Types of Hearing Loss

Parts of the ear

Outer ear. The outer ear is made up of

• The part we see on the sides of our heads, known as pinna.
• The ear canal.
• The eardrum, sometimes called the tympanic membrane, which separates the outer and middle ear.

Middle ear. The middle ear is made up of

• The eardrum.
• Three small bones called ossicles that send the movement of the eardrum to the inner ear.

Inner ear. The inner ear is made up of

• The snail-shaped organ for hearing known as the cochlea.
• The semicircular canals that help with balance.
• The nerves that go to the brain.

Auditory (ear) nerve. This nerve sends sound information from the ear to the brain.

Auditory (hearing) system. The auditory pathway processes sound information as it travels from the ear to the brain so that our brain pathways are part of our hearing.

Four types of hearing loss

• Conductive hearing loss. Hearing loss caused by something that stops sounds from getting through the outer or middle ear. This type of hearing loss can often be treated with medicine or surgery.

• Sensorineural hearing loss. Hearing loss that occurs when there is a problem in the way the inner ear or hearing nerve works.

• Mixed hearing loss. Hearing loss that includes both 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.

Degree of hearing loss

• 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 when a person is 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.

Hearing loss can also be described as:

• Unilateral or bilateral. Hearing loss is in one ear (unilateral) or both ears (bilateral).

• Pre-lingual or post-lingual. Hearing loss happened before a person learned to talk (pre-lingual) or after a person learned to talk (post-lingual).

• Symmetrical or asymmetrical. Hearing loss is the same in both ears (symmetrical) or is different in each ear (asymmetrical).

• Progressive or sudden. Hearing loss worsens over time (progressive) or happens quickly (sudden).

• Fluctuating or stable. Hearing loss gets either better or worse over time (fluctuating) or stays the same over time (stable).
• Congenital or acquired/delayed onset. Hearing loss is present at birth (congenital) or appears sometime later in life (acquired or delayed onset).