| Description of good practice: |
Hearing loss occurs if any part of the auditory system is damaged, be it one ear or both. It is generally described as mild, moderate, severe, or profound depending on how well a person can hear the intensities or frequencies most associated with speech.
A conductive hearing loss related to a damage or obstruction is in the outer or middle ear; damage of the inner ear results in sensorineural loss. Conductive hearing losses usually do not end up with severe impairment: a person with this type of hearing loss can take advantage of a hearing aid. A sensorineural loss frequently ranges from mild to profound, and even with amplification the person hears sounds as distorted. In this case the ability to understand speech clearly is diminished because parts of words and sentences are missed; sometimes application of a hearing aid is impossible.
Prosthetic technology has recently brought a revolutionary innovation to this kind of impairment – the cochlear implant and the digital hearing aid – i.e. “an electronic assistive listening device surgically implanted within the inner ear to stimulate hearing” and “… designed to provide useful sound information by directly stimulating the surviving auditory nerve fibres in the inner ear”; “candidates for cochlear implants have severe to profound sensorineural hearing loss and do not benefit from high-powered hearing aids”. A child with a cochlear implant needs an intense auditory and language rehabilitation.
Impairments of auditory function have two major effects: loss of input information and inability to verify one’s own speech output. The latter can cause significant impairment in oral communication and verbal language acquisition. Consequently, especially if the loss is severe, such children may experience serious difficulties in school learning: particularly linguistic – grammatical and syntactic – development affecting both receptive and productive language. Later, these complications can create obstacles in certain logical and problem solving activities, especially if they are mediated by the language use.
The adoption of a bilingual approach (national verbal and sign language), as it is becoming more common in the United States, has proven more effective to support learning, even the verbal language.
• There are several AT approaches to provide oral communication assistance to people with a hearing impairment. One approach grounds on a feedback, either visual or tactile, that represents the person’s speech patterns to typical speech. Regarding the tactile feedback, two types of haptic devices could be applied – systems for vector force feedback and devices that convey distributed sensations. The work of such tools is based on the skin sensation of human organism.
• Another approach provides alternatives to oral communication, such as visual displays (subtitles) read by the listener, or translation in the national sign language.
AT for learning and for school activities:
Automatic systems of speech recognition give teachers the possibility to arrange audio-visual materials with subtitles. Some of them facilitate the simultaneous translation of spoken language into written words on the screen, so that the teacher’s verbal lesson can be supported by the written visual code. Unfortunately, these systems are expensive; their
application may be justified if large groups, not a small number of students, are being coached.
• The computer systems allow to capture (convert the TV sound into written words) audio-visual materials. As it was mentioned above, the software that gives visual feedback of some characteristics of speech from the screen into a microphone (e.g. the tone and the pitch) is available; the interface can be serious or funny depending on the user’s age. These
systems can be regarded as educational and assistive technologies, but they are used for rehabilitation purposes mostly.
General comfort and working conditions:
To improve listening in the large areas, such as classrooms, they may be equipped with wireless assistive listening systems being based on radio frequencies, infrared systems, or on audio induction loop. The more profound is the auditory impairment, the more demanding are the students’ needs in terms of space planning. Since the possibility of communicating is restricted to their visual field, the desks should be set so that the
interlocutors can look at each other; the natural and artificial light sources are also important to avoid back lighting.
For traditional software applications, the PC use by students with hearing impairments does not require specific adaptations. The situation is different in multimedia applications: sound (especially speech) in multimedia documents is significant, as it conveys a lot of information. In some cases it can be useful to transform the auditory hints of some
software applications into visual flashing hints; it is achieved through ‘Access Windows’ within the Windows system. |
