Some of the incidents we are experiencing today might seem as if they have no precedent – this is both true and false; yes, no precedents on the scale we see today; and no, for violence is something we human beings have always been prone to. Thus, peacebuilding is not possible via revisions in educational policies alone; it is to a no lesser degree relevant to human character, virtue, and moral development. And these are some of the discussions you will find in our coverage in this issue.

The lead article focuses on value transmission in education of the young and how it is so critical for a nation to maintain its existence. Johnston McMaster discusses pluralist democracy and global citizenship as two main goals which education should be geared towards. Michael A. Samuel shares his observation of Turkish teachers inspired from Fethullah Gülen and the Hizmet philosophy who migrated to South Africa with a sense of “responsibility to guide the world to a better realization of its potential fullness of being; towards a greater goal of good.” Zekeriya Ozsoy warns teachers that an imbalanced conduct of reward might shift the motivation of some students to material prizes and cause them lose their intrinsic capacity to strive and achieve.

Two special contributions from Nigeria give us hope that sound-thinking leaders and scholars might enable this African star to be rescued from the current violence based on religious and ethnic differences.

Original Article: Lewis, G.D. et al., Science Translational Medicine 2, 33 (2010).

Visits to biochemistry labs are frequent in our lives. Often we give blood to know levels of different metabolites, such as glucose or cholesterol. Instead of looking at a handful of metabolites, a group of scientists from Harvard Medical School has screened more than 200 metabolites before and after exercise. Interestingly, the levels of 21 of these metabolites changed significantly following exercise. The study also showed significant differences between physically more fit and less fit individuals after exercise. Following exercise, more fit people had greater increases in the biological markers of fat-burning and had decreased oxidative stress -a state where the balance between oxidants and antioxidants shift towards damaging oxidant side. Hence, fit people can get better results following exercise by efficiently removing waste materials. Moreover, exercise increased the levels of “niacinamide”, a compound which modulates insulin sensitivity. This increase was more prominent in leaner individuals and was maximized in fast marathon runners after exercise. It has been long known that obese and less-active individuals had greater tendencies to develop Type II diabetes where insulin action is impaired due to decreased sensitivity of the body to this molecule. Understanding the biochemistry behind the exercise may lead to identification of small molecules mediating its beneficial effects. These molecules may then be used to boost up metabolism or treat diseases. Until then, it is best to exercise and stay fit.

2- Our scents make us targets

Original Article: Carey, A.F. et al., Nature 464, 66 (2010).

Are you avoiding spending time outdoors in summer evenings because most of your time has to be spent chasing away the unwelcomed attention of mosquitoes? If so, then you must be one of those “lucky” people whose perspiration contains a key chemical that makes you irresistible to the six-legged bug. Scientists at Yale University have identified a key chemical compound that is detected by one of the mosquitoes’ 27 smell-receptors in their antenna. These smell-receptors are tuned to detect the key chemicals from hundreds of meters away which make people who secrete large amounts of these key chemicals in their sweat vulnerable to frequent mosquito attacks. Depending on the species, usually only the female mosquitoes bite humans, mainly on their feet or lower legs. More importantly, mosquitoes carry several deadly diseases such as Malaria and West-Nile dengue fever. In fact, Malaria is one of the deadliest and the most neglected diseases, affecting more than 500 million people and killing more than 3 million every year, mostly in sub-Saharan Africa. Sadly, the majority of deaths occur among children. Therefore, these types of studies, far from being trivial, may in fact lead to a better understanding of those mosquito-borne diseases, and hopefully may lead to the production of more effective drugs both for the prevention and the cure of diseases as well as better mosquito repellents and traps.

3- We are not alone in our body: Genomes of microbes living with us

Original Articles: Qin, J. et al., Nature 464, 59 (2010) & The Human Microbiome Jumpstart Reference Strains Consortium, Science 328, 994 (2010).

New advancements in DNA sequencing technology allow scientists to sequence genomes of microorganism living in their natural habitat. Human body contains roughly ten times as many microbes as human cells. As part of Human Microbiome Project, scientists are decoding the DNA sequences of all microbes living in several parts of our body such as skin, mouth, gut, respiratory tract and urogenital tract. Two independent teams from US and Europe have produced the first results of DNA sequences of microbes living with us. The projects have initially focused on bacterial genomes but intent to sequence viral and fungal genomes as well. The US team has generated a set of 178 bacterial reference genomes and is aiming to generate many more. In the second project funded by European Union, scientists sequenced the entire microbial DNA in the gut instead of sequencing them individually. They have sequenced more than 3 million bacterial genes, nearly 150 times more than our own (humans have only ~20 thousand genes). Importantly they have found that bacterial species are different in healthy individuals compared to the individuals with inflammatory bowel disease. Throughout these projects, scientists are trying to reveal significant information about the role of different microbial species in health and disease states.

4- Seeing with the sound

Original Article: Yovel Y et al., Science 327, 701 (2010).

Bats, dolphins, shrews and swiftlets use sound waves for navigation and hunting. They emit short sonar pulses and listen to the echoes reflecting back from solid objects. Microsecond differences in the arrival times of echoes are coded by detector neurons and used as a main cue for positioning objects in an environment. This phenomenon is known as biosonar. A recent study published in Science reveals one unknown part of this perfect sound processing strategy. The study shows that bats do not center the sonar beam on the target. Instead, they aim to match the maximum slope of the beam to the target in order to increase the signal-to- noise ratio. Around the sharp edge, small variations of the target position can be detected as a clear signal change in reflected sound intensity. Furthermore, the researchers showed that if the environment is very noisy, bats could bias this critical point to increase amplitude of the echoes. As it turns, this powerful technique has already been employed by humans in engineering and used in various technological tools such as atomic force microcopy. Whether this strategy is used in general by other echolocating animals remains to be answered.

In our interview with Dr. Charles Townes from California, a Nobel laureate, the core message of the lead article is further developed; Townes notes “the most fundamental and human question is the meaning of life.” According to Townes, religion and science are much more consistent with one another than people think and questions like “why are we here and what should we do? How did life begin, why is the world the way it is?” can be answered by studying both.

In this issue we have two pieces on music. In our interview with Dr. Jeffrey Thompson he notes that sound is used in all cultures on earth “as a prominent technique in healing or religious rites or as a means of attaining a change of consciousness, one way or another.” Starting from being a fetus in our mother’s womb, human beings are first exposed to sound at a younger age and more predominantly than other senses, like sight. Sounds can provide a form of relaxation therapy when the right tones are found and played in a way that connects us to our primordial state, taking us away from the din of our daily activities.

Julie Ann Cunningham discusses the healing power of music in human history and today. She explains how healing was made possible in ancient civilizations from the priest-physicians of Egypt to musicologists and mystics of India to Abu Bakr Razi, who treated patients suffering from depression more than a thousand years ago. For Cunningham, “music is a language that crosses the barriers of human vocal languages.”

We invite you to embark on a journey with us to explore some fascinating perspectives that shed a light on our relationship with sound and music.

Dr. Jeffrey Thompson, the Founder and Director of the Center for Neuroacoustic Research in California (www.neuroacoustic.com), is recognized as a worldwide expert in the field of acoustic pacing frequencies that are incorporated into musical sound tracks. A consummate musician and composer in his own right, he has established a method for using modulated sound-pulses that change states of consciousness for optimal “Mind-Body” healing. Dr. Thompson believes that the sounds in nature resonate with us because they take us back to the beginning of our journey and our primary senses.

Matter&Beyond: Why are sound and music so central for us, both culturally and personally?

I don’t think I’ve found a single culture on earth which at some point hasn’t used sound as a prominent technique in healing, in religious rites, or as a means of attaining a change of consciousness in one way or another. I think the tradition probably dates back to the first use of sound as a soothing or healing means for mothers; that is lullabies for babies.

M&B: Is this our earliest experience with sound? Is this what you call primordial sounds?

If you go back to before the lullabies, we’re talking about womb experiences and it’s one of the primal things we all share; this is what I call primordial sounds. Certain type of sounds have the same influence on anyone who hears it, no matter what age you are, what sex you are, what culture you were brought up in, what language you speak; womb sounds fit that criteria.

M&B: Why is it sound, but not the vision?

Because at 16 weeks, when the fetus is very small, the nervous system is developed enough that all the senses are functioning; however it is dark, so the eyes aren’t working, no information is being received and the nose and the mouth are filled with fluids, so there is no tasting or smelling, but sound travels through water five times better than it does through air; therefore the ears are working but amplified by five times, and the largest sense organ we have, the skin, is a huge sense organ for vibrations. Thus, we’re experiencing vibration and sound for nine months in the womb and that sound environment is a very specific type of environment; the amniotic fluid sounds, the watery bubbly sounds, the mother’s heartbeat through the placental artery, respiratory sounds from the diaphragm, noises of the internal organ; it’s a rich complex, three-dimensional sound environment that is exactly the same for everyone of us; we all experienced this in the same way.

M&B: How does the fetus perceive this sound?

Remember the fetus is small and the ear is small; the eardrum is extremely small. If the eardrum was blown up to the size of my eardrum and the mother’s heart was blown up in proportion it would fill this room. So what kind of sound would such a heart make? It wouldn’t be the sound that you would expect it to be listening to the adult’s heart with a stethoscope from the outside; it would be a very large, slow sound, a large thumping sound.

M&B: How is this related to the use of sound in therapy or for relaxation?

Most of us who have gone on vacations and have explored nature feel a peaceful, beautiful return to nature; why?

Because if you take the sounds of the amniotic fluid and you slow those sounds down, they sound a lot like the ocean. The size of the sound waves compared to the eardrum would make these watery sounds sound like they have also slowed down. So many of the watery sounds in the womb sound like other sounds that we can hear later in nature. This can spark a similar kind of primordial recognition which is beyond the control of the rational thinking mind.

So when we build up these kinds of sounds on a soundtrack you can then push the button and the body will automatically go back to what it felt like to have a natural experience; when we combine the sounds of nature with music this makes a relaxation tape. So I would say that the sounds of nature provide secondary primordial sounds, as not all of us would have heard the same natural sounds in our lives.

The idea is to extend the power of the primordial recognizable components of sound in order to create a physical response. The technique is to connect with a primal recognition at a subconscious level; this will tap into experiences that you have had in the womb and at other times.

M&B: You not only use sound for relaxation, but also in order to combat stress. Could you please talk about this?

When a person has a fight-or-flight response, a stress response, we know very precisely what happens physiologically. The very first thing, the most sensitive organ, to respond to stress is the heart and thus when we look at the heart waves we can gain important information.

M&B: Why the heart and not the brain?

The reason for this is that the heart is the perfect system in the nervous system; it is called the autonomic nervous system or the automatic functioning nervous system; it knows how to organize and control my organs and glands and body chemistry and perform biomechanics that I’m not aware of and can’t control.

My rational-thinking brain can control physical body movements and thinking processes, but there’s another section that controls the automatic functioning of how my body runs. There is another control of this autonomic nervous system, which has two large branches of nerves that innervate all the organs and glands; these two branches of the nerves are the sympathetic and the parasympathetic nervous system.

While the sympathetic nervous system switches on, the parasympathetic switches off and mobilizes energy from the higher brain centers, from my digestive system, from my elimination system and from my immune system, it pulls that energy into my muscles to fight for my life.

This is when the brain freezes when you take an exam. You’re frightened about the exam; it is your final exam and you’re frightened that you’re not going to pass it or that you’re not going to do well. That fright causes the sympathetic system to switch on and drain the energy out of your brain; this is a self-fulfilling prophecy. You don’t have a brain left, because all the energy has gone to your muscles. At the moment the sympathetic system switches on, it mobilizes the pituitary which signals the adrenal glands; these fires adrenaline, the adrenaline starts the heart and the respiration and a number of other things. At the same time it suppresses the pancreas and lets loose extra glucose so you can fight for your life more and so what you end up with is the very first thing that happens.

M&B: What is the normal stress response and how do we return to a normal state?

When a person is required to carry out special tasks, like running or fighting for one’s life, then the sympathetic nervous system has to switch on, mobilize the energy from various places and send it to my muscles. If I am injured, but I survive and win, then the parasympathetic system is going to switch on and build up; that energy will be sent to my immune system, healing centers and recuperation areas for my muscles; when this is finished these are basically switched off, because we don’t need this energy anymore. This is certainly the normal way of functioning.

Thus, there are certain normal ways in which the body should function when a person is okay and normal. When the patient comes in and lies down on their back we hook them up and look at what’s happening in the autonomic nervous system. Normally when you lay down for three to five minutes your system should relax. Gravity isn’t affecting you, your heart doesn’t have to do extra work to pump the blood up to your brain; as a result the muscles relax and the sympathetic system and parasympathetic nervous systems should be at a level playing field. Now they can conserve their energy and this state of balance in the autonomic nervous system is known as homeostasis. The best state of health you can have is in homeostasis, where you’re not using energy in an unnecessary way. Homeo means unity, one, within my body, while stasis is a perfect state of rest.

M&B: What are the results of your studies to date? How many of us return back to homeostasis in three to five minutes?

Clinically what I see is maybe two patients with a normal response; I’ve been checking every patient with the real time heart rate variability system now for 7 years. This means thousands of patients; in all of that time I have seen one, maybe two patients with a normal response. I hook the patient up, and see what the response is. Most people’s response is abnormal; what this abnormality says is that after five minutes they have not attained a balance, and they have a good strong, healthy, dominant sympathetic stress response which never stops.

M&B: What do you think is the reason for this?

This state is constant because of the artificial, extremely stressful world that we have artificially created for ourselves. It wasn’t supposed to be like this; you are supposed to wake up in the morning and grab your spear and go catch a rabbit and that’s your workday; when you get there and you see that rabbit the sympathetic system turns on and the heart rates increase, the same thing happens with the rabbit, and it’s all going to be over in a couple of minutes. You’re going to catch the rabbit or he’s going to get away and then everything goes back, the clutch pushes in. Let’s say you get the rabbit, and the clutch pushes in; everything is fine and you are going to go home. Now you hear a growl behind you and there’s a saber tooth tiger looking at you, thinking about dinner; now the sympathetic system switches on, the heart rate is up, and you are running and he is running. It is all going to be over in a couple of minutes and either you are going to get away or you’re not.

But what I’m talking about here is that the nervous system, at its core, and its stress response are both designed for a sprint and not a marathon; but what we have had in the twenty-first century and throughout the twentieth century is a marathon of stress; but these are the kind of stresses that we can’t see, i.e. invisible stresses. They’re electromagnetic frequencies; the walls in this room, television channel frequencies, military frequencies, microwave frequencies, air pollution, food pollution and traffic jams when going to work to a job that doesn’t pay enough money for a boss who has the emotional development of a three-year old are all problems for us. The stress goes and then it’s back again; it’s time to get dinner for the kids and watching 7:00 news. This doesn’t stop; the nervous system’s solution to surviving this is to invent a mechanism of merely stepping on the gas, switching on the emergency sympathetic system on and bulldozing your way through the stress for the rest of your life with great momentum; but at nighttime, when it’s time to go to bed the nervous system doesn’t want to let go of this momentum that it has built up to get through the day.

M&B: And this has devastating effects on our health?

You can’t keep running in high gear for the rest of your life without some horrible consequences; the body’s not designed for it. You can only do this for a few decades before your heart or your brain blows up, the two biggest killers in Western society are heart attacks and strokes – there is also high blood pressure and diabetes. But what can we expect if our sympathetic nervous system is all the time working, which means by definition that our heart pressure is up and the pancreas is suppressed, so there is extra glucose being sent out? So people who don’t have the constitution to handle the stress blow a fuse; they have no way to handle the stress and as a result they have immune system problems, digestive problems, and problems that come from that colon cancer, irritable bowel syndrome, autoimmune diseases, allergies.

M&B: You are using sound in order to help people return to their normal healthy state. How does this work?

I’ve come up with a way to use sound to force the autonomic nervous system to push in the clutch, removing us from a place of high stress from which you can leave by using sound; we do this by using the heart-rate variability to see how bad the heart rate is and then explore various precisely tuned sound frequencies which will actually force the nervous system to push in the clutch. There will be a very specific tone for every person; this is like a glass vibrating if I sing the right note. An opera singer can sing the right note to make the glass vibrate. Well, now let’s imagine that your autonomic nervous system is the glass and we’re going to explore various sound frequencies that are very precisely tuned to find out which one affects your autonomic nervous system function; when we find it the response will be like pushing in the clutch and sending it into a state of relaxation. So we hit the right note and we get the response; this is what I’ve been looking for. Now we can see this phenomenon clinically. Once we’ve got the tone that’s associated with the pushing in of the clutch of the autonomic nervous system we can use that therapeutically through a specially designed sound table that I have made; this consists of low-frequency sound components which drive the low frequencies right into your cells via headphones. This relaxation mode is introduced to your nervous system over an extended period of time. We can burn this sound onto a CD and you can take it home and work with it at home on your stereo; it is like an internal training program. Every time your nervous system pushes in the clutch, the ability to push in the clutch grows, just like working a muscle in a gym.

This is a kind of high-tech stress reduction training program for the nervous system with sound. This is one of the three components I mentioned earlier; there are three parallel processes using sound for healing. This one is the idea of using the physical resonance to cause an effect on the nervous system to relax people.

M&B: This is what is called a sound table, right?

Yes, the sound table I needed had to have specific requirements, which is why I had to make my own to attain the exact clinical results I wanted. The power in the table actually delivered more power to your body than I wanted to be delivered. Therefore, I had to be able to have the sound that was coming from the table split into the right and left speakers, but none of those that were available on the market could do that. So I had to have it specially designed. As a composer, musician and audio engineer I was able to design the sounding board of that table and the transducers so that a lot of free sound could be delivered and spread out, therefore it is much more effective and delivers the sound to your body via headphones. Thus there is a lot going on in that table that you cannot see and this is what makes it work properly.

Interview conducted by Mustafa Tabanli for Ebru TV for the Emmy Award winning television series Matter and Beyond.

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.

Life without me is only silence

Every artist wishes to present his work to admiring eyes. In the whole universe, from atoms to star systems, God shows all the details of His art to you, a conscious being; and among His works, He has installed the most splendid ones in your body. He has given you reason and knowledge so that you can easily see and understand them. With knowledge, you can appreciate the meaning and different qualities of existence. However, you need another tool, your five senses, through which you will look at and learn about the material world around you and then turn this knowledge into an appreciation of the meanings behind God’s creation.

If you were not able to perceive light and color (by your eyes), your knowledge of material existence would be insufficient. Similarly, if God had not placed me in your skull, you would not be able to hear and know the songs of birds, the rustling of trees, the babbling of water, or the whistling of wind, which are each a note in the divine musical harmony throughout the universe. Indeed, everything speaks in its own tongue in order to introduce God to people. You use your eyes to perceive the things that speak with the wavelengths of light. You use me to perceive other wavelengths called “sound,” which is caused by the vibration of molecules.

The wavelength of the sounds that I can perceive ranges between 20 and 20,000 Hertz. I am unable to sense frequencies of sound that are above or below those limits. Indeed, it would be better to call this an advantage given by God rather than an “inability.” If the Creator of everything in the universe had not created me with this limited capacity, you would be facing unbearable pain in your head. If He had made me work with a wider range of hearing, you would be disturbed by the footsteps of a little ant, the moaning of an insect laying eggs, the buzzing of beehives, and the sound of the fluttering birds. Therefore, the fact that I have sufficient sensitivity for you to meet your needs is an advantage and an indication of God’s mercy. After all, my Creator gives everybody exactly what they need in a most suitable way and in the best measurements; He never does anything absurd. Do not ever want to have an ear like that of a bat. I am the best one for you.

Do not ever think that my outer, visible part is too simple. My outer ear, which sometimes turns red when you are nervous, is placed in the best position according to the shape of your head so that it can receive sounds in a most efficient way. Because it is made up of elastic cartilage, my outer ear (A) is very flexible, and it won’t break when you lie on it. The curves on me (known as the helix) and the hairs inside my channel are not made without a reason, either. My cartilages have the perfect shape to channel the sound down towards my middle ear according to the intensity of the sound and the direction it comes from. Because this special shape is formed according to the genetic code of a person, it is different in every person. The hairs in the canal serve to protect me from foreign objects like insects or dust. The canal that connects my outer part to my middle part is pretty wide, but if too much fatty wax accumulates here, I might experience temporary hearing loss.

My outer part is followed by my middle ear, which begins with the ear drum (tympanic membrane) (C). Attached to this thin ear drum are three bones: the malleus (D), the incus (E), and the stapes (F), which are all placed in order. These little bones are jointed to each other at an angle of 105 degrees. With an action like a piston, they amplify even the smallest sound vibration coming from the ear drum and transmit it to the middle ear. My middle ear space is connected to your pharynx by a very thin canal called the Eustachian tube (G). In order to protect my ear drum from rupture, I recommend that you open your mouth during an explosion or an intense sound. In that way, the sound waves that enter through your mouth will balance with the sound waves in my canals so that my ear drum is protected.

My inner part, followed by my middle part, is the most vital and sensitive area. Therefore, it is surrounded and protected by the bones of your skull. This inner part, which is an amazing piece of art and technology, comprises two wonderful receptor components. Those two little parts are placed in the same narrow area inside the temporal bone, but they perform different tasks. One of them is the cochlea (H), which is involved with hearing. The other part is the balance (vestibular) canals, which consist of the semicircular canals (I), the saccule (J), and the utricle (K). This balance organ enables you to stand straight and walk, run, or move without bumping or falling.

Like carved marble or forged metal, those parts are crafted out of bones that form a beautiful and intricate whole. My cochlea is divided widthwise by a bony tube. The upper compartment above the tube is connected to an oval window, which is an outlet to the middle ear. The lower compartment below the tube is connected to a round window. My inner part is a labyrinth of fluid-filled tubes. The fluid in the bony labyrinth, between the bone and the membranes, is called perilymph, and the other fluid within the membranous structure is called endolymph.

Situated on the basilar membrane (L) of my cochlea is a very small and special organ that you call the organ of Corti. The organ of Corti contains the hearing cells (or hair cells), the receptors (M) that are sensitive to sound waves, and other supporting cells. Because the length of the cells in the organ of Corti varies, different parts of my cochlea are sensitive to sounds of different wavelengths.

The sound waves travel via the malleus, the incus, and the stapes and through my oval window, agitating the perilymph of my cochlea. After that, the sound waves cause Reissner’s membrane (N) in my cochlea to vibrate, which then results in a wave movement in the endolymph. The wave movement continues along this membrane until it reaches my organ of Corti. The special receptor cells (or hair cells) of the organ of Corti are the ultimate vibration receptors. Their surfaces consist of very small strands (cilia). Those little strands bend and twist when the sound waves are received. Right at this point, a very important event occurs: it is the movement of these strands which converts the mechanical energy (that is produced by the vibrations of the sound waves) into electrical impulses. Those electrical impulses are then sent to your brain via the auditory nerve (nervus cochlearis) of the brain, where they are perceived as “sound.” The same sound waves continue their way to the perilymph and pass into the round window, the section between the middle ear and the inner ear. The round window pushes out to dissipate the sound vibrations in the perilymph and thus lessens their pressure.

The speed of the hearing depends on the speed of the sound that travels through my membrane and little bones. However, once the sound waves begin to pass to your brain as an electrical impulse along the auditory nerve, the hearing process increases its speed. Then your brain immediately interprets and reacts to the sound waves. You are not aware of all these rapid activities which are done perfectly in fractions of a second. You only say that you can hear something ordinarily. Have you ever thought before about how hearing takes place? Do you think you would have a clue about the sounds and music in the universe if God had not created me as your hearing organ?

Think about it, Peter! God knows exactly what you need for your life and equips your body accordingly. If there were no God, would such a complicated organ as your ear form by itself in your skull? Can it be a simple “coincidence” where some biological mechanisms take place successfully and in order without any plan or project and they produce such a splendid organ as me with all my sections? Like every reasonable and thoughtful person, you now understand that I cannot be the result of simple coincidence but only a creation of our God Almighty, don’t you?

Maintaining your balance

So far, what I have told you about is my duty to hear. Now I must also tell you about my duty of balance, so that you can better understand how miraculous I am.

Have you ever seen an acrobat walking on a rope or a mountain climber in action? Or shall I give a better example that might be more familiar to you? Remember what you do on your bicycle to keep from falling off. At the slightest mistake, the acrobat might topple from the rope, the climber might slip off the cliff face, and you might fall off your bicycle. While you are making unconscious (reflex) movements to keep your balance, have you ever thought about what busy operations are going on in my system? I have been equipped with very sensitive receptors which help you stay stable during your continual, different movements. Those receptors immediately recognize the changes occurring as a result of your slightest motion; they warn your body to adjust to your new position by sending out information to the spinal cord and to the brain about the new situation.

You may wonder how these two processes, hearing and balance, can take place in such a small area of the body, the inner ear. It is our Creator, God, who puts microscopic cells in a narrow place and runs the most sensitive and important operations via those little cells.

How do you feel the sensation of balance and how do you react with the right reflex action? To find an answer to that, you need to re-examine my anatomical structures mentioned before. At the base of my semicircular canals is a bulb-like enlargement which opens to the saccule and the utricle. My three semicircular canals are situated at 90-degree angles to each other in three-dimensional space.

My semicircular canals contain few sensory hair cells but there are plenty of them in the bulb-like enlargement. The strands of these cells, which are placed delicately, have enough elasticity to twist and bend during a movement. The receptors for balance in the saccule and the utricle are covered by a thin membrane which contains a gelatinous layer and tiny calcite crystals (cupula terminalis). Depending on its density, the endolymph fluid in my semicircular canals moves against the direction that your head and body move in. Similar to the uncontrolled movement of passengers in an accelerating or moving vehicle, depending on the speed and the direction, the movement and the speed of the endolymph differs from the general movement of your body. For example, when a car turns right, the passengers move to the left with the turning acceleration, and when a fast-moving car brakes suddenly, the passengers are thrown forward. Similarly, depending on its acceleration and momentum, every change in your movement causes the fluid in my semicircular canals to move. Triggered by the movement of the endolymph fluid, the gelatinous mass with the calcite pieces is displaced, causing the strands of the receptors to twist. Every movement of your head warns the cells of different parts, and via the vestibular nerve (nervus vestibularis) the nervous system is notified of changes occurring in your balance.

Thankfulness and contemplation

You have now seen what amazing works my two compartments, the balance and the hearing organs produce. All through your life, the former serves you by maintaining your balance without missing any of your movements, while the latter enables you to learn about the thousands of types of sounds in the world. Once you consider all of your movements in your life, you will see that my two organs perform their duties perfectly without ever getting tired, giving up, or complaining. We do not ask for any fee from you in return for those benefits, either. In fact, when God Almighty created you, placed us in your skull and set up our connection with the related center in your brain, He did not ask for any fee from you. All He wants you to do is to think about those blessings and be thankful to Him.

If you visited a hospital, you might see a lot of scenes which would lead you to think about God’s blessings on you and thank Him. Serious ear illnesses include middle ear infection (otitis media), which is frequently seen in children; otosclerosis, which is the limited ability of the stapes to transmit sound waves because its base becomes fixed to the oval window; and several hearing disorders which might be present at birth or occur later in life, depending on the level of damage to the auditory nerve. Witnessing the effects of those illnesses, you would understand how important it is to be able to hear and stand straight and balanced, and so see how blessed you are. At every step you take, when you are lying down or standing up, or every time you hear the twittering of birds, a nice melody, or the sweet voice of your parents, you will now appreciate the greatness and the mercy of our Lord God Almighty, who has engraved the meanings of all those sounds in your mind.

Peter! Until now, you have used me to listen to others, but today it was my turn to be listened to while I told you about myself. However, I must admit that I have only been able to explain to you the details of about one-hundredth of the beauties displayed in me and my delicate anatomical structure. If I attempted to present you with all the details about me discovered by developing technology and science and the meanings attached to them, there would not be enough pages in the magazine that you are holding now. Indeed, you do not need that much information either. My main aim here is to draw your attention to me, and thus let you know our God and bring you closer to Him. I hope I am successful in that. From now on, you will hear my ringing occasionally and remember me so that you will be saved from your heedlessness once again.

Irfan Yilmaz is a professor of biology at Dokuz Eylul University, Izmir, Turkey.

The sound of the sun

Sound waves are seismic waves which cause up-down and forward-backward movements. According to some scientists with poetic hearts the sound of the sun is like the sound of the heart beat. When a human’s heart beats, it makes varying sounds by contracting and relaxing, and cardiologists use these sounds to determine if there is a problem with the heart. Like the cardiologists who listen to our hearts, helioseismologists (scientists who research the sun’s seismic waves) listen to the sounds of the sun to learn more about its structure and mysteries. The power produced by these sounds makes the sun oscillate like a bell or tremble like someone suffering from a high fever. Another interesting point is that millions of different sounds have been discovered to emanate from the sun and every sound oscillates on a distinct frequency and displays a different pattern on the sun’s surface. If we compare the sun to a piano, a piano has 88 metal wires which produce sounds with varying tones, whereas the sun produces ten million notes. So the sun is like an enormous piano with ten million notes producing sounds at roughly five-minute intervals which create harmonic acoustics resembling the heart beat.

Scientists are trying to decipher these ten million different sounds, which brings us to another interesting point; we cannot hear the sound frequencies because they are too low (between 1–4 millihertz) for the human ear (the lowest range of human hearing is 20 Hz). 1–4 millihertz equals to a time span of 200–1,000 seconds, meaning that the sun oscillates once every 3–16 minutes. Even if our hearing ability was suitable, the sound would not reach us because there is no air or layer of gas between the earth and the sun to convey sound. If we could increase the sounds of the sun by 20,000–40,000 times, the sound humans would hear would only resemble a whisper. The sun is like a musical instrument that plays a continuous concerto of ten million notes every day in the sky above us, and we do not even perceive it. Can you imagine the astronomical music if we were to include the galaxy’s 200 million stars?

Scientists gather important information about the sun’s core by studying the echoes that appear on the sun’s surface from the energy produced from these ten million notes. The solar oscillations are divided into three categories called the p, g, and f modes. The p mode is the pressure of acoustic waves, g mode is gravity and the f mode refers to the surface-gravity waves. There are ten million of the p and f modes alone and the combination of these modes produce ten million different sounds.

In Bediüzzaman’s Risale-i Nur, his explanation of the letter “Lam” in the verse 36:38 in chapter Ya Sin in the Qur’an, affirms that everybody obtains understanding of this chapter according to his or her own spiritual senses and every chapter of the Qur’an contains thousands of aspects from which everyone benefits according to his or her own depth of understanding, from the common public to scholars, from scholars to the philosopher of the cosmos. In The Words, Nursi goes on to say, “Precise and wise scholars consider li to be causal and adverbial. They understand that since the All-Wise Maker operates behind the veil of apparent causality, He has tied the planets to the sun by His law of gravity and causes them to revolve with distinct but regular motions according to His universal wisdom. To produce gravity, He has made the sun’s movement on its axis an apparent cause. Thus a resting place means that “the sun moves in the place determined for it for the order and stability of its own (solar) system.” Like the Divine laws, that motion produces heat, heat produces force, and force produces gravity. … The sun is a light-diffusing tree, and the planets are its moving fruits. But unlike trees, the sun is shaken so that the fruits do not fall. If it were not shaken, they would fall and be scattered. They also may imagine the sun to be a leader of a circle reciting God’s Names, ecstatically reciting in the circle’s center and leading the others to recite. Elsewhere, I expressed this meaning as follows: ‘The sun is a fruit-bearing tree; it is shaken so that its traveling fruits do not fall. If it rested, no longer shaken, the attraction would cease, and those attracted to it would weep through space” (Twenty-fifth Word).

It is interesting that the sun’s oscillation, which modern science discovered in the 1960s, was mentioned much earlier by Bediüzzaman. In fact he went further and even explained the wisdom and necessity of the sun’s oscillation as a law of gravitation keeping the earth and the other surrounding planets in orbit. This is a subject which has only recently begun to be researched by scientists of the present. If we were to look further into the history of the valuable discoveries of Imam Rabbani, Ibrahim Haqqi of Erzurum, Ulug Bey, and many other scholars, we would be sure to encounter many other scientific facts.

References

1. “Solar Ellipticity Fluctuations Yield No Evidence of g-Modes,” J. R. Kuhn, K. G. Libbrecht and R. H. Dicke, Nature 319, 128 (1986).
2. “The Excitation and Damping of Solar Oscillations,” K. G. Libbrecht, B. D. Popp, J. M. Kaufman and M. J. Penn, Nature 323, 235 (1986).
3. “What do Observations Tell us about the Excitation of Solar Oscillation Modes?” K. G. Libbrecht, Proceedings of IAU Symposium 123, Advances in Helio- and Astroseismology (1988).
4. “Seismology of Solar Oscillation Line Widths,” J. Christensen-Dalsgaard, D. O. Gough, and K. G. Libbrecht, Astrophys. J. Letters 341, L103 (1989).
5. “Frequencies of Solar Oscillations,” K. G. Libbrecht, M. F. Woodard, and J. M. Kaufman, Astrophys J. Supp. 74, 1129(1990).
6. “Advances in Helioseismology,” K. G. Libbrecht and M. F. Woodard, Science 253, 152 (1991).

There is no similarity between the systems through which insects produce or receive sounds. Furthermore, even the frequencies of the sounds they produce or hear may not be the same. The wisdom behind this might be that the receptors of some insects are devised in a way that will enable them to detect sounds produced by their enemies. Moths can be given as a typical example of this. They can detect sounds between 1,000-140,000 Hz. Their sensitivity is best between frequencies of 20,000-40,000 Hz, but interestingly, most moths do not have any organs to produce sounds at these frequencies. In other words, moths do not seem to use their tympanal organs in order to communicate with one another. Discovering the real function of the tympanal organ of the moths has taken researchers quite a long time.

The mysterious relation

Every being in nature is created to assume a role in the ecological balance and no creature has been equipped with a useless organ. Researchers have discovered that the tympanal organ plays an important role in defense. Moths spend the day resting in corners and only become active after sunset. Researchers have come to the conclusion that they are not searching for food, since the nutrition they need is stored in their bodies during the larva stage. Thanks to this blessing, moths do not spend their short life span in search of food. The aim of their night flights is reproduction.

The essential duty of moths is to find the plants where they will lay their eggs and on which their larvae will feed. As slow moving animals, it is almost impossible for the moth larvae to go and find their own food. As all creatures are provided in accordance with their need, these helpless larvae are born on their food. Another amazing fact about their nutrition is that the moth larvae eat their own protein-rich eggshells before eating leaves. Research has shown that those larvae which eat their eggshells are more resistant to environmental conditions.

As the moths try to continue their species by laying their eggs in the darkness, some other creatures try to continue their own existence by feeding on the moths. Bats eat insects and are also active at night. As is well known, bats fly comfortably in the dark thanks to the radar system they have been equipped with. This innate system is perfectly devised to enable bats to pinpoint a tiny insect flying through the darkness, and moths are a prey that is easily spotted by bats. The astonishing fact is that the moths’ sensitivity to the sound waves is perfect for picking up the sounds emitted by bats. The moths are able not only to detect the bats, but also to judge their distance from the frequency of the waves. If the distance is greater than 30 meters, the moth leaves the area immediately. If the bat is closer however, the moth takes a zigzag course or tries to avoid danger by plunging down and staying still.

The balance here is so perfect that while bats are skilled enough hunters to obtain provision, the moths are good defenders and are able to continue their existence. Both species fulfill their roles in balance with creation. Some bats are able to catch some moths, but there is no excess on either side. Nothing is left to blind chance in nature; not only did the Creator equip the bat with a perfect radar system, He did not leave the moth helpless but granted them perfect receptors to rescue themselves from bats. If it were not for the Power that established the mysterious balances in the universe, how would a bat find its way through the darkness and how would moths be protected from extinction?

Every different type of moth which forms another ring in the chain of food in nature lays its eggs on different plants. If moths did not feed on certain fast-growing plants and if their growth is not kept under control, these plants would invade the space of other plants and wipe them out. The moths and other creatures that feed on plants ensure that no one plant is allowed to upset the balance of the chain of nutrition. Similarly, the perfect balance established between bats and moths prove that nothing in this universe is left on its own. When confronted by the perfect order in nature, one cannot help but think about the verse:

You do not see any fault or incongruity in the creation of the All-Merciful. Look yet again: can you see any rifts?

Then look again and yet again, (and however often you do so, with whatever instruments to aid your looking) your sight will fall back to you dazzled (by the splendor of God’s creation), and awed and weakened (being unable to discern any flaw to support any excuse for claiming that there could be any sharing in the dominion of the universe). (Mulk 67:3)

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.

No one else, you, the candidly expected

A voice unreserved, sentimental

Nourishing sermons forever in memories

The sublime pundit,

Within an exalted sound

You left us an earnest legacy

More than a touching discourse

Guiding the devout minds

Into soulful sincerity.