The real, profound worth of life is revealed when one’s life is dedicated to the well-being of humanity. It thus gains an otherworldly dimension and attains a quality comparable to that of the dwellers of heaven. Centering life around such an ideal renders one’s life many times more fruitful. Those awakened souls experience such a state of rapture that it cannot be contained in a single lifetime. Then they begin to feel this cramped world as if it were but one of the spacious relieving climes of the eternal realms. Such individuals aspire to breathe life into everybody. With every revival they inspire, their hearts overflow with exuberance, as if they too are experiencing a resurrection on the path of being a life for other souls. Saving a single person is akin to saving all of humanity, says the Divine word, and this message constantly rings in the ears of their hearts.

Given that even a single human life in this transient world bears this much importance, it isn’t an exaggeration to say that an endeavor for a worldwide revival is likely to break the scales of good deeds on the Day of Judgment. With a zest for blowing life into others, a champion of revival is ever-conscious of the fact that humanity has been blessed with the best pattern of creation amongst all living creatures. These champions feel that the consciences of those who are spiritually paralyzed resemble a grim autumn scene. They are so compelled by their mission that ceasing it would qualify as a sinful act. They compose melodies of revival from the tongues of their hearts for those in spiritual death throes; they run to help these lost ones, as if running from one intensive care unit to the next.

This exhausting run is nothing to be overstated in their eyes. They spur their free will on toward the horizons of lofty ideals as being truly human necessitates. They serve as guides on this path of idealism for those who do not know the way, blow energy into those weary of walking, and become compasses for the masses who are without navigation. To those who have their backs to the sun and so keep following only their own shadow, they inspire them always to return to the source of light. These people become a support and prop for those who are weak and prone to stumble, and provide guardianship for those who are left crawling in misery from the impact of various calamities. They try to soothe sobs echoing on all sides, share the troubles of the wearied ones, forbear various separations with the resolve to keep company with the needy, and come between the growls of oppressors and groans of the oppressed. They keep running like firemen to extinguish one fire after another. As this sense of revival is preserved deep in their consciences, they strive to fulfill this spiritual endeavor in sincerity and only for Divine approval.

A person with this depth of feeling and thought brings to mind the notion of the “journey from God”; they are in a constant state of metaphysical vigilance. Their groans are their pain at how to bring happiness to others instead of themselves. They seek to effect peace in the hearts of others instead of self-indulging in the pleasures of this world. They view life always from a perspective of the sufferings and joys of others and build torches along the path of those who try to make their way through darkness. Reaching success is dependent on making others succeed; they regard indifference to laments as akin to being a mute devil and see remaining lively as conditional to blowing life into others; walkers on the path of Divine guides are their inheritors.

These actions by champions of revival yield such surprise fruits when the due time comes; they are like a kernel in the soil that flourishes into some 20-30 ears. It gives messages of being modest to hundreds of thousands of people and encourages smiles all around as hundreds of new ones have begun walking as one.

Jacobs J. et al. Direct recordings of grid-like neuronal activity in human spatial navigation. Nature Neuroscience, 2013

Do you happen to have a poor sense of direction? Do you often find yourself holding a map upside-down? Well, now you can blame your grid cells. Using direct human brain recordings, researchers have identified a novel type of cell in the brain that helps people keep track of their relative location while navigating through an unfamiliar environment. Scientists got this rare opportunity to identify these unique cells while they studied brain recordings of epilepsy patients via electrodes implanted deep inside their brains. These cells have been called “grid cells” because they are activated in a triangular grid pattern. The “grid cell” is distinct among brain cells because its activation represents multiple spatial locations, which allows the brain to keep track of navigational cues, such as how far you are from a starting point or your last turn. This type of navigation is called path integration. During brain recordings, 14 study participants were asked to play a video game where they ride a virtual bicycle to navigate from one point to another to retrieve objects and then recall how to get back to the places where they found the objects. While participants were playing the game, researchers examined the relation between navigation and the corresponding activity of individual neurons. Results were striking: each grid cell responded at multiple spatial locations that were arranged in the shape of a grid suggesting that the navigation information is principally encoded in our brains through this triangular grid pattern. Without grid cells, humans would frequently get lost or have to navigate based solely on landmarks. Differences in how well the grid cells work could potentially explain why some people have a better sense of direction than others. In addition, grid cells are located in the entorhinal cortex which is a critical component of human memory. The entorhinal cortex is also the first brain region affected in Alzheimer’s disease. Thus, understanding how grid cells work could potentially help us to understand why people with Alzheimer’s frequently become disoriented as well as to develop new strategies to improve brain function in the affected individuals.

Giant viruses open Pandora’s box

Philippe N. et al. Pandoraviruses: amoeba viruses with genomes up to 2.5 Mb reaching that of parasitic eukaryotes. Science, 2013 Jul 19

On a fairly ordinary day, two French biologists were analyzing water samples collected off the coast of Chile. What they saw under the microscope was quite amazing: a previously unidentified organism, about the size of a bacterial cell, appeared as a large dark spot. Astonishingly, these new organisms seemed to be infecting and killing the amoeba in the water. Later, another group of researchers found a similar organism in a pond in Australia. Both groups soon realized that they discovered a type of “giant” virus which is at least twice as big as the largest known viruses. The biggest virus discovered so far was called Mimiviruses, with a size of 700 nanometers and carrying more than 1000 genes. The newly discovered viruses are called Pandoraviruses, which are 1 micrometer long and 0.5 micrometers across. Pandoraviruses are visible under a light microscope and contain more than 2500 genes. A viral genome consisting of 2500 genes is extremely large compared to known viruses, such as the Influenza or HIV, which only contain 10 genes or less. More importantly, 93% of the genes did not resemble any known lineage in the natural world, suggesting Pandoraviruses are not related to any known virus family and may represent a new life form. These findings generated new perspectives about how scientists see viruses. It raised the possibility that there might be many different kinds of giant viruses out there to be discovered. Some biological features in these giant viruses could easily blur the line between life forms and viruses, which are considered to be non-living. Although Pandoraviruses do not infect human cells, there might be other giant viruses out there that could infect human cells. There are still a lot of human diseases known to have an infectious component but for which no infectious agent has been identified yet. This study will definitely encourage people to actively look for the role of giant viruses in some diseases.

See through the Ears

Haigh A. et al. How well do you see what you hear? The acuity of visual-to-auditory sensory substitution. Frontiers in Psychology, 2013 Jun 18

Scientists have created a revolutionary device for the blind that allows them see the world through their ears. The device “vOICe” trains the brain to invoke mental images of what they are hearing around them. The first test trial of vOICe has been performed on blindfolded sighted people. The participants took a standard eye test where they were asked to view the letter E turned in four directions and in various sizes. The best visual acuity is considered 20/20 (distance in feet/size of the E) and the majority of participants were able to achieve the best performance possible, nearly 20/400 sight. This is an impressive result when compared to an alternative stem-cell based sight restoration technique, which only yielded 20/800 visual acuity. In addition, the affordable and non-invasive nature of vOICe would offer a unique option. But, how might this work in practice? One can imagine that visually-impaired people would wear a discreet head-mounted camera such as Google Glass and receive wireless audio information through mini earbuds. As the person turns to look in various directions, the device scans images and correlates those with soundscapes, then the person’s brain would momentarily translate those into mental images of the objects — like braille for the ears. These sensory substitution devices could potentially be employed in combination with other alternative invasive techniques to train the brain to see again, or even to see for the first time.

Funny though, sometimes while walking in the enchantment of the awakening nature around me, I run into a tree, and I hug it as if I met a friend. You can imagine how entertaining I am to the passers-by.

It was one of those days when I felt the presence of a second person near me. Strange enough, though, he wasn’t laughing at my hugging the tree.

“Hi fellow, what is wrong with you? Why aren’t you laughing at this lunatic who is in love with trees instead of people?” I asked.

I was shocked upon hearing his answer:

“The sight of people is of no value to me because I cannot see the light coming from them. But you are certainly shining through your voice.
“For me, people shine through their presence; they change my heart beat.”

I exhaled the air that was hiding in my lungs with anxiety, and teased: “So, I should be careful when I am talking to you since I cannot hide my true feelings from you!”

“You bet. But don’t worry; your voice is giving me positive signals.”

Then, I quickly returned: “I am happy to hear that. So, shall we play a game together?”

“Like what?”

“Alright. Only by listening, we are going to try to predict the coming of the next person.”

“I’ll take your challenge,” he said.

And, we kept silent in order not to miss the clues of an approaching person. Believe it or not, we waited for minutes and not a single person passed by. We could hear voices of kids running in the distance, wind rubbing the leaves, trunks of the trees squeaking as they swing, flies, birds flying or landing, etc., but not a single person passing by. Suddenly he said:

“Maybe we should play something else.”

“You know what? You are the ever first person with whom I can play the game of solitude. We are together but not like cans on a shelf. We are together like two flowers smiling at each other although we cannot see or hear one another. Outsiders may think we are lonely. But in essence, we are hand in hand in the depths of our hearts.”

“It is strange that you say this. Why should you enjoy solitude?” he asked.

I did not answer that question. Actually my silence was the answer; and I think, or hope, he got my answer. I didn’t want my discovery of a solitude-mate to disappear so abrupt.

“Here comes one!” he exclaimed. I could feel his joy of catching the first person. I smiled; and he felt it because I give out a warm and vibrating breath when I smile.

“It is so alive,” he said.

“What? The person?” I was startled. Why was he using “it” for a person?

“No, your smile. I don’t feel many smiles like yours. I usually hear frozen laughs and smiles of mass-production, which carry no sincerity.”

I was embarrassed by his compliment. Again I kept silent, but my face was burning up, and he felt that as well.

“Now you are as flushed as I was when we started talking.”

“Yeah, what had happened to you? Why were you so flushed earlier?” I inquired.

“I climb this tree often. I actually do this whenever there is nice weather. Sometimes, I feel the footsteps of someone, whom I want to catch. I rush down to the ground hoping not to miss the encounter. But always, I miss the person. Now, that spirit is standing before me.”

Once more, I was embarrassed. I didn’t know what to say. We both kept silent for a while. Then, I heard my daughter calling: “Dad, it’s time.”

She was the one predicted by my solitude-mate.

“Forgive me for disturbing your conversation,” she added.

“A conversation by presence cannot be disturbed by words,” replied my friend. We all chuckled.

I felt my daughter pulling my arm – an authoritative sign meaning “let’s go.” I grasped her hand firmly, turned back to my solitude-mate, and gave a goodbye silence, and he did the same to me. Then I gave him that lively smile, and he went through that shower of heat. I picked up my cane and started knocking on his ears again as I returned home with my daughter as my guide.

He has granted you from all that you ask Him. Were you to attempt to count God’s blessings, you could not compute them. But for sure, humankind is much prone to wrongdoing (sins and errors of judgment) and to ingratitude. (Ibrahim 14:34)

Today a large part of modern science focuses on understanding the human body. Researchers working on life sciences hope that one day the secrets of every single detail that make us human will be revealed. Every year billions of dollars are spent by scientific institutions on learning more about us. Actually this fact by itself is enough to suggest how little control we have over things happening in our bodies, and we know even less about the mechanisms of moving, touching, speaking, seeing, or hearing, and so on.

As a scientist, I really cannot guess whether life scientists will ever be able to learn enough to solve the puzzles of the human body, but I feel a lack of satisfaction when the knowledge we have gained from scientific discoveries is compared with what is unknown. In my opinion this is why one of the most intelligent physicists in history, the Nobel laureate Richard Feynman, once said, “I was born not knowing, and have only had a little time to change that here and there” [1]. My understanding is that such a conclusion must be inevitable if the primitive knowledge given to us by modern sciences is not interpreted in the light of a far superior logic that is meant to explain the whole creation. In that sense, I believe that we have to consider every single detail in creation as a vital part of the whole in order not to feel lost before the grand picture of this masterpiece.

Last year, in a seminar at Osaka University Graduate School for Frontier BioSciences, I was thrilled to hear Professor Keichi Namba say, “Japan’s fastest supercomputer dissipates more than billion times the power dissipated by a fly’s brain, yet it is not able to simulate the brain of such a tiny animal.” This worked as a wakening call or a reminder for me to think again about the magnificent arts of the Creator. In particular, I wanted to revise my research on a hearing-related protein from a new perspective, rather than using the mechanical attitude that is followed most of the time.

This article is an attempt to explain an amazing mechanism in our ears that enables us to hear the faintest whispers. A mechanism that is switched off at loud cries to protect us from disturbing noises, yet amplified to make the softest sounds audible. Before starting to explain the basic anatomy of the human ear, I should mention that today the ear’s active amplification mechanism is still being investigated in research centers by biologists and physicists together.

How do we hear? What is happening in the inner ear?

Findings from the last century have shown that our ears are not just simple receivers as we had imagined. In 1979, David Kemp of University College, London discovered that mammalian ears can also emit sound vibrations. By placing a very sensitive microphone close to the eardrum he could detect whistles, implying that there is a source of vibration within the ear [2]. However, before trying to explain the cause of vibrations in the ears, we have to go over the mechanism of hearing briefly: The delicate design of the outer ear, the tympanic membrane (eardrum), and the tiny bones (malleus, incus and stapes) enables to collect sound waves traveling in the medium and transfer them to the inner ear (Figure 1a). In the inner ear the sound waves are sorted according to their frequency and amplitudes and then converted into electrical signals which can be transported to the brain via nerves. At the onset of this process the sound waves are transformed into standing waves on the basilar membrane which is laid along the organ resembling a snail, the cochlea (Figure 1b). The frequency of the incoming sound wave determines the positions of the distortions along the cochlea: High pitches create vibrations at the basal end of the cochlea (i.e. adjacent to the middle ear) whereas low frequencies vibrate closer to the apical end (Figure 1c) where the cochlea gets narrower. This geometry helps our ears to act as a frequency analyzer.

The efferent and afferent nerves that connect the ear to the central nervous system are attached to the organ of Corti, which is situated right next to the basilar membrane, extending over the cochlea. In other words, Corti is the sense organ of hearing, converting the motion of the basilar membrane into electrical signals that are conducted to the brain via neuronal cells [3]. The organ of Corti is also lined with multiple rows of sensory hair cells.

The hair cells of the organ of Corti

Corti is decorated with two different sets of sensory cells: single row of inner hair cells (IHCs) accompanied with 3–4 rows of outer hair cells (OHCs), both spanning the whole cochlear tube (Figure 2a). They are called “hair cells” because both IHCs and OHCs have typical bundles of stereocilia that contain mechanosensitive ion channels (Figure 2b).

The major function of IHCs is to detect the sound waves and then convert them into equivalent electrical signals that are to be interpreted by the brain. When the basilar membrane is perturbed by the incoming sound waves, the IHCs found in that region sense this activity by the movement of their hair bundles (bundles of stereocilia). The hair bundles of IHCs deflect and re-align as the basilar membrane moves up and down (Figure 3). We should note that this is an amazingly sensitive process such that deflections of the stereocilia on the order of a few nanometers (one millionth of a millimeter) can be detected and converted into nerve signals by the IHCs [4].

However, this by itself is not sufficient for hearing; no matter how effective IHCs work, the fluid that fills the cochlear tube is a threat to the sound waves traveling in the inner ear. In 1948, a young astrophysicist named Thomas Gold was the first person who has pointed out that the fluidic nature of the cochlea would dampen the sound vibrations and make them too weak to be detected by IHCs. He has concluded that an inherent vibration amplification mechanism is necessary in order to overcome such a problem [5]. Unfortunately, Gold’s statements were overlooked by the physiologists of his time who had performed their hearing related experiments on dead cochleas.

Gold’s predictions were justified around ten years later by William Rhode, a physiologist from University of Wisconsin, who has shown that the vibrations of the basilar membrane in live tissue samples are stronger than anticipated [6]. In the present day the existence of an amplification mechanism within a live cochlea is a well accepted fact. The only disagreement among scientists is about how the mechanism of the amplification works. Several scientific laboratories have reported different experiments performed on the organ of Corti and they have proposed different models. At the center of one of these models is prestin, a membrane protein which is not found in any cell but OHCs in the human body.

Electro-motile outer hair cells and prestin

In 1985, the distinctive properties of OHCs were first discovered by William Brownell, a University of Geneva neuroscientist, who has shown that these cells can convert electrical signals into motion: A phenomenon called electromotility. Electromotile OHCs can elongate or shrink in response to electrical charge density changes in their membranes. About a decade ago Peter Dallos and co-workers from Northwestern University in Chicago discovered a membrane protein, unique to OHCs, that can respond to electrical signals [3]. The Dallos group coined the name “prestin” for this protein in an analogy with the musical term “presto” (quickly) due to its rapid response to electrical signals. Various kinds of mammalian cells genetically engineered to produce prestin at their membranes displayed the electromotile responses that are very similar to OHCs.

According to Peter Dallos prestin protein works as a tiny machine which is a crucial element for cochlear amplification [7]. His theory is verified by recent studies which show that cochlear sensitivity in mice decreases hundredfold when prestin activity is disrupted by genetic means [8]. As the sound waves reach the inner ear, prestin-driven electromotility enables the OHCs to move like pistons. The piston movement in phase with the basilar membrane motion amplifies the vibrations and makes them stronger for IHC detection (Figure 4a,b). The prestin-driven vibrations were what Thomas Gold proposed and David Kemp had detected so many years ago. However, scientists are still searching and learning new things about this nanometer scale machine. One of the discoveries showed that prestin can adjust itself according to the amplitude of the incoming sound waves: Basically, the amplification is stronger when the sound waves are hard to hear but gets weaker as the volume increases.

Up to this point, we have briefly explained how the amplification mechanism of hearing in mammals works. Unfortunately, even though it took decades of research for scientists to discover and define the active nature of the mammalian ear, this explanation highlights only a minuscule part of the whole picture. That is why we are still incapable of curing most hearing problems. For example, hearing loss due to slightly disturbed hair cells with damaged stereocilia turns out to be chronic (Figure 5). The medical treatments we have to hand are too primitive to mend such delicate structures. Moreover, hearing aids made by today’s technology are not nearly as effective and functional as needed.

On the other hand, the delicacy of the hair cells and the limited control scientists have over them are not the only lessons we have learned from research on the inner ear. We cannot overlook the other messages attached to the research on the grounds that the time given to us is just too short to comprehend. It is an undeniable fact that the sense of hearing is designed in the best way to serve human beings. The different characteristics of hearing amplification at different sound levels make life much easier for us: Prestin-driven hearing is most effective when the sound waves are weak and harder to hear. This way the incoming sound waves are amplified enabling us to hear the faintest whispers. However, as the sound strength increases, the prestin-driven amplification gradually gets weaker and finally diminishes after a point to make sure that loud noises are less disturbing and hazardous for us. In my opinion, this amazing quality of a tiny protein found in our ears is one of the pieces of evidence that remind us of the necessity of pondering the favors of our Creator. Qur’anic verses such as Ibrahim 34 at the beginning of this article give us clues about how to interpret scientific findings that reveal the amazing qualities of our bodily organs. May the Creator of our ears allow us to reflect more on His favors and live accordingly.

Hamdi Sener is a biophysicist living in Boston. He can be contacted at hamdisener@gmail.com.

References

1. Gleick, J., Genius: The Life and Science of Richard Feynman. Reprint ed. 1993: Vintage. 560.
2. Kemp, D.T., The evoked cochlear mechanical response and the auditory microstructure- evidence for a new element in cochlear mechanics. Scand Audiol Suppl., 1979. 9: p. 35–47.
3. Zheng, J., et al., Prestin is the motor protein of cochlear outer hair cells. Nature, 2000. 405(6783): p. 149–55.
4. Robles, L. and M.A. Ruggero, Mechanics of the mammalian cochlea. Physiol Rev., 2001. 81(3): p. 1305–52.
5. Gold, T., Hearing II. The physical basis of the action of the cochlea. Proc. Roy. Soc. B., 1948. 135: p. 492–498.
6. Rhode, W.S., Observations of the vibration of the basilar membrane in squirrel monkeys using the Mossbauer technique. J. Acoust. Soc. Am. , 1971. 49: p. 1218–1231.
7. Cho, A., What’s Shakin’ in the ear? Science, 2000. 288: p. 1954-1955.
8. Liberman, M.C., et al., Prestin is required for electromotility of the outer hair cell and for the cochlear amplifier. Nature, 2003. 419: p. 300-304.
9. Fettiplace, R. and C.M. Hackney, The sensory and motor roles of auditory hair cells. Nat Rev Neurosci., 2006. 7(1): p. 19-29.
10. Dallos, P. and B. Fakler, Prestin, a new type of motor protein. Nat Rev Mol Cell Biol, 2002. 3(2): p. 104-11.

Looks ecstatic with a Godly gown,

With spangled Paradise all around,

Proclaims Who holds the crown.

In the broad wondrous sky on high

Like an imperial azure eye,

Evoking awe beyond confusion,

Our Lord displays His heavenly dye.

The moon twitters with solemn impulsion

Amidst the shooting stars and the sun,

Ears and eyes of enthusiasm, deeply enjoys

How its Glorious Lord has revealed His art.

Power and dominion under His Hand,

The soil, the air, the water, surrender.

Every being adores the same Lord

While every entity reflects His splendor.

Victor H. Earnest

The human ear and hearing

The human ear can be divided into several functional sections: the outer ear, the middle ear, the inner ear, and the auditory nerve. Sound goes through a series of changes as it travels through these sections until reaching the brain. The outer ear picks up sound pressure waves, amplifies them and then converts them into mechanical vibrations on the ear drum, which is connected to a series of small bones in the middle ear. These small bones further amplify or diminish the mechanical vibrations in the ear drum and transfer them to the cochlea, a snail-shaped cavity filled with fluid which is located in the inner ear. Change in fluid pressure caused by vibrations within the cochlea lead to changes in the flexible membrane, called the basilar membrane. These changes contain information about the frequency and strength of the sound that has entered the ear. Attached to the basilar membrane are mechanical receptor cells, called hair cells, which are bent according to the deflections of the basilar membrane.The hair cells have hair-like structures. The bending of these hairs assists the release of an electrochemical substance that causes neurons to send electrical signals to the brainstem through the auditory nerve. These signals are in the form of a message (or a code) that the brain understands.

Cochlear Implant (CI) devices

If there is a broken link in any part of the auditory pathway, the brain does not receive any coded signals, and hearing impairment occurs. If a large number of hair cells or auditory neurons in the cochlea have been damaged, then the person is diagnosed as profoundly deaf. The hair cells can be damaged by certain diseases (e.g., meningitis, Meniere’s disease), by congenital disorders, by certain drug treatments, or by other causes. One negative outcome of damaged hair cells is that they can subsequently lead to the degeneration of adjacent auditory neurons. Research has indicated that the most common cause of deafness is the loss of hair cells (>95%) rather than the loss of auditory neurons. This has encouraged scientists to try implanting a device inside the iner ear or cochlea, bypassing the normal hearing mechanism of the ear, to stimulate the remaining auditory neurons directly through electrical signals. These are called Cochlear Implant (CI) devices, which can restore partial hearing in profoundly deaf people . A standard CI system, shown in Figure 1, composes of and performs the following functions: a microphone picks up sound pressure waves and converts these into electrical signals. The signals are sent to the speech processor that is worn by the patient. The speech processor analyzes and encodes these sound signals, sending them back to the external pick-up coil . After passing through a wireless radio link that lies between the external and implanted coils and an implanted electronic devise, coded signals are sent to the implanted array of electrodes in the cochlea to electrically stimulate the remaining auditory neurons , and the brain receives what it interprets to be sound.

Electrical stimulation of the ear, or CI research, can be traced back to the 1800s. The Italian scientist Alessandro Volta used a battery as a research instrument to demonstrate that electric stimulation could result in a number of human sensations . After connecting a 50- volt battery to his ears, he noted that “…at the moment when the circuit was completed, I received a shock in the head, and some moments after I began to hear a sound, or rather noise in the ears, which I cannot well define: it was a kind of crackling with shocks, as if some paste or tenacious matter had been boiling…”. That electric stimulation of the auditory nerve provides hearing sensation in deaf people was reported more than 100 years after Volta . Electric stimulation in two deaf patients resulting in hearing was reported in 1957. These successes resulted in intensive research into helping deaf people hear in the 1960s and 1970s. One of the early successful single-channel CI devices was developed in the early 1970’s (3MCorp/House) and became the first commercially available CI device approved in the United States in 1984. The University of Utah developed a six electrode implant called the Ineraid or the Symbion device in the early 1990s. It was followed by other devices in Europe, the United States, and Australia.

The present status of Cochlear Implants

Today, around 10% of the population in developed countries suffers from hearing impairment. At present, the number of CI users has reached more than 100,000 worldwide, and is still growing rapidly. Functionally, CI has evolved from the single-electrode device that was used as an aid for lip-reading and

sound awareness to a modern, multielectrode device that can allow an average user to talk on the telephone. Even though significant technological progress has been achieved in the last 50 years, there are still many mysteries about the human hearing process and the parts of the ear. Here, we will compare some aspects of the healthy human ear and CI devices, looking to the future. The human ear operates over a range of sound pressures (its dynamic range) which is greater than one million to one (120dB), with as many as 200 discrete steps in the range. In contrast, today’s CI devices typically provide a dynamic range of three to one (10dB) to ten to one (20dB) with 20 discrete steps. This major difference is mainly due to the fact that the human ear is very adaptive in noisy environments, and is able to suppress noisy background, while picking up and processing appropriate sound signals for better perception. CIs do not differentiate between sounds, but amplify all sounds, which results in poor sound perception. Today, a typical multi-channel CI system uses 16 to 24 electrodes implanted in the cochlea with 8 to 22 signal processing channels. A potential shortcoming of having so many electrodes and channels in current CI technology is the electrical interference of electrodes during simultaneous electrode stimulation. These electrical interactions can disrupt the stimulus waveform prior to neural activity and degrade sound perception. The normal ear contains roughly 3,500 inner hair cells in the cochlea that are tuned to different frequencies from 20 to 20,000 Hz. They are connected to about 35,000 auditory nerves. Hair cells work as signal processing channels, yet each of the inner hair cells has also been wired in a sophisticated and little-understood fashion to 10-20 auditory nerve fibers that carry information to the central nervous system. Since they work in the chemical domain, they do not have the gross interference issues of CI electrodes. While good speech understanding has been achieved by users of modern multi-electrode CIs operating in quiet environments with 70–80% sentence recognition, allowing users to talk on the telephone, the CI devices do not discriminate between noise and the meaningful signals, only achieving speech understanding at between 70% and 80%, which falls to 10% or lower in noisy environments. It is a great challenge for CI users to appreciate music. Some CI listeners reported that they can enjoy music and are able to recognize melodies, but most described musicas sounding unpleasant and noisy, and performance could not be increased with current CI technology. CI users have difficulty in identifying differences in frequencies. Typically, they cannot discriminate any frequency difference for frequencies higher than 500 Hz, while the normal ear can hear up to 20,000 Hz with frequency discrimination between 2 to 3Hz at best. This gross difference is related to the issues surrounding signal processing strategies and electrodes of current CI systems. Predicting post-surgical performance based on presurgical conditions and tests of a CI candidate is still a problem for the physician. The cost of surgery is still high; in the United States, for example, a typical cost is between $40,000 and $75,000. Beyond these issues, the moral, cultural and ethical issues related to CIs are very complex. They are still debated, and are an important part of CI development in the world today. The hair cells in the human ear naturally deteriorate and die as we grow older. This process is typically sped up with exposure to loud noise. In common with all mammals, new hair cell generation in human ears stops right after the birth. However, in fish and amphibians, very similar cells are present and reproduce throughout life. Recently, it was found that hair cells of birds are repaired after being damaged by exposure to noise or ototoxic agents. It was also discovered that hair cells in the mammalian vestibular (balance) organ, very similar to those in the hearing system, can regenerate. These findings, along with other advancements in medical fields, lead to long-term research into different aids for hearing- impaired people. Despite the fact that hearing loss is usually permanent, scientists are optimistic that it may eventually be possible to reverse the damage in the ear by repairing or regenerating the sensory hair cells through gene therapy, stem cell transplantation, or ultimately by replacing the human cochlea with an artificial one. Today, Auditory Brainstem Implants are also being tried on humans for direct brainstem stimulation, bypassing the ears and the auditory nerves. Human beings and most animals on earth are born and equipped with a pair of ears for a good reason: having two ears enhances hearing and sound localization. Scientists are examining whether this is also true for deaf children who receive not one, but two CIs.

Conclusion

The sense of hearing is a gift for human beings which they hold dear and are grateful for, as much as for any of the other senses with which they have been equipped. It is important to strive to find cures for all kind of diseases, yet, more important than the cure is prevention of harm to our body and its amazing senses. Here, we have tried to open a small window onto human hearing, to examine how related impairments are being dealt with through cochlear implant (CI) devices, as well as looking at the issues related to these devices and the future directions of research for restoring hearing to deaf people. It is obvious that we have learned much about human hearing and ear in the past century; yet, this may well be just the tip of the iceberg.

References

1. S.U. Ay, F.-G. Zeng, B.J. Sheu, “ Hearing with bionic ear,” IEEE Circuits & Devices Magazine, Vol. 13, No. 3, pp.18-23, May 1997.

2. F.-G. Zeng, “Trends in cochlear implants,” Trends in Amplification, Vol. 8(1), pp.1-34, 2004.

3. A. Volta, “On the electricity excited by mere contact of conducting substances of different kinds,” Royal Soc. Philos.Trans., vol. 90, pp.403 431, 1800.

4. A.M. Andreev, G.V. Gersuni, A.A.Volokhov, “On the electrical excitability of the human ear: On the effect of alternating currents on the affected auditory apparatus,” Journal of Physiology USSR, Vol. 18, pp.250-265, 1935.

We have been brought up in an atmosphere in which the victories of love are in our eyes and the sound of the drums of love resounds in our hearts. Our hearts beat with excitement when we see the flag of love waving. We have become so intertwined with love that our lives become purely dependent on love, and we dedicate our souls to it. When we live, we live with love, and when we die, we die with love. In every breath, we feel it with our whole existence; it is our warmth in the cold, and our oasis in the heat.

In this over-polluted world, where evil is everywhere, if there is something that has been left untouched and clean, that is love; among all the fading ornaments of this life, if there is a beauty that has preserved its magnificence and charm without fading, that is also love. There is nothing more real or more lasting than love in any nation or society in this world. Wherever the sound of love, softer and warmer than a lullaby, is heard, all other voices, all instruments, are muted, and they all join together in a contemplation of silence with their most melodic strains.

Creation is the result of lighting the wick of the candle of love, the wick of “being known and seen.” If the Lord did not love creation, there would be neither moons, nor suns nor stars. The heavens are all poems of love, with the Earth being the rhyme. In nature, the heavy blow of love is felt, and in relationships between people, the flag of love can be seen to wave. In society, if there is a currency that maintains its value, it is love, and again the value of love is found in itself. Love weighs more if weighed against with the purest gold. Both gold and silver can lose their value in different markets and places, but the doors of love are closed to any kind of pessimism and nothing can alter its inner stability and harmony. Up to this very moment, only those who are immersed in hatred, wrath and enmity plan to resist and struggle against love. Ironically, the only cure that will calm these brutal souls is love. Beyond the effect of worldly treasures there are other problems that only the mystical keys of love can solve. It is not possible that any value on this earth can overcome or even compete with love. The cartels of gold, silver, coin, or any other object of value, are almost always conquered in this marathon by the devotees of affection and love. When the day comes, despite all the splendid, pompous life styles of the owners of material wealth, their coffers are empty, their fires have burned out; yet the candle of love always burns, giving light and diffusing this into our hearts and souls.

Those fortunate people who have kneeled in front of the altar of affection and who have devoted their lives to spreading love have not left even the smallest space in their vocabulary for words like hatred, wrath, conspiracy, or resentment, and even if it means putting their very lives at risk, they have never indulged in enmity. Their heads are humbly bowed, filled with love, they have never greeted anything other than love. When they rise, feelings of enmity try to find a haven in which to hide, feelings of hatred become jealous, recoiling from the blow delivered by love.

The only magic, the only spell that can destroy the tricks of Satan, is love. The messengers and prophets extinguished the fires of hatred and jealousy kindled by the pharaohs, the Nimrods, and other tyrannous kings; they used nothing but love. The saints have tried to gather together the undisciplined and rebellious souls, spread all over like loose pages; they have used love to try to introduce humane behavior to others. The power of love was great enough to break the spells of Harut and Marut,* and effective enough to extinguish the fires of Hell. Hence, there is no doubt that a person who is armored with love needs no other weapon. Indeed, love is strong enough to stop a bullet or even a canon ball.

Our interest in our environment and our love for humankind – that is, our ability to embrace creation – depends on knowing and understanding our own essence, our ability to discover ourselves, and to feel a connection with our Creator. In parallel with the ability to discover and feel our inner depths and hidden potential within our essence, we will also be able to appreciate that others also possess the same potential. Moreover, because these inner values are directly related to the Creator, and because a respect for the riches that are hidden in every creature is nurtured, we will start to see every living thing from a different perspective and in a different manner. In reality, the level of our understanding and appreciation of one another depends on how well we recognize the qualities and riches that each person possesses. We can summarize this concept with a thought based on a saying of the Prophet, peace and blessings be upon him, “A believer is the mirror of another believer.” We can enlarge on this saying as “a human is a mirror of another human.” If we are able to succeed in doing this, as well as being able to understand and appreciate the riches hidden within every person, we will also understand how to relate these riches to their true Owner, and thus we will accept that anything in this universe that is beautiful, affectionate, or loving belongs to Him. A soul that can sense this depth says, as did Rumi, a famous Muslim saint, presenting us tales from the language of the heart: “Come, come and join us, as we are the people of love devoted to God! Come, come through the door of love and join us and sit with us. Come, let us speak one to another through our hearts. Let us speak secretly, without ears and eyes. Let us laugh together without lips or sound, let us laugh like the roses. Like thought, let us see each other without any words or sound. Since we are all the same, let us call each other from our hearts, we won’t use our lips or tongue. As our hands are clasped together, let us talk about it.”

In our present culture, it is not so easy to witness such a deep understanding of these humane feelings and values; we cannot find these easily in Greek or Latin thought or in Western philosophy. Islamic thought sees each one of us as a different manifestation of a unique ore, as different aspects of one reality. Indeed, the people who have gathered around common points, such as the Oneness of God, the Prophet and the religion resemble the limbs of a body. The hand does not need to compete with the foot, the tongue does not criticize the lips, the eye does not see the mistakes of the ears, the heart does not struggle with the mind.

As we are all limbs of the same body, we should cease this duality that violates our very union. We should clear the way to unite people; this is one of the greatest ways in which God grants people success in this world, and how He transforms this world into a Paradise. It is in this way that the doors of Heaven will be opened wide in order to give us a warm welcome. Hence, we should remove all ideas and feelings that pull us apart, and run to embrace one another.

* Two angels, whose story is told in the Qur’an (2:102), taught the fundamentals of magic to people and warned them against abusing it.