Assignment Sample on Advanced Engineering and Vibration
Introduction
Hearing is the most important process of the human in which ear transforms sound through the external environment like ear to the nerve systems and then passed to the brain, whenever the person felt the sound. The ear has the ability to identify the subjective based of a sound such as high pitch noise and lordliness by identifying and also analysis of the various physical behaviors’ of the waves. Here, pitch is known as the view of the frequency of the sound waves and the same if normally measured as the cycle per second or hertz. The human ear can able to feel from 1000 hertz to 4000 hertz, but the same way young ears has the possibility to hear the sound extension from 20 hertz to 20,000 hertz. Loudness refers the intensity of the sound which can be measured by the decibels – dB. The human hearing can be extended from 0 dB to 130 dB but may be leads to the painfulness.
This report discuss the various test methods, working of the human ear, possible categories of the hearing loss, causes about the hearing loss, plot between the threshold levels as well as the frequency with its description and different factors which are affecting the graph’s shape.
1. The working of the Human Ear
The description of the human hearing mechanism says that the sound waves are allowed to the ear and it travel via the natural external canal to the tympanic membrane, which affects the membrane and then form the chain of ossicles to feel the vibration. This vibrate feel stimulates the sensor cells in corti, adjust with the basilar membrane, and finally reaches through the nerve impulse to the human brain (Hawkins, 2021).
The human ear is the best organ to hear as well as the balance. The human ear has three levels such as outer, middle and inner ear. The external or also known as outer ear include the parts like Pinna or auricle, auditory canal or tube, and the tympanic membrane also called eardrum can split the external ear from the middle ear.
The middle ear includes the ossicles, which has the three bones are connected as well as the sound to the inner ear. The bones are referred as malleus, incus and the stapes. Eustachian tube helps to compensate over the middle ear, which leads to the very good and proper direction of sound hearing. The inner ear includes the part such as the cochlea for hearing, vestibule for balances and the semicircular canals for balances the same.
The outer human ear accepts the frequency of the sound via the external factors to the tympanic – membrane and the portion of the outer human ear named auricle gather the sound along with concha, which is the cavity of the entrance force to the external canal. This canal can able to enhance the sound waves to reach the membrane. The most sensitive relative wavelength with its frequency range from 2000 hertz to 7000 hertz are the consonants of the various sound waves.
The tympanic – membrane and the ossicles operations are effectively applied as the remedy of the impedance mismatch issues among the air and cochlear fluids. The middle ear does transmit the sound by the ossicular chain with the support of tensor tympani as well as the stapedius (Hawkins, 2021). Figure 1 depicts the image of the human ear about its hearing processes, which is referred from the Encyclopedia Britannia, Inc.
The photogrammetric model was used a camera to store the size as well as the 2D image of the external ear from the scale of references. This model is easy to handle as high as adopt the shot angle (Luximon, 2020) . In the 3D anthropometry have the different data models such as the 3D anthropometry, CT and the scanning of the 3D can be possible to get 3D model with an external ear. The major challenges with the method have the restriction over the current models. As an example, a per have the hair over her / his ear that region of the person becomes tricky to observe the same while try to collect the data and also the air canal was become too critical to assess the same by the light dependent scanner as the direct mode.
The ear has three semicircular canals such as superior, horizontal and posterior. The first two canals are able to intersect overt the right angles. The last two canals are creates the stem or known as crus. Each of the canals are has too tiny diameter with personal ampulla. The cross portion of the ear is cochlea, which may cover the endolymph. It can form the cone with 9 mm as diameter and the 5 mm in height.
2. Hearing Threshold test methods
Normally a person’s hearing ability can be mention with the following facts such as watch ticking, coin – clicking, usual speech, voice modulation, lack of tuning fork and identifying the variation from themselves.
The following testing methods are followed to test the hearing thresholds.
3.1 Tuning – fork tests
The measurement of the hearing loss is applied by a tuning fork method. This method performs the test with the skull and its bones by ability of the sound hearing process.
- The test name called “Rinne test” the mastoid process is used to place the tuning fork of the sensed sound. While testing examiner release the fork and use the prongs to handle the ear canal. The normal human ear can hear 45 seconds.
- Positive Result – incomplete hearing ability with impairment.
- Negative Result – Presents of deafness and the fork can be hearing longer period.
- Schwabach test – The normal hearing person cannot able to hear the bone conducted frequencies with the presence of sensorineural impairment. An individual along with hearing loss can able to hear the same.
- Weber test – When fork is placed over the forehead of the person and tests his/her hearing ability. The lesion is fit on the one ear; the person can sense the sound at opposite ear. A person has any conductive loss, that person feels the bad ear.
3.2 Audiometry
This audiometry test can be conducted by the audiometer which includes the oscillator or a generator, an amplifier, attenuator to control the tunes and earphones or else loudspeaker. The intensity of the same is limited from 100 dB by the steps of 5 dB. A graph showing the process of the each human ear with the octaves of the range from 125 hertz to 8000 hertz is called as the audiogram. The two categories of tests are followed like
- Speech reception threshold – averagely 500 hertz, 1000 hertz and 2000 hertz
- Discrimination score –evaluates hearing impairments
Screening – audiometry is the commonly preferred widely. It has very minimal procedure by check the person’s tone signals with the corresponding threshold level. In this case fixed frequencies are observed while level of the corresponding threshold increases the given screen (Sergey Naida, 2019).
While considering the noise perceptions which are combined the high sound waves, competitive speech and cues (Hannah Guest, 2018) . The person has to do the report of the color and the various speeches by the opposite talker. The expected level of sound waves based on the one down, one up procedure, obtaining the threshold signal to noise ration with respect to the 50 percentage of the psychometric process.
3. Types of hearing loss and their causes
Commonly three types of hearing loss are applied such as
4.1 Sensorineural hearing loss
This Sensorineural type of loss is the commonly used method to test the hear loss. The inner ear problems and the hair cells damages leads to this issue. And also the reason likes aging, damage of noise or unexpected reasons. This type of loss usually did not able to solve by the medicine or any operations. And can be solved by the support of hearing aids. This may produce the outer as well as the inner hair cells nerve fibers or else synapse (Courtney L. Ridley, 2018).
This type of loss also called as the Hidden hearing loss. Thresholds have noise situation leads the loss of lower level fiber range. This concept gives the function as well as the quantity of the variation of the thresholds value in the noise which did not based on the quiet threshold. Some of the studies said like no hair with the loss and also the both audiometric with otoacoustic results are becomes normal stage.
4.2 Conductive hearing loss
This conductive hearing type of loss is usually obstruction over the outer as well as the middle human ear and also due to the tumors, fluid, and some earwax or else ear formation. It avoids the sound directs into the inner human ear. This type of loss is possible to be treated by any medical surgery or with the tablets.
4.3 Mixed hearing loss
This mixed type of hearing loss refers the combination of the Sensorineural as well as the conductive hearing loss. This type also can able to identify the loss with any type of condition specify the particular person has in advance. Need the proper guidance with the proper hearing study also support to identify the loss type, causes of the particular loss and the range or degree of the person’s hearing loss.
4.4 List of causes about the hearing loss
There are many factors to the hearing loss and most common causes are listed as follows:
- Aging factor
- Heavy noise pollution
- Head ache
- Some viruses
- Diseases
- Genetics issues
- Ototoxicity
- Heredity problems
- Obesity
- Hypertension
The National Institute for communication disorder said the 25 percentage of the person those who age limit from 65 to 74 mostly felt the hearing loss. This loss also referred as decreased level of hearing, deafness, loss of hearing ability and conduciveness’ of the hearing loss.
The losses named ear infections, allergies over the ear, swimmers ear – refers those who regular swim and also the swimming competitors, wax over the ear are comes under the conductive loss. Sensorineural hearing ability loss has the following factors such as variation in sound waves –unique, as usual – normal, louder or not clear sound, birth defect leads the normal view of the ear, aging factor, regular work place surrounds the nose pollution, head pain or skull, unknown disease and neuroma. Some of the few type of infection is also leads to the same such as measles, mumps and also the meningitis.
Few of the symptoms are listed by the experts such as less hearing ability suffers the regular activities, does have improve instead worse or else does not leave, loss is worse in any one ear, sudden changes in hearing, ringing in the ear, severe pain, head-aches, numbness and weakness. Some of the instant treatments for the symptoms are such as chills, breathing with quicker, stiffness over the neck, sensitiveness about the lights, and agitation over the mental health.
4. Analysis of the threshold level and the frequency with plot:
Hearing threshold data of seven young male participants are
Table 1: Left Ear Threshold in dB measurements
| 125Hz | 250Hz | 500Hz | 1000Hz | 2000Hz | 4000Hz | 8000Hz | |
| L | L | L | L | L | L | L | |
| A | 15 | 10 | 10 | 5 | 20 | 20 | 25 |
| B | 20 | 0 | 5 | 10 | 10 | -5 | -5 |
| C | 25 | 15 | 15 | 10 | 5 | 10 | 20 |
| D | 25 | 20 | 10 | 10 | 15 | 5 | 20 |
| E | 25 | 20 | 5 | -10 | 5 | -10 | 5 |
| F | 5 | 5 | -5 | -10 | -10 | -10 | -10 |
| G | 20 | 15 | 5 | 0 | 10 | 10 | -10 |
Figure 4: Plot between the Threshold levels and frequencies of the Left Ear
Table 2: Right Ear Threshold in dB measurements
| 125Hz | 250Hz | 500Hz | 1000Hz | 2000Hz | 4000Hz | 8000Hz | |
| R | R | R | R | R | R | R | |
| A | 10 | 15 | 5 | 5 | -5 | 20 | 25 |
| B | 20 | 5 | 10 | 10 | -5 | -10 | -10 |
| C | 20 | 15 | 15 | 5 | 0 | 5 | 10 |
| D | 20 | 20 | 20 | 10 | 5 | 5 | 15 |
| E | 15 | 15 | -5 | -5 | 10 | -10 | 10 |
| F | 15 | 10 | 15 | 5 | 0 | -10 | -10 |
| G | 15 | 15 | 5 | -5 | 0 | 0 | -10 |
Figure 5: Plot between the Threshold levels and frequencies of the Right Ear
Table 1 and the Table 2 are the given data of the 7 young male persons with age between 23 and 25 years old. The frequency ranges are 125Hz, 250Hz, 500Hz, 1000Hz, 2000Hz, 4000Hz and 8000Hz. The corresponding plot of the both table are shown in the Figure 4 and the Figure 5. The LINE plot’s X – axis refers the above frequencies and the Y – axis refers the seven male persons. Each person’s frequency as well as the threshold values are represent in the unique colors.
From the Figure 4, seven of three showed the reverse slope occurred from 500Hz onwards (Jungeun Won, 2019) . Here, does not follow every measurement has an increased graph shape by the negative slope. We can able to analyze the hearing ability of the persons are not having stability. Those are always dependent on the natural – external factor are affecting their body as well as their health status (Pavlenko, 2018). Here, the hearing ability can be measured periodically. In order to measure the sensitivity standard deviation was followed.
The person has the normal hearing ability shows the highest hearing sense thresholds variation with higher frequencies as like the Figure 3 and Figure 4. The thresholds range with the corresponding frequency range 1000Hz to 8000Hz always varied. From this analysis given data right ear in the external canal may be compensating the frequency range and the measurement of the ear is the independent surety of the sound waves.
5. The factors that affects the shape of the graph plotted
There are many factors which are disturbing the hearing ability. Those are listed as follow
- Silence speech and some other sound waves
- Usual background noise and also the crowd
- Trouble about hearing consonants
- Loud speech unexpectedly becomes too low leads to unclear voice
- Raising the volume of the media
- Conversation ends
- Try to limit the few social settings
Some of the common sound waves with decibels with safe range are as follows
- Undertone – 30 decibels
- Refrigerator – 40 decibels
- Normal conversation – 60 decibels
- Dishwasher – 75 decibels
Some of the common sound waves with decibels with risky range are as follows
- Heavy traffic – 85 decibels
- Motorcycle – 95 decibels
- Snowmobile – 100 decibels
- Jackhammer, symphony – 110 decibels
- Sandblasting – 115 decibels
- Ambulance siren, thunder – 120 decibels
- Fire cracker, fire arms – 140 to 165 decibels
- The processes which are prevent the hearing loss by the noise pollution and also avoid the age factors. The following factors do the same like protect ears, hearing test and avoid the entertaining risks.
6. References
- Courtney L. Ridley, J. G. K. S. T. N. M. P. G. a. D. M. R., 2018. Using Thresholds in Noise to Identify Hidden Hearing Using Thresholds in Noise to Identify Hidden Hearing. l., s.n.
- Hannah Guest, K. J. M. a. C. J. P., 2018. Acoustic middle-ear-muscle-reflex thresholds in humans with normal audiograms: No relations to tinnitus, speech perception in noise, or noise exposure.
- Hawkins, J. E., 2021. The Physiology of Hearing.
- Jungeun Won, G. L. M. P.-C. H., 2019. Assessing the Effect of Middle Ear Effusions on Wideband Acoustic Immittance Using Optical Coherence Tomography. Ear and Hearing.
- Luximon, F. F. a. Y., 2020. A systematic review on ear anthropometry and its industrial design applications. Wiley Periodicals.
- Pavlenko, S. N. a. O., 2018. Newborn Hearing Screening Based on the Formula for the Middle Ear Norm Parameter. l., s.n., pp. 287 -291.
- Sergey Naida, V. D. O. P. N. N., 2019. Objective Audiometry Based on the Formula of the Middle Ear Parameter: A New Technique for Researches and Differential Diagnosis of Hearing. l., s.n.
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