What is Hearing Loss?

There are Three Types of Hearing Loss:

Conductive
This type of loss is due to a problem somewhere within the middle ear which consists of the ear canal, the eardrum, the middle ear cavity and the ossicles (three tiny ear bones). Hearing loss of this nature is typically the result of otitis media (ear infection), fluid (either infected or non-infected) in the middle ear, wax impaction in the ear canal or problems with the ossicles. Conductive hearing losses are often treated via medication or surgical intervention. Hearing aids are also an option for some individuals with conductive hearing loss.

Sensorineural
This kind of hearing loss is caused by damage to the cochlea or cochlear nerve. Tiny hair cells in the cochlea are typically damaged or missing, causing sound to be processed abnormally. Some individuals with this type of loss may experience, in addition to poor hearing, other symptoms such as sound distortion, poor word understanding or sensitivity to loud sounds. Sensorineural loss is not generally helped by surgical intervention with the exception of cochlear implant surgery for profoundly deaf people or middle ear implant surgery. Hearing aids are usually the most useful intervention for this type of loss, as they provide more opportunity for the use of remaining hearing by giving increased sound input in the pitch ranges where it is needed.

Mixed
A mixed hearing loss consists of a conductive component in addition to a sensorineural loss.

The Following are Some of the Causes of Sensorineural Hearing Loss:
• Noise exposure
• Hereditary or genetic factors that affect hearing either at birth or sometime later
• The aging process (we call this type of loss "presbycusis")
• Exposure to ototoxic medications or chemicals (substances which cause cochlear damage)
• Damage to or pathology of the cochlea or cochlear nerve pathways due to accidents or medical problems such as infection
• Abnormal anatomy and/or physiology of the cochlea or cochlear nerve
• Tumors of the cochleovestibular nerve


Degree Of Hearing Loss
Hearing Loss is Categorized into the Following Levels:
• Normal Hearing: 0 to 25 dB for adults and 0 to 20 dB for children
• Mild: 30 to 40 dB for adults and 25 to 40 dB for children
• Moderate: 45 to 55 dB
• Moderately-Severe: 60 to 70 dB
• Severe: 75 to 90 dB
• Profound: 95 dB or greater

The term "Hearing Impaired" typically characterizes all patients who have a hearing loss and is an all-inclusive, general label. It indicates that hearing is not normal but does not specify the degree of hearing loss or its impact on communication. The two main categories of hearing impairment below are more specific, descriptive categories. It is important to understand that people with hearing impairment do not fit neatly into categories. A more useful way to describe hearing difficulty would be to describe the audiometric degree of loss and how the individual functions with that loss, behaviorally and communicatively, with and without hearing aids.

The term "Hard-of-Hearing" generally implies that hearing can be used for communication either with or without hearing aids or assistive listening devices. Reliance on visual cues to supplement auditory cues is common and many people in this category make use of lip-reading skills to supplement what they hear. Most people who identify themselves in this category rely on aural-oral (auditory-verbal) communication as their primary way to relate to others, although some may use visually-oriented communication methods as well such as American Sign Language (ASL) or Cued Speech. Hard-of-hearing children who have residual hearing can learn to use their hearing and communicate orally with the help of audiologic management and habilitation, including the use of hearing aids and other appropriate technology.

The term "Deaf" can include a myriad of meanings. The term can be used to describe degree of deafness, effects of deafness, or a person's cultural identification.

A person is "deaf" in terms of a medical-audiological definition if the average of their hearing thresholds at 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz is 90 dB or worse. Audiologically deaf persons may be aware that someone is talking but have no speech understanding without the use of hearing aids and/or lip-reading. There may also be some awareness of environmental sounds; they may be able to hear a jet taking off, for example, but it would sound soft.

In general, people who are deaf cannot use their ability to hear for communication purposes without hearing aids or a cochlear implant. This is complicated by the fact that people's ability to make use of residual hearing with hearing aids varies and is independent of their precise degree of loss. Many people who meet the criterion above can achieve useful and socially acceptable levels of oral communication ability with appropriate training. Therefore, use of the term "deaf" does not necessarily mean that there is no useful hearing ability or that the person cannot learn to talk. However, the term "deaf" is commonly used to refer to persons who have or seem to have no real usable or functional hearing and who communicate using sign language. Use of the label deaf can also depend on how a person is functioning independent of whether they are receiving the help they would need to hear. For example, an audiologically hard-of-hearing child might function as and be labeled as a deaf child by parents and teachers, prior to intervention with hearing aids and aural rehabilitation.

Another important dimension to consider in understanding hearing loss is how people view their own loss and how they identify themselves in terms of that loss. For example, a child with a moderate to severe hearing loss may have good potential to communicate auditorily with hearing aids. Sometimes when people with this degree of loss come from a family and community of deaf people, they may identify themselves as "deaf," and be immersed in deaf culture, using only American Sign Language (ASL) for communication. Such a person is "deaf" in terms of their cultural identification, but is not audiometrically deaf.

The legal term used to identify all children shown to have impaired hearing is "hearing disabled." This term replaces the older term "hearing handicapped." In practical discussions of hearing difficulties, sometimes the term "disability" is used to refer to the actual physiologic or sensory condition and the term "handicap" is used to describe the functional effects of the disability. These are useful distinctions since the functional effects of a hearing loss vary widely. A great deal of control can be exercised over how much the actual disability limits a child or adult in life, as its effects can be minimized through appropriate interventions, education and training and the use of available technology.