Hearing Loss is defined as any decline in the ability to hear. This can range from mild hearing loss, needing no treatment, to the inability to hear at all.
There are 3 types of hearing loss, each type is defined by the part of the auditory system that is impaired and the severity of the impairment.
Three basic types of hearing loss:
- Conductive hearing loss
- Sensorineural hearing loss
- Mixed hearing loss
Conductive hearing loss occurs when sound cannot go through the the outer ear canal to the eardrum and the tiny bones (ossicles) of the middle ear. Conductive hearing loss can cause a mild to moderate hearing loss making soft sounds difficult to hear.
- Middle ear fluid or Eustachian tube dysfunction - May be resolved with treatment of infection or placement of ventilating tubes
- Absence of an outer ear or ear canal - May be surgically repairable, but will likely require hearing aids for some time
- Absence of the middle ear - usually requires permanent use of hearing aids
Sensorineural hearing loss (SNHL) results from damage to the inner ear (cochlea) or to the nerve pathways from the inner ear to the brain. It is the most common type of hearing loss. This type of hearing loss usually cannot be medically or surgically corrected. SNHL reduces the ability to hear faint sounds; speech that is loud enough to hear may sound muffled or unclear.
Mixed hearing loss describes a condition where a conductive hearing loss occurs in combination with a sensorineural hearing loss (SNHL). Examples in children occur when a child has SNHL and also experiences conductive loss because of otitis media, (ear infections) causing hearing to be poorer than it was from the SNHL alone.
The degree or severity of hearing loss is described by the threshold of loudness at which sound can be heard. Hearing loss is measured in ranges of decibels.
- Mild hearing loss (26 to 40 dB HL)
- Moderate hearing loss (45 to 60 dB HL)
- Severe hearing loss (65 to 85 dB HL)
- Profound hearing loss (91+ dB HL)
The configuration or shape of a hearing loss refers to its degree and pattern across tones. This is illustrated in a graph called an audiogram. For example, hearing may be good in the low tones and poor in the high tones. Some hearing loss is the same for low and high tones.
The degree and shape of hearing loss are considered when the audiologist is selecting and recommending hearing aids.
The most common symptoms associated with hearing loss in children is speech and language delays and academic difficulties.
Brief description of evaluation:
There are different tests that check different parts of the auditory system. The audiologist may use a combination of these tests based upon your child’s age and ability to respond to speech and sounds.
Common rehab treatment interventions:
Depending on the cause and severity of the hearing loss, interventions may include medical treatment, surgery and/or hearing aids or cochlear implants. Speech and language therapy and aural habilitation may also be recommended to help the child learn speech, language and listening skills.