovich reviewed the history of defining hearing loss using the audiogram versus other measures such as speech or objective measures, explaining how the past five decades encapsulated the rationale for 15- 25 dB HL as the limit for normal hearing.5 Importantly, the author noted strong correlation between pure tone average and perceived hearing difficulty. Most interesting, Spankovich reported that when asking audiologists what normal hearing is, “not surprisingly, you get a variety of responses.” 

How does the variability across clinicians transcend to the general population’s understanding of normal hearing? 

For example, Cochlear’s industry research highlights how people described hearing and noted the variability. Some used words such as mild, moderately severe, significant or deaf, while others used percentages of loss or percentages of hearing remaining.

So, do people know what is normal hearing? The team decided to go out on the street to find out:

Raising awareness of a simple metric, such as 20 dB PTA, for normal hearing may help the general population understand hearing health. Further, it may provide guidance on when to seek clinical evaluation, treatment and even what type of treatments to consider. This becomes increasingly important as the options expand to include over-the-counter devices in addition to hearing aids or hearing implants, making it more important for consumers to get the support of an audiologist or ENT. A simple and consistent metric streamlines to the process for consumers and allied health providers to monitor and act on hearing health, as they are likely to do with other health considerations such as vision or cholesterol.  

Is this a call to action for hearing health care providers to align on the simple answer that the general public can understand?  Please share the video with your colleagues and start the conversation so we can work together to improve access to appropriate hearing healthcare.

To learn more, subscribe to Cochlear ProNews.

About the author: Patricia’s 25 years in the hearing healthcare industry includes roles in research and clinical studies, product management, education and training, sales and marketing. As Cochlear America’s VP of Marketing, Patricia is responsible for the marketing strategy, communications and public relations, brand ambassador program and product management. Her organization is responsible for positioning Cochlear Americas growth strategy, cultivating opportunities in new and existing customer markets and growing demand for Cochlear’s hearing solutions in the region.

References:

1. Abrahms, H and Kihm, J (2015) MT9 reveals renewed encouragement as well as obstacles for consumers with hearing loss. Hearing Review https://www.hearingreview.com/practice-building/marketing/introduction-marketrak-ix-new-baseline-hearing-aid-market (accessed on Sept 14, 2020)  

2. Quick Statistics About Hearing. (2020, October 2). NIDCD. https://www.nidcd.nih.gov/health/statistics/quick-statisticshearing#:~:text=One%20in%20eight%20people%20in,based%20on%20standard%20hearing%20examinations.&text=About%202%20percent%20of%20adults,54%20have%20disabling%20hearing%20loss.

3. Holder, J., Reynolds, S., Sunderhaus, L., Gifford, R. (2018) Current Profile of Adults Presenting for Preoperative Cochlear Implant Evaluation Trends in Hearing Jan-Dec.

4. Kochin, S. (2007) MarkeTrak VII: Obstacles to adult non-user adoption of hearing aids, he Hearing Journal: April 2007 – Volume 60 – Issue 4 – p 24-51

5. Spankovich, C. (2020) Some observations on normal hearing and hearing loss.  Audiology Today Sep/Oct 2020 pgs. 32-41.

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TIMS

Case study: Intraoperative correction of a CI632 placement using the Nucleus® SmartNav System and TransImpedance Matrix recording

June 21, 2022

By Nauman F. Manzoor, M.D. * and Viral Tejani, Au.D., Ph.D. *

Department of Otolaryngology-Head and Neck Surgery, University Hospitals / Case Western Reserve University School of Medicine

*Co-authors with equal contribution to the write-up

Patient background

An 88 year old female was referred for bilateral progressive sensorineural hearing loss and remote history of left- sided Meniere’s Disease. She no longer had any episodic vertigo but did endorse mild imbalance. She was using bilateral traditional amplification but over the last year had noticed decline in speech understanding. Based on comprehensive audiometric testing, she was a cochlear implant candidate in both ears. Vestibular testing showed left-sided weakness and hence this ear was selected for cochlear implantation. Pre-operative computed tomography (CT) imaging was normal with no cochlear or labyrinthine abnormality (images below). Normal mastoid anatomy and facial nerve course was appreciated. Prior magnetic resonance imaging (MRI) scan was also negative for any retrocochlear lesion.

Device selection / Electrophysiology background

In all standard cochlear implant cases, we use CI632 Slim Modiolar Electrode (SME) for modiolar proximity and good cochlear coverage. While clinical studies indicate a low tip fold-over rate1-5 with the SME, our institution still routinely confirm device placement via electrophysiologic measures and an intraoperative x-ray using a modified stenver view.

While effective, these imaging measures add to the surgical costs, expose patients to radiation (albeit a small amount), and add to the surgery time3. Thus, electrophysiological measures of TransImpedance Matrix (TIM) have been previously proposed and has shown promise in identifying tip fold-over5-6.  Essentially, the TransImpedance Matrix show how voltage is distributed along the electrode array when the cochlear implant is stimulated.

The TransImpedance Matrix tool is available in Custom Sound® and has also been incorporated into the recently created Nucleus® SmartNav platform. The SmartNav platform is an iPad based platform that wirelessly interfaces with the internal CI; it monitors insertion speed and conducts a “Placement Check” as well as impedance and AutoNRT recordings once the CI is inserted.  The placement check is a TransImpedance Matrix recording.

Surgical course

              A standard mastoidectomy was performed and a facial recess approach was used. Round window anatomy was normal, and an extended round window approach was utilized. The electrode array was deployed in a standard manner keeping a co-planar trajectory to the basal turn. After placement, the SmartNav System was used to conduct a Placement Check.  As shown by the screenshot below, the placement check indicated a tip fold-over at electrodes 19-22.

To verify the Placement Check results and obtain more detailed measure, a TransImpedance Matrix recording using Custom Sound was performed.*  These results are plotted in the below figure.  The left axis shows the recording electrode, while the bottom axis shows the stimulating electrode.  In a normal TransImpedance Matrix plot, a dark black / red diagonal line from the lower left hand corner to the upper right hand corner is expected, which shows normal voltage distribution. However, the below figure indicates abnormal voltage spread at the apical electrodes starting around E15-22 (see lower left hand corner plot). For example, when looking at stimulating electrode 22, one can see two peaks (as signified by the red points at recording electrode 22 and recording electrode 15/16).  This signifies that electrodes 15 and 22 are very close to one another due to the high voltage recordings.

*TIM is only available in Custom Sound® EP and requires a regional key and access code.

This was confirmed via an intraoperative X-ray. It does appear that there is fold-over starting and that electrode 22 and electrodes 15/16 are very close to one another.

The electrode was removed, reloaded into the sheath, and the array was reinserted without incident. SmartNav Placement Check was normal.

The TransImpedance Matrix recording was also normal (see below figure).  As previously stated, in a normal TransImpedance Matrix plot, we expect a dark black / red diagonal line from the lower left hand corner to the upper right hand corner.

Intraoperative X-ray was also normal. 

Conclusions

This case study provides proof-of-concept regarding the utility of TransImpedance Matrix recordings (as embedded in SmartNav or as separately available in Custom Sound) in evaluating cochlear implant placement.  Given the low tip-foldover rate reported across the literature for the SME array1-5, large scale studies are needed to generate a sufficient patient sample size to verify the sensitivity and specificity of TransImpedance Matrix recordings in identifying tip-foldovers and compare these metrics to the sensitivity of intraoperative imaging.

Get an inside look on the SmartNav System here!

About the authors:

Dr. Manzoor is a board-certified otolaryngologist and head & neck surgeon with fellowship training in otology-neurotology and lateral skull base surgery. He has expertise in the diagnosis and treatment of a wide range of otologic, neurotologic and skull base conditions. He completed his otolaryngology training at University Hospitals Cleveland Medical Center and completed his fellowship training at Vanderbilt University Medical Center. He is particularly passioned about hearing rehabilitation and strives to deliver cutting edge treatment options for patients with hearing disorders. He is also an avid researcher with 60 peer reviewed publications related to otologic-neurotologic disorders and outcomes.

Viral Tejani, AuD, PhD, is a Cochlear Implant Audiologist and Assistant Professor of Otolaryngology.  He sees cochlear implant patients in the clinic and is also involved with both NIH-funded and industry-funded research. His particular expertise/passions are in cochlear implant psychophysics, electrophysiology, electric-acoustic stimulation, as well as improving outcomes of cochlear implantation. He completed his AuD at University of Maryland and his PhD at University of Iowa, where he remained as an Otolaryngology faculty member until relocating to Cleveland.

References

  1. Aschendorff, A., Briggs, R., Brademann, G., Helbig, S., Hornung, J., Lenarz, T., Marx, M., Ramos, A., Stöver, T., Escudé, B., & James, C. J. (2017). Clinical investigation of the Nucleus Slim Modiolar Electrode. Audiology & neuro-otology, 22(3), 169–179. https://doi.org/10.1159/000480345
  2. Friedmann, D. R., Kamen, E., Choudhury, B., & Roland, J. T., Jr (2019). Surgical Experience and Early Outcomes With a Slim Perimodiolar Electrode. Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology, 40(3), e304–e310. https://doi.org/10.1097/MAO.0000000000002129
  3. Klabbers, T. M., Huinck, W. J., Heutink, F., Verbist, B. M., & Mylanus, E. (2021). Transimpedance Matrix (TIM) Measurement for the Detection of Intraoperative Electrode Tip Foldover Using the Slim Modiolar Electrode: A Proof of Concept Study. Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology, 42(2), e124–e129. https://doi.org/10.1097/MAO.0000000000002875
  4. Shaul, C., Weder, S., Tari, S., Gerard, J. M., O’Leary, S. J., & Briggs, R. J. (2020). Slim, Modiolar Cochlear Implant Electrode: Melbourne Experience and Comparison With the Contour Perimodiolar Electrode. Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology, 41(5), 639–643. https://doi.org/10.1097/MAO.0000000000002617
  5. Shew, M. A., Walia, A., Durakovic, N., Valenzuela, C., Wick, C. C., McJunkin, J. L., Buchman, C. A., & Herzog, J. A. (2021). Long-term Hearing Preservation and Speech Perception Performance Outcomes With the Slim Modiolar Electrode. Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology, 42(10), e1486–e1493. https://doi.org/10.1097/MAO.0000000000003342
  6. Zuniga, M. G., Rivas, A., Hedley-Williams, A., Gifford, R. H., Dwyer, R., Dawant, B. M., Sunderhaus, L. W., Hovis, K. L., Wanna, G. B., Noble, J. H., & Labadie, R. F. (2017). Tip Fold-over in Cochlear Implantation: Case Series. Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology, 38(2), 199–206. https://doi.org/10.1097/MAO.0000000000001283   

SmartNav offers a variety of measurements. These insights are one source of information and do not guarantee clinical outcomes.

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Cochlear implant access: Are we making progress? (By: Jourdan Holder and René Gifford)

July 25, 2018

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Guest authors: Jourdan T. Holder, Au.D. and René H. Gifford, Ph.D.

 

Jourdan Holder

Rene Gifford

 

According to the World Health Organization (WHO), there are approximately 466 million individuals with disabling hearing loss (World Health Organization (WHO), 2018). This makes hearing loss one of the top three most common chronic conditions; however, most hearing losses can be at least partly remediated with hearing aids, auditory implants, and other assistive devices. Focusing on auditory implants, less than 10% of those meeting the strictest cochlear implant (CI) candidacy criteria have pursued cochlear implantation (Holder, Reynolds, Sunderhaus, & Gifford, 2018), despite CIs being named the most successful neural prosthesis (Lasker Foundation, 2013; Wilson & Dorman, 2008). Further, CI candidacy criteria is less strict than it once was (Centers for Medicare and Medicaid Services (CMS), 2005), suggesting that an even lower percentage of patients who qualify are benefitting from this technology.

A recent study from our research lab (Holder et al., 2018) sought to answer the question: are we increasing access to CI technology for a broader population of individuals with hearing loss? In order to answer this question, we compiled data from all of our adult patients (n = 287) who presented to our clinic for a CI candidacy evaluation between August 2013 and August 2015. Taking a thorough look at the demographics of this population is an important step toward making CIs accessible to more people who are struggling to communicate. Our results showed that 64.8% of adults presented with severe-to-profound sensorineural hearing loss, and the average word recognition score prior to CI was just 8.7% for the ear being considered for implantation. We then compared these results to previous clinical trials (Balkany et al., 2007; Parkinson et al., 2002) and discovered that our current average word scores are only 5-6 percentage points higher than individuals receiving CIs nearly 20 years ago. This finding suggests that we have much room for improvement if we are to significantly increase access to this technology.

In addition to defining the hearing status of our current CI candidates, we also discovered that out of 287 patients, only 14 (5%), did NOT meet candidacy criteria. In other words, nearly 100% of the patients being referred for a preoperative CI candidacy evaluation were, indeed, CI candidates. This statistic suggests that even at a large university medical center, well-known for cochlear implantation, we are receiving conservative referrals, and many hearing aid users that could benefit from a CI are not being referred. This trend may result from a lack of continuing education regarding current indications for adult CI amongst referring providers. Patients who report that their referring provider told them that they were not a CI candidate have anecdotally confirmed this speculation. These findings clearly show that CI professionals and manufacturers must increase education and communication efforts regarding CI candidacy and outcomes to increase referrals.

In addition to increasing appropriate referrals, there are various potential reasons why CI candidates are not receiving this life-changing technology. For years, individuals with sensorineural hearing loss may have been counseled that they had “nerve deafness” and that there was no treatment beyond power hearing aids. The term “nerve deafness” is a misnomer, as the overwhelming majority of individuals with hearing loss have intact auditory nerves, which are viable for cochlear implantation. Rather, most sensorineural hearing losses originate inadult CI the cochlea (https://www.nidcd.nih.gov/health/how-do-we-hear). Indeed, severe-to-profound damage to the delicate cochlear structures renders traditional hearing aid amplification relatively ineffective. Thus, what often happens is that patients give up on their hearing aids and resort to a life of auditory isolation.

While CIs may look similar to hearing aids, they work much differently and do not have the same limitations as traditional hearing aids.  CIs are the standard-of-care treatment for adults and children with severe-to-profound sensorineural hearing loss. In fact, adults with moderate-to-profound sensorineural hearing loss meet candidacy criteria as outlined by both the Food and Drug Administration (FDA) and the Centers for Medicare and Medicaid Administration (CMS).

 

When counseling your CI candidates, Dr. Holder and Dr. Gifford offer the following suggested language with candidates (and referral resources):

If you are an adult with considerable hearing loss and are wondering whether or not you are a candidate for a cochlear implant, consider the following questions pertaining to your listening experience with your current hearing aids:

  • Are you able to talk on the phone without visual cues (such as video calls or caption calling)?
  • Are you able to understand television programs without closed captioning?
  • Are you able to effectively engage in conversations at large group gatherings such as dinner parties?
  • Do you feel that you obtain significant communication benefit from your current hearing aids?
  • Take the interactive quiz here: https://www.cochlear.com/us/ci-landing-page/quiz.html

If you answered “no” to at least two questions, it is time to see an audiologist for a comprehensive hearing assessment and CI evaluation. Even if you do not meet candidacy currently, a CI candidacy evaluation will equip you with valuable knowledge about your hearing health and technology options to help you communicate now and in the future.

The typical CI evaluation will involve the audiologist looking in your ear with an otoscope, and may introduce a small puff of air in your ear canal to ensure that your eardrum is functioning normally, and a standard hearing test to document the softest sounds that you can hear at various frequencies or pitches. In addition to these standardized assessments, the audiologist will also verify your current hearing aid settings, which involves placing a very small tube-like microphone in your ear and measuring the sound output from your hearing aids. If your hearing aids are not programmed according to your hearing loss specifications, the audiologist will either reprogram your hearing aids or program stock hearing aids to complete the remainder of the testing. The next part of the CI evaluation focuses on your speech understanding while wearing your hearing aids. Various words and sentences will be presented from a loudspeaker placed in front of you, and you will be asked to repeat what you hear, guessing if needed. This part of the assessment is often the least favorite for the patient because the tasks can be difficult, and some patients may feel defeated because they cannot complete the task. Although this assessment may be bothersome, it is necessary to determine your candidacy for a CI and to document your hearing difficulties in order to seek insurance coverage.

Should you be identified as a CI candidate, your audiologist will then provide you with a comprehensive overview of the function and the wearing options for your CI. At this point, you may be seen by an otolaryngologist or ear, nose, and throat (ENT) surgeon. The surgeon may complete a thorough evaluation of your ears and review radiographic images (CT and/or MRI scans) of your temporal bone to characterize the cochlear and auditory nerve anatomy. At this point, the audiologist and surgeon may work together to determine if a CI is right for you. The surgeon will also explain the outpatient CI procedure. The typical CI surgery takes just one to two hours under general anesthesia. It is an outpatient procedure, meaning that under typical circumstances, you will return home the same day as the procedure, and the typical recovery time for adults is generally about 2-5 days. For additional information about the CI surgery, please see: https://www.acialliance.org/page/Surgery.

Following surgery, your new hearing journey has just begun! Similar to an orthopedic surgery, your ear will require ‘physical therapy’. You will work closely with your audiologist and practice daily listening exercises to increase your performance and train your brain to listen with your new CI. It is certainly not an immediate or perfect fix, but the first step is to consider a candidacy evaluation to see if a CI could improve your hearing and overall quality of life.

About our Guest authors:

Jourdan Holder, Au.D., is a clinical and research audiologist with the cochlear implant team at Vanderbilt University Medical Center. Dr. Holder obtained her undergraduate degree from The University of Texas at Austin and her AuD degree from Vanderbilt University. She currently serves adult and pediatric cochlear implant patients in the clinic in addition to completing her PhD in Vanderbilt’s Cochlear Implant Research Lab under the direction of Dr. René Gifford.

René Gifford, Ph.D. is an Associate Professor at Vanderbilt University and Director of the Cochlear Implant Program and the Cochlear Implant Research Laboratory at the Vanderbilt Bill Wilkerson Center. Her research has been funded by the NIDCD for over 10 years and focuses on combined electric and acoustic hearing including basic auditory perception, spatial hearing, and speech perception. She has nearly 70 peer-reviewed papers and is the author of the book entitled “Cochlear Implant Patient Assessment: Evaluation of Candidacy, Performance, and Outcomes.”

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Balkany, T., Hodges, A., Menapace, C., Hazard, L., Driscoll, C., Gantz, B., … Neely, J. G. (2007). Nucleus Freedom North American clinical trial. Otolaryngology – Head and Neck Surgery, 136(5), 757–762. https://doi.org/10.1016/j.otohns.2007.01.006
Centers for Medicare and Medicaid Services (CMS). (2005). CMS Manual System, Pub 100-03, Medicare National Coverage Determination, Subject: Cochlear Implantation Transmittal 42. Baltimore, MD: Department of Health & Human Services, Center for Medicare and Medicaid Services.
Holder, J. T., Reynolds, S. M., Sunderhaus, L. W., & Gifford, R. H. (2018). Current Profile of Adults Presenting for Preoperative Cochlear Implant Evaluation. Trends in Hearing, 22, 233121651875528. https://doi.org/10.1177/2331216518755288
Lasker Foundation. (2013). 2013 Lasker Awards. Retrieved from https://www.laskerfoundation.org/awards/show/modern-cochlear-implant/
Parkinson, A. J., Arcaroli, J., Staller, S. J., Arndt, P. L., Cosgriff, A., & Ebinger, K. (2002). The Nucleus 24 Contour Cochlear Implant System: Adult Clinical Trial Results. Ear and Hearing, 23(1 Suppl), 41S–48S. https://doi.org/10.1097/00003446-200202001-00005
Wilson, B. S., & Dorman, M. F. (2008). Cochlear implants: A remarkable past and a brilliant future. Hearing Research, 242(1–2), 3–21. https://doi.org/10.1016/j.heares.2008.06.005
World Health Organization (WHO). (2018). Deafness and hearing loss. Retrieved from https://www.who.int/news-room/fact-sheets/detail/deafness-and-hearing-loss
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