My psychophysics as a bilateral cochlear implant user
claude.ai
claude.ai
After being hard-hearing since early childhood (bad living conditions -> tuberculosis -> ototoxic antibiotic, streptomycine iirc), my mum had a CI for a # of years. But due to infections, it got removed at some point. Since then I've always wondered if there's other routes to get sound into the brain. Say, using vibrations on the skin. Or an electrode-stuffed 'helmet' of sorts.
Even if temporary, it can be a life-changing experience for someone who's never experienced sound.
Any research in that direction?
and
> I was born with normal hearing. I began losing my hearing in childhood ... After I was registered, I started wearing hearing aids. People's voices became clear, and for a few months things were good. ... A specialist told me that I badly needed cochlear implant surgery, but I hesitated because it was very expensive.
I'm confused what's going on here.
This inability (inabilities actually, because I can't do visual recall that well either) of mine makes me wish I had those super powers. It would have allowed me to relive wonderful experiences of sight and sound.
At least I can dream and there's photographs and video and audio recordings.
Perhaps there is an evolutionary reason for not having strong sensory experiencial recall capabilities -- one could get dopamine hits simply by recalling and not actually moving and exploring.
Edit: just thought id mention a slight draw back, i get a lot of awful and annoying pop songs that can get stuck in my head. If i hear a song in my head and its that clear then often it will just play on repeat over and over until i hear something else, or force myself to think of a different song which is hard to do when you have a song crystal clear playing on the radio in your head.
I can recall some short clips in "mind's ears" but for very few pieces of music and for short clips.
Yes, I can have songs/tracks stuck in my head (though all too often in the form of some obsessively looping motif), or voluntarily "play" them with a varying but generally satisfying degree of accuracy and completeness.
I don't want to exaggerate it though. It's not as if I'm having full-on auditory pseudohallucinations, for one thing (I get to the other thing after a couple more paragraphs). Just as typical visualization is a quasi-visual experience that has a "visual feel" but is distinct from retinal visual input, this is a quasi-auditory experience. It is (for me) clearly not the same as hearing actual sound. It's only some part of the experience that lies somewhere downstream of the physical sensation of sound hitting my eardrums.
But it's not simply all of the perception part with the stimulation part cleanly omitted. Then I can only imagine it would have a hallucinatory nature (which it does for a few[1]). It's further "detached" to some varying degree. Sometimes it's rather effortful, and other times it can feel nearly real in the sense that I don't have to actively make it be there.
Even so, it comes out with what feels like at least adequate fidelity. Right now, for example, while "playing" the beginning of Julie Andrews singing "Do-Re-Mi" from The Sound of Music, it seems like I'm getting a lot of the nuances of her articulation and intonation. Those nuances may or may not be quite accurate to the original, but it's enough to passably emulate the experience of actually listening to it, except for the part where it feels like I have to do a lot of the work myself.
So with one such relatively uncomplicated "stream" to deal with, there is "bandwidth" for a good amount of detail like that. Beyond that it degrades in a way, which brings me to the other thing: It's not as if I'm having a perfectly complete experience in which all the parts are present all at once. There's a focal point (usually the vocals, if present) and usually maybe one other thing can be happening along with it in a way that seems more or less complete and concurrent. Beyond that, parts will fade or drop out entirely, come back during lulls in the other parts, and drop out again. A sort of skeleton that overall delivers an acceptable composite of sorts.
> actually able to play a sound in their head without humming
For a parallel example, consider kinesthetic mental imagery -- imagining doing something physically (not visualization, but what I think your coach really means when he tells you to "visualize" an action). Here, similarly, the skeletal muscles are minutely engaged (according to some paper or other that I can't cite at the moment and am not really qualified to assess). This is, IIRC, shown to be at least somewhat as effective as actually practicing the action, and also hints vaguely that there could be something to your idea about the spoofed dopamine reward.
In this way, with the music, it's kind of like an aborted subvocalization, and if I let it be a sort of subvocalization, with the little movements of the vocal cords, it supports more "streams". I have to do this to just barely manage to "play" a three-note chord such that I feel like I can be aware of each tone at the same time (I say "feel" because it's fragile/shaky enough that I get the sense I could just be doing some deft plate-spinning). All of which (since the quote up there) is to say that I think needing to hum is at least probably on the same continuum rather than being something utterly divorced from some kind of supernatural feat of sound-conjuring.
1. e.g., Brian Wilson of the Beach Boys and his auditory hallucinations of intricate arrangements (See the very beginning of "Wouldn't It Be Nice" for one example of the sort of thing that some will recognize as very obviously originating from such a hallucination): https://en.wikipedia.org/w/index.php?title=Musicianship_of_B...
2. https://www.hurlburt.faculty.unlv.edu/codebook.html#target4
3. And maybe all of these different forms of imagery-as-aborted-stimulation converge into "unsymbolized thinking"?
Aborted experience has the right ring to it.
It is always interesting to explore the inner world of someone else, be it with such a limited channel of language.
I wouldn't normally describe hearing a voice as hearing "vibrations". Vibrations are indeed the physical basis of sound, and the auditory system detects changes in air pressure caused by them. But vibrations can also be perceived through touch, and the subjective experience of hearing is quite different from the tactile sensation of feeling something vibrate. When talking about feeling vibrations, I usually think of the touching sensation.
Still, both sensations originate from the same physical phenomenon. You can try to feel your own vocal chords vibrate by placing your fingers on your throat while humming. It's certainly a very different sensation, and touch generally conveys fewer acoustic details than typical hearing, but you're sensing the same underlying physical event.
One interesting example is Dani Valeska (Instagram: @daniivaleska), a Brazilian Sign Language interpreter whose husband is deaf (I couldn't find his name). She shares content about their experiences, and I remember seeing a video in which her husband used the vibrations of her voice, felt by touching her throat, to reproduce what she was saying. This resembles a technique called "tactiling", which has been studied as a tactile aid to speechreading (https://researchers.mq.edu.au/en/publications/tactiling-a-us...).
(Sorry if my last post seemed to have some mistakes. I was tired yesterday and didn’t review it carefully, so there were a few contradictions. I’m trying my best to write as accurately as possible)
> Miku
Interestingly, the same researcher in charge of the VOCALOID software is now in charge of research for Voicemod.
That's not to say that it's not very tricky, just that the difficulty kind of arises from one core reason.
Edit: OK, one s as /s/ after the c and another s as /z/ between vowels is also tricky and doesn't have to do with Greek.
The English plural suffix follows a standard pattern:
It’s voiced (/z/) after voiced sounds and voiceless (/s/) after voiceless sounds. That’s why it shows up as /s/ at the end of “physics” (/fɪzɪks/). /k/ is voiceless.
The -ics ending of physics comes from a plural.
No helpful pattern underlying the middle “s” unfortunately.
All trial-level data, the analysis code and Lean 4 checks of the apps' logic are on GitHub (non-commercial licenses): https://github.com/mi-rae-lab/ci-psychophysics-data
I do not speak English. The page was translated with Claude, and I will use AI to read and answer replies, so my answers may be slow.
This is my first time visiting Hacker News, and my first post here. I don't know the culture here well yet, but I deeply respect it and support it.
It is past 1 a.m. here in Korea and I am very tired, so I need to get some sleep. I will check back around 9:30 a.m. Korean time (00:30 UTC).
I always told myself I would try and do some fun things with my cochlear implant (Med-El Sonnet) but I never did so reading this was like dusting off some old thoughts of mine.
I was the same, I was born relatively hearing, but started to lose it rapidly - due to a mitochondrial disease (mutation A7445G) which is very rare, but is in a few families around the world. I wore hearing aids for most of my childhood and then got the implant when I was mid 20s.
I've heard a lot of your complaints from others. My sister for example, didn't have a great journey, and even today she reckons everything is still robotic sounding. She however went with a Cochlear Nucleus system, and I was the only one in 30+ people in extended family to go with Med-El (because I liked their tech better) and it's always sounded crisp and clear to me.
I'd have liked to have gotten two, but I was only funded for one - plays havoc with directional hearing. You could have 50 people turn towards a sound, and then there's me turning the opposite direction! :)
I'd be really keen to know if you have any other experiments planned.
How much do these cost?
Moisture is a big destroyer. It never occurred to me at the time, but now I am beholden to Med-el for life, it's literally a lifetime subscription :)
AI can write such programs quickly.
Metaphor: If there is a problem with the lunar lander, or the Mars robots we can't easily go fix them, we can't send someone to "turn it off and back on again", so we find a work around instead. In your case we may not be able to change the physical connections easily, or heal the damage there, but we may still have some options. ...
Most of us here at hackernews are programmers or technologists, not medical experts. So if there is a medical reason / short, malfunction, or other problem with the underlying connection to your brain (or to your brain itself in that small connection area around the implant), that is outside of our expertise.
## Suggestion: This suggestion to "translate"/transform the speaking ranges DOWN into the ranges that you can actually hear is a great one. So you'd be looking/asking claude for software that would take any/all microphone input at normal speaking frequencies, and in real time, shift/adjust the frequency Downwards until the average speaking midpoint was below 70Hz . then if your brain can hear differences in the lower frequencies, it would just be a matter of training/learning them in those lower frequencies. It may still take some time to hear specific speech, but you need to get it into a range that you can actually detect some changes.
An audio recording or mixing technician may be able to help with suggestions about which frequencies usually contain male, female, child voices and things like "s" sounds or sharper hisses at the end of a sound which tend to be a higher frequency than the main words. But the main goal would be to make ANY speech detectable to your ears.
There may be multiple ways you could try stretching out or reshaping the word sounds
For faster testing, start with a single recorded word at normal ranges. As a starting place, Have a friend record a single word and verify that they can hear it on your computer when it plays (this is important!). Then you would try variations for your software to shift the word into lower and lower frequencies until it becomes legible/hearable to your brain. Once you are able to hear something then record the range that its shifting down into as the "sweet spot". Try a few alternatives above and below that spot to try to find your " best" hearing frequencies. Once you've done that, you'll just need to play that word over and over again until you are able to hear the edges of it, the articulation of the syllables which should sound like hills and valleys. In most languages including English and Korean, The beginnings and the ending sounds (and how abruptly they stop or start), like edges to a sword (wielded by an expert swordsman), or like the movements of a dance (sometimes a slow smooth movement, sometimes an abrupt stop, then movement again). Thise are the same kinds of things we do with our voices to make sounds. A shape of the syllable like a body dancing shape, the lights come up on the stage, then movement(air&vibration) starts in a certain way, then movement (fast or slow) into another mouth shape. Usually the beginning and middle are particularly important, many dialects and creoles tend to drop or slur the ends of words, since if you have already heard the beginning and middle of the word so many times, then you already know the end part. Similarly, if you watch your favorite dance or ballet over and over again, you remember and can know the shape of the body in the next beat before the dancer gets there.
Best of luck on this, please report back if you make any progress, we are all cheering for you, and we hope you're able to make progress!
Reminder: to retrain your brain on different inputs takes time. Make sure you can hear something in the changes, but then when you're in the "sweet spot" range, give it time. Listen hard! Be a learner and always be expecting for that dancers shape to come through. Spend time doing it every day, maybe with a blindfold so that you can focus ONLY on the sounds, otherwise your smart brain will try to work around it, picking cues from visuals.
You mention a lot of ethics concerns; I am totally uneducated on medical ethics but I think those are pretty important questions. It doesn’t sound like you’ve had a lot of support from this startup.
I might suggest to you that you publish this on a website - GitHub pages comes to mind as something Claude or codex could do for you easily - it would let you segment this information in a way that someone who wanted to help with the medical questions could get right to that stuff, and someone who wanted to help with ethics could also jump to what they were interested in.
Either way, thank you for the write up! Your curious and open attitude is lovely.
Right off the bat after skimming this I'm caught up with a detail that you confirm multiple times - that you can tell literally nothing apart given any input over 70 hz. You have had this measured a few times and you definitely say that nothing is coming across above 70 hz.
Yet you are trying to hear all sorts of things that have most all of their information content above 70hz.
The Hatsune Miku music? You're hearing the bass and the kick drums and maybe some subharmonics generated in the reverberation of the higher stuff. But that is a tiny fraction of the music, and, I hate to tell you this, but that computer girl singing is all way, waaay up higher than 70hz. The beautiful sounds you are getting across are the cool synth basses of all that music. It's very modern, punchy music and the bass of that type of electronic music is very different from other classical music so whatever modulation your implants are doing to it from 70 hz down likely sounds very cool compared to a lot of other music, for sure.
But, stop- you're getting nothing by noise and wind sounds with no information differentiation over 70hz because your brain isn't demodulating that information, maybe due to something about how the implant was... implanted... or just your specific condition, who knows, but what you can do is work in the band you have.
You mention not getting human voices because the fundamentals of human voices are more than 2x where your cutoff is.
Have you tried using a program like Audacity - or - Get claude to write a script for you that takes in MP3's of modern music and slows them down 300-400 %. The music will be very slow, but it will shift instruments from higher up (pianos, horns, people's signing) down into the 20-70 hz range, and you will maybe hear patterns that are new. Did no one in the study post-op sit with you and go thru this kind of thing? You have all these external trials listed but most all of it is moot if everything above 70hz is missing and you aren't able to modify the modulator hardware.
Note that the type of rhythms in the bass of the bass synthesizers of that Hatsune Miku tracks are different that the more complex rhythms and melodies played by instruments higher up (like pianos and lead synths). (This is true for most all music genres...) Shifting those higher up things down in frequency, even if that means they play back slower, may give you an different musical experience.
Continuously pegging your implant modulation hardware with frequency content above 70hz attempting to discover something about how it interacts with your brain when you continuously get nothing but broadband noise over 70hz seems like a dead end exercise.
I mean hell, have you tried putting a low pass filter to block out on everything in the music/microphone input above 70hz just to make sure that information isn't somehow overloading the way the implant works with your brain, and maybe just causing confusion.
Lastly it sounds like you could benefit from talking with someone with a real audio / digital signals processing / electrical engineering background that can inspect your hardware directly and make suggestions because educating yourself with just GPT runs might be spinning you in circles.
For instance... you mention things like " The logic of my test apps, which generate the test sounds and move the staircases, was checked with the Lean 4 formal verifier,"
Man... this has nothing to do with needing a 'Lean 4 formal verifier' to check your app or whatever. You need someone to sit with you and your damn hardware and work with some audio input. You need the someone that setup the original implant modular to explain the hardware mapping and filtering options to you and see if you can go back and change how that works, to get more options. You're getting some wildly mixed signals (bad pun) about how all this works, I think.
You don't need to slow them down, you can just pitch shift everything into the 0-70 hz range. If there were a way to figure out how his brain is demodulating the signal, you might even get something pretty reasonable out - the essay describes sounds like cars as hissy rather than heavy.
The real difficulty is keeping genuinely inaudible frequencies (<40 hz? but who knows how his implant works) from swamping the rest, I would think.
Any computer sound card will high-pass anything over about 16-18 hz and thus new lower stuff won't swamp, and it seems like his implant amplifier does indeed deal with low frequencies because he mentions using an 18hz tone to keep the device key'ed on.
Another thing then to mention would be 'binning' audio that has been pitch shifted own using notch filters / comb filters. Because it is possible that however the implant is wired could use some band gaps to help his brain 'decode' things more clearly and less muddy.
Again, all this is simple shit and I find it really surprising that there isn't someone to help run these tests on hardware with this person, and their blog post here has this very strange rabbit hole feel to it and I can't tell if it is because there is a lot lost in translation, or if there is a lot more to this that is coming across in translation... or if this person in being led down some near-AI-psycosis and is struggling because they simply don't have someone to sit with that can help.
It all comes off to me as very, very strange.
I agree with the broader instinct that OP deserves a clinician to help with the hardware side (having their map and device parameters alone would go a long way), but it seems OP is taking any step they can towards this effort.
I regret that I don't have anything to actually add towards helping OP. Their posture towards understanding is refreshing and the Lean bit reads to me more as a cute testament to that than anything eerie or strange.
If I'm a bit more imaginative on this 2nd read of their 'experience' of these tests it seems that maybe yes, they hear 'something' at higher frequencies but it just just broadband noise- broadband noise mind you, is, all frequencies... so I was confused at how someone could say they 'don't hear anything above 70hz' and yet can somehow hear 'noise' at '2000 hz'. But it is dawning on me that the implant / associated driver hardware may simply be 'saturating' when the spectral content of audio is too large at all those frequencies, and OP can actually 'hear' something, but it just blurs into white noise when the spectral power is too high - kinda like there is a massive amount of reverb being applied to everything over 70hz.
But again they talk about their struggles with understanding voices and whatnot but if they are hearing parts of music at all then they could be hearing people' voices shifted into bands and toned down to amplitudes that helps them. Like, clinicians with experience here should be helping with this and it is kinda insane that this person is attempting to discern anything themselves.
The exposition is strange and again that could just be the translation and writing style but some of those little bits and just the way I've seen some people literally start spiraling when they start to pair-autodiadict with AI - coupled with the fact this is a medical condition and a life-altering disability - along with a few other small oddities in this post - make me kinda worried there is a lot more to this than posted and OP may need other kinds of help with their situation.
In a CI, voice pitch actually _does_ arrive as amplitude modulation at the F0 rate. The processor keeps only each channel's envelope, and the harmonics of a voice that share a channel beat against each other at F0. So a 70 Hz flutter ceiling and vocal ranges do belong in the same breath.
> ... so I was confused at how someone could say they 'don't hear anything above 70hz' and yet can somehow hear 'noise' at '2000 hz'. But it is dawning on me that the implant / associated driver hardware may simply be 'saturating' ...
The TMTF carrier was noise by design, so above 70 Hz the flutter vanished and the noise that was already there is all that's left. No saturation is needed to explain it. The “wind” in SRD is what a spectral ripple sounds like through limited spectral resolution. This is a resolution problem, not a level problem.
> The exposition is strange and again that could just be the translation and writing style...
This paragraph was why I initially made a comment. They were radically honest with their methodology and obviously living inside the problem. OP is actually reading this thread, for what it's worth.
I would think you could take the audio processor out of the loop and run diagnostics on the implant itself using an EEG to determine how the brain is responding. They test the hearing of newborns with the tech, you don't need to "trust" a person or even need them to be able to communicate. Its right there in the data.
Based on my read of everything it feels like there is some issue with the implant sending electrical signals, but the nerve not actually picking them up and sending them on. Perhaps related to the original reason for the hearing loss. And the company should want to dig info it more. I know I would if it were my tech.
I see your situation more clearly after re-reading and also seeing your new responses here in these threads.
I think if you write more on this topic, especially more about your history of hearing and what you can in fact perceive, and publish more on the internet, you will find people who are very interested in this kind of topic - it is something that will 'nerd snipe' many tech minded people - and I am sure you could absolutely make friends in Korea who are interested to help. Having someone with an audiology background, or even a student in neurology who knows their way around audio signals processing / has a DSP / EE background etc. sit in with you for some experiments as you use the line input for you device - someone who also hears what the input is, and can talk with you about it - would be invaluable and could also be a fun social connection- maybe university students, etc. If I spoke Korean and lived in your city I would definitely find it fascinating to try and help out.
Wikipedia is not bad on the subject: https://en.wikipedia.org/wiki/Hearing_range
That's pretty misleading, we tend to have excellent hearing anywhere in the 100 hz - 6000 hz range. Much of music and all fundamental frequencies produced by the human voice (except people with very rare whistle register abilities) is below 2000 hz. We're most sensitive to the range you're talking about because it's the most useful for discriminating between different sounds, but still only slightly more sensitive to that range than to lower frequencies.
I also think there are some relatively cheap options for getting or building a simple EEG. At least in the US, I don't know about Korea. Which could allow for some more interesting tests. Let it play various sounds and tones while recording with no visual stimulus to go with it, and see how they correspond to the EEG data.
https://hzgenerator.com/sweep-generator
https://onlinetonegenerator.com/frequency-sweep-generator.ht...
A looping 10 to 70 Hz sweep got the best result with my 20+ year old Apple sound sticks because they have a subwoofer.
With typical hearing, it sounds like almost a dozen distinct frequencies to me. Higher frequencies are just a matter of degree, they aren't qualitatively different IMHO. But I'm not musically inclined, and only have synesthesia when I sort of see color in various gray patterns on the computer screen, which look more blue or whatever sometimes, so I'm sure someone will disagree with me because they sense feelings in audio that I don't.
I'd bet that improvements in technology over the next few years (especially with the help of AI) might get the upper end to perhaps 100 Hz or more, where it begins to sound more like a tone than a hum. Loosely, a beat (like a drum) sounds like perhaps 10 to 20 Hz. A hum sounds like 60 Hz (like electricity). Also I wonder if a cochlear implant can hear below 10 Hz because it's electrical stimulation instead of physical, to maybe hear frequencies that typical hearing can't? But I don't know.
I'm fascinated by this stuff, because sometime in the next 5-10 years we'll get direct digital signal to nerve implants. That could allow people to hear above 20 kHz (like a dog) or even restore smell in people who have had it diminished due to illness or injury.
Many people can see ultraviolet light after getting cataract surgery, which supposedly looks like a blacklight but more blue because there is a little rise in the red visual receptor the overlaps blue to make violet. So technically the blue receptor ends up being a violet receptor because red isn't removed normally. Which means that violet and purple are different colors, because the visual cortex makes sense of them differently at opposite ends of the spectrum based on how much green is present. Of course all of those distinctions may go away when someday the visual nerves can be stimulated directly with an implant and make color more of a continuous spectrum like sound, rather than having distinct color bands like in a rainbow.
Subjectively, I've noticed when I wake up in the morning that the ceiling has grey and yellow splotches, because we have fewer blue receptors in the fovea at the center of the eye, and they haven't adjusted yet. Also at dusk, the rods begin to sense more, so the world fades from color to cyan and then gray. I feel like similar things might happen with audio, because I feel like I can hear better when I'm camping, especially in the morning, but I don't know why.
There are interesting experiments where they put goggles on chickens to flip the world upside down. After 2 weeks, the chickens saw normally again due to neuroplasticity. Then when they took the goggles off, the chickens walked goofy until their brains readjusted.
Also I've read that lion's mane mushrooms regrow neural connections and may even increase neuron synthesis. I've had neurological injuries due living a rough and tumble life that seemed to have healed somewhat after drinking mushroom coffee for a few weeks. Also magic mushrooms scramble nerve connections and let them reestablish themselves, sort of like starting over with a blank slate in neural networks. Mushroom medicine research has been blocked by a century of ignorant legislation, so people have missed out on spiritual healing that strays outside of what science can explain. I think of a brain or neural net as an antenna that resonates with the consciousness field, which is some sort of 5D-like field that transcends our normal 4D spacetime (otherwise it would be a frozen crystal with no observer or passage of time). When our brains get rewired after learning/trauma/injury/illness/healing, our attention shifts to different things, which alters our subjective experience. Meaning that in a very real sense we perceive the world differently and/or feel like we've shifted to a different (often better) timeline. Plant medicines and spiritual practices may allow changes to subjective experience that science can't yet talk about.
Anyway, not sure what point I'm trying to make here with these breadcrumbs, other than that the future isn't written yet, and in fact there are infinite futures, which I believe free will allows us to choose. So there is always hope and a reason to keep going.
You typically should feel sound as a 3d point, it maps roughly to the same sensory system that maps light or touch direction. Loud noise would feel as directional and material as bright sun or strong poke to a head. (Brain does this mapping transparently based on the small difference of time it takes the sound to reach your ears.) Sometimes the sound is not clear, you would either hear from a vague direction or with no direction channel provided from your brain at all.
The science behind Head Related Transform Functions [0] is fascinating, and includes additional tricks. For example, the shaped fleshy bits of your ears modify incoming sound differently depending on the direction, so that the noise from "up and in front" has a signature which differs from "down and behind". There's also a component that comes from sound traveling through your head, where traveling through the front is different than traveling though the back.
I particularly remember this because long ago I had an Aureal A3D [1] sound-card which made great positional sound (over headphones) by simulating HRTFs and sound-reflection off of game-world geometry. Unfortunately they were sued into bankruptcy by Creative, whose EAX technology was much less-impressive.
[0] https://en.wikipedia.org/wiki/Head-related_transfer_function