1. Sound Wave Entry: Sound waves enter the ear through the auditory canal and strike the eardrum (tympanic membrane). The eardrum vibrates in response to these sound waves.
2. Middle Ear Bones: The vibrations from the eardrum are transmitted across the three small bones of the middle ear, known as the ossicles: the malleus (hammer), incus (anvil), and stapes (stirrup). The stapes, the last bone in the chain, transfers the vibrations to the oval window.
3. Oval Window: The oval window is a membrane-covered opening between the middle ear and the inner ear. When the stapes vibrates, it pushes on the oval window, creating pressure waves in the fluid-filled cochlea of the inner ear.
4. Cochlea: The cochlea is a spiral-shaped, fluid-filled structure in the inner ear. The pressure waves cause the fluid inside the cochlea to move. This movement creates waves in a membrane called the basilar membrane.
5. Hair Cells and Auditory Nerve: On top of the basilar membrane are thousands of tiny hair cells, which have microscopic hairs called stereocilia. As the fluid moves, it causes these hairs to bend. The bending of the hairs generates electrical impulses.
6. Signal Transmission: These electrical impulses are then transmitted via the auditory nerve (also known as the cochlear nerve) to the brain.
7. Sound Perception: The brain processes these electrical signals, interpreting them as sound, allowing you to recognize and understand the noises you hear.

This intricate process enables us to perceive and interpret a wide range of sounds, from the faintest whispers to the loudest noises.

Did you know that your ear is also part of your balance system? The semicircular canals contain special cells that sense the motion and position of your head.

Near Normal/ Borderline (21-25 dB)

• Hears almost everything well.
• May need to listen carefully in important situations.
• High-pitch sounds might be challenging.

Mild Hearing Loss (26-40 dB)

• Difficulty understanding speech, especially in noisy environments.
• Can hear well in quiet settings with few speakers.
• Trouble with soft-spoken individuals, like women and children.

Moderate Hearing Loss (41-55 dB)

• Listening requires effort; sustained attention is challenging.
• Trouble understanding speech even in ideal conditions.
• Needs to be close to the speaker; substantial difficulty in noisy environments.
• Often needs repetition.

Moderately Severe Hearing Loss (56-70 dB)

• Can hear only when the speaker is within 3-5 feet.
• Great difficulty communicating in most situations.
• May seem inattentive.

Severe Hearing Loss (71-90 dB)

• Identifies environmental noises but has difficulty with speech.
• Can distinguish vowels but not consonants.
• Might appear to ignore communication.
• Can hear loud voices from very close range.

Profound Hearing Loss (91 dB and above)

• Considered deaf; hears only very loud sounds.
• Does not use hearing as a primary means of communication.

In adults:

• Inherited from parents or acquired from illness.
• Ototoxic (ear damaging) drugs
• Very Loud noise (Noise Induced hearing loss) can cause permanent loss of hearing.
• Otosclerosis (middle ear disease)
• Tumor (Acoustic Neuroma)
• Physical injuries
• Presbycusis (loss of hearing due to aging process)

In children:

• Otitis Media , inflammation of the middle ear due to build-up of fluid
• Congenital causes, hearing loss present at birth.
• Acquired causes, hearing loss after birth (ex. Meningitis, Measles, Mumps)