For a person with a hearing disability, the hearing does not operate normally. However, this term may be referred to in various ways, depending on the degree of hearing loss.
According to estimates, in Switzerland alone, over a million people are affected by a hearing impairment. Of these, about 10'000 can hear nothing at all. This statistic makes it clear that hearing impairments are not all equally disadvantaging. The spectrum ranges from mild hearing loss, as often occurs in older people, to profound hearing loss or complete deafness.
Hearing impairment from a medical point of view
From the point of view of an audiologist or an ORL specialist, there are several gradations of hearing impairments, depending on the average residual hearing, also known as medium hearing range. The hearing loss is determined by means of an audiogram performed in different sound frequencies.
- Hearing loss then refers to a mean hearing loss of around 50 decibels (dB). In addition, a distinction is also made between a mild hearing loss (corresponding to a loss of 20 to 40 dB) and severe hearing loss (60 to 80 dB).
- Residual hearing is defined as a hearing loss of approximately 90 decibels. This can also be referred to as "hardness of hearing bordering on deafness".
- Actual deafness occurs when the hearing loss correpsonds to more than 120 dB.
To illustrate this: the ticking of a watch is about 20 decibels, while a normal conversation is about 55 decibels. Normal traffic is approximately 75 decibels and a car horn is acoustically perceptible even with a hearing loss of about 110 decibels.
People who become deaf in later years are also considered as hearing impaired. Regardless of the extent of the hearing loss, these people are taken into account separately if the loss of hearing occurs post lingual, i.e. after natural language acquisition - usually after 3 years old. This means that those affected had already learned the spoken language in the normal way. This distinction is important for the early intervention aimed at learning the spoken language. Consequently, different educational concepts are required.
Hearing aids for the hearing-impaired
Medical progress provides opportunities to compensate for hearing loss, or at least partially. The most widespread tool is the hearing aid, or hearing device. A modern, digital hearing aid can compensate for a hearing loss of more than 50 decibels, depending on the damage.
The cochlear implant (CI) - an inner ear prosthesis in which electrodes are introduced in the cochlea - promises better hearing outcomes with a greater range of perceptible sound frequencies. There are also a number of electronic aids that convert acoustic signals into visual or tactile signals, making them accessible to the hearing-impaired. Examples include light ring, vibration alarm, as well as subtitles. In situations where help is needed to communicate with people who do not know sign language, deaf people can also consult sign language interpreters. Script interpreters, who simultaneously translate the spoken in the written language, are another alternative for this.
Causes of hearing impairment
Deafness can be caused by a genetic predisposition (birth-related hearing impairment), however this group represents only a fraction of hearing-impaired people. According to Pro Audito Switzerland, around one to two per mil of all infants are born already deaf. Much more often, the hearing impairment is caused by an illness, either before, during or after birth. During pregnancy, for example, rubella can cause hearing loss. During childbirth, lack of oxygen or birth traumas can also lead to loss of hearing.
Some diseases that can lead to deafness after birth include meningitis, scarlet fever and measles. Also, damage caused by drugs or medication can sometimes trigger a hearing disability. The association for the promotion of sign language for children is committed to provide help for these children and offers a large spectrum of information and articles.
The cultural perspective
Many if not most hearing-impaired people see themselves less as "people with a hearing impairment" than as part of a cultural and linguistic minority. The visual-manual sign language is at the center of their community. In Switzerland, due to the large linguistic diversity, different sign languages are being used. The Italian, French and German part of Switzerland all speak different variations of the sign language, based on the local dialect or local language.
Text: Thomas Mitterhuber – 01/2013
Translation: MyH (Text slightly abridged.)
Photo: pixelio.de, kestner.de