Clinical Quick Tips: How to pair a Nucleus® 7 Sound Processor to compatible Apple® devices

• ‌Approximately 5 minutes to read
• Learning objectives:
  • Understand the benefits of EAS
  • Understand EAS candidacy
  • Understand current EAS programming parameters

What is Electric-Acoustic Stimulation (EAS)?

Electric-acoustic stimulation (EAS) is a system that utilizes viable postoperative low-frequency hearing thresholds in combination with electrical stimulation for cochlear implant patients. EAS systems are underutilized and have the potential to provide not only better outcomes, but a better patient experience. Manipulation of additional parameters when fitting EAS can provide an even better experience for our patients overall and should be more often applied. 

A brief history of EAS

‌In 2013 the Cochlear™ Nucleus® Hybrid L24 CI system was the first of its kind to receive FDA approval. The Nucleus 6 Sound Processor was capable of providing EAS, giving patients with residual low-frequency hearing the ability to utilize a combined listening experience. As further advancements in both surgery and technology continue to progress, so does the ability to preserve low frequency hearing. Utilizing the EAS system, when appropriate, provides additional benefits compared to traditional electric stimulation.¹ Benefits of EAS are improved speech understanding, improved music recognition, improved localization, decreased listening effort, access to binaural low-frequency cues, and providing a more naturalistic sound quality.^1,2,3,4,5

Who could be a candidate for EAS?

EAS should be considered for patients who have preoperative thresholds of less than or equal to 60 dB HL through 500Hz. “Functionally aidable” is a term commonly used to describe hearing loss that may receive benefit when fit with an appropriate hearing aid. The recommendation for fitting EAS is for those with low frequency thresholds less than or equal to 70 dB HL postoperatively. 

How do I program a sound processor with an acoustic component?

‌ The utilization of earmolds can be beneficial when fitting a patient with EAS. Clinicians have options when fitting the acoustic component, including domes, however, in the cases where the patient utilized a custom-fit earmold, utilization of this mold with the EAS system can provide better retention, additional comfort, proper venting, increased low frequency sound quality, and address feedback concerns. Should the patient not have a custom earmold, one can be ordered from an outside manufacturer, or the patient can be fit using an appropriate dome. 

The default boundaries for the acoustic component should be set less than or equal to 866 Hz, while the cochlear implant frequency boundaries should be set less than or equal to 438 Hz. This reallocation of lower frequency boundaries may provide additional performance or sound quality benefits, especially in noise^2,3 and may also provide the patient with a more natural and preferable listening experience.⁴ Further manipulation of these boundaries may provide additional benefit. 

‌A study conducted by Gifford et. al, revealed significant speech recognition and subject listening difficulty benefit in those who utilize EAS3. This study showed the less overlap in cutoff frequencies between acoustic and electric stimulation, resulted in better outcomes, with the highest outcomes achieved when the low frequency cutoffs were set closest to the audiometric thresholds. Overall, significant benefits were observed in speech recognition and subjective listening ease for individuals using bimodal and optimally aided EAS conditions, as opposed to those with only a CI. Furthermore, individuals benefited from a low-frequency cutoff program, showing significant improvement in speech recognition and subjective listening difficulty vs the default program.²

For additional information on programming using an acoustic component, check out our Electric-acoustic stimulation (EAS) fitting flow guide.

1. Dunn, C. C., Perreau, A., Gantz, B., & Tyler, R. S. (2010). Benefits of localization and speech perception with multiple noise sources in listeners with a shortelectrode cochlear implant. Journal of the American Academy of Audiology, 21(01), 044-051. 
2. Gifford, R. H., & Stecker, G. C. (2020). Binaural cue sensitivity in cochlear implant recipients with acoustic hearing preservation. Hearing Research, 390, 107929.
3. Gifford, R. H., Sunderhaus, L. W., Dawant, B. M., Labadie, R. F., & Noble, J. H. (2022). Cochlear implant spectral bandwidth for optimizing electric and acoustic stimulation (EAS). Hearing Research, 108584.
4. Parkinson, A. J., Rubinstein, J. T., Drennan, W. R., Dodson, C., & Nie, K. (2019). Hybrid music perception outcomes: implications for melody and timbre recognition in cochlear implant recipients. Otology & Neurotology: Official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology, 40(3), e283. 
5. Shim, H., Kim, S., Hong, J., Na, Y., Woo, J., Hansen, M., & Choi, I. (2022). Differences in neural encoding of speech in noise between cochlear implant users with and without preserved acoustic hearing. Hearing Research, 108649