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Assistive Technology Project Presented By: Rose Aldan. Hearing Aid. How Your Ear Works. An auditory wonder
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How Your Ear Works • An auditory wonder • Your ears appear to be relatively simple structures. But they are, in fact, only part of the complex auditory system — passageways, vibrating structures, nerves and specialized areas of the brain that work together to gather and interpret sound. • In people with normal hearing, the ears can detect a child's whisper or a crack of thunder, the single call of a songbird or the entire range of instruments in an orchestra.
How You Hear The ear is made up of three primary parts: the outer ear, middle ear and inner ear. Each section is composed of structures that play distinct roles in the process of converting sound waves into signals that go to the brain.
Outer Ear The outer ear is composed of the visible part of the ear (pinna), the ear canal and the eardrum. The cup-shaped pinna (PIN-uh) gathers sound waves from the environment and directs them into the ear canal. When a sound wave strikes the taut, but somewhat flexible eardrum (tympanic membrane), the eardrum vibrates.
Middle Ear The middle ear is an air-filled cavity that holds a chain of three bones: the hammer, anvil and stirrup. The middle ear is connected to the back of your nose and upper part of your throat by a narrow channel called the auditory tube, or eustachian tube. The tube opens and closes at the throat-end to refresh the air in the middle ear, drain fluids and equalize pressure in the ear. Equal pressure on both sides of the eardrum is important for normal vibration of the eardrum.
Bones of the Middle Ear The middle ear contains three tiny bones, including the: -Hammer (malleus), which is attached to eardrum. -Anvil (incus), which is in the middle of the chain of bones. -Stirrup (stapes), which is attached to the oval window, the membrane-covered opening to the inner ear. The vibration of the eardrum triggers a chain of vibrations through the bones. Because of differences in the size, shape and position of the three bones, the force of the vibration increases by the time it reaches the inner ear. This increase in force is necessary to transfer the energy of the sound wave to the fluid of the inner ear.
Inner Ear The inner ear contains a group of interconnected, fluid-filled chambers. The snail-shaped chamber, called the cochlea (KOK-le-uh), plays a role in hearing. Sound vibrations from the bones of the middle ear are transferred to the fluids of the cochlea. Tiny sensors (hair cells) lining the cochlea convert the vibrations into electrical impulses that are transmitted along the auditory nerve to your brain.
Inner Ear The other fluid-filled chambers of the inner ear include three tubes called the semicircular canals (vestibular labyrinth). Hair cells in the semicircular canals detect the motion of the fluids when you move in any direction. They convert the motion into electrical signals that are transmitted along the vestibular nerve to the brain. This sensory information enables you to maintain your sense of balance.
Traveling to the Brain Electrical impulses travel along the auditory nerve and pass through several information-processing centers. Signals from the right ear travel to the auditory cortex located in the temporal lobe on the left side of the brain. Signals from the left ear travel to the right auditory cortex. The auditory cortices sort, process, interpret and file information about the sound. The comparison and analysis of the all the signals that reach the brain enable you to detect certain sounds and suppress other sounds as background noise.
Hearing Loss In 90 percent of cases, hearing loss results from damage to the hair cells in the cochlea, the National Institutes of Health says. This is called "sensorineural hearing loss." The damage can occur as a result of genetic factors, aging, illness, certain medications and exposure to loud noise. When the hair cells in the inner ear are damaged, electrical signals are not transmitted as effectively. This causes impaired hearing. Sensorineural hearing loss is the main type of hearing loss that can be "reversed" with a hearing aid.
What is a Hearing Aid and How does it Work? All hearing aids consist of a microphone, an amplifier, a miniature loudspeaker, or receiver, and a tiny battery. The microphone catches sounds and transforms them into electrical impulses. The amplifier modulates the electrical signals. Finally, the receiver converts the amplified signals into sounds and transfers them into your ear canal. Although the basic components of all hearing aids are the same, hearing aids differ in design, amplification technology and special features.
Why Wear A Hearing Aid Hearing problems might restrict your daily activities. You might have trouble communicating and following instructions in school or at work. When damage to the inner ear is the cause of your hearing loss, you don't have to struggle through life because you can't hear. A properly fitted hearing aid might make sounds easier to hear. An audiologist or otolaryngologist can help you determine which type of hearing aid would be best for your condition.
Why People Don’t Wear Hearing Aids Some people don't want a hearing aid because they think it is too expensive. Others feel it is embarrassing to wear one because they associate it with old age, low intelligence or disability. This is odd when you think about it, as many of the same people happily wear vision aids, such as contact lenses or glasses. Shunning hearing aids to avoid looking old can be self-defeating. If you have trouble hearing, your conversation partners might think of you as old or unfriendly. There is nothing embarrassing about wearing a hearing aid, and people most likely won't notice as most hearing aids are so small that they are practically invisible.
Cost Hearing aids for children cost between $1,000 and $4,000 per ear. A few health insurance companies will pay for children hearing aids, but most do not. Medicaid will pay for children hearing aids for those who qualify.
History of Hearing Aids The first hearing aids were enormous, horn-shaped trumpets with a large, open piece at one end that collected sound. The trumpet gradually tapered into a thin tube that funneled the sound into the ear.
The development of the modern hearing aid might not have been possible had it not been for the contributions of two of the greatest inventors of the late 19th and early 20th centuries. Alexander Graham Bell electronically amplified sound in his telephone using a carbon microphone and battery -- a concept that was adopted by hearing aid manufacturers. In 1886, Thomas Edison invented the carbon transmitter, which changed sounds into electrical signals that could travel through wires and be converted back into sounds. This technology was used in the first hearing aids
History of Hearing Aids In the 1990s, hearing aids went digital. Sound quality improved and became more adjustable. Also during this time, programmable hearing aids were introduced. At the turn of the 21st century, computer technology made hearing aids smaller and even more precise, with settings to accommodate virtually every type of listening environment. The newest generation of hearing aids can continually adjust themselves to improve sound quality and reduce background noise.
How Reliable are Hearing Aid’s • Reliability and appropriateness are crucial when your hearing is at stake. Also remember that some prices include an evaluation and checkups. • If they are well cared for, hearing aids should last for five to seven years. Most of the problems that send hearing aids in for repairs are caused by dirt, earwax and oil from the skin that blocks the microphones and receivers.
Accessibility in the CNMI • Commonwealth of the Northern Mariana Islands Assistive Technology Project • Department of Public Health • Marianas Health Services • Public School System • Office of Vocational Rehabilitation • Insurance
Sources -Google Images -Department of Public Health -www.livestrong.com
