Audiologists are among a team of hearing healthcare professionals who work to identify and assess disorders of hearing and balance in both pediatric and adult populations. If hearing loss is identified as impacting the patient’s life the audiologist can also recommend, select, and fit appropriate amplification. Additional assessments may also be needed to find out if the patient is a cochlear implant candidate or could be helped through other hearing assistive technology devices (HAT).
Identification of hearing loss has never been easier than it is now. Patient populations of all ages and developmental levels can be tested subjectively or objectively to provide information about the function of their auditory system. Specialized testing for difficult to test populations has become more widely accepted and is able to be performed safely and easily. Some or all of the following testing may be performed as part of a battery of tests to assess your auditory system.
- Pure Tone Audiometry: Utilizing age appropriate techniques
- Speech Audiometry: Speech Detection Threshold, Speech Reception Threshold, Word Recognition Score
- Immitance Measures: Tympanometry, Acoustic Reflexes, Acoustic Reflex Decay
- Otoacoustic Emmissions
- Auditory Brainstem Response (ABR) Testing
- Hearing in Noise Testing
Types of Hearing Loss
There are three types of hearing loss:
Sensorineural Hearing Loss
For the majority of individuals, a sensorineural hearing loss is caused by a problem with the structure or function of the inner ear (sensory) or the auditory nerve (neural). Because it is often difficult to determine the exact location of the problem, this type of hearing loss is referred to as a sensorineural hearing loss.
Typically, there is no medical or surgical treatment that will correct or even reduce the severity of the hearing loss. Fortunately, hearing aids or cochlear implants provide good benefit to individuals with sensorineural hearing loss.
Common causes of sensorineural hearing loss include:
- Congenital (present at birth) factors
- Hereditary or genetic factors
- Exposure to medications that are toxic to hearing
- Viral or bacterial disease
- Excessive exposure to loud noise
- Aging (presbycusis)
Conductive Hearing Loss
A problem in the outer or middle ear will cause a hearing loss known as a conductive hearing loss. Causes of conductive hearing loss include any condition that prevents the sound from reaching the eardrum, that prevents the eardrum from vibrating effectively and/or that prevents the middle ear bones from vibrating effectively. With all of these conditions, the inner ear and the hearing nerve may be completely normal; however, they are not receiving sounds properly because transmission of sounds through the outer and/or middle ear is reduced. Generally, conditions that cause conductive hearing loss are medically or surgically treatable, and there is potential for hearing to improve.
Common ear problems that can cause conductive hearing loss include:
- Ear canal blocked with wax
- Infection in the ear canal
- Malformed or absent ear canal at birth (congenital atresia)
- Hole in the eardrum
- Fluid in the middle ear (otitis media)
- Infection of the bony tissue around the middle ear (mastoiditis)
- Stiffness of the middle ear bones
- Discontinuity or trauma to the middle ear bones
Mixed Hearing Loss
A mixed hearing loss can exist in which there are problem with the outer or middle ear, as well as the inner ear. This can happen when a person has more than one medical problem at the same time. In these cases, it may be possible that the conductive hearing loss can be corrected, while the sensorineural loss remains permanent.
Many children with sensorinerual hearing loss can experience additional conductive hearing loss caused by middle ear fluid. This conductive loss overlays the exisiting sensorineural hearing loss and increases the severity of the hearing loss. It is very important to monitor your child for ear problems, or a noticeable change in hearing, and to seek medical assistance if concerns arise.
Degree of Hearing Loss
While hearing loss type is important the affect on a patient’s life is often determined by the degree of hearing loss. In the past, audiologists and physicians may have defined hearing loss through a percentage (i.e. 20% loss, 50% loss etc). However, due to the fact that most hearing losses are not flat the degree of loss may vary at different pitches. It has become widely accepted practice to describe the hearing loss based on a classification system.
- Mild hearing loss: Speech may be hearing in quiet but becomes difficult to understand when terhe is background noise in the environment or when speech is at a distance.
- Moderate hearing loss: Speech can be heard at a normal level only in quiet and in very close proximity.
- Moderately- severe hearing loss: Even in a quiet environment speech must be loud in order to be heard, understanding may be impaired even with this louder signal.
- Severe hearing loss: Speech is very difficult to understand in all situations.
- Profound hearing loss: Communication can be very difficulty even with hearing aids.