The causes of congenital blindness in deafness are diverse and lead to populations with different health, auditory, visual and sensory, neurological, and motor manifestations, all of which influence the development of communication and decisions made as to which communication methods are used and taught.
For many people, language is unlikely to develop to a functional level or become the most effective means of communication. Achieving the symbolic understanding necessary for any form of language development is also a challenge. You can find the deaf blind interpreting services via the web.
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Many AAC methods are introduced under the assumption that spoken language is not suitable for communication and therefore visual language symbols provide an alternative pathway for language development and lead to better communication.
Presenting this visual system to deaf people must be done with a good understanding of the visual abilities of deaf people and then designing visual symbols that are included in these abilities.
Another way to include sound symbols that can be felt rather than seen is to change the visual manual character to include a touch component. Remember, however, that touch and sight can be used together, not exclusively.
Information from one sense can be used to confirm or supplement the information obtained by another. The tactile signature method used on people with congenital deafblindness usually needs to be distinguished from the tactile signature form used on people with acquired blindness.