By Nels Angelin
I am continuing the miracle story of hearing as a most marvelous journey that we might take for granted because it works so well. It is the glory of God that normal hearing works so that all the sound waves that make the world of hearing enter your ear down to the eardrum, vibrating the drum and moving the three tiny ossicle bones. The waves of air are transferred into the cochlea through the oval window to become fluid waves of sound, it becomes a hydraulic system of fluid vibrations into the center of the cochlea. The waves travel the spiral pathway all the way to the top of the little snail-shell shaped helix, a bony encased organ no bigger than 35 mm. The cochlear duct is formed by the vestibular membrane on one side, going up to the helicotrema and back down the tympanic duct, bound by the basilar membrane at the base. Here in the Scala Media, all the fluid vibrations are focused into the tiniest of organs wherein lies the brains of what you hear. Nestled in the base of the basilar membrane, is the organ of Corti. This is where all the thousands of hair cells are located and where the sound waves are again transferred, finally, into electrical signals at the base of the hair cells by their supporting cells that join nerve ganglions traveling to the cochlear nerve and on to your brain to be interpreted as sound. The miracle of all these structures, down to the cellular level, is so complex and wonderful. There is so much more to this orchestra of sound I can’t fit it all into this small space of writing.
This is the miracle the Creator has made for everyone who hears normally all of their life. Each part interacts with the other, synchronized with the individual frequencies of sound and plays on the individual cells designed for picking up sound waves characterized by the nature of where the sound has come from. All along that tiny Basilar Membrane each note is picked up according to the frequency that stimulates the nerve endings. This is known as tonotopic organization. Notice in the word, you recognize, “tone.”
When hearing is damaged by loud sounds or disease, the little hair cells die and are lost. Hearing decreases beginning with the higher frequencies and on as damage is increased. hearing aids can help when placed in the outer ear to amplify sound reaching into the middle and inner ear through the process of what is left that will then make use of the miracle of the nerve fibers. There is another way that hearing can be restored after hearing aids are no longer effective and deafness takes the toll. The cochlear implant is a device that has been developed over 20 years to reach past the middle ear to access directly to the same nerve the little hair cells added their system of stimulation for hearing. An internal processor is surgically placed under the skin. An external processor collects all the world of sound with microphones and transfers the sound information to the internal unit magnetically. The processed data is sent through a very thin, flexible electrode bundle array that is carefully inserted directly into the cochlea through the round window and follows upward into the spiral of the tympanic duct, nestled beside the basilar membrane where the same nerve fibers can be again stimulated to approximate the hearing process. The brain, at the auditory cortex, is then is stimulated to reprocess the electronic sound information. The world begins to come back alive. Birds sing, crickets chirp, clocks tick, floors creak, whispers are heard. It is not perfect—22 sensors versus 16,000 hair cells placed by the creator is a monumental contrast—but the window does open to make communications sharp and clear.
I had to laugh when my cochlear was first turned on. I was asked, “Could I understand what my audiologist was saying”? No, every sound was only squeaks and chirps like a synthesizer. But the next morning, words magically began to come back alive out of the chaos. First, single familiar words, then more and more, clearer than years before. Still with only one ear, it is a bit hard to distinguish a sound source. Far sounds may sound near. The sounds among many can be lost in the mix. Retraining what the brain hears improves with time. What about really loud sounds? The device is designed to quickly cancel any sound that is above a safe decibel level. Patterns of listening types are programmable on my smartphone directly to the processor. The volume can also be adjusted. Sounds now seem often too loud, so the volume can be turned down.
God is perfect in all His ways. What we have to look forward to is this: our great God who is the builder and maker and designer of our bodies will be at work again when He returns. The skill of God is immediate. “Behold, I tell you a mystery: We shall not all sleep, but we shall all be changed. In a moment, in the twinkling of an eye, at the last trumpet…We shall be changed” (1 Corinthians 15:51,52). We will then be able to see the face of God and His joy. “He will joy over you with singing” (Zephaniah 3:17). The curse will be ended. With forever-bodies we will grow up in the perfection of His likeness.