The Ear and Hearing LossThe ear is the organ of hearing and balance in vertebrates. The earconverts sound waves in the air, to nerve impulses which are sent to the brain,where the brain interprets them as sounds instead of vibrations. The innermostpart of the ear maintains equilibrium or balance. The vestibular apparatuscontains semicircular canals which in turn balance you. Any movement by thehead, and this apparatus sends a signal to the brain so that your reflex actionis to move your foot to balance you.
The ear in humans consist three parts: The outer, the middle, and theinner portions. The outer ear, or pinna, is the structure that we call the ear.
It is the skin covered flap of elastic cartilage, that sticks out from the sideof the head. It acts like a funnel catching sound and sending it to the middleportion of the ear. The middle portion contains the ear drum and the connectionbetween the pharynx and the drum, the Eustachian tube. The inner ear containsthe sensory receptors for hearing which are enclosed in a fluid filled chambercalled the cochlea. The outer and middle ears purposes are only to receive andamplify sound. Those parts ofd the ear are only present in amphibians andmammals, but the inner ear is present in all vertebrates.
The ear can hear in several different ways. They are volume, pitch, andtone. Pitch is related to the frequency of the sound wave. The volume dependson the amplitude or intensity of the sound wave. The greater the frequency, thehigher the pitch. Humans can hear about 30 and 20,000 waves or cycles persecond. High pitch sounds produce more of a trebly sound, while low pitchsounds produce a rumbling bass sound.
When a person loses these abilities to comprehend sound, it is referredto as deafness. It can be caused by disease, toxic drugs, trauma, or aninherited disorder. Those causes can be classified as conductive, sensorineural,or both.
A conductive hearing loss results from damage to those parts of the earwhich transmit sound vibrations in the air to the fluids of the inner ear. Thistype of damage is usually to the eardrum or small bones known as ossicles.
Ossicles conduct sound from the eardrum to the cochlea. They cannot performsuch an action if the eardrum is perforated, if the middle ear cavity is filledwith fluid, or if the bones become separated, are destroyed by disease, or areovergrown by a spongy bone ( a disorder called otosclerosis). In conductivehearing loss, sound intensity is reduced, but sound isn’t distorted.
Sensorineural hearing loss is more resistant to therapy because itinvolves damage to the delicate sensory cells of the organ of Corti, which islocated in the cochlea. Sensorineural hearing loss has to do with bothdistortion of sound and loss of sound intensity. The closer the damaged tissueis to the auditory cortex, the more complex and subtle are the types ofdistortions. The hair cells of the organ of Corti cannot grow once they aredamaged. Sensorineural hearing loss is rarely reversible.
The hearing losses caused by salicylates such as asprin and the earlystages of Meniere’s Disease are reversible, however. The latter condition ischaracterized by an imbalance of fluid pressures within the inner ear. If thisimbalance is correct soon enough, before hair cell destruction has occurred,hearing will return to its normal level. Sensorineural hearing loss is oftenaccompanied by ear noise, or tinnitus, which is a high-pitched ringing heardonly by the patient. Because the inner ear has no pain fibers, damage is notaccompanied by pain.
Hearing loss is usually measured by an instrument called an audiometerwhich measures the weakest intensity at which a person can hear at mostfrequencies in the range of human hearing. The instrument is calibrated againstthe lowest intensity heard by normal humans at each frequency, according to aninternational standard. Audiometry can determine the amount of hearing loss-whether it is conductive or sensorineural in nature, and how much of each typeof damage has occurred.
Rehabilitation is available for patients with hearing losses. There arelots of programs and resources for these people. Most are special schools. Oneexample might be Cleary’s School for the Deaf. These schools try to provide anenvironment that is as close to a normal classroom as possible. As a matter offact, sometimes they use regular classroom’s but they provide special teachingassistants to help individual student’s.
The next step away from a normal classroom is the special schools. Thismay be a day school or a residential institution. Day schools are organizedfor one or more typed of handicap. Such schools also exist in all parts of theworld. There are, for example schools for the blind, deaf, and mentallyretarded in nearly every state in the US.
For children who cannot obtain the schooling they require in their owncommunities, there are residential schools with dormitories and dining hallsthat enroll children on a 24 hour a day basis. These schools are designed toserve children who do not have access to normal services or whose handicap makesit difficult to for them to adapt to a regular school. Residential schools arethe most common although occasionally there may be a school in a hospital.
Hearing devices are also available. Hearing Aids operate on battery.
They amplify the sound waves that the ear would normally receive. They rangefrom $500 to $6000.
INTERVIEWQuestion: How did you become about this disability? Answer: I was born with ahearing disabilityQ: When we talk, what exactly do you hear? A: The sound volume is lower but nodistortionQ: Would you consider yourself hard on hearing? A: No, and I say no because Ican hear when I pay attention but when I am not paying attention, it is like Iam in my own world. Also, sometimes, I can see their lips moving which signalsme to listen closely.
Q: Did you ever go for any treatment? A: No, I didn’t feel that it was necessarysince it was just a matter of paying attention.
Q: Do you wear any hearing devices? A: No, (same reason as last question)Q: Was it hard at all to communicate either as a child or as an adult? A: Allthe time I face the problem of someone talking to me and I don’t even know it.
Once someone mistakenly accused me of ignoring them.
Q: Do you know what your overall score was on an audiometer? A: No, I was nevertested