Every hearing loss doctor knows that hearing affects every aspect of your life, particularly your personal family and professional relationships.
The ear has three major components: the external ear, the middle ear and, the inner ear. The external ear is composed of the auricle/pinna and external ear canal that gathers sound and directs it to the eardrum. The middle ear is comprised of the eardrum and three small bones called the stapes (stirrup), incus (anvil) and the malleus (hammer). The middle ear transfers the sound vibrations to the inner ear. The inner ear is composed of the cochlea and semicircular canals that contain microscopic hearing and balance “hair cells”. These hair cells send the acoustic information to the auditory nerve and ultimately the brain for processing.
A Hearing Loss Doctor Explains the Types of Hearing Loss
There are three different types of hearing loss: sensorineural, conductive and mixed. Sensorineural hearing loss or “nerve loss” is the most common type of hearing loss and usually encompasses damage to the inner ear (cochlea) and/or the auditory nerve. This typically is related to an aging process of the inner ear and exposure to loud noises. Other potential causes of sensorineural hearing loss include illness, drugs that are toxic to hearing, familial genetics, head trauma, and malformation of the inner ear. Most of the time, sensorineural hearing loss cannot be treated medically or surgically and therefore is a permanent type of loss. Over 90% of people who wear hearing aids have a “nerve loss”.
A conductive hearing loss occurs when sound is not properly transmitted through the external ear canal, eardrum, and/or the three bones of the middle ear. Conductive hearing losses can occur from impacted earwax, a hole in the ear drum, middle ear infection/fluid (otitis media), infection in the ear canal (external otitis), disease or malformation of the bones of the middle ear, allergies, and/or a foreign body in the ear canal. Many times this type of loss can be corrected medically or surgically.
A mixed hearing loss is a combination of sensorineural and conductive hearing loss.
According to the National Institute on Deafness and Other Communication Disorders (NIDCD), approximately 36 million American adults have some degree of hearing loss. Additionally, about 2-3 out of every 1,000 children born in the United States have some degree of hearing loss. Despite these numbers, only 1 out of 5 people who could benefit from a hearing aid actually wear one.
How Is Hearing Measured?
Hearing loss is measured in decibels (dB HL) and displayed in a graph format called an audiogram. Loudness is plotted from the top (soft) to bottom (loud) on the “y” axis. Frequency (pitch) is plotted from left (bass) to right (treble) on the “x” axis. Hearing loss is not measured in percentage, but rather in degree as follows:
|Normal Hearing||0 – 25 dB HL|
|Mild Hearing Loss||26 – 40 dB HL|
|Moderate Hearing Loss||41 – 70 dB HL|
|Severe Hearing Loss||71 – 90 dB HL|
|Profound Hearing Loss||91+ dB HL|