child, headphones, listen, happy, how we hear

HOW WE HEAR

Hearing is possibly one of our most important senses next to eyesight. It affects everything we do in how we connect with one another, in understanding and learning, and in how we interact with our environment.

“Most people take their hearing for GRANTED. That is until they lose it”


Jude Law

1. HOW DO WE HEAR?

As a sound enters the outer ear, it causes the eardrum to vibrate.

The sound is transmitted by three tiny bones (connected to eardrum) from the middle to the inner ear. 

The inner ear contains a snail-like shaped structure called the cochlea which is filled with fluid and lined with sensory cells with microscopic fine hairs.

These hairs move with the vibrations and transform the sound waves into nerve impulses which are sent to the brain.

The result is the sound you hear.

Inner, middle, outer ear, eardrum, canal, cochlea, auditory nerve, eustachian tube
 
2. TYPES OF HEARING LOSSES AND CAUSES
Sensorineural hearing loss

Occurs when there is damage to the inner ear (cochlea) or to the nerve pathways from the inner ear to the brain.

Causes

  • Exposure to loud noise

  • Head trauma

  • Virus or disease

  • Autoimmune inner ear disease

  • Hearing loss that runs in the family

  • Aging (presbycusis)

  • Malformation of the inner ear

  • Meniere’s Disease

  • Otosclerosis

  • Tumors

Conductive hearing loss

Occurs when sound is not able to reach the inner ear, due to an obstruction in the middle ear.

Causes

  • Malformation of outer ear, ear canal, or middle ear structures

  • Fluid in the middle ear from colds

  • Ear infection (otitis media - an infection of the middle ear in which an accumulation of fluid may interfere with the movement of the eardrum and ossicles)

  • Allergies

  • Poor Eustachian tube function

  • Perforated eardrum

  • Benign tumors

  • Impacted earwax

  • Foreign body in the ear

  • Otosclerosis

Mixed hearing loss

Combination of sensorineural- and conductive hearing loss.

hearing loss, sensorineural, conductive, mixed, causes, ear, listen
3. CONSEQUENCES OF HEARING LOSS
 

Untreated hearing loss can result in communication, social and emotional signs:

Emotional
  • Embarrassment

  • Anger, frustration

  • Anxiety

  • Depression

Social
  • Avoiding groups and strangers

  • Becoming silent and withdrawn

Communication

  • Conversations are shorter

  • Less use of/difficulty using the telephone

  • Others need to repeat themselves

  • Going along with conversations

communication
social
emotional
 
4. HOW THE BALANCE SYSTEM WORKS

The balance of the body works through numerous systems:

  • The eyes (visual system)

  • Ears (vestibular system)

  • Muscles, tendons and joints (proprioceptive input)

The balance system functions through a continuous process of position detection, feedback and adjustment using communication between the inner ear, eyes, muscles, joints and the brain.

Symptoms of balance disorders

  • Vertigo: spinning or whirling sensation; a feeling that the world is moving when it is not

  • Dizziness: lightheaded, floating, or rocking sensation

  • Nausea or vomiting

  • Headache

  • Changes in hearing (especially if one ear only)

  • Sensation of fullness in ears

  • Tinnitus (Ringing in the ears)

  • Light and sound sensitivity

  • Facial weakness and slurred speech

  • Difficulty focusing eyes

  • Memory loss

  • Hear internal body sounds

balance, hearing
Balance disorder, vestibular system, enlargement of crista, mecula