In part one, we discussed the very real challenges one has when they have severe sensorineural hearing loss. When you have severe loss, you may also lack clarity due to inner hair cell death/damage. You will have difficulty hearing speech even with the best hearing aids you can buy.
When hearing aids are no longer enough to provide a patient with clear enough hearing to communicate, they can be considered for cochlear implant(s). Implants are often given on one side only; sometimes there will be a second one fitted at a later date, but not always. This is because implantation is a one-way journey, destroying your inner ear’s ability to hear naturally. If your other ear works, you will likely want to keep it. The non-implanted ear may receive a special NHS hearing aid that communicates with the implant so you can hear from both sides e.g. on a mobile phone. If you have been wearing private hearing aids, you will no longer have them.
People become eligible on the NHS when they have two points on their hearing test that are 85dBHL or worse. The criteria also looks at the benefit they are getting from traditional hearing aids. Criteria for NHS implants has improved in recent years, so more people are eligible*.
A cochlear implant has three components:
Implant/Electrode Array: this is surgically fixed to your inner ear (the cochlea - a snail-shell-looking organ between your visible ear and your brain), and it is buried in the skull behind your ear. It has electrodes which correspond to different frequencies (pitches), taking over the job of your inner hair cells, sending electrical messages along your hearing nerve to your auditory cortex (part of the brain that deals with incoming sound). The cochlea usually receives signals via your ear canal, eardrum and middle ear bones. Inside the cochlea, sound creates a wave along a membrane, making different parts of the hearing nerve fire at different frequencies. The auditory cortex does the clever stuff, the cochlea just separates out the different frequencies you’re hearing, along with volume and timing.
Transmitter. This communicates information to the implant from the sound processor.
Sound processor. The implant needs to know what signals to send along the nerve. A sound processor detects sound and communicates what it has “heard” to the implant. Information on frequency, volume, timing is sent to the implant, which turns it into perfectly timed signals to the brain. If you have two implants (or a hearing second ear), the brain can also decide which direction sound is coming from.
Options for Sound Processor and Transmitter
The implant can only be as good as the sound processor, so it’s important to have a good one. There are different options here. One option is a large “hearing aid” device (top left in the images below), worn behind the implanted ear, which connects to the magnetic transmitter via a wire.
More recently, we have the option of a combined magnetic unit which houses the sound processor and transmitter inside it. I am so happy about this development, as my vanity was really putting me off the implant. I’ve spent a lot of time and money getting the smallest and most discreet aids I can, so the thought of having a large processor sat behind my ear was not welcome! I know, I should be a better role model, but I have the same feelings as anyone else!
So, with modern implants we have the electrodes implanted inside, not visible, with healed skin/hair over the top. We also have a removable disc (pictured below) which sticks to the skull, processing sound and communicating it to the implant. All that is visible to others is this disc (pictured below), which is about 1.5 inches across. This version has a safety wire/clip to attach it to your hair and prevent you losing it.
After the Operation: What Happens Now?
The surgeon implants the electrodes under general anaesthetic. You may have an overnight stay in hospital or you may be allowed out that same evening. The wound will heal and you’ll wait around 3 weeks, with no hearing on that side, until you are fitted with the processor. At the fitting, you’ll have the sound introduced at a low level. It will sound very strange at first! My patient described it as robotic. You’ll be hearing frequencies that you perhaps haven’t heard for years. Even the best hearing aids won’t be able to amplify all frequencies, so you may find some things, like birdsong, are very new at first; similar to when you first got hearing aids.
You’ll have follow up appointments with a specialist audiologist. Over these appointments you’ll be rehabilitated to speech and the processor will gradually have more volume added, until you reach your target.
Rehabilitation - The Longer Journey
Getting used to hearing aids can happen in days/weeks/a few months, depending on your age and how long you were without normal hearing. With hearing aids, improvement is normally immediate and welcome - suddenly you can hear clearly! With a cochlear implant, it will take months to get used to sound and you must be prepared for that. Speech will not be clear, effective and pleasant at first.
I met with one of my former hearing aid patients to discuss this. She tells me that, 18 months in, she is still noticing improvement to her implanted hearing. The first few months was a challenging time, while she learned to hear again. From then on it was a case of gradual improvement as the sound became clearer and clearer. There is no doubt that today she is managing better than I am in certain listening situations. In noisy places she is finding it difficult to hear, just like me. She has one hearing aid too, so one side is better than the other. However, in a quieter situation she is doing better than me with my two aids. In a room with some background noise, she’s way better off than me.
Summary
The key concept that I took away from meeting my implanted patient is this: she’s going to keep on improving, while my hearing ability can only get worse. My hearing loss is progressive, and with each decrease in my ability, hearing aids can only do so much for me now. Hearing aids - private ones anyway - are excellent. Compared to my natural hearing ability, aided hearing is phenomenal. I am so very grateful to have them. I will tell people every day that they are worth every penny and more, to have that improvement in your hearing. However, once you have severe/profound loss and cochlear dead regions like I do, you’re still going to find it difficult to hear speech clearly. You may have a sense of dread about what your future holds.
I hope that the majority of my patients never need an implant. I wish I didn’t have this in my future! But the fear that I had has now vanished. I’m actually excited to know that at some point I will start moving back up again, to a clearer future, where long-forgotten sounds like birdsong come back to me. I can’t wait!
* Talk to your audiologist if you think this might be for you, or your GP if you are an NHS aid user. Your audiologist can help put forward the case for implant (a referral to your GP or directly to the implant service).
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