Augmentative and alternative communication

Augmentative and alternative communication (AAC) is an umbrella term that encompasses the communication methods used to supplement or replace speech or writing for those with impairments in the production or comprehension of spoken or written language. AAC is used by those with a wide range of speech and language impairments, including congenital impairments such as cerebral palsy, intellectual impairment and autism, and acquired conditions such as amyotrophic lateral sclerosis and Parkinson's disease. AAC can be a permanent addition to a person's communication or a temporary aid. Modern use of AAC began in the 1950s with systems for those who had lost the ability to speak following surgical procedures. During the 1960s and 1970s, spurred by an increasing commitment in the West towards the inclusion of disabled individuals in mainstream society and developing the skills required for independence, the use of manual sign language and then graphic symbol communication grew greatly. It was not until the 1980s that AAC began to emerge as a field in its own right. Rapid progress in technology, including microcomputers and speech synthesis, have paved the way for communication devices with speech output and multiple options for access to communication for those with physical disabilities. AAC systems are diverse: unaided communication uses no equipment and includes signing and body language, while aided approaches use external tools. Aided communication methods can range from paper and pencil to communication books or boards to speech generating devices (SGDs) or devices producing written output. The symbols used in AAC include gestures, photographs, pictures, line drawings, letters and words, which can be used alone or in combination. Body parts, pointers, adapted mice, or eye tracking can be used to select target symbols directly, and switch access scanning is often used for indirect selection. Message generation is generally much slower than spoken communication, and as a result rate enhancement techniques may be used to reduce the number of selections required. These techniques include 'prediction', in which the user is offered guesses of the word/phrase being composed, and 'encoding', in which longer messages are retrieved using a prestored code. The evaluation of a user's abilities and requirements for AAC will include the individual's motor, visual, cognitive, language and communication strengths and weaknesses. The evaluation requires the input of family members, particularly for early intervention. Respecting ethnicity and family beliefs are key to a family-centered and ethnically competent approach. Studies show that AAC use does not impede the development of speech, and may result in a modest increase in speech production. Users who have grown up with AAC report satisfying relationships and life activities; however, they may have poor literacy and are unlikely to be in employment. The Convention on the Rights of Persons with Disabilities defines augmentative and alternative communication one of communications as well as display of text, large-print, tactile communication, plain language, accessible multimedia and accessible information and communications technology. Augmentative and alternative communication is used by individuals to compensate for severe speech-language impairments in the expression or comprehension of spoken or written language. People making use of AAC include individuals with a variety of congenital conditions such as cerebral palsy, autism, intellectual disability, and acquired conditions such as amyotrophic lateral sclerosis, traumatic brain injury and aphasia. Prevalence data vary depending on the country and age/disabilities surveyed, but typically between 0.1 and 1.5% of the population are considered to have such severe speech-language impairments that they have difficulty making themselves understood, and thus could benefit from AAC. An estimated 0.05% of children and young people require high technology AAC. Well-known AAC users include physicist Stephen Hawking, broadcaster Roger Ebert and poet Christopher Nolan. Award-winning films such as My Left Foot and The Diving Bell and the Butterfly, based on books by AAC users Christy Brown and Jean-Dominique Bauby respectively, have brought the lives of those who use AAC to a wider audience. The field was originally called 'Augmentative Communication'; the term served to indicate that such communication systems were to supplement natural speech rather than to replace it. The addition of 'alternative' followed later, when it became clear that for some individuals non-speech systems were their only means of communication. AAC users typically utilize a variety of aided and unaided communication strategies depending on the communication partners and the context. There were three, relatively independent, research areas in the 1960s and 1970s that lead to the field of augmentative and alternative communication. First was the work on early electromechanical communication and writing systems. The second was the development of communication and language boards, and lastly there was the research on ordinary (without disability) child language development.