The ear is made up of three parts: the outer, middle, and inner ear. All three parts of the ear are important for detecting sound by working together to move sound from the outer part through the middle and into the inner part of the ear. Ears also help to maintain balance.
The outer ear includes:
The outer part of the ear collects sound. Sound travels through the auricle and the auditory canal, a short tube that ends at the eardrum.
The middle ear includes:
The inner ear includes:
The brain and auditory system work together to control how we hear and how we balance ourselves. The human ear is a complex organ and many scientists consider hearing to be the most complex of the human senses.
Sound can be detected whether a person is on land, underwater or in the air. Hearing is our ability to perceive sound by detecting vibrations that travel through our ears. The main purpose of the ear is to turn sound waves from the air into electrical signals that are interpreted by the brain.
Sound travels through the auricle and the auditory canal, a short tube that ends at the eardrum. Sound entering the outer ear travels through the middle ear and causes the eardrum and ossicles in the middle ear to vibrate. As it travels, it amplifies (gets louder) and changes from air to liquid. When the stapes moves, it pushes the oval window, which then moves the cochlea. The cochlea takes the fluid vibration of sounds from the surrounding semicircular ducts, translates them into signals sent to the brain by nerves like the vestibular nerve and cochlear nerve. The brain translates the information into recognizable sound patterns. It is a complex process but it occurs in a split-second of time.
The human ear can detect different tones and loudness levels, which can help a person determine the direction of something (locate where the sound comes from), and helps to pick out specific sounds despite lots of background noise. Specifically, when someone is speaking, the sounds may be vocalized or non-vocalized.
Vocalized sounds require a combination of air passing through the vocal cords and mouth shapes.
When a person is speaking, the vocal cords are in vibration. There is no closure of the throat or mouth with these sounds. And, in almost all languages, words must contain at least one vowel.
Non-vocalized sounds are created strictly from mouth shapes. Lipreading is the process of visually detecting non-vocalized sounds.
When a person is speaking, the quietest sounds are those that are actually easier to detect visually. When a person can see someone speak, they can understand him or her better. This combination of seeing what is heard contributes to a better sense of understanding.
The auditory pathways begin in the nerve fibers in the inner ear, where sound waves get converted into nerve impulses. These impulses then travel via the auditory nerve to the highest cerebral levels in the cortex of the brain.
Hearing loss can happen for many reasons. Some people may be born with hearing loss while others may lose their hearing slowly over time. There are diseases, infections and cancers that affect specific parts of the ear and can lead to hearing loss in children and adults.
Approximately 36 million American adults report some degree of hearing loss. Consider these facts:
Cancers of the ear usually occur on the skin of the outer ear. Cancers of the ear can develop inside the ear too, but these are very rare. There are different types of cancers (carcinomas and melanomas) that can affect the ear. Most ear cancers are squamous cell carcinoma on the outer ear, but basal cell carcinoma and malignant melanoma can also occur inside the ear.
Symptoms: A scabbed area of skin that is jagged and irregular with crusting and oozing—usually on the upper edge of the outer part of the ear. This area may be present for many years and may or may not be associated with a swelling or lump in the neck.
Cause: Long periods of time in the sun.
Treatment for people with small cancers of the skin of the ear includes surgery to remove the affected area. Often no further treatment is required, especially if the cancer is confined to the outer edge of the ear.
Cause: Unknown—but may be more common in adults with long history of outer ear infections.
Treatment for people with cancer of the auditory cancel includes surgery to remove parts of the middle ear.
Cause: Unknown—but may be more common in adults with history of discharge from ears for long periods of time.
Treatment of people with cancer of the middle ear includes surgery and radiation, which targets rays of energy at small areas of cancer cells that might not have been removed during surgery.
Otosclerosis is the buildup of spongy or bone-like tissue in the middle ear that prevents the ossicles, namely the stapes in the middle ear, from working properly. The impaired movement and function reduces the sound that actually reaches the ear. Otosclerosis usually results in conductive hearing loss, a hearing loss caused by a problem in the outer or middle ear.
If the buildup of tissue spreads to the inner ear, it is called Cochlear Otosclerosis. This can cause permanent sensorineural hearing impairment due to interference with how the nerves in this part of the ear work.
Scientists aren't sure about the exact cause but there is some research suggesting a relationship between otosclerosis and the hormonal changes associated with pregnancy and also with viruses.
Treatment for people who are diagnosed with otosclerosis depends on the extent of hearing loss and may include surgery to replace some or all of the ossicles with artificial ones. It is important to discuss the risks and possible complications of this and any procedure, as well as the benefits, with a doctor and a surgeon.
If the hearing loss is mild, surgery may not be an option but a properly fitted hearing aid may help some people with otosclerosis. A hearing aid is designed to compensate for a hearing loss by amplifying sound.
Ménierè's disease affects the inner ear and the vestibular system, which is the system that helps to maintain balance. In this disease, a part of the cochlea called the organ of Corti becomes swollen, leading to a loss of hearing that may come and go over time. It can also cause severe dizziness, lack of balance, tinnitus (ringing/buzzing sound in the ears), ear pain, and pressure. The disease can exist in mild or severe forms.
Approximately 615,000 individuals have been diagnosed with Ménierè's disease in the United States. Another 45,500 are newly diagnosed each year. Diagnosis is based on symptoms and results of hearing tests. Unfortunately, doctors don't know what causes Ménierè's disease, and there is no cure. Researchers think that it may have to do with fluid levels in the inner ear.
Treatment for people with Ménierè's disease includes medicines to help control dizziness and fluid retention in the body, and devices that deliver air pulses to the middle ear. Surgery may also be required. Estimates suggest that 6 out of 10 people will get better on their own or can control the symptoms with diet, drugs, or devices.
Germs such as bacteria and viruses can get into the ear and cause an infection. In particular, the middle ear cavity behind the eardrum can fill up with fluid. Treatment may include managing the pain and taking antibiotics, which are medications that fight infections. Ongoing fluids in the middle ear and ongoing infections over time may cause hearing problems or other difficulties.
Infections of the middle ear are one of the most common reasons for children to see a doctor. Three out of 4 children experience ear infection (otitis media) by the time they are 3 years old. Children are more likely to have ear infections like otitis media that come from bacteria or viruses than adults because of their developing ear anatomy. The middle ear is connected to the back of the nose by the auditory tube (also called the eustachian tube) and its location allows easier access to germs. This may lead to a buildup of fluid and pressure, painful infections, and even hearing loss. Infections in children can affect early speech and language development.
If the infection is due to bacteria, treatment is possible with antibiotics but if the infection is viral, antibiotics won't work. Surgery is another treatment option, especially for children with ongoing infections. Small tubes placed inside of childrens' ears help fluid drainage and relieve pressure in the ears so that hearing improves.
Chronic otitis media can affect adults, too. It is a long-lasting middle ear infection that can damage the ossicles (middle ear bones), and even lead to a perforation in the eardrum. Perforations can heal but when a chronic infection is present this is less likely and hearing loss can occur.
If you're experiencing hearing difficulties and aren't sure where to turn, schedule a consultation with your local hearing healthcare professional.