Five features of a CI system for listening to music with a cochlear implant

Eva Kohl

The sound of a black key and the adjacent white key on the piano differs by exactly one halftone step. Can you hear a halftone step like that? Do you hear whether music is played in major or minor? These so-called "sound genders", which are common to us, differ only in three places by such a half-tone step. Many people of our Western culture intuitively feel that major music is cheerful, whereas minor is melancholic.¹ In order to consciously perceive a semitone audibly, practice is required – for normal hearing people as well as for users of cochlear implants, in short: CIs.

The bilateral CI user and professional musician Laura Korhonen (centre) regularly stands on stage with her group SATUO, in addition to giving music and dance lessons. Click here for an audio interview with Finnish-born Laura Korhonen: https://youtu.be/v-NKg8xYYus ©mattobserve.com

The right cochlear implant for listening to music

For CI users, technical and physiological features of the CI system are also crucial in order to be able to perceive and enjoy music in a differentiated way and to be able to play music actively. In addition to tone differentiation, it is about tone spectrum and tone colour as well as volume dynamics. Users of current CI systems can do this. They even sing in the choir or play instruments – even those that lack optical or haptic aids such as keys or grip holes to determine the pitch: for example, violin or alphorn. Five key features of modern CI systems make this possible.

1. The length of the electrode

The acoustics of music pose greater challenges to hearing systems than to language: think of the deep sound of a tuba, which is significantly deeper than any human voice, while the highest child’s voice does not reach the pitch of the piccolo flute. Spoken language ranges from about 125 hertz to 8000 hertz.² Instrumental music even starts at just over 30 hertz.³

In order to reproduce this wide frequency range as undistorted as possible, the electrode carrier of the cochlear implant must cover the cochlea as completely as possible. Their length, however, varies: Usable are typically between 28 and 34 millimetres. Even users of shorter electrode carriers can hear everything: The sound spectrum is compressed to fit the electrode that is actually too short. It is understandable that those affected take time to get used to the altered sound.

Only the Austrian CI manufacturer MED-EL offers electrode carriers of this length. Its extensive portfolio also includes short electrode carriers for uncharacteristically short inner ears. With the unique OTOPLAN planning software, the surgeon can determine the ideal length of the electrode carrier even before the operation. In this way, CI users gain access to the entire frequency spectrum – including the low tones that are perceived in the tip of the cochlea. This significantly improves the music experience!⁴

2. Anatomically correct adjustment

While the authors of a study published in 2025 critically question some of their findings themselves, their data clearly shows one thing: “The study participants experienced improvements in music perception with the image-guided cochlear implant programming strategy.”

The aforementioned OTOPLAN software also helps here: After implantation, it can show the actual position of each individual electrode contact and which pitch would be naturally perceived at this point of the cochlea. The CI technician or speech therapist adjusts the frequency distribution of the CI system when setting the audio processor according to this: Anatomical-based adaptation for an even more natural sound image.

3. Fine structure coding

The timbre is important for distinguishing instruments. Most cochlear implant technologies use only the slower time aspects of the signal, the so-called “envelope curve”, in their coding strategies. The pitch is only transmitted via the position of the electrode contact in the cochlea.

The MED-EL FineHearing technology also uses frequency-matched coding to stimulate low-frequency sounds synchronously with the fine structure of the sound. This combination of frequency- and location-adapted coding improves the perception of the timbre and brings users closer to natural hearing.⁵

We can compare that to a DJ console: if you play music faster, it not only gets faster, it sounds higher. For an accurate perception of pitch – especially low tones – a CI system must slow down the stimulation until it corresponds to the oscillation frequency of the sound. ^{6 7 8 9}

4. Additional channels through Intelligent Parallel Stimulation

For quiet speech, only a few transmitted frequency ranges may suffice. Understanding speech in noise is more challenging. Music, after all, forms a complex sound carpet of many layers. Transmission requires significantly more frequency channels.

In previous CI systems, the number of channels corresponded to the number of contacts or contact pairs on the electrode carrier. However, this is limited, since contacts that are too close influence one another. MED-EL, on the other hand, uses the unique Intelligent Parallel Stimulation to simulate up to 250 different pitches for richer and more natural sound.

5. Wide dynamic range of volume

The volume of a piece of music ranges from piano pianissimo to forte fortissimo, although fortissimo can really get very loud in an orchestra. In order to reproduce this even with CI systems, it needs front-end processing with a large dynamic range and with programmes specially developed for music: for optimum compression in each case. Only in this way can CI users perceive the dynamic complexity of music without too much impairment of the volume modulation.¹⁰

CI user and folk musician Heinz Kirchschlager: "Music is especially important for me!" Here you can find more information about CI user and hearing consultant Heinz Kirchschlager: https://www.hoerverlust.at/berater/heinz/" ©Max Breynck

Cochlear implants as a music receiver

If these requirements are met, modern CI systems enable their users to perceive the more complex sounds of music in detail in addition to language. Structured music training can further improve results.

In earlier studies, users of CI systems at that time typically could only perceive a pitch difference of at least three half-tones.¹¹ A scientific study to accompany the music training programme MELUDIA¹² shows that today 80 percent of MED-EL users can even master lessons to distinguish individual half-tones!¹³ This is also illustrated by the numerous music lovers, leisure and even professional musicians with CI.

[1] On other continents, this is sometimes felt differently 

[2] https://blog.medel.pro/audiology/cochlear-implants-and-music/

[3] Music and Cochlear Implants - MED-EL Professionals Blog; https://sound-au.com/articles/fadb.htm, 2.5.2025 11:56; Auditory perception and cognitive performance, in: Helmet-mounted displays: Sensation, perception and cognition issues, p.391-490, C.E. Rash, M.B. Russo, T.R. Letowski, E.T. Schmeisser, U.S. Army Aeromedical Research Laboratory, 2009, DOI:10.13140/2.1.3160.1925 

[4] Landwehr et al. Effects of various electrode configurations on music perception, intonation and speaker gender identification. Cochlear Implants Int. 2014 Jan; 15(1): 27-35.

[5] Müller et al. Clinical trial results with the MED-EL fine structure processing coding strategy in experienced cochlear implant users. ORL J Otorhinolaryngol Relat Spec. 2012; 74(4): 185-98.

[6] Schatzer, R. et al. (2014) Electric-acoustic pitch comparisons in single-sided-deaf cochlear implant users: frequency-place functions and rate pitch. Hear Res., 309, 26-35.

[7] Rader, T. et al. (2016). Place dependent stimulation rates improve pitch perception in cochlear implants with single-sided deficiency. Hear Res., 339, pp. 94-103.

[8] Landsberger, D.M. et al. (2016). Qualities of single electrode stimulation as a function of rate and place of stimulation with a cochlear implant. Ear Hear., 37(3), 149-159.

[9] Prentiss, S., Staecker, H., & Wolford, B. (2014). Ipsilateral acoustic electric pitch matching: a case study of cochlear implantation in an up-sloping hearing loss with preserved hearing across multiple frequencies. Cochlear Implants Int., 15(3), 161-165.

[10] Gilbert, M. et al. (2021). Cochlear Implant Compression Optimisation for Musical Sound Quality in MED-EL Users. Ear And Hearing, 43(3), 862-873. https://doi.org/10.1097/aud.0000000000001145

[11] Kang, R. et al., 2009. Development and validation of the University of Washington clinical assessment of music perception test. Ear & Hearing, 30(4): 411-418. doi: https://doi.org/10.1097/AUD.0b013e3181a61bc0.

[12] Meludia.com, free access for users of MED-EL CIs via myMEDEL

[13] Boyer J, Stohl J. MELUDIA - Online music training for cochlear implant users. Cochlear Implants Int. 2022 Sep;23(5):257-269. doi: 10.1080/14670100.2022.2069313. Epub 2022 May 9. PMID: 35534440.