First Steps:

About your ear

(The following information is provided as a brief overview of the how the ear works in relation to how it affects your hearing)

The ear is divided into three parts, the outer ear, middle ear, and inner ear.  The assessment of your hearing involves looking at each part of your ear to see if it is contributing to your hearing status. 

The external auditory canal is inspected to insure that it is not occluded with cerumen (earwax) and that it is healthy and open to the eardrum.  If your ear is filled with cerumen or if there is evidence of a medical problem with your external ear canal, you will be referred for medical management.  Hearing evaluation may be delayed until these conditions are resolved.

The middle ear is composed of the tympanic membrane (eardrum), the middle ear bones: malleus (hammer), incus (anvil), and stapes (stirrup).  The middle ear is ventilated by the Eustachian tube. When your ears pop, it is an indication that your Eustachian tube is working to equalize the air pressure so that it is the same on each side of the eardrum.  When your Eustachian tubes work poorly, your ears may feel plugged.  Middle Ear Analysis may be performed to assess the status of your middle ear systems.  This battery of test is termed acoustic immittance measurements and include tympanometry (pressure in the ear canal is changed as the ease of sound transmission is monitored and plotted) and acoustic reflex measurements (middle ear muscle reflexes monitored).  If middle ear problems are identified (middle ear fluid, stiffening of the middle ear bones, disarticulation of the middle ear bones, holes in the eardrums, etc.), you will be referred for medical evaluation and management of these conditions.  A complete hearing test will often be performed to document how much of a contribution the middle ear problem is making toward the overall hearing loss.  Hearing loss involving the middle ear is termed conductive hearing loss if the underlying sensory hearing is normal.  If the loss involves both middle and inner ear components, then the loss is termed mixed hearing loss.

The inner ear contains the sensory system for hearing and balance.  The cochlea is the sensory organ for hearing.  Hearing loss involving the inner ear is termed sensorineural hearing loss and is the most common type of hearing loss.   Within the cochlea is the Organ of Corti containing the inner and outer hair cells.  The outer hair cells are unique cells in the body. They elongate and contract to either enhance or inhibit soft or loud sounds.  When we lose outer hair cell function, two things happen: we lose the ability to hear soft speech and loud sounds are more bothersome.  Inner hair cells are responsible for transmitting the information to the auditory areas of the brain.  The brain sends back signals to the inner ear to help regulate the information so it is heard optimally.  Intervention for sensorineural hearing loss may include speech reading, counseling, amplification, and for profound hearing loss – cochlear implants. 

In addition, to problems with the middle and inner ears, you may experience problems with neural transmission of with the processing of the information by the brain. 

Sensorineural hearing loss is defined by the degree of loss and the frequency at which the loss occurs.  The results of the hearing test are plotted on a graph called an audiogram.  Zero equals normal hearing.  As you go higher in dB HL, it is taking more and more volume for you to just barely hear.  Frequency is plotted from low to high pitch across the graph from left to right, respectively.  Hearing loss from 20 to 60 dB typically represents loss of outer hair cell function. People with this amount of loss will do well with amplification that is appropriate for their usable hearing range.  Hearing loss from 60 to 80 dB will benefit from amplification, assistive listening devices, speech reading, and will have difficulty understanding speech, especially in adverse listening situations.  Hearing loss from 80 to 100 dB will have great difficulty hearing and understanding speech even in optimum communication environments.  Use of hearing aids, lip reading, tactile aids, sign language, assistive listening devices, and possibly cochlear implants may be considered.