Topical Blog Week #10 (Due Thursday)

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What I would like you to do is to find a topic from the chapter you read for Monday that you were interested in and search the internet for material on that topic. You might, for example, find people who are doing research on the topic, you might find web pages that discuss the topic, you might find youtube clips that demonstrate something related to the topic, etc. What you find and use is pretty much up to you at this point. But use at least 3 sources.

Once you have completed your search and explorations, I would like you to say what your topic is, how exactly it fits into the chapter, and why you are interested in it. Next, I would like you to take the information you found related to your topic, integrate/synthesize it, and then write about it. At the end, please include working URLs for the three websites.

Once you are done with your post make list of the terms and terminology you used in your post.

Let me know if you have any questions.

42 Comments

A topic I found especially interesting to learn about from chapter 9 was the physiology of the middle ear, because I have always enjoyed learning about the anatomy and physiology of the human body and the ear is one of my favorite things to learn about. I used to always study the poster diagrams of the outer, middle, and inner ear at the doctor’s office when I was younger, and still do if they’re available. Below are links to images of the outer, middle, and inner ear because I find visual representations effective and helpful to my increased understanding of concepts, especially anatomy and physiology concepts. There is also a link to a site with photos of insects and objects that have gotten into or lodged into individual’s ears, resulting in medical attention. These insects and foreign objects that were lodged inside these people’s ears disrupting the normal structure and functioning of the auditory system, causing infections, hearing loss, and other conditions needing medical attention. These are real photographs, and could be disturbing/unsettling to some people so don’t view the last link at the bottom of the blog if that material is uncomfortable to you.

The outer ear is made up of the pinna, which is the outer, funnel-like portion of the ear, and the ear canal, which conducts sound vibrations from the pinna to the tympanic membrane and prevents damage to the tympanic membrane, or the eardrum. The tympanic membrane transforms sound waves into mechanical vibrations that stimulate the inner ear. I thought it was interesting to learn that puncturing your eardrum will not lead to deafness in that ear, but that the tympanic membrane will heal itself, but it’s possible to damage it beyond repair so we should still be careful. This tympanic membrane is the border between the outer and middle ear, which consists of three small bones, the ossicles, which amplify sound waves. The malleus, the first ossicle, receives vibration from the tympanic membrane and is attached to the eardrum on one side and to the second ossicle the incus on the other. The incus is connected to the stapes, which transmits the vibrations of sound waves to the oval window of the cochlea, another membrane which represents the border between the middle and inner ear. These ossicles, the smallest bones in the body, amplify vibrations in two ways. The joints between the bones are hinged in a way that makes them work like levers, and this lever action increases the amount of pressure change by about 33%. The second way these tiny bones increase the energy transmitted to the inner ear is by concentrating energy from a larger to a smaller surface area. The tympanic membrane is approximately 18 times larger than the oval window, thus the pressure on the oval window is increased 18 times relative to the pressure on the tympanic membrane.

I’m also interested in this topic because the amplification provided by the ossicles is essential to our ability to hear quiet sounds. The inner ear is made up of a collection of fluid-filled chambers, important because without the fluid the sound waves that were transmitted to the oval window directly would bounce back without moving the oval window at all. “For physiologic hearing to occur, a precochlear amplification system must be present to address the impedance mismatch that exists between air and water.” (Bruns, 2011) Proper impedance matching requires the normal anatomy and functioning of an outer ear and a middle ear with an intact tympanic membrane, a normal ossicular chain, and a well-ventilated tympanic cavity. Any dysfunction or disease of these components results in a conductive hearing loss, and clinically, an individual’s inability to properly hear sound.

The ossicles are also important for loud noises, too. The middle ear has two muscles attached to the tiny bones. The tensor tympani, attached to the malleus, and the stapedius, attached to the stapes, have the responsibility of tensing when sounds are very loud by decreasing vibration, which restricts the movement of the ossicles and muffles the pressure changes that might be so great as to damage the delicate structures in the inner ear. The disadvantage of this acoustic reflex is that it follows the onset of loud sounds by about one-fifth of a second. This means it helps in environments that have sustained periods of loud noises, but does not protect against abrupt loud sounds, like a gun shot. A very interesting thing I learned about the muscles of the middle ear is that they can also be tensed during swallowing, talking and general body movement, helping to keep the auditory system from being overwhelmed by sounds made by our own bodies.

I really enjoyed learning about the structure and function of the middle ear and how it functions with the outer and inner ear, because I sustained hearing loss from chronic ear infections as an infant and child, and these additional readings have helped me to better understand how that happened.

Sources:

http://emedicine.medscape.com/article/874456-overview

http://www.enchantedlearning.com/subjects/anatomy/ear/

http://emedicine.medscape.com/article/874456-overview#aw2aab6b5

http://www.entusa.com/external_ear_canal.htm

Terms: middle ear, pinna, ear canal, tympanic membrane, eardrum, ossicles, malleus, incus, stapes, oval window, cochlea, amplification, inner ear, outer ear, tensor tympani, stapedius, auditory system, sound waves, acoustic reflex

Good post. Lots of detail.

Tropical Blog
Tympanic Membrane
The Tympanic Membrane or eardrum, which is an important part of the chapter because it relates to hearing and the perception of hearing, is actually a very simple body part that scientists seem to understand rather well. Its size is generally between 8 and 10 millimeters across and its function is to send sound waves to the ossicles which are three small bones inside of the middle ear. The membrane is tightly stretched across a ring called the tympanic annulus. The edge of the ring where the membrane and bone connect is the thickest part of this structure. While searching form information on this topic I learned that if an infection occurs in this part of the ear and is not quickly taken care of or cleared up the tympanic membrane can burst/rupture or cause an earache which can become chronic and/or cause myringitis. These problems can cause hearing impairment as well as pain. If your tympanic membrane does rupture it is likely that it will heal itself within a few weeks, although, you are more likely to get an infection in your ear during this time.
My main question about the tympanic membrane was whether you can see it vibrate or not. Generally you cannot but in one YouTube video I was able too. This looked very neat and I am not sure as to why I could see it move in this one and not the others. Maybe it has something to do with the zoom of the camera that was used or the closeness of the scope to the eardrum. While on YouTube I also came across some very fascinating yet disgusting ear wax removal videos! If your ear canal becomes too blocked by ear wax, which is a mixture of dust and environment debris collected by the cilia (tiny ear hairs), you can have trouble hearing and even get a fungus in your ear, yuck!

Terms: tympanic membrane, ossicles, tympanic annulus. hearing impairment, myringitis, ear canal, and cilia.

http://emedicine.medscape.com/article/858558-overview
http://www.youtube.com/watch?v=kdy9FUzphRY
http://www.youtube.com/watch?v=cJL5Zg-FE7Y
http://www.mayoclinic.com/health/ruptured-eardrum/DS00499

So I had to check out that ear wax removel because you said it was so gross and you were right...I couldn't watch the whole thing

After reading chapter 9 I became I interested in the section about hearing loss. I was particularly interested in the conductive hearing loss and how it can be caused by otitis media, which is pretty much an infection in the ear that is caused by buildup or inflammation in the ear. This was interesting to me because as a child I can remember having many ear infections and when I was two I had to have tubes put in my ears, so this was something I wanted to look into a little further.

Otitis media happens in the middle ear, between the tympanic membrane (also known as the ear drum) and the inner ear. It causes the middle ear to become infected because there is pressure behind the tympanic membrane (this is what casuist it to be painful). In some cases if there is no treatment it can cause the tympanic membrane to rupture and this allows the buildup of fluid to drain into the ear canal, but the tympanic membrane usually heals on its own if this happens. It is also known as an ear infection or an earache. Although otitis media can be painful it usually heals on its own within a couple weeks.

After researching I found that otitis media usually occurs in children that are younger than seven, this is because their ears (mainly the eustachain tubes) are not yet fully developed, and also because younger children don’t have a built up immune system like adults do. It is also very common in young children; about 75 percent of young children have at least one case of otitis media before they reach the age of three. I also found that it is more common in children who have had respiratory issues, are in a daycare facility, around second hand smoke, and some research suggests it is more common in children who were bottle fed more than nursing. It has been suggested if a mother is to breastfeed her child for at least the first year the child will be less likely to have otitis media.

Otitis media is not contagious, but the common cold is. Bacteria and viruses (like the common cold) cause otitis media, so usually the child our adult will get a cold before the symptoms of otitis media occur. When a doctor knows a child has otitis media they will usually be prescribed antibiotics to help with the infection, but in some cases nothing will be prescribed. In children who have reoccurring systems of otitis media usually doctors will place ear tube in their ears to avoid getting infections all the time.

So how does this related to the chapter? Otitis media can cause hearing loss, which was mention in the chapter. Children or adults who have many and reoccurring cases of otitis media are more likely to develop a conductive hearing loss. This is because there is so much fluid built up in the middle ear, or because there has been so much damage to the tympanic membrane. Usually the hearing loss is temporary, but research has shown it may also have an effect on the child’s speech; they may have attention problems, and they may even have educational problems.

The main reason I believe I had so many ear infections (or otitis media) was because I was born about two months early. I was not fully developed, which made it easier for me to get infections. My lungs were the main area that was not developed fully, and this caused me to have many upper repertory infections. Having upper respiratory infection is one of the biggest and most common reasons children develop otitis media.

Terms: otitis media, conductive hearing loss, middle ear, tympanic membrane, inner ear, ear canal, eustachain tubes

http://en.wikipedia.org/wiki/Otitis_media
http://www.medicinenet.com/ear_infection/article.htm
http://www.umm.edu/altmed/articles/otitis-media-000121.htm

I used to have ear infections all the time. I remember it being pretty terrible. Interesting to learn more about a few of the causes from your post.

One thing that interested me in this chapter is how we can tell the difference between two sounds, especially two sounds with the same frequency and pitch. This is called timbre, or the perceptual quality of a sound. This is something that is particularly useful to musicians because it helps to tell the difference between different instruments. What is interesting is that two instruments can play the same note, at the same frequency and pitch, and we will still be able to tell the difference between the two sounds. The perception of the sound also depends on the context of the sound. Timbre is very sensitive to background noises, and when distracted, it is not a clear distinction.

Timbre is also in close association with harmonics. Where timbre allows for differentiations between two similar sounds, harmonics allow us to hear the richness of the sound. Harmonics depend on the vibration of the sound. The lowest frequency vibration is called the fundamental frequency, which is commonly used to name the note. In attrition to the harmonics, the timbre is also affected the it’s envelope. An envelope is the overall amplitude of the sound. This includes attack, the start of a sound and decay, the end of a sound. If the start of a sound is unclear, then the timbre will also be unclear. Attack and sound are also used to help us differentiate between words that sound similar. Some examples include bark and shark, or dog and fog; the meaning would be unclear if the attack was unclear. This is why the envelope is crucial to the effectiveness of the timbre.

I chose to write on this topic because I had never thought to consider how I can tell the difference between musical instruments. I was in band in middle school, but I never gave much thought, it was just something that I did naturally. Now after learning about timbre, I realize how much of a process my auditory system goes through to experience and differentiate musical tones.

Terms: Timbre, Frequency, Pitch, Harmonics, Fundamental Frequency, Attack, Decay, Envelope

http://www.youtube.com/watch?v=BLoM9bBr8lc
http://en.wikipedia.org/wiki/Timbre
http://hyperphysics.phyastr.gsu.edu/hbase/sound/timbre.html

Pretty interesting that the instruments that make different sounds are decoded by our auditory system. Sometimes it seems difficult to piece apart which instrument is which.

The topic I wanted to know more about was about otosclerosis. Otosclerosis, according to Wiki, is an abnormal growth of bone near the middle ear, and it may result in hearing loss. The primary type of hearing loss that one with otosclerosis suffers from is conductive hearing loss. Conductive hearing loss, according to wiki, is where sounds reach the eardrum but are incompletely transferred via the ossicular chain in the middle ear, thus partly fail to reach the cochlea. This starts in one ear and eventually affects both ears. The reason I chose this topic was because I thought it was interesting. I found it interesting because it was something I had no previous knowledge of before and thought it was a strange condition that I wanted to know more about.

Otosclerosis a very rare condition as it is estimated that 0.5% of the population will suffer from this condition. It has been said during post mortem studies they think really 10% of the population really suffers from otosclerosis but it goes undetected, because there has been a large number of people that had otosclerotic lesions on their temporal bone, but never showed symptoms. Otosclerosis has been known to also affect sensorineural hearing loss. Sensoreneural hearing loss is the loss of high-frequency sounds. This is less common and usually occurs late in the disease. Caucasians are the most susceptible to otosclerosis, while it has been much less prevalent in the Black and Asian populations. Otosclerosis has also been seen to be about twice as likely to occur in women than in men but in recent years has only seen a slight difference in the occurrence of it happening in men compared to women.

Otosclerosis has been considered to be a hereditary disease, although this has and still is up for debate, and has been argued. To diagnose otosclerosis doctors check for conductive hearing loss, a normal tympanic membrane, no evidence of middle ear inflammation, and they check the cochlear promontory for a pink tinge to see the vascularity of the lesion. High resolution CT scans are used to detect any subtle bone structures in the ear that may be causing issues. The two main treatment options for people suffering from otosclerosis are hearing aids, and a surgery called a stapedectomy. A stapedectomy is a surgery in which they remove a portion of the sclerotic stapes footplate and replace it with an implant that is secured to the incus. A newer surgery that slightly differs from the stapedectomy is a stapedotomy. During a stapedotomy the surgeon drills a small hole in the stapes footplate with a laser, and then insert a piston like prothesis. These two surgeries have about the same success rate, but the stapedotomy has seen fewer complications from the surgery and has evolved into the preferred operation. There has been various other types of treatments but have yielded less successful, as well as unsuccessful results.

Terms- Otosclerosis, conductive hearing loss, cochlea, middle ear, temporal bone, sensorineural hearing loss, tympanic membrane, cochlear promontory, stapedectomy, stapedotomy, and incus.

http://en.wikipedia.org/wiki/Otosclerosis#Treatment
http://www.nlm.nih.gov/medlineplus/ency/article/001036.htm
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002031/

I didn't know the technical name for it! Interesting post. Seems like you learned a bit a bout it.

After reading chapter 9, I took great interest in the anatomy of the ear. I easily understood the parts of the outer ear and the middle ear but the inner ear was a little bit confusing to me. So for my topical blog I figured that I would try and understand and figure out what the inner ear all entails. I also wanted to learn more about how a sound wave is transformed into a neural impulse.

First, I thought I would explain the process how a sound wave gets to the inner ear. Sounds are first collected in the Pinna, which is the funnel part of our ears. From there it travels down the ear canal to the tympanic membrane. The tympanic membrane (eardrum) is a thin sheet of skin at the end of the outer ear canal. The eardrum vibrates when sound hits it and the vibrations then transfer to the parts of the middle ear.

In the middle ear, the vibrations start at the ossicles, which are the smallest bones in the body. There are three parts to the ossicles, the malleus, incus, and stapes. The ossicles play a big role in amplifying sound so that we can hear faint sounds just as well as louder ones. There are also two muscles that have a big role in the middle ear. The tensor tympani and stapedius muscles purpose are to tense up when large sound waves enter the middle ear. They help protect the inner ear by muffling pressure changes that could harm the inner ear.

Once the sound wave enters the inner ear there are two main parts it goes through. The semicircular canals and cochlea are the two main areas where sound transforms into an electrical impulse. Semicircular canals are used to detect acceleration in three perpendicular planes. They make use of hair cells that detect movement of fluid in the canals caused by pressure shifts from the oval window, which is where the middle ear and inner ear connect. The cochlea is a structure with three fluid filled parts. Two of the canals in the cochlea are used for transmission of pressure and is a sensitive organ of corti. The tympanic and vestibular canals are filled with fluid and shifts in those by pressure change cause the hairs cells in the organ of corti to excite. When the hair cells are excited they send a tiny voltage pulse called an action potential down the nerve fiber. The impulses are then transferred to the auditory areas of the brain for processing. The organ of corti is able to determine the perception of pitch and loudness. I always find so cool how so much information is determined in areas outside of the brain. I used to think everything was processed through the brain but a majority of the work is done through other parts of the body.

Terms- organ of corti, hair cells, oval window, outer ear, inner ear, middle ear, malleus, incus, ossicles stapes, tensor tympani, stapedius, cochlea, vestibular canal, tympanic canal, semicircular canals, neural impulse, pinna, ear canal, tympanic membrane.

http://hyperphysics.phy-astr.gsu.edu/hbase/sound/eari.html
http://www.medicinenet.com/script/main/art.asp?articlekey=21685
http://en.wikipedia.org/wiki/Inner_ear

Interesting stuff. Got technical with it, which is probably necessary given the complexity of the ear and its functions that give rise to our ability to perceive sounds.

I chose to research hair cells in the organ of corti and dizziness. I wondered if hair cells had to do with balance, because someone once told me that when you spin around in circles, you get dizzy because of the hair cells in your ear. It turns out that this is basically true! What happens when you spin around in circles in a rapid pace, the hair cells send mixed signals to the brain, causing the dizziness. Around your hair cells is a jelly like substance called otoconia which moves around as your head moves. The more one spins the more the fluid makes the hair cells move in one direction. Soon enough we stop, but the fluid and hair cells keep sending the signal that you are moving even when you have stopped, creating the “dizzy” feeling.
Terms: hair cells, organ of corti, otoconia.
http://www.bbc.co.uk/science/humanbody/body/factfiles/balance/balance_animation.shtml
http://www.coolquiz.com/trivia/explain/docs/dizzy.asp
http://www.centralcarolinaent.com/vertigo-carolina-ent-raleigh-nc.htm

Kinda went short that week, huh? Its ok, we all get busy with life. Try to get a bit more in depth in future posts.

From this chapter I found the information on hearing loss interesting. There are two main causes for hearing loss. Conductive hearing loss is from damage or blockage so that the sound waves cannot properly move through the ear. This can be caused by having wax build up, having an ear infection, damage to the tympanic membrane, or dislocated ossicles. The second type of hearing loss is called sensorineural. this type of hearing loss happens when something happens to the hair cells or the nerves in the ear. This can happen from long periods of loud noises, pressure trama from water, head trama, Ototoxic drugs, genetics, some infections like mumps, and old age. Roughly 50% of people over the age of 75 have some hearing loss and about 1/3 of people from 65-75 have some hearing loss. People can also suffer from both types of hearing loss. This can be a result of chronic ear infections.

There are options for people with hearing loss. A choclear implant is a possible option. It sends electrical impluses that take the place of the hairs that are not working. However this option is very expensive and takes patient training to be effective. People in the deaf community often look down on those who have their children fitted with one. People with hearing loss can also get hearing aids. A hearing aid amplifies the incoming sounds. This however is not an effective method of treatment. There is also gene therapy that has restored choclear cells in guinea pigs. This however is not 100% effective and has not yet been tried on humans.

Terms: tympanic membrane, ossicles, conductive hearing loss, sensorineural hearing loss,cochlear,

http://en.wikipedia.org/wiki/Deafness
http://www.emedicinehealth.com/hearing_loss/page2_em.htm
http://www.mayoclinic.com/health/hearing-loss/DS00172

It would have been cool if you followed up with your stats on how many people who have hearing loss get cochlear implants. Is it a large proportion of people or based more on the expense of the procedure?

It would have been cool if you followed up with your stats on how many people who have hearing loss get cochlear implants. Is it a large proportion or based more on the expense of the procedure?


For the topic blog this week, I chose to dive into the topic of psychoacoustics more. Psychoacoustics is the study of the study of the psychological correlates of the physical dimensions of acoustics; a branch of psychophysics. Simple put it’s more of the study of how the brain reacts to and processes of sound, both physical and psychological characteristics it has to listeners. Though a sense we take for granted, sound in more scientific terms and put into the process of how it’s reacted and processed within our brains is a complex matter. These are the people that work with the perception of hearing with humans and animals alike, humans being able to hear can normally hear from a 20 Hz to 20,000 Hz. Within this science, the unite of measurement they use that is called a hertz, a physical characteristic these scientists’ measure and which is expressed in frequencies. A frequency is the number of times per second that a pattern of pressure change repeats, while pitch is what listeners here and is the psychological aspect of sound related mainly to the fundamental frequency. In the same case intensity is the physical characteristic; the amount of sound energy falling on a unit of area, it is loudness that a listener hears, which is the psychological aspect of sound related to perceived intensity or magnitude. Timbre, also applies within the studies, as it is the psychological sensation by which a listener can judge that two sounds with the same loudness and pitch are dissimilar; timbre quality conveyed by harmonics and other high frequencies. All of these things go into the study of psychoacoustics and how sound affects a person’s hearing and how they perceive that sound. In some cases within studies the researchers utilize the masking affect to participants in the research. Masking is the weaker sound is masked if it is hidden or inaudible within a louder sound. Good example of this could be trying to hear a cell phone ring while at a large and loud party or sporting event.

As there is more to study about our perception and processing of hearing and sound itself, there are plenty more to explore. However, already psychoacoustics has been used in things we use every day to possibly being potential weapons. Military apparently have been seeking ways in to make acoustics weapons, while at the same time such things are used in our MP3s, music itself, and software development the list could go on as new things are discovered with our auditory system and our perceptions of hearing.

Terms: psychoacoustics, timbre, masking effect, hertz, frequency, pitch, intensity, loudness,

http://en.wikipedia.org/wiki/Psychoacoustics
http://www.music.miami.edu/programs/Mue/mue2003/research/mescobar/thesis/web/Psychoacoustics.htm
http://www.naturespace.com/pages/psychoacoustics.php

What would the acoustic weapons be? Where did you find the information about that? Would it just be aversive sounds? or could it be positive distracting sounds to throw us off guard by distracting our attention?

My topic that I was interested in after reading Chapter 9 was hearing loss. I believe this fits into the chapter because it affects nearly 30 million Americans and something this large and important, I believe it should be researched and studied. I find hearing loss very interesting because of the middle and inner ear being so delicate there are so many reasons why someone has hearing loss. I’m also interested in this subject because I believe this issue may be preventable depending on the type of hearing loss. Hearing loss is the decreasing ability to hear using someone’s auditory system. In order to completely understand hearing loss we need to know that there are 2 different systems sound waves produce our hearing, the air conduction and bone conduction. In air conduction, sound waves move through the air in the external auditory canal. The sound wave then hits the tympanic membrane, otherwise known as the eardrum and causes it to move. In the middle ear, there are bones that are connected to the tympanic membrane. When the typmpanic membrane moves, the 3 main bones (mallerus, incus, stapes) all move as well that cause pressure waves in the inner ear which contains fluid. Within the inner ear, there is also the cochlea which contains small hairs. Pressure waves cause these fluids to move. This movement stimulates the auditory nerve which results into different sounds of pitch. Hearing by bone conduction occurs when a sound wave causes the bones of the skull to vibrate. These vibrations transfer to the fluid surrounding the cochlea which in results to sound. Now that we have a somewhat understanding of how we can hear sounds, we can now look at what happens to our auditory system that allows us to not hear.


There are 2 main types of hearing loss, conductive and sensorineural. Conductive hearing loss can causes such as obstructed external ear canal, perforated tympanic membrane, otitis media (middle ear infection) or otitis external (swelling of the ear canal). Sensorineural hearing loss can range from damage to the hair cells to the nerves that sense sound waves. This type of hair loss seems to be a larger range. This type of hearing loss can be anything from acoustic trauma, head trauma, ototoxic drugs (drugs that affect hearing), vascular diseases, meniere disease and of course presbycusis (otherwise known as aging) along with a multitude many others.


Researchers are stumped by the fact that certain animals can regrow hair cells, such as birds, fish and amphibians but humans cannot. Luckily two scientist, Zhengqing Hu and Jeffrey Corwin, both of the University of Virginia School of Medicine, invented a new technique for isolating cells from the inner ears of chicken embryos and growing them in their laboratory. This technique is believed to be the first step to understanding more about the difference between species and what we can now do to try and regrow human hair cells. Individuals may experience hearing loss very sudden or it may be gradual. It is possible that hearing loss be bilateral (both ears) or unilateral (one ear). Depending on the type of hearing loss, treatment is possible. Though hearing loss affects millions of people, it is preventable. Experts suggest using protective wear when working with loud noises. They also suggest to not using a cotton ball when cleaning your ears out. Also if an individual is experience an ear infection to make sure to seek medical treatment immediately.

Terms: middle ear, inner ear, air conduction, bone conduction, auditory system, tympanic membrane, eardrum, external auditory canal, mallerus, incus, stapes, cochlea, small hairs, auditory nerve, pitch, conductive, sensorinerual, otitis media, otitis external, acoustic trauma, ototic drugs, vascular disease, Meniere disease, presbycusis, bilateral, unilateral.

http://health.nytimes.com/health/guides/symptoms/hearing-loss/overview.html

http://www.medicalnewstoday.com/releases/83516.php

http://www.emedicinehealth.com/hearing_loss/page10_em.htm

Cool post. I like how you included information about how people have done recent research to isolate some of the mechanisms surrounding the hearing loss.

I am going to do my Topical on sensorineural hearing loss. Sensorineural hearing loss or “SNHL” is a type of hearing loss in which the root cause lies in the vestibulorcochlear nerve, the inner ear, or the central processing centers of the brain. The Weber test, which is conducted when a tuning fork is touched to the midline of the forehead, localizes to the normal ear in people with this issue. The Rinne test, which tests the condition of the air versus bone conduction positivity through both bone and air conduction are reduced equally.

The great majority of SNHL is caused by abnormalities in the hair cells of the organ of Corti in the cochlea. There are also very interestingly unusual sensorineural hearing impairments that involve the eighth cranial nerve or the auditory portions of the brain. In the rarest forms of this hearing loss condition, only the auditory centers of the brain are affected. In this certain situation, central hearing loss, sounds may be heard at normal thresholds, but the quality of sound perceived is so poor that not even speech can be understood.

Most sensory hearing loss is due to poor hair cell function. The hair cells may be abnormal at birth, or damaged during the lifetime of an individual. There are both external causes of damage, like noise trauma and infection, and intrinsic abnormalities, like deafness genes. Sensory hearing loss that results from abnormalities of the central auditory system in the brain is called central hearing impairment. Deafness being caused by the central area cause is quite unusual. This type of hearing loss can also be caused by prolonged exposure to a very loud noise. An example would be not wearing ear protection in a very loud work environment or having headphones set to high for very long periods of time.
Hearing loss can be inherited. Both dominant and recessive genes exist which can cause mild to profound impairment. If a family has a dominant gene for deafness, it will persist across generations because it will manifest itself in the offspring even if it is inherited from only one parent.

TERMS: organ of Corti ,the Rinne test, sensorineural hearing loss, vestibulorcochlear nerve

http://en.wikipedia.org/wiki/Sensorineural_hearing_loss
http://emedicine.medscape.com/article/856116-overview
http://www.nlm.nih.gov/medlineplus/ency/article/003044.htm


It would have been cool if you would have done hearing loss in general, then gotten into the specific types of hearing loss and how they occur, what they affect, etc. etc. This way, you would have integrated and synthesized the information from your topic! Just a good habit to get into.

Hearing loss is the topic that I chose to do further research on. I thought it would be interesting to research it because hearing loss affects such a great amount of people. In my research I found that 50% of people over the age of 75 have some hearing loss and about 33% of people from 65-75 have some hearing loss. It is also very unique to note that hearing loss is something that cannot be reversed.
The two main reasons for hearing loss are conductive hearing loss and sensorinueral. Conductive hearing loss is the problem when sound waves are unable to pass through the ear. The reason this usually happens is because an individual has an excess amount of earwax in their ears. When the hearing loss is sensorinueral the problem is an individual has probably been exposed to loud noises for an extended period of time. Due to this exposure to loud noise the hair cells in the inner ear are destroyed and they never regenerate. Hearing loss is also something that can be inherited through ones genes. Others may incur hearing loss because of job occupation or certain medications they take.
Going about the treatment of hearing issues could be either very simple or a lot more complex. When wax need to be removed a doctor may be able to do this by simply loosening the way with oil and then flushing it out. When hearing loss is caused by inner ear damage a hearing aid may be needed. In other cases that are considered to be more severe one may even need cochlear implants. These implants serve as compensation for damaged or non working parts of ones inner ear.
One research study I found discussed the neurons that turn the ear off to help protect the ear from loud sounds. Although we have these neurons it is not a perfect system. Tests were done with mice to see if this system could be improved in any way. These molecular receptors in mice were genetically changed and when exposed to a loud noise for extended periods of time. The results showed that the hearing loss in these mice was minimized. The researchers called this technique transgenesis in mice. The downfall to this is that ear become less sensitive to lower level sounds. Researchers are now looking for drugs that could have similar effects in humans however. Currents results of research suggest that there is a drug that could be taken depending on situation of loud noises one would be in. This would be a lot safer for overall hearing.

Key terms: hearing loss, conductive hearing loss, sensorinueral hearing loss, cochlea

http://www.npr.org/templates/story/story.php?storyId=99800024

http://en.wikipedia.org/wiki/Deafness

http://www.asha.org/research/reports/hearing.htm

http://www.mayoclinic.com/health/hearing-loss/DS00172

Cool mice research you talked about. How many people sufferring from hearing loss find it annoying enough to get treatment? What are the prevalence rates?

For this week’s topical blog, I decided to focus on cochlear implant technology. Among all the individuals who suffer from hearing loss, the root cause most commonly occurs at the cochlea, deep inside the inner ear. Fortunately for all these potentially deaf or hearing-impaired people, though the technology is far from perfect, hearing restoration technologies are light-years ahead of corresponding treatments with the other four senses. As of 2004, around 82,500 people across the globe had been fitted with a cochlear implant device, which is pretty amazing when you consider that these implants have only existed for a couple of decades – even electronic hearing aids have only been around for half a century!

Nevertheless, despite our great success at rehabilitating individuals’ ability to perceive and distinguish human speech and language, we are still nowhere close to restoring much beyond that mere fraction of the auditory system’s intended capacity. Most notably (and tragically), this includes perception of music and melody. Even to this day, cochlear implant recipients continue to struggle hearing music properly – and oftentimes it sounds so horrible that they cannot enjoy the experience at all! A bit reason for this challenge is because while language is limited and precise, music is extremely broad and abstract. The acoustics of music are far more difficult than those of language because it occupies a much wider potential range of frequencies and decibels, not to mention the added complexities of perceiving several pitches of different timbre and tone quality all at once. This pitch perception challenge is probably even more daunting than most realize – perception of a musical note can be off by as much as two octaves! This is even more ridiculous when you consider the fact that shifting a melody by even a single semi-tone can completely alter the complexion of a piece.

From my research, it seems that the lower threshold for cochlear implants has been set at around 250 Hz. This is because any pitches lower than that in the outside world can mess with a user’s speech perception (as we learned in our textbook when sounding simultaneously, lower frequencies tend to mask higher ones). This comes at a severe cost in music, considering that the lowest string on a guitar sounds at a pitch of 83 Hz – and there are much lower-pitched instruments in a band, orchestra, or heck, even the human voice! The other major hang-up that comes with any potential widening of the pitch range of a cochlear implant is that there are a limited number of channels to accommodate each sub-range of frequencies. Widening the overall implant frequency spectrum means that resolution will be reduced because each channel has to cover a broader range of frequencies. Even as recently as FOUR days ago, the most advanced implant currently on the market offers a measly 120 channels, when the human ear itself has the equivalent capacity of around 3,500 channels!

Even with this state-of-the-art ClearVoice technology from Advanced Bionics, the press release is very careful in how it phrases the device’s capabilities in regards to music: “enhanced lyric understanding for music enjoyment”. Despite having increased the number of auditory channels offered fifteen-fold over the past decade, cochlear implant companies still cannot guarantee any sort of musical enjoyment beyond the clarity of diction that would otherwise come with normal everyday speech. Though this challenge is great, it is by no means insurmountable – all it takes is increasing the number of channels over time while providing more sophisticated software to better represent music by use of advanced algorithms to better place and time the sound impulses that are sent to the implant’s electrodes.

http://www.marketwatch.com/story/advanced-bionics-launches-clearvoice-in-the-united-states-2012-03-19

http://www.ted.com/talks/charles_limb_building_the_musical_muscle.html

http://www.wired.com/wired/archive/13.11/bolero.html?pg=2&topic=bolero&topic_set=

Terms: cochlear implant, cochlea, inner ear, frequency, decibel, timbre, tone quality, pitch, hertz, masking, auditory resolution channels

Yes! Finally, someone talked about how many people actually have had the procedure. Nice approach within your post to coming full circle on your topic! Good work.

I wanted to look into different types of ear surgery. This fits into the chapter by looking at ways to correct different types of hearing loss and what hearing loss can be corrected through surgery. Over spring break I was tested and approved as a candidate for LASIC eye surgery. Since I myself my soon be looking at corrective surgery for my eyes, I wanted to know the ways to correct hearing loss. The surgery I am a candidate for will involve a laser (not a blade), I was surprised to learn that lasers are also used to correct hearing loss.

There are three types of lasers that can be used to correct hearing loss; CO2, Arogo, and KTP. These lasers make it easier and more accurate to remove pieces of the ear like the malleus, incus, or stapes when they have become immobilized and no longer vibrate. If one bone cannot vibrate then it cannot vibrate the other parts/bones in the ear resulting in hearing loss because the vibration never makes it to the hair cells in the ear that translate the vibration into a signal for the brain to interoperate into noise. This type of hearing loss is called otosclerosis or stapedectomies. Otosclerosis is a condition where there is a buildup of calcium around one of the bones in the middle ear making it restrained. This condition affects people between the ages of 20-30 but has been known to affect more women than men. Some have speculated that this condition in particular may be the result of a hormonal balance. Someone with otosclerosis or stapedectomies can be fitted for a hearing aid or chose to have surgery to correct the issue. In surgery, the doctor used one of the three lasers to go in through the tympanic membrane and remove the tissue or bone that is the source of the hearing loss. If it is part of the ossicles that is removed, it will be replaced by a tiny piece of medal that will perform the job that the immobilized piece was no long able to perform. The differences between the lasers tends to be that Arogo and KTP are a much stronger laser then CO2, but have a greater risk of causing more surrounding nerve damage because the laser is wider and more powerful. Even though the CO2 laser is smaller and weaker, it is more accurate in its precision. The result from the introduction of lasers into otosclerosis surgery is a decrease in symptoms felt by patients after surgery.

http://www.earsurgery.org/site/pages/surgery/laser-ear-surgery.php
http://www.earsurgery.org/site/pages/surgery/stapedectomy/stapedectomy---co2-laser-animation.php
http://www.youtube.com/watch?v=mqESmXhtyBo


Terms: CO2, Arogo, KTP, malleus, incus, stapes, hair cells, otosclerosis, stapedectomies, middle ear, hearing aid, tympanic membrane, and Ossicles.

Cool post! I didn't know they were using lasers to work on the inner ear! That is cool stuff.

The terms that really interested me, the most, from chapter nine, dealt with the different anatomy parts and sections of the ear. I found that I learned a lot of knowledge dealing with the outer, inner, and middle ear, and how they all work together to allow a properly functioning auditory system. With this presentation of information, I was able to more readily understand auditory senses and how they relate to me. However, I decided to take a different route, once again, and chose to do more research on a topic that does not readily relate to myself, but affects others. I want to gage a better understanding of what individuals who are suffering from hearing loss of their auditory system have to go through every day. Approximately thirty million Americans alone have a hearing impairment. Hearing is a slightly different term than sound. Hearing refers to the ability to recognize sound through vibrations from the ear. One way that hearing loss occurs is from some type of obstruction in the ear canal. Similar to the way wax buildup or sticking objects into your ear (like ear plugs) blocks the canal in an intentional way. Another possibility might include altitude change where there is different tension and pressure built up within the ear. Hearing can be damaged from any structure within the ear; this includes any part of the outer, middle, and inner ear. With blockage of the canal, it can be fixed as long as the tympanic membrane is not severely damaged. The tympanic membrane, also known as the eardrum, is a tiny sheet of skin located towards the end of the outer ear that responds to sound through vibration. Damage to this part of the ear does not necessarily mean loss of hearing or deafness. The tympanic membrane is capable of fixing itself when damaged. Though, it is possible to permanently damage it beyond repair. One specific type of hearing loss is known as “conductive hearing loss”. When there are problems within the middle ear bones someone may be experiencing conductive hearing loss. When the ossicles, bones in the middle ear, are impaired, they lose their ability to conduct vibrations from the tympanic membrane. One way which damage can occur with the ossicles would be a fluid buildup, most often occurring in children. When ear infections occur, there is an increased pressure and blocking of the eustachian tube that effect both the motion of the ossicles and tympanic membrane. This type of hearing loss, that I found interesting, deals with the middle ear, is known as otitis media. Otitis media is defined as the inflammation of the middle ear and deals with the infections that children get. The big problem with this infection comes from a mucus build up, when the mucus dissipates back into surrounding tissue of the ear, hearing comes back to normal. Though this type of infection and disturbance of the middle ear ossicles occurs in millions of children, it is possible that reabsorption can take months. This form of chronic otitis media can follow with persistent damage to the middle ear and the tympanic membrane. Otitis media is correlated with symptoms of sore throats, colds, and respiratory problems. Usually pain is experienced from the bulging of the tympanic membrane. Since there may be various problems with the ossicles of the middle ear, when otosclerosis occurs, there is an abnormal growth from those bones. This is just one more variation of hearing loss impairment due to the middle ear and the ossicles. Otosclerosis has one specific bone that causes this type of hearing loss, and that is the stapes. The stapes is one of the three ossicles and transmits vibrations to the membrane of the oval window. With otosclerosis the stapes bone is grown abnormally in a fixated position. In order for proper hearing this specific bone needs to be able to move freely within the middle ear. Otosclerosis can occur in both female and male gender and develop around the mid twenties. This is a genetic component of hearing loss as well. If one parent has otosclerosis there is a twenty five percent chance the offspring will develop it, and if both parents have otosclerosis it increases to a fifty percent chance of the offspring having it. A procedure that removes the stable strapes bone is called a stapedectomy. Though these different types of damages within the middle ear cause hearing loss, the most common and severe form of hearing loss is known as sensorineural hearing loss. When there is damage to the auditory nerve or chochlea one will experience this sensorineural hearing loss. This occurs when the hair follicles are damaged. Ototoxic drugs have adverse effects on these auditory nerves dealing with hearing loss. They directly kill the hair cells. The final link at the bottom of the page gives a youtube video that helps to describe sensorineural hearing loss and gives a nice visual aid to help identify and understand this type of impairment. Hearing loss is a serious thing that affects people all over the world. Age is a common factor, but there are other various types of components and variables that also relate to the loss of hearing.

http://en.wikipedia.org/wiki/Conductive_hearing_loss
http://www.medicinenet.com/ear_infection/article.htm
http://www.entnet.org/HealthInformation/otosclerosis.cfm
http://www.youtube.com/watch?v=YpIptQSEEjY
Terms: Hearing, tympanic membrane, conductive learning loss, ossicles, Eustachian tube, otitis media, otosclerosis, stapes, sensorineural hearing loss, ototoxic.

So, other than age, what would you say are the most common factors/risk factors contributing to various types of hearing loss?

You’ve briefly talked about auditory illusions in previous lectures, and it has intrigued me. I think that next chapter is going to be more about speech perception, so I thought auditory illusions would be more fitting here. The reason why I am interested in auditory illusions is much like the interest I have in optical illusions; they are somewhat playful in nature but also gives insight to human sensation and perception. Auditory illusions are somewhat more interesting to me because I have never heard of such a thing before this class. So, not only does this give me a new experience, I am also able to find truths about the auditory system.

The first auditory illusion is called the Barber’s shop illusion. You can find the clip for that here https://www.youtube.com/watch?v=IUDTlvagjJA . I will also put the link below, but I felt it was more fitting in its respective paragraph. The Barber’s shop illusion play’s with your auditory system’s sense of space and depth in the environment. If your left ear is receiving the same but stronger signal than the right ear, your brain will assume that the source of the noise is closer to the left side of your body. Also, if the sound is very soft but increases in intensity; your brain will assume that the source of the sound is coming closer to you. This illusion works best if you have a good set of headphones and you have your eyes closed. With those prerequisites, you are able to create a 3-d scene; with multiple objects in it. As stated in the video, your ability to sense where each object that is creating individual sounds is, is because of your brains ability to calculate the differences between the two ears.

Another cool illusion is called the McGurk effect. The video can be seen here https://www.youtube.com/watch?feature=player_embedded&v=73LE1vKGfy4 ; however, if you are going to watch the clip, you must watch it with your eyes closed first, eyes open the second time, and muted the third time. When I watched this clip, the first time (with my eyes closed) I heard BA-BA. When I watched it with my eyes open, I heard DA-DA. Finally, when I watched it muted, his lips looked like he was saying GA-GA. I might have to do some further research into this specifically; however, the reason why this happens is because the sound clip is BA-BA (as heard when you had your eyes closed), and the video clip is of a guy saying GA-GA (as seen when you muted the video). However, when they take GA-GA out of the original video, and instead have the audio of the guy saying BA-BA, your visual system fuses with your auditory system. This fusion helps in most cases, where the two senses provide better accuracy. However, if we control this fusion, and make the two stimuli from different sensory systems contradict each other, you perceive a whole different stimuli all together (DA-DA). Pretty cool.

The final illusion is called the Temporal Induction of Speech. This illusion is where a sentence is spoken, but it is interrupted by a cough. http://www4.uwm.edu/APL/audioBook/11Phon_Rest_Single.mp3 You probably didn’t hear anything wrong with the sound clip, but a phoneme has been emitted during the cough. You can hear a stark difference in this clip, where the cough has been taken out. http://www4.uwm.edu/APL/audioBook/13Phon_Rest_NoCough.mp3
This shows your brain’s ability to fill in gaps of details that have actually been omitted. This rings true with all of human perception, but this illusion shows how it pertains to the auditory system as well.

Sources:
http://listverse.com/2008/02/29/top-10-incredible-sound-illusions/
https://www.youtube.com/watch?v=IUDTlvagjJA
https://www.youtube.com/watch?feature=player_embedded&v=73LE1vKGfy4
http://www.newscientist.com/article/dn13355-music-special-five-great-auditory-illusions.html
http://www4.uwm.edu/APL/audioBook/11Phon_Rest_Single.mp3
http://www4.uwm.edu/APL/audioBook/13Phon_Rest_NoCough.mp3

YES! You found the McGurk Effect! I always thought that was an interesting illusion. I remember first coming across it when taking this exact class with Dr. MacLin. Good post! Good links and sources.

One thing that interested me in this chapter is how we can tell the difference between two sounds, especially two sounds with the same frequency and pitch. This is called timbre, or the perceptual quality of a sound. Timbre is particularly useful to musicians because it helps to tell the difference between different instruments. It is interesting is that two instruments can play the same note, at the same frequency and pitch, and we will still be able to tell the difference between the two sounds. The perception of the sound also depends on the context of the sound. Timbre is very sensitive to background noises, and when distracted, it is not a clear distinction.
Timbre is also in close association with harmonics. Where timbre allows for differentiations between two similar sounds, harmonics allow us to hear the richness of the sound. Harmonics depend on the vibration of the sound. The lowest frequency vibration is called the fundamental frequency, which is commonly used to name the note. Frequency is actually a result of the vibrations from the sound waves. When the sound wave reaches its lowest vibration is when the fundamental frequency technically occurs. In addition to the harmonics, the timbre is also affected by its envelope.
An envelope is the overall amplitude of the sound. This includes attack, the start of a sound and decay, the end of a sound. If the start of a sound is unclear, then the timbre will also be unclear. Attack and sound are also used to help us differentiate between words that sound similar. Imagine if you were listening to someone speak and you missed the first part of the word they said. Would you be able to determine exactly what they said? This would be an issue if one was trying to tell the difference between words with that have similar syllables but have different attacks. Sometimes the attack makes the word different, for example- bark and shark, or dog and fog. In both of these cases, if the attack was unclear, then we would not know the difference and the message would be unclear. Attack is important in the musical world too because if the first note of a song is unclear, then the other musicians may not know when to start playing. This is why the envelope is crucial to the effectiveness of the timbre.

I chose to write on this topic because I had never thought to consider how I can tell the difference between musical instruments. I was in band in middle school, but I had close to zero musical talent. Having admitted that, I was still able to tell the difference between a clarinet and a flute without any technical training. It was just something that I picked up naturally. Now after learning about timbre, I realize how much of a process my auditory system goes through to experience and differentiate musical tones. I also enjoy how timbre does not have a clear, absolute definition. It is a psychological experience of sounds, and I believe this to be the most important take away message from this chapter because I can apply it to the sounds around me. As I sit here, I can pick out the sounds in the music that I’m listening to, I can hear the guitar, the piano, and the voice of the musician. Before researching this topic, I would have thought of it all as one sound, but I enjoy picking out all of the individuals sounds that make up the harmonic timbre.

Terms: Timbre, Frequency, Pitch, Harmonics, Fundamental Frequency, Attack, Decay, Envelope

http://www.youtube.com/watch?v=BLoM9bBr8lc
http://en.wikipedia.org/wiki/Timbre
http://hyperphysics.phyastr.gsu.edu/hbase/sound/timbre.html

My great-grandma is 101 years old and she can still hear me, but my dad is 50 and I have to constantly repeat myself to him. This is why I have chosen to write about hearing loss for this blog entry. Hearing loss is something that is common with old age. However, it affects everyone differently. There are three parts of the ear that can be damaged which results in hearing loss: the outer ear, the middle ear, and the inner ear. Sound waves are directed inside your outer ear, like a funnel, into the middle ear. Once they are in this part of the ear, the vibrations are softened to protect the inner ear; the most important ear structure. The inner ear is where the auditory processing occurs. It consists of hairs and mucus that are sensitive to the vibrations caused by the sound waves. When the frequency from the sound waves are too intense, then sometimes the hair will lay flat instead of vertically, as intended. Once the hairs lay flat, then they are damaged and they no longer function as they once would have.

As I said earlier, the hairs are function when the sound waves are too strong. Loud sounds can only be sent into the inner ear if the middle or outer ear is damaged. Damage can occur in a few ways. The most common way is constant exposure to sound. Though loud sounds such as motorcycles or rock concerts cause damage, research has shown that the most damaging of sounds are the frequent sounds that humans experience every day, such as traffic and trains. Another way to experience damage is if ear wax is built up and the pressure from the blockage damages the ear drum. Therefore, if the middle ear and outer ear are protected, then the inner ear will also be protected.

An interesting phenomena is that my great-grandma cannot hear anyone if she is in a noisy room. She is unable to pick out an individual voice. But if she is in a quiet room, she can hear every word that you said. I was unable to find a reason for this, it must have something to do with the confusion of sound waves. Also, the more hearing loss that is experienced, the lower the frequency of sound that can be heard becomes. More specifically, the more one loses their hearing, the lower tones they experience. An example of this is when my great-grandma wears hearing aids. Sometimes if the hearing aids aren’t sitting properly in her ear, they will buzz in a very high pitch tone. The pitch is very sharp and it pains the ears of many of us at the table, but my grandma is unable to hear it. The younger a person is, the higher a pitch they can perceive. So, when this happens at the dinner table, the younger kids always throw a fit, but grandma never knows why because her ears cannot detect the sound. A fun way to test your hearing, is to go to this website and listen to the different sounds. As the sounds get higher in pitch, the less people are able to hear it (depending on their age). http://www.freemosquitoringtones.org/.

I wrote about this topic this week because hearing loss is something that is applicable and that many people deal with, or will deal with, on a daily basis. So, the more information that I can get on the topic, the more I can watch myself and protect my ears in the future.

Terms: hearing loss, outer ear, middle ear, inner ear, hairs, mucus, vibrations, sound waves, frequency, ear drum, pitch, tones.

http://www.mayoclinic.com/health/hearing-loss/DS00172/DSECTION=causes
http://www.hearingloss.org/
http://en.wikipedia.org/wiki/Deafness

In Chapter 9, I found the hearing loss to be the most interesting thing to me. When I was younger, my parents were constantly having my hearing checked because they were certain that I was deaf. They assumed this because I always had the television loud, and I would not answer them sometimes. However, all of the tests came back negative, and the doctor told my parents that I just have selective hearing and was tuning them out. Well, that wasn't much fun for me...thanks doctor!!

Otitis media is very interesting to me because as a child, I constantly had ear infections. For the first five years of my life, I was going in every year to have tubes inserted inside my ears. I haven't had an ear infection in a really long time. Otitis media is when the mucus is missing from the tissue. Otosclerosis is different though. Otosclerosis is caused by an abnormal growth of the middle-ear bones and surgery can help improve your hearing.

An ear infection usually occurs after a child has a sore throat, cold, or other upper respiratory infection. The middle ear—which is where ear infections occur—is located between the eardrum and the inner ear. Within the middle ear are three tiny bones called the malleus, incus, and stapes that transmit sound vibrations from the eardrum to the inner ear. The bones of the middle ear are surrounded by air. My second website source discussed this as well, but also included some pretty cool pictures.

Sometimes, the eustachian tube may malfunction. For example, when someone has a cold or an allergy affecting the nasal passages, the eustachian tube may become blocked by congestion in its lining or by mucus within the tube. This blockage will allow fluid to build up within the normally air-filled middle ear.

Terms: hearing loss, otitis media, otosclerosis, middle-ear, mucus, respiratory infection, eardrum, inner ear, malleus, incus, stapes, vibrations, eustachian tube, congestion, tube

Sources:
http://www.nidcd.nih.gov/health/hearing/pages/earinfections.aspx
http://emedicine.medscape.com/article/764006-overview
http://kidshealth.org/parent/infections/ear/otitis_media.html

Glad you were just tuning them out and not actually deaf!

I chose to do my topical blog planes traveling faster than sound creating a sonic boom because I think that it is interesting that this is plausible. Although the chapter described the sonic boom using planes as an analogy, sonic booms can be created by other things as well. They can be created by space shuttles when they re-enter the atmosphere and also by humans, using a bull whip. When one lashes a whip the whip is actually moving faster than sound often times and the sound occurs after the whip hits. This could technically be considered a sonic boom.
For the purpose of this blog I will limit the discussion to planes for simplicities sake. Sonic booms fit into the chapter because the chapter is about how sound waves move and why they are perceived the way that they are. The sonic boom happens because when something moves through the air it creates pressure waves in front of the object and behind it. These waves travel at the speed of sound so when the object moves faster than the speed of sound, they cannot get out of the way of each other and it creates a single shock wave moving at the speed of sound.
It was in the 1950s that aircrafts supersonic aircrafts were beginning to be tested. The Valkyrie (North American B-70) was tested at very high altitudes (70,000 feet) because they thought that this would deter the sonic boom from occurring but that was false. During these tests the N-wave was first characterized. The sound of a sonic boom is different depending on where you are in relationship to the aircraft and is also different depending on the shape of the aircraft. If you are very close to the aircraft you hear the boom as more of a crack or a bang. If you are inside the air craft you actually hear nothing, which I think is really interesting. If you are far enough away from the aircraft, you actually hear two booms. The sound is very deep and most times the air craft is far away or not even in sight at all. One of the booms is produced by the nose of the plane breaking through the air and the other boom is produced by the back of the plane.
In 1964 the NASA and Federal Aviation Administration was performing the Oklahoma City sonic boom tests. They caused 8 sonic booms a day for 6 months there were over 15,000 complaints and a class action law suit was filed which they lost so they had to stop doing the testing. But this was crucial to what we know about sonic booms because valuable data was collected though these tests.

When the plane gets up enough speed that it is actually traveling faster than sound you can actually see a cone shaped white thing at the end of the plane. This is caused by all the air molecules being pushed together all at once and them not having anywhere to go. You can see this for yourself on the video link below. I thought it was really interesting that the duration of the sonic boom is really brief, lasting anywhere from 100 milliseconds, to 500 milliseconds. The sonic booms reach the ears of people 2-60 seconds after the aircraft flies over head. This can vary depending on functions of air temperature. As we know from the chapter, sound travels differently through different temperatures, humidity’s, winds, and atmospheric pollution and through water. I also think that it is interesting that things like concrete and pavement on the ground, large buildings, ect., can cause reflections that will amplify the sound of the sonic boom. Grassy fields and lots of trees and such can actually decrease or rather deter the sound of the sonic boom. I think that is really interesting.

http://en.wikipedia.org/wiki/Sonic_boom
http://www.sky-flash.com/boom.htm
http://www.youtube.com/watch?v=-d9A2oq1N38

Cool post. Good application of the material to something we've probably all experienced but never really knew what the science behind it was.

After reading the color chapter, I really wanted to focus on the research on color blindness, because I know many individuals that are color blind, and wanted to learn more about this color deficiency.




1. The first youtube video I found discussed how color is an illusion because it is made up from our brains interruption of color. The wavelengths and ranges on a particular scale help our visionary part of our brain to distinguish color. However, when a person is color blind they may mistake the colors green and red, or even blue. What one person says is red, could portray differently to another person. Fundamentally everyone is different and especially in color blindness. An example of this would be if a person is color blind you can try to describe the color but they would be confused and not see the color you are seeing. Tests are produced to determine if a person is color blind and able to see and interrupt different colors. However, the question that remains from the video: is your red the same as my red?


http://www.youtube.com/watch?v=evQsOFQju08



2. A second article breaks down to children how color blindness works. The cones in your eyes are cells in the retina and we each have a red, blue and green cone. The cones can be sensitive and use the combination of the cones to ultimately distinguish between the colors. However, you need all of the cones to see the colors. The brain retrieves signals, and if the brain is not getting the correct message from the cones then the color red or green could look grey. The article also states that color blindness is almost always inherited from a parent. Typically color-blindness occurs in males and there are tested by dots and objects inside of the dots in different colors to show if a color blind person can see those colors or not.
-I thought this article was very useful, especially to explain to children about color blindness. The visual ads and breaking down the process is easier to understand why people can not see certain colors that appear “normal” to others.



http://kidshealth.org/kid/talk/qa/color_blind.html#a_Color_Blindness_Is_Passed_Down



3. The third article I found was on a WebMd website explaining the disorder in vast detail. One particular thing I found interesting is that color blindness does not mean they can not see any color at all it means that those individuals have a problem telling the differences between red and green objects. The article states that color blindness does not always arise from being “born with it” it can happen from aging, eye problems, injury to the eye, and side effects to certain medications. Many individuals that do not know about color blindness would probably think that people can not see all colors in general, but color blindness is having trouble MIXING or separating red, green and blue. I would suggest this overview of color blindness article to those that have children or think they are having issues seeing the colors that they once were able to see.



http://www.webmd.com/eye-health/tc/color-blindness-topic-overview

vocab- retina, color blindness, cones, color vision tests

This week, I chose to look at white noise for my topical blog. We use this term all the time in childcare and I want to see how it functions in a psychological manner.

One of the first things I noticed while just searching a regular search on google was that there are so many websites that will generate white noise for you. Also, there are several online shopping websites that sell white noise generators. This basically confirms my daycare talk about how white noise helps children sleep, but now my question is why?
https://www.google.com/search?q=white+noise&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&channel=sb

I hate using wikipedia, but for this topic, it was hard to find a normal scholarly website about white noise. I actually found wikipedia to be useful, however and I learned a lot about this process of white noise. One of the things I found most interesting is that white noise is constant and always the same throughout. When I hear white noise, I can almost hear fluctuations, but according to this, that isn't the case. I thought that was interesting. I like how wikipedia used a metaphor to say that white noise is like talking without meaningful speech. This would be that white noise is sound without any specific tone or change in tone. This really helped me to understand the meaning of this term.
http://en.wikipedia.org/wiki/White_noise

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