1 Disability and Assistive Technology Systems

Learning Objectives

Significant changes have taken place in the last decade in the position of disabled people in our societies and communities. A combination of factors has led to new legislation, regulations and standards in many countries to attempt to remove existing discrimination against disabled people and enable them to participate fully in education, employment and the community. These factors include increasing awareness of the benefits to society as a whole of increasing the involvement and independence of disabled people and increasing assertiveness and activity by organisations of disabled people. Implementation of this legislation will involve the further development of assistive technology, as well as better information about what is currently available. This will require an effective and ongoing dialogue between the disabled end-user community and the various professionals, including engineers, technicians, occupational therapists, social workers and medical practitioners, involved in developing and providing assistive technology. In order to support this dialogue there is a need for common definitions and models describing the framework for assistive technology systems. Developing and presenting this framework, which will allow analysis and synthesis of assistive technology systems, as well as appropriate matching to potential end-users, is the main aim of this chapter. This modelling framework is developed within the social model of disability.

Although the medical model, which is closely associated with rehabilitation engineering for people with physical and cognitive impairments, is still more commonly used, it is the social model with a focus on removing social barriers and discrimination rather than rehabilitation that is preferred by organisations representing disabled people. Disabled people and their organisations have had a significant role in achieving the social and attitudinal changes which have led to recognition of the necessity, as well as the social benefits of full social inclusion of disabled people and accessibility of the social infrastructure. This has resulted in new legislation on accessibility and integration. However, much of this legislation is still strongly influenced by the medical model. For example, the definition of a disabled person used in the UK Disability Discrimination Act 1995 is a medical one. Thus social and medical models, as well as the social role of assistive technology are described in Section 1.1 of this chapter.

21 Disability and Assistive Technology Systems

It is useful to have some means of measuring the effectiveness of assistive technology in overcoming social and infrastructural barriers and improving the quality of life of disabled people. Although not a complete answer, quality of life assessment, sometimes through the use of an index, has a significant role to play. However, it should be noted that there is an important subjective component, which is more difficult to assess, to (disabled) people’s experiences and quality of life. Developments in the area of quality of life assessment are described in Section 1.2 of this chapter.

Section 1.3 presents the background to the assistive technology modelling framework developed by the authors. It includes discussion of a number of existing models, including the human activity assistive technology (HAAT) model due to Cook and Hussey (2002), as well as discussion of existing approaches to modelling human activities. A list of criteria to be met by the modelling framework is also presented.

The comprehensive assistive technology (CAT) model developed by the authors is presented in Section 1.4 and some applications of its use are given in Section 1.5. This modelling framework is based on further developments of Cook and Hussey’s human activity assistive technology (HAAT) modelling approach. The CAT model represents a holistic paradigm that can be used for assistive technology analysis and synthesis (development of specifications for new devices), as well as for matching assistive technology to a particular end-user. It also has pedagogical value, since it provides a common descriptive framework to support discussion and dialogue within all the disciplines involved in developing and providing assistive technology. The chapter closes with Conclusions in Section 1.6.

The learning objectives for this chapter are:

•Understanding the genesis and content of the social model of disability.

•Appreciating the nature and uses of quality of life assessment.

•Reviewing the different modelling approaches that have been used for modelling assistive technology systems.

•Understanding the structure and uses of the CAT model for assistive technology systems.

1.1 The Social Context of Disability

Since the intended users of assistive technology are disabled people, the definition of assistive technology depends on the definition or model of disability being used. Therefore, before considering definitions of assistive technology, the different models of disability will be presented. There are two main approaches – the medical and social models.

The medical model is based on the international classification of “impairment”, “disability” and “handicap” (sometimes referred to as the ICIDH model) developed by the World Health Organisation (WHO) in 1980 (WHO 1980). The WHO defined “impairment” as “any loss or abnormality of psychological, physical or anatomical

structure or function”. A “disability” then occurs when the impairment prevents a person from being able to “perform an activity in the manner or within the range considered normal for a human being”. Hence a “handicap” results when the person with a disability is unable to fulfil their normal role in society and the community at large. Thus the medical model views disability as residing in the individual and focuses on the person’s impairment(s) as the cause of disadvantage leading to the approaches of occupational therapy and rehabilitation. It should be noted that organisations of disabled people dislike the term “handicap” and it should not be used.

The social model of disability emphasizes the physical and social barriers experienced by disabled people (Swain et al. 2003) rather than their impairments and considers the problem to be in society rather than the disabled person. It is compatible with the empowerment of disabled people and user-centred and participative design approaches (Damodaran 1996; Rowley 1998). The social model was first developed by the Union of the Physically Impaired Against Segregation (UPIAS 1976) and then modified by the Disabled Peoples International (DPI) (Barnes 1994). The model is based on the two concepts of impairment and disability. “Impairment” is defined as the functional limitation caused by physical, sensory or mental impairments. “Disability” is then defined as the loss or reduction of opportunities to take part in the normal life of the community on an equal level with others due to physical, environmental or social barriers.

To illustrate the difference in focus of the two models, the medical model identifies the disability of a partially sighted person as related to their inability to read standard sized print whereas the social model identifies their disability as a consequence of the fact that, for instance, only some books are available in large print versions. Or, more simply, in the social model it is the steps that are the problem not the wheelchair. Organisations of disabled people influenced by the social model of disability have had an important role in changing attitudes towards disabled people and accessibility in the community and securing new services and rights for disabled people. However, considerable further work remains to be done to secure full rights for disabled people, most professionals are still influenced by the medical model and many services and facilities are still provided within a rehabilitation framework.

The importance of the social model was recognised in an update of the WHO classification system. In the new version, commonly termed ICIHD2, the terms “impairment, disability and handicap” were replaced by “disability, activity and participation” (WHO 2001). This model considers disablement to be the result of the interaction between an individual’s health and contextual factors. However, it is still the individual’s condition rather than external factors that is the main driver of the classification. This differs from the social model in which impairment is considered simply to be part of human diversity, but disability is recognised as being created by social and community environments that have been designed without taking the needs of disabled people into account.

The social model of disability is generally more appropriate for the research, design and development of assistive technology, as the aim of assistive technology products and devices should be to extend opportunities and break down barriers.