Cochlear Implants
by Rebecca Cale

Clinical Programming Series: ESRT

September 16, 2024
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  • Approximately 5 minutes to read
  • Learning objectives:
    • Understanding what ESRT measurements are
    • Understanding ESRT clinical applications and correlations
    • Understanding how to optimize ESRT measurements

Electrical Evoked Stapedius Reflex Thresholds (ESRT) can be used as an objective measure for cochlear implant programming when clinically appropriate. Studies support the use of postoperative ESRTs for MAP verification ¹˒²˒³˒⁴˒⁵. Cochlear suggests using ESRT in conjunction with behavioral loudness scaling to ascertain upper stimulation levels.

What are ESRT measurements?

The stapedius reflex serves as a protective mechanism for the inner ear against excessively loud and potentially harmful sounds. In individuals with normal hearing, this reflex is activated by sound pressure levels (SPL) ranging from 70 to 90 dB SPL. Exposure to a loud noise causes the stapedius muscles in both ears to contract. This contraction moves the anterior stapes away from the oval window and increases the rigidity of the ossicular chain, thereby reducing the amount of vibrational energy reaching the cochlea.

ESRT is the minimal level of electrical stimulation necessary to induce a stapedius muscle contraction, which can be detected through middle ear measurements, such as acoustic admittance, or visually. It is typically measured post-operatively but can also be assessed intra-operatively.

How do we use this information clinically?

Post-operative ESRTs are estimated to be present in approximately 70% to 80% of implant users. ¹˒⁵˒⁶˒⁷ Examining research dating back to 1988 reveals several studies that demonstrate a strong correlation between C levels and ESRT.⁸ Additional research indicates a robust relationship between ESRT and upper stimulation levels ¹˒²˒⁶ and that ESRT measurements typically align with, or are slightly higher than, patients’ psychophysical assessments of upper stimulation levels. ⁶˒⁹˒¹⁰

What factors to consider to ensure optimal ESRT outcomes?

Ipsilateral ESRT measurements are possible; however, our programming guides generally advise to start with the contralateral ear due to the typical absence of responses following cochlear implant surgery, which may effect immittance of the middle ear system. Nonetheless, if there is no response in the contralateral ear, an ipsilateral measurement can be considered. Another consideration to help with the success of obtaining ESRT measurements is to consider changing the probe tone frequency or starting with a higher probe tone (226 Hz, 678 Hz, 1000 Hz).¹¹

Some tips and tricks for ESRT include:

  • Ensuring a properly fit probe tip. The probe tip must maintain a proper seal without assistance from the clinician. Adjust the probe tip size as necessary. For a proper seal, Otoferm may be used. The probe tip should keep a seal without manual assistance.
  • To address hyper-compliance, increase the probe tone. Apply positive pressure manually to stabilize the tympanic membrane, up to +50 daPa.
  • ESRT measurements are also sensitive to conditions such as middle ear disease or obstructions and necessitate a quiet and still patient. Moreover, the relationship between intraoperative ESRT, postoperative ESRT, and C-levels requires further investigation.¹²

What additional resources are available for ESRT measures?

ESRT is a valuable tool for cochlear implant audiologists, especially when combined with behavioral loudness scaling to set upper comfort levels. It can be extremely useful in situations when programming for individuals who are unable to provide reliable psychophysical loudness judgments. For guidance on conducting ESRT measures, detailed instructions are available, including the necessary equipment, protocol setup, and test procedures here:

FUN5188 ISS1 FEB24 ESRT Guide in CS ProDownload
  1. Hodges, A., Balkany, T., Ruth, R., Lambert, P., Dolan-Ash, S., & Schloff man, J. (1997). Electrical middle ear muscle refl ex: Use in cochlear implant programming. Otolaryngology—Head & Neck Surgery, 117(3 Pt 1), 255–261. 3.  3
  2.  Jerger, J., Fifer, R., Jenkins, H., & Mecklenberg, D. (1986). Stapedius refl ex to electrical stimulation in a patient with a cochlear implant. Annals of Otology, Rhinology, & Laryngology, 95, 151–157. 4. 4
  3. Messersmith, J., Entwisle, L., & Stout, A. (2002). Electrically evoked stapedial refl ex threshold: A procedure. Perspectives of the ASHA Special Interest Groups, 9(3), 4-11. 5. 6
  4. Rene Gifford, Ph.D., Maximizing Performance in Cochlear Implant Recipients: Programming Concepts NYU, December 5, 2022 2.  8
  5. Wolfe, J., & Kasulis, H. (2008). Relationships among objective measures and speech perception in adult users of the HiResolution Bionic Ear. Cochlear Implants International, 9(2), 70–81. 11
  6. Spivak, L.G., Chute, P.M., Popp, A.L. & Parisier S. C. (1994). Programming the cochlear implant based on electrical acoustic reflex thresholds: patient performance. Laryngoscope, 104(10), 1225-1230. 9
  7. Van Den Abbeele, T., Noël-Petroff, N., Akin, I., Caner, G., Olgun, L., Guiraud, J., . . . Arnold, L. (2012). Multicentre investigation on electrically evoked compound action potential and stapedius reflex: How do these objective measures relate to implant programming parameters? Cochlear Implants International, 13(1), 26–34. 10
  8. Jerger J, Oliver TA, Chmiel RA. (1988). Prediction of dynamic range from stapedius reflex in cochlear implant patients. Ear Hear, 9, 4–8. 5
  9. Han, D., Chen, X., Zhao, X., Kong, Y., Li, Y., & Liu, S. (2005). Comparisons between neural response imaging thresholds, electrically evoked auditory reflex thresholds and most comfortable loudness levels in CII Bionic Ear users with HiResolution sound processing strategies. Acta Oto-Laryngologica, 125, 732–735. 2
  10. Pitt, C., Munoz, K., Schwartz, S., & Kunz, J. (2020). The long-term stability of the electrical stapedial refl ex threshold. Otology & Neurotology, 42, 188-196. 6. Wolfe, J., & Kasulis, H. (2008) 7
  11. Wolfe, J., Gilbert, M., Schafer, E., Litvak L.M., Spahr A.J., Saoji A., Finley C. (2017). Optimizations for the Electrically-Evoked Stapedial Reflex Threshold Measurement in Cochlear Implant Recipients. Ear Hear, 38(2), 255-261.  12
  12. Caner, G., Olgun, L., Gultekin, G., & Balaban, M. (2007). Optimizing fitting in children using objective measures such as neural response imaging and electrically evoked stapedial reflex threshold. Otology & Neurotology, 28, 637–640. 1

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Slim Modiolar electrode

CI532: The Perimodiolar Advantage

January 22, 2019

By guest author: Wade Colburn

Wade Colburn

 

 

Cochlear introduced our first perimodiolar electrode array in 2000. Perimodiolar arrays reduce the distance to the modiolus to improve performance1,2 and allow for more focused stimulation3,4. In a study conducted at Washington University by Holden et al5, they showed a correlation between the position of the electrode with respect to the modiolus (often referred to as the “Wrapping Factor”) and CNC word score. The group showed that those electrodes with proper perimodiolar placement had a lower wrapping factor and improved performance.

Cochlear continually innovates with the intent of making perimodiolar electrodes thinner, less traumatic and consistent in placement, and with the ultimate goal of improving patient performance. The perimodiolar advantage has been observed by many clinicians over the years, which is demonstrated by the fact that 2 out of every 3 Cochlear™ Nucleus® implants are perimodiolar6.  Cochler Slim Modiolar Electrode

Currently, two perimodiolar electrodes are available for purchase, the Contour Advance (CI512) and the new Slim Modiolar (CI532).  Contour Advance has been available since 2005 and is still used among surgeons. The new Slim Modiolar electrode improves upon a few key design elements and redefines any historical assumptions surrounding perimodiolar arrays, such as scalar translocations and limitations on surgical approach. While there are certain patients that can benefit from the stylet-based Contour Advance, the sheath-based Slim Modiolar has shown performance benefits7.

The Slim Modiolar electrode redefines the perimodiolar advantage in four major areas:

Performance:

While the performance benefits of a perimodiolar electrode is well understood 1,2,3,4,5, a recent publication by Shaul et al7, demonstrated that in a matched population (post-lingual patients with all electrodes in scala tympani) phoneme score at 12 months was significantly better with Slim Modiolar (79.5% (mean), 14% (SD)) compared to Contour Advance (69.4% (mean), 17% (SD)).

Placement in Scala Tympani:

In multiple published surgical papers on Slim Modiolar, successful scala tympani location was seen in 90 to 100% of the patients 7,8,9,10. Slim Modiolar redefines the reputation of perimodiolar electrodes and presents an opportunity to combine the benefits of being close to the hearing nerve with consistent scala tympani location.

Preservation of Structures:

The Slim Modiolar is designed with a sheath-based delivery system, which allowed for a 60% reduction in volume compared to Contour Advance, making it designed to preserve the delicate inner ear structures. The thin design and smooth insertion with a sheath delivery showed in a temporal bone study that 98% of the bones that were implanted experienced “no trauma”. The Slim Modiolar is designed to preserve the natural structure of the cochlea.

Preference of Insertion:

Another benefit of the Slim Modiolar electrode is the ability to use the preferred surgical approach, including a round window insertion. Contour Advance design was limited to cochleostomy insertion, but Slim Modiolar is designed to be implanted via round window, extended round window and cochleostomy. In Aschendorff et al8, 44% of the cases were performed with round window insertion, 22% with extended round window and 34% with cochleostomy. This study demonstrated that Slim Modiolar could be implanted with all surgical approaches, while still maintaining consistent scala tympani location.

Slim Modiolar electrode (CI532) is designed intentionally to take the great elements of the Contour Advance and improve upon them to create an ideal electrode for your patients. Closer to the hearing nerve has proven to be a benefit and CI532 has redefined the perimodiolar advantage for the better.

To learn more about CI532 and practice insertions in a simulated model, contact your Cochlear representative.

 

About our guest author:

Wade Colburn is the Product Manager for the Cochlear™ Implant product portfolio within Cochlear Americas.  Wade’s responsibilities include product positioning and messaging, life-cycle management, new product launches and surgical support and training. Wade has recently joined Cochlear and comes from an engineering background within the medical device field, including previous otology experience.

 

 

References:
  1. Lazard D. S, et al. Pre-, per- and postoperative factors affecting performance of postlinguistically deaf adults using cochlear implants: a new conceptual model over time. PloS one. 2012; 7:e48739
  2. Blamey P, et al. Factors affecting auditory performance of postlinguistically deaf adults using cochlear implants: An update with 2251 patients. Audiology & neuro-otology. 2013; 18:36-47.
  3. Hughes, ML, Abbas, PJ. Electrophysiological channel interaction, electrode pitch ranking, and behavioral threshold in straight versus perimodiolar cochlear implant electrode arrays. J Acoustic Soc Am. 2006; 119(3):1538-47.
  4. Cohen L., Richardson L., Saunders E., Cowan R. Spatial spread of neural excitation in cochlear implant recipients: comparison of improved ECAP method and psychophysical forward masking. Hearing Research. 2003; 179 (1-2):72-87.
  5. Holden LK, Finley CC, Firszt JB, Holden TA, Brenner C, Potts LG, et al. Factors affecting open-set word recognition in adults with cochlear implants. Ear Hear. 2013; 34(3):342-60
  6. Internal sales data on file.
  7. Shaul C, Dragovic AS, Stringer AK, O’Leary SJ, Briggs RJ. Scalar localization of peri-modiolar electrodes and speech perception outcomes. J Laryngol Otol 2018; 1-7. https://doi.org/10.1017/S0022215118001871
  8. Aschendorff et al. Clinical investigation of the Nucleus Slim Modiolar Electrode. Audiology & Neurotology. 2017; 22:169-179. https://www.ncbi.nlm.nih.gov/pubmed/29059669
  9. Data on File: US Multicenter CI532 Study. 2018.
  10. Cuda, D, Murri, A. Cochlear Implantation with the nucleus slim modiolar electrode (CI532): a preliminary experience. European Archives of Oto-Rhino-Laryngology. 20017; 12:4141. https://www.ncbi.nlm.nih.gov/pubmed/29032420
  11. EA32 Electrode Insertion Safety and Performance Study Report. Data on File (Document Number: 473386)
pediatric cochlear implant

Guide to Cochlear’s new expanded pediatric indication

June 26, 2020

On March 17, 2020, Cochlear received FDA approval to lower the age of cochlear implantation from 12 months to 9 months for children with bilateral, profound sensorineural hearing loss. 

Here are four resources to further your understanding about the lowered indication:

AudiologyOnline interview: Expanding Possibilities for Pediatrics: A New Indication for the Cochlear™ Nucleus® Implant System

Megan Mears, audiologist and Clinical Project Manager at Cochlear Americas, discusses the implications of the new indication for professionals and recipients, such as positively impacting spoken language outcomes.1,2

AudiologyOnline course: The Evolution of Pediatric Candidacy for Cochlear Implants: A New Indication

This course discusses hearing loss treatment from a pediatric patient standpoint and provides information on pediatric candidacy for cochlear implants.

Course Details

Presented by Melissa Tribble, AuD

Pediatric Audiology Practice Manager at Stanford Children’s Health

Recording available.

New TECH Talk: Age of implantation and critical development window

Dr. Jace Wolfe, clinical audiologist and Director of Audiology and Research at the Hearts for Hearing Foundation in Oklahoma City, examines results from the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) Study based out of Australia to understand the long-term impact of early access to sound.

A Review of Research: Pediatric Evidence Summary

Read key insights from significant research studies around the benefits of cochlear implants for pediatric patients. Topics include:

  • The importance of early access to sound
  • Two ears are better than one
  • Progress tracking and monitoring
  • Social communication
  • Technology to make everything easier – especially in noise

For more helpful resources, subscribe to the Cochlear ProNews.

References:

1. Ching TYC, Dillon H, Leigh G, Cupples L. Learning from the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study: summary of 5-year findings and implications. Int J Audiol. (2018 May); 57(sup2).

2. Ching TYC and Dillon H. Major Findings of the LOCHI study on children at 3 years of age and implications for audiological management. Int J Audiol. (2013 Dec); 52:sup2, S6-S68

In Canada, the cochlear implant system is intended for use in children 12 to 24 months of age who have bilateral profound sensorineural deafness and demonstrate limited benefit from appropriate binaural hearing aids. Children two years of age or older may demonstrate severe to profound hearing loss bilaterally.

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This material is intended for health professionals. If you are a consumer, please seek advice from your health professional about treatments for hearing loss. Outcomes may vary, and your health professional will advise you about the factors which could affect your outcome. Always read the instructions for use. Not all products are available in all countries. Please contact your local Cochlear representative for product information.

 

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