Cause of Hearing Loss 

Journey of Sound to Brain 

You hear because of a series of steps in your ear that change sound into electrical signals​

  • The outer ear collects sound waves and works like a funnel to send them through a narrow tube (ear canal) that leads inside the ear. At the end of the ear canal is the ear drum (tympanic membrane).

  • The tympanic membrane is a thin membrane that vibrates when sound waves strike it. It divides the area called the outer ear from the middle ear. It is attached to a set of three tiny bones in the middle ear.

  • These bones are called the hammer (malleus), anvil (incus), and the stirrup (stapes). The bones pass the vibrations of sound waves to a small organ in the hearing part of the inner ear called the cochlea, which is a coiled structure like a snail shell.

  • The inner ear is filled with a thin fluid that transmits pressure changes throughout the cochlea. Inside the cochlea are tiny hair cells (stereocilia) that pick up sound vibrations from the fluid and cause nerve impulses in the auditory nerve.

  • The auditory nerve carries the message to the brain, where it is interpreted as sound.​

Loss of Hearing ​

  • Sensorineural hearing loss due to lessened transmission of sound from the outer ear to the auditory nerve because of stereocilia damage and reduced cochlear function. In humans, the damage is irreversible. This damage can occur as a result of disease, illness, age, injury from exposure to noise or certain medicines, or as the result of a genetic disorder.

  • Conductive hearing loss occurs when sound waves cannot transmit through the outer or middle ear or both. This can, for example, be caused by earwax, fluid in the middle ear space, or a punctured eardrum. Medical or surgical treatment can often restore hearing in people with a conductive hearing loss.

  • Mixed hearing loss is a combination of conductive and sensorineural hearing loss due to reduced middle ear and cochlear function.

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