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Understanding Hearing Loss

Many different things can happen in the ear to cause a hearing loss.

Doctor looking in a child's ear.Our ear and hearing are made up of many parts:

These terms describe hearing loss where the part of the ear that is not working in a usual way:

  • A conductive loss — hearing loss caused by something that stops sounds from getting through the outer or middle ear.
  • A sensorineural loss — hearing loss that occurs when there is a problem in the way the inner ear or hearing nerve works.
  • A mixed hearing loss — hearing loss that includes a conductive and a sensorineural hearing loss.
  • Auditory Neuropathy Spectrum Disorder — Hearing loss that occurs when sound enters the ear normally, but because of damage to the inner ear or the hearing nerve, sound isn't organized in a way that the brain can understand. For more information, visit the National Institute of Deafness and Other Communication Disorders.

These terms describe the degree or the amount of hearing loss a child has:

  • Mild Hearing Loss — a person with a mild hearing loss may hear some speech sounds but soft sounds are hard to hear.
  • Moderate Hearing Loss — a person with a moderate hearing loss may hear almost no speech when another person is talking at a normal level.
  • Severe Hearing Loss — a person with severe hearing loss will hear no speech of a person talking at a normal level and only some loud sounds.
  • Profound Hearing Loss — a person with a profound hearing loss will not hear any speech and only very loud sounds.

These terms describe when the hearing loss happened:

  • Pre-lingual — the hearing loss occurred before the child learned to talk.
  • Post-lingual — the hearing loss occurred after the child learned to talk.

These terms describe the side or sides on which the hearing loss occurs:
  • Unilateral — there is a hearing loss in one ear.
  • Bilateral — there is a hearing loss in both ears.

Parents and professionals will use these terms to describe a child's unique type of hearing loss when talking to others.

If professionals and other parents use terms that you don't understand, please ask questions.

Outer Ear: The outer ear is made up of the parts we see (pinna), the ear canal, and eardrum (tympanic membrane).
Middle Ear: The middle ear is made up of the eardrum and three small bones (ossicles) that send the movement of the eardrum to the inner ear.
Ossicles: The chain of three tiny bones in the middle ear (malleus, incus, stapes).
Inner Ear: The inner ear is made up of the snail shaped organ for hearing (called the cochlea) and the nerves that go to the brain.
Cochlea: The cochlea is in the inner ear. It's a snail-shaped tube that is filled with fluid and has tiny hair cells. Sound that comes into the cochlea moves the hair cells back and forth. This turns sounds into electrical signals that are sent to the brain through the auditory (hearing) nerve.

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Contact Us:
  • Centers for Disease Control and Prevention

    National Center on Birth Defects and Developmental Disabilities

    Hearing Loss Team

    1600 Clifton Road
    MS E-87
    Atlanta, GA 30333
  • 800-CDC-INFO
    TTY: (888) 232-6348
  • Contact CDC-INFO The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Rd. Atlanta, GA 30329-4027, USA
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