Just like with a flat tire, there are ways to solve the problem of hearing loss. While hearing aids are effective for conductive hearing loss, sensorineural hearing loss requires a cochlear implant. Cochlear implants replace damaged hearing cells and stimulate the auditory nerve to transmit sound, and although they require surgery and rehabilitation, they play an important role in restoring hearing.
What should you do if your tire goes flat? The answer is simple. You just need to fill the tire with air. If it’s impossible to do so because the tire is punctured, you can buy a new one and replace it. Although it’s a bit of a hassle and expensive to replace the tire, it can be a final solution. However, what if you can’t hear well? In this case, things can be a little more complicated. Of course, you can wear hearing aids in your ears to help you hear better. Hearing aids are a simple and effective solution for many people with hearing loss. But what if you can’t hear well even with hearing aids? It’s just as simple. Replace your ears!
When we hear sound, vibrations originating from the sound source are transmitted as vibrations in the medium, which vibrate the outer and middle ear. This causes the medium and tiny hair cells in the inner ear to vibrate. This is how electrical signals are transmitted to the auditory center by stimulating the auditory nerve. If any part of this process is impaired, from the outer ear, where sound enters the body, to the brain, where sound is interpreted, we have trouble hearing. There are many different causes of hearing loss. If there’s a problem with the outer and middle ear that prevents the physical transmission of sound waves, it’s called conductive hearing loss. In this case, you can wear a hearing aid to amplify the sound. However, amplifying sound doesn’t solve all hearing loss. Hearing aids only make sounds louder, but they don’t address the sensory component of sound perception.
On the other hand, if the hair cells inside the cochlea fail to transmit physical signals to the auditory nerve, this is known as sensorineural hearing loss. In this case, hearing aids alone are not a solution. Hearing aids work by taking in sound, converting it into a digital signal, amplifying it, and transmitting it back to sound waves. This method simply amplifies the sound, which is why it’s only marginally effective for people with sensorineural hearing loss, who have difficulty perceiving sound stimuli. In their case, they need to be able to hear the sound itself, not just amplify it.
A cochlear implant is a device that is surgically inserted inside the cochlea where the hair cells are located and takes over the task of converting sound waves into electrical signals, just like replacing a flat tire with a good one. Cochlear implants are divided into two main parts: the sound processor, which is worn on the outside of the body, and the implant, which is placed inside the body. When sound arrives, an external microphone receives the sound waves, which are analog signals, and then the sound processor converts them into digital signals. This signal is then transmitted through a coil to the implant inside the cochlea. The implant converts this digital signal into an electrical impulse signal and outputs the electrical impulse to the electrodes. The output electrical impulses directly stimulate the auditory nerve, allowing the patient with hearing loss to hear sounds at a normal level. Because they directly stimulate the auditory nerve, cochlear implants can provide a solution for all cases of hearing loss, except for those in which the auditory nerve and auditory center itself are abnormal.
However, cochlear implants are not a perfect solution. First, unlike hearing aids, which can be simply worn and used, cochlear implants require surgery to insert them into the ear canal. Surgery isn’t suitable for everyone, and there’s also a period of recovery and rehabilitation afterward. In addition, the cables that connect the implant to the sound processor outside the body must also be installed inside the body, so it’s not without the potential for side effects. Furthermore, although cochlear implant surgery is aimed at patients with very little residual hearing, the process of inserting the implant removes the remaining hair cells, resulting in a permanent loss of residual hearing. Because of this, cochlear implants are not suitable for everyone with hearing loss.
Finally, the sound transmitted to the person through the cochlear implant does not exactly match what the person hears. This means that the cochlear implant’s conversion of sound waves into electrical impulses and the human auditory system’s conversion of sound waves into electrical impulses are not perfectly matched. Because of this, patients who have undergone cochlear implant surgery must re-learn how to receive auditory stimuli through the cochlear implant, which requires a retraining process. This can take time, and the quality of the sounds heard can vary depending on the degree of training.
Therefore, the ultimate goal of cochlear implants will be to make the sounds heard with the cochlear implant the same as those heard with the normal ear. Progressive research continues on many fronts, including the signal transduction process between hair cells and the auditory nerve, the final form of stimulation received by the auditory nerve, and the technology to generate artificial stimulation. Technological advances in recent years have greatly improved the performance of cochlear implants, but there is still much room for improvement. The human auditory system is extremely complex, and it is not easy to perfectly mimic its intricate processes. But thanks to these efforts, creating the perfect spare ear is no longer a pipe dream.
When you can’t get the sound information you want, whether it’s from a broken speaker or earphone or an out-of-sync video, you realize how important sound is. Cochlear implants can give people with hearing loss a new pair of ears, breaking the silence they’ve been living in for what seems like forever.
