Hearing Loss

TYPES OF HEARING LOSS

There are three types of hearing loss: sensorineural, conductive, and mixed.

Man-with-hand-on-ear

Sensorineural hearing loss (SNHL) is the most common form of hearing loss. According to the National Institute on Deafness and Other Communication Disorders (NIDCD), more than 90% of those with hearing loss have the sensorineural type of loss. Sensorineural hearing loss occurs when there is damage to the inner ear (cochlea) and the nerves leading up to the brain. SNHL is typically the more permanent style of hearing loss that warrants the use of hearing aids. Possible causes of sensorineural hearing loss include:

  • Aging
  • Noise exposure or trauma
  • Ototoxic medications such as chemotherapy
  • Genetics (family history)
  • Trauma

Conductive hearing loss is a loss of hearing arising from transmission issues in the outer and middle ear. Sound travels through the ear canal to the eardrum and through tiny bones called ossicles in the middle ear. This type of hearing loss is typically corrected with medical intervention such as surgery or with medication. Possible causes of conductive hearing losses include:

  • Ear infections
  • Eustachian tube dysfunction
  • Swimmer’s ear
  • Excess cerumen (earwax)
  • Fluid in ear due to cold or allergies
  • Hole in eardrum

Mixed hearing loss is a combination of both sensorineural and conductive hearing loss. This means there may be damage to the outer or middle ear and the inner ear. With this type of hearing loss, a referral to an Ear, Nose & Throat (ENT) physician is typically recommended. Upon medical clearance, patient’s with mixed hearing losses benefit greatly from amplification.


DEGREE OF HEARING LOSS

Degree refers to the severity of hearing loss. Your hearing loss may fall in a range such as a “mild to severe” where the hearing may vary in different frequency regions. Your audiologist can break down your hearing loss and show hearing loss affects different speech sounds.


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

Source: Clark, J. G. (1981). Uses and abuses of hearing loss classfication. Asha, 23, 493-500


CONFIGURATION OF HEARING LOSS

Configuration of hearing loss refers to the shape of your hearing loss. Hearing loss can differ in the low frequencies (bass or volume of sound) as compared to the high frequencies (treble and clarity of sound). Examples of configuration include flat, rising, or falling. Different configurations of hearing loss can radically affect how one communicates in the real world.

Longitudinal-And-Transverse-Wave length diagram