Types of Hearing Loss

There are different types of hearing loss, depending on which part of the hearing pathway is affected. There are three basic types of hearing loss: conductive hearing loss, sensorineural hearing loss and mixed hearing loss.

Conductive Hearing loss

InnerEar_Conductive

Conductive Hearing Loss occurs when sound is not conducted efficiently through the outer ear canal to the eardrum and the tiny bones, or ossicles, of the middle ear. Conductive hearing loss usually involves a reduction in sound level, or the ability to hear faint sounds. This type of hearing loss can often be medically or surgically corrected. Those with this type of loss stand to benefit greatly from a hearing aid, because what they need most is amplification. Common causes of this loss include:

  • Fluid in the middle ear from colds, allergies, poor Eustachian tube function, ear infection, 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

InnerEar_Sensor

Sensorineural Hearing Loss occurs when there is damage to the inner ear (cochlea) or to the nerve pathways from the inner ear (retrocochlear) to the brain. Sensorineural hearing loss cannot be medically or surgically corrected. It is a permanent loss. Most physicians call this condition “nerve deafness”. Sensorinerural hearing loss not only involves a reduction in sound level, or ability to hear faint sounds, but also affects speech understanding, or ability to hear clearly. Common causes include:

  • Diseases
  • Birth injury
  • Drugs that are toxic to the auditory system
  • Genetic syndromes
  • Noise exposure
  • Viruses
  • Head trauma
  • Aging
  • Tumors

Mixed Hearing Loss

InnerEar_Mixed

Frequently, a person experiences two or more types of hearing impairment, and this is called mixed hearing loss. This term is used only when both conductive and sensorineural hearing losses are present in the same ear. However, the emphasis is on the conductive hearing loss, because available therapy is so much more effective for this disorder.

Degree of hearing loss Hearing loss range (dB HL)
Normal -10 to 15
Slight 16 to 25
Mild 26 to 40
Moderate 41 to 55
Moderate Severe 56 to 70
Severe 71 to 90
Profound 91+

Fact: 1 in 10 Canadians suffers from hearing loss