Our Ears

ANATOMY AND PHYSIOLOGY OF EAR

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Structure of our ear:

The ear is the organ of hearing and balance. There are three parts of ear: outer ear, middle ear and inner ear.

External or outer ear, consisting of:

  • Pinna or auricle. This is the outside part of the ear.
  • External auditory canal or tube. This is the tube that connects the outer ear to the inside or middle ear.
  • Tympanic membrane (also called the eardrum). The tympanic membrane divides the external ear from the middle ear.
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Middle ear (tympanic cavity), consisting of:

  • Ossicles. Three small bones that are connected and transmit the sound waves to the inner ear. The bones are called: Malleus, Incus and Stapes
  • Eustachian tube. A canal that links the middle ear with the back of the nose. The Eustachian tube helps to equalize the pressure in the middle ear. Equalized pressure is needed for the proper transfer of sound waves. The Eustachian tube is lined with mucous, just like the inside of the nose and throat.
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Inner ear, consisting of:

  • Cochlea (contains the nerves for hearing)
  • Vestibule (contains receptors for balance)
  • Semicircular canals (contain receptors for balance)
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How hearing mechanism work?

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How our ear functions and how brain receives and perceives sound impulses hold the key to better understanding of hearing and hearing loss. The process of hearing starts with a properly functional outer ear that collects the sound waves emitted from a source and passes it through ear canal to the eardrum (Tympanic Membrane). The impact of sound waves on the eardrum creates vibration, which further results in movement of three bones located in the middle ear.

The movement of the bones, especially of stapes, which is also the smallest of the three, results in vibration of the oval window situated between middle and the inner ear. This vibration impacts the fluid in the inner ear which further transmits the signals to cochlea, the organ which is responsible for hearing.

The vibration of the fluid inside the inner ear bends the hair cells that act as receptors. The bending of these cells triggers impulses that are transmitted to the brain through auditory nerves. Brain on receiving the impulse translates into the sound and comprehends it for further processes.

What Is Hearing Loss?

Hearing loss is when your ability to hear is reduced. A hearing loss makes it more difficult for you to hear speech and other sounds. The most common causes of hearing loss are noise and ageing. In most cases a hearing loss cannot be cured. Hearing loss, or hearing impairment happens when there is a problem with one or more parts of the ear or ears, the nerves coming from the ears, or the part of the brain that controls hearing.

Hearing loss is different in every person. People also may use the words deaf, deafness, or hard of hearing when they're talking about hearing loss. Actually, in other words we can say Hearing loss is a loss of the loudness or clarity of sounds. Most people have had temporary hearing loss at least once in their lives.

Hearing tests should always be performed by an experienced audiologist (a professional specialized in hearing), who will test hearing in order to determine the type, cause and severity. These tests vary according to the patient’s age and needs. The results are then discussed with the patient and/or their family.

The degrees of hearing loss vary from a mild hearing loss (affecting one’s ability to hear soft sounds) to a moderate, severe or even profound hearing loss (where the individual cannot hear most sounds).

Hearing loss also has types, according to the affected part of the ear. These include:

  • Conductive Hearing Loss Any problem in the outer or middle ear that prevents sound waves from travelling naturally to the inner ear is known as a conductive hearing loss. Conductive hearing losses are usually mild or moderate in degree.
  • Sensorineural Hearing Loss Which results from missing or damaged sensory cells (hair cells) in the cochlea (our snail shaped hearing organ) or neural hearing loss and is usually permanent. Sensorineural hearing loss can be mild, moderate, severe or profound.
  • Mixed Hearing Loss This is a combination of a sensorineural and conductive hearing loss. It results from complications in both the inner and outer or middle ear.
  • Neural Hearing Loss The least common of hearing loss types, resulting from the absence, damage or malfunction of the auditory nerve.

Hearing Loss Symptoms

Causes of Hearing Loss

Age

Age related degeneration of middle ear, inner ear and nerves that are responsible for hearing are main cause of hearing loss.

Disease

Measles, mumps or any other such type of viral infection, along with diseases like Meniere's syndrome, tumours of the hearing nerve and meningitis are the second largest reason for hearing loss.

Drugs

There are certain drugs that are known to hamper the functionality of hair cells present in the inner ear; causing hearing loss. Quinine, aminoglycosides, aspirin are some of such drugs that can trigger hearing loss.

Infections

Otitis media is a condition that causes formation of fluid in the middle ear. This fluid hampers hearing to a great extent and can be triggered due to sore throat and inflamed tonsils.

Malformation

If the outer ear or the ear canal is malformed; then it causes acute hearing loss.

Noise

Excessive noise pollution or if exposed to loud noise for a long period of time, then such exposure can cause permanent hearing loss.

Perforation

Drastic change in the air pressure over the eardrums in comparison to the air pressure maintained in the inner ear; such as during adventure sports like paragliding or scuba diving; there are chances of perforation of eardrums, resulting in hearing loss.

Wax

Ear canal, if is blocked due to Wax build-up, then it stops sound to travel towards the inner ear and thus can also cause hearing loss. However, such type of hearing loss can be easily treated with proper medical attention and personal hygiene.

The main cause of hearing loss is something we all have to come to terms with - our age. However, it can also be a result from disease,trauma or long-term exposure to damaging noise.

Can hearing Loss Be Cured By Drugs or Surgery?

At the moment, some hearing losses can be treated by either drugs or surgery. Most people with hearing difficulties find that a hearing aid recommended by a Hearing Aid Audiologist will improve their hearing.

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