Deafness and Hearing Loss
Hearing impairment is defined by IDEA as "an impairment in hearing, whether permanent or fluctuating, that adversely affects a child's educational performance."
Deafness is defined as "a hearing impairment that is so severe that the child is impaired in processing linguistic information through hearing, with or without amplification."
Thus, deafness may be viewed as a condition that prevents an individual from receiving sound in all or most of its forms. In contrast, a child with a hearing loss can generally respond to auditory stimuli, including speech.
It is useful to know that sound is measured by its loudness or intensity (measured in units called decibels, dB) and its frequency or pitch (measured in units called hertz, Hz). Impairments in hearing can occur in either or both areas, and may exist in only one ear (unilateral hearing impairment) or in both ears (bilateral hearing impairment). Hearing loss is generally described as mild, moderate, severe or profound, depending upon how well a person can hear the intensities or frequencies most greatly associated with speech. Generally, only children whose hearing loss is greater than 90 decibels (dB) are considered deaf for the purposes of educational placement.
There are four types of hearing loss:
- Conductive hearing losses are caused by diseases or obstructions in the outer or middle ear (the conduction pathways for sound to reach the inner ear). Conductive hearing losses usually affect all frequencies of hearing evenly and do not result in severe losses. A person with a conductive hearing loss usually is able to use a hearing aid well or can be helped medically or surgically.
- Sensorineural hearing losses result from damage to the delicate sensory hair cells of the inner ear or the nerves that supply it. These hearing losses can range from mild to profound. They often affect the person's ability to hear certain frequencies more than others. Thus, even with amplification to increase the sound level, a person with a sensorineural hearing loss may perceive distorted sounds, sometimes making the successful use of a hearing aid impossible.
- A mixed hearing loss refers to a combination of conductive and sensorineural loss and means that a problem occurs in both the outer or middle and the inner ear.
- A central hearing loss results from damage or impairment to the nerves or nuclei of the central nervous system, either in the pathways to the brain or in the brain itself.
Hearing loss or deafness does not affect a person's intellectual capacity or ability to learn. However, children who are either hard of hearing or deaf generally require some form of special education services in order to receive an adequate education. Such services may include:
Academic support of a Teacher of the Deaf/Hard of Hearing (TOD)
Regular speech, language, and auditory training from a specialist
- Amplification systems
- Services of an interpreter for those students who use sign language
- Favorable seating in the class to facilitate lip reading
- Captioned films/videos
- Assistance of a note-taker, who takes notes for the student with a hearing loss, so that the student can fully attend to instruction
- Instruction for the teacher and peers in alternate communication methods, such as sign language
People with hearing loss use oral or manual means of communication or a combination of the two. Oral communication includes speech, lip reading and the use of residual hearing. Manual communication involves signs and finger spelling. Total Communication, as a method of instruction, is a combination of the oral method plus signing and finger spelling.
Credits: Medem Medical Library "Deafness and Hearing Loss" http://www.medem.com/medlib/article/ZZZTUYIR08C