Conductive Hearing Loss

Conductive hearing loss occurs when sound is not trasmitted through the outer ear and middle ear efficiently. Conductive hearing loss usually involves a reduction in the ability to hear faint sounds. This type of hearing loss can often be corrected medically or surgically.

 
Causes of conductive hearing loss include:

• Fluid in the middle ear
• Ear infections (otitis media)
• Allergies (serous otitis media)
• Poor eustachian tube function
• Perforated eardrum
• Benign tumors
• Impacted earwax (cerumen)
• Infection in the ear canal (external otitis)
• Presence of a foreign body
•  Absence or malformation of the outer ear, ear canal, or middle ear
  
   

Sensorineural Hearing Loss

Sensorineural hearing loss (SNHL) occurs when there is damage to the inner ear (cochlea) or to the nerve pathways from the inner ear to the brain. Most of the time, SNHL cannot be medically or surgically corrected. This is the most common type of permanent hearing loss.

SNHL reduces the ability to hear faint sounds. Even when speech is loud enough to hear, it may still be unclear or muffled.

Causes of SNHL include:

• Illnesses
• Drugs that are toxic to hearing
• Hearing loss that runs in the family (genetic or hereditary)
• Aging
• Head trauma
• Malformation of the inner ear
• Exposure to loud noise

Mixed Hearing Loss

Sometimes a conductive hearing loss occurs in combination with a sensorineural hearing loss. In other words, there may be damage in the outer or middle ear and in the inner ear (cochlea) or auditory nerve. When this occurs, the hearing loss is referred to as a mixed hearing loss.