5 Rehabilitation Engineering And Assistive Technology

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5 Rehabilitation Engineering And Assistive Technology

Transcript Of 5 Rehabilitation Engineering And Assistive Technology

Andrew Szeto, PhD, PE
Chapter Contents
5.1 Introduction 5.1.1 History 5.1.2 Sources of Information 5.1.3 Major Activities in Rehabilitation Engineering
5.2 The Human Component 5.3 Principles of Assistive Technology Assessment 5.4 Principles of Rehabilitation Engineering
5.4.1 Key Engineering Principles 5.4.2 Key Ergonomic Principles 5.5 Practice of Rehabilitation Engineering and Assistive Technology 5.5.1 Career Opportunities 5.5.2 Rehabilitation Engineering Outlook Exercises Suggested Reading
At the conclusion of this chapter, students will: & Understand the role played by rehabilitation engineers and assistive technologists in the rehabilitation process. & Be aware of the major activities in rehabilitation engineering. & Be familiar with the physical and psychological consequences of disability.


& Know the principles of assistive technology assessment and its objectives and pitfalls. & Discuss key engineering and ergonomic principles of the field. & Describe career opportunities and information sources.

Since the late 1970s, there has been major growth in the application of technology to ameliorate the problems faced by people with disabilities. Various terms have been used to describe this sphere of activity, including prosthetics/orthotics, rehabilitation engineering, assistive technology, assistive device design, rehabilitation technology, and even biomedical engineering applied to disability. With the gradual maturation of this field, several terms have become more widely used, bolstered by their use in some federal legislation.
The two most frequently used terms today are assistive technology and rehabilitation engineering. Although they are used somewhat interchangeably, they are not identical. In the words of James Reswick (1982), a pioneer in this field, ‘‘rehabilitation engineering is the application of science and technology to ameliorate the handicaps of individuals with disabilities.’’ In contrast, assistive technology can be viewed as a product of rehabilitation engineering activities. Such a relationship is analogous to health care being the product of the practice of medicine.
One widely used definition for assistive technology is found in Public Law 100-407. It defines assistive technology as ‘‘any item, piece of equipment or product system whether acquired commercially off the shelf, modified, or customized that is used to increase or improve functional capabilities of individuals with disabilities.’’ Notice that this definition views assistive technology as a broad range of devices, strategies, and/or services that help an individual to better carry out a functional activity. Such devices can range from low-technology devices that are inexpensive and simple to make to hightechnology devices that are complex and expensive to fabricate. Examples of low-tech devices include dual-handled utensils and mouth sticks for reaching. High-tech examples include computer-based communication devices, reading machines with artificial intelligence, and externally powered artificial arms (Fig. 5.1).
Several other terms often used in this field include rehabilitation technology and orthotics and prosthetics. Rehabilitation technology is that segment of assistive technology that is designed specifically to rehabilitate an individual from his or her present set of limitations due to some disabling condition, permanent or otherwise. In a classical sense, orthotics are devices that augment the function of an extremity, whereas prosthetics replace a body part both structurally and functionally. These two terms now broadly represent all devices that provide some sort of functional replacement. For example, an augmentative communication system is sometimes referred to as a speech prosthesis.


A brief discussion of the history of this field will explain how and why so many different yet similar terms have been used to denote the field of assistive technology



Figure 5.1 Augmentative communication classification system (from Church and Glennen, 1992).
and rehabilitation. Throughout history, people have sought to ameliorate the impact of disabilities by using technology. This effort became more pronounced and concerted in the United States after World War II. The Veterans Administration (VA) realized that something had to be done for the soldiers who returned from war with numerous and serious handicapping conditions. There were too few well-trained artificial limb and brace technicians to meet the needs of the returning soldiers. To train these much-needed providers, the federal government supported the establishment of a number of prosthetic and orthotic schools in the 1950s.


The VA also realized that the state of the art in limbs and braces was primitive and ineffectual. The orthoses and prostheses available in the 1940s were uncomfortable, heavy, and offered limited function. As a result, the federal government established the Veterans Administration Prosthetics Research Board, whose mission was to improve the orthotics and prosthetic appliances that were available. Scientists and engineers formerly engaged in defeating the Axis powers now turned their energies toward helping people, especially veterans with disabilities. As a result of their efforts, artificial limbs, electronic travel guides, and wheelchairs that were more rugged, lighter, cosmetically appealing, and effective were developed.
The field of assistive technology and rehabilitation engineering was nurtured by a two-pronged approach in the federal government. One approach directly funded research and development efforts that would utilize the technological advances created by the war effort toward improving the functioning and independence of injured veterans. The other approach helped to establish centers for the training of prosthetists and orthotists, forerunners of today’s assistive technologists.
In the early 1960s, another impetus to rehabilitation engineering came from birth defects in infants born to expectant European women who took thalidomide to combat ‘‘morning sickness.’’ The societal need to enable children with severe deformities to lead productive lives broadened the target population of assistive technology and rehabilitation engineering to encompass children as well as adult men. Subsequent medical and technical collaboration in research and development produced externally powered limbs for people of all sizes and genders, automobiles that could be driven by persons with no arms, sensory aids for the blind and deaf, and various assistive devices for controlling a person’s environment.
Rehabilitation engineering received formal governmental recognition as an engineering discipline with the landmark passage of the federal Rehabilitation Act of 1973. The act specifically authorized the establishment of several centers of excellence in rehabilitation engineering. The formation and supervision of these centers were put under the jurisdiction of the National Institute for Handicapped Research, which later became the National Institute on Disability and Rehabilitation Research (NIDRR). By 1976, about 15 Rehabilitation Engineering Centers (RECs), each focusing on a different set of problems, were supported by grant funds totaling about $9 million per year. As the key federal agency in the field of rehabilitation, NIDRR also supports rehabilitation engineering and assistive technology through its Rehabilitation Research and Training Centers, Field Initiated Research grants, Research and Demonstration program, and Rehabilitation Fellowships (NIDRR, 1999).
The REC grants initially supported university-based rehabilitation engineering research and provided advanced training for graduate students. Beginning in the mid-1980s, the mandate of the RECs was broadened to include technology transfer and service delivery to persons with disabilities. During this period, the VA also established three of its own RECs to focus on some unique rehabilitation needs of veterans. Areas of investigation by VA and non-VA RECs include prosthetics and orthotics, spinal cord injury, lower and upper limb functional electrical stimulation, sensory aids for the blind and deaf, effects of pressure on tissue, rehabilitation robotics, technology transfer, personal licensed vehicles, accessible telecommunica-



tions, applications of wireless technology, and vocational rehabilitation. Another milestone, the formation of the Rehabilitation Engineering Society of North America (RESNA) in 1979, gave greater focus and visibility to rehabilitation engineering. Despite its name, RESNA is an inclusive professional society that welcomes everyone involved with the development, manufacturing, provision, and usage of technology for persons with disabilities. Members of RESNA include occupational and physical therapists, allied health professionals, special educators, and users of assistive technology. RESNA has become an adviser to the government, a developer of standards and credentials, and, via its annual conferences and its journal, a forum for exchange of information and a showcase for state-of-the art rehabilitation technology. In recognition of its expanding role and members who were not engineers, RESNA modified its name in 1995 to the Rehabilitation Engineering and Assistive Technology Society of North America.
Despite the need for and the benefits of providing rehabilitation engineering services, reimbursement for such services by third-party payers (e.g., insurance companies, social service agencies, and government programs) remained very difficult to obtain during much of the 1980s. Reimbursements for rehabilitation engineering services often had to be subsumed under more accepted categories of care such as client assessment, prosthetic/orthotic services, or miscellaneous evaluation. For this reason, the number of practicing rehabilitation engineers remained relatively static despite a steadily growing demand for their services.
The shortage of rehabilitation engineers with suitable training and experience was specifically addressed in the Rehab Act of 1986 and the Technology-Related Assistance Act of 1988. These laws mandated that rehabilitation engineering services had to be available and funded for disabled persons. They also required an individualized work and rehabilitation plan (IWRP) for each vocational rehabilitation client. These two laws were preceded by the original Rehab Act of 1973 which mandated reasonable accommodations in employment and secondary education as defined by a least restrictive environment (LRE). Public Law 95-142 in 1975 extended the reasonable accommodation requirement to children 5–21 years of age and mandated an individual educational plan (IEP) for each eligible child. Table 5.1 summarizes the major United Stated Federal legislation that has affected the field of assistive technology and rehabilitation engineering.
In concert with federal legislation, several federal research programs have attempted to increase the availablity of rehabilitation engineering services for persons with disabilities. The National Science Foundation (NSA), for example, initiated a program called Bioengineering and Research to Aid the Disabled. The program’s goals were (1) to provide student-engineered devices or software to disabled individuals that would improve their quality of life and degree of independence, (2) to enhance the education of student engineers through real-world design experiences, and (3) to allow the university an opportunity to serve the local community. The Office of Special Education and Rehabilitation Services in the U.S. Department of Education funded special projects and demonstration programs that addressed identified needs such as model assessment programs in assistive technology, the application of technology for deaf–blind children, interdisciplinary training for students of communicative



TABLE 5.1 Recent Major U.S. Federal Legislation Affecting Assistive Technologies

Legislation Rehabilitation Act of 1973, as
Individuals with Disabilities Education Act Amendments of 1997
Assistive Technology Act of 1998 (replaced Technology Related Assistance for Individuals with Disabilities Act of 1998)
Developmental Disabilities Assistance and Bill of Rights Act
Americans with Disabilities Act (ADA) of 1990
Early Periodic Screening, Diagnosis, and Treatment Program
From Cook and Hussey (2002).

Major Assistive Technology Impact
Mandates reasonable accommodation and least restricted environment in federally funded employment and higher education; requires both assistive technology devices and services be included in state plans and Individualized Written Rehabilitation Plans (IWRP) for each client; Section 508 mandates equal access to electronic office equipment for all federal employees; defines rehabilitation technology as rehabilitation engineering and assistive technology devices and services; mandates rehabilitation technology as primary benefit to be included in IWRP
Recognizes the right of every child to a free and appropriate education; includes concept that children with disabilities are to be educated with their peers; extends reasonable accommodation, least restrictive environment (LRE), and assistive technology devices and services to age 3–21 education; mandates Individualized Educational Plan for each child, to include consideration of assistive technologies; also includes mandated services for children from birth to 2 and expanded emphasis on educationally related assistive technologies
First legislation to specifically address expansion of assistive technology devices and services; mandates consumer-driven assistive technology services, capacity building, advocacy activities, and statewide system change; supports grants to expand and administer alternative financing of assistive technology systems
Provides grants to states for developmental disabilities councils, university-affiliated programs, and protection and advocacy activities for persons with developmental disabilities; provides training and technical assistance to improve access to assistive technology services for individuals with developmental disabilities
Prohibits discrimination on the basis of disability in employment, state and local government, public accommodations, commercial facilities, transportation, and telecommunications, all of which affect the application of assistive technology; use of assistive technology impacts requirement that Title II entities must communicate effectively with people who have hearing, vision, or speech disabilities; addresses telephone and television access for people with hearing and speech disabilities
Income-based (‘‘means-tested’’) program; eligibility and services differ from state to state; federal government sets general program requirements and provides financial assistance to the states by matching state expenditures; assistive technology benefits differ for adults and children from birth to age 21; assistive technology for adults must be included in state’s Medicaid plan or waiver program
Mandatory service for children from birth through age 21; includes any required or optional service listed in the Medicaid Act; service need not be included in the state’s Medicaid plan
Major funding source for assistive technology (durable medical equipment); includes individuals 65 or over and those who are permanently and totally disabled; federally administered with consistent rules for all states

disorders (speech pathologists), special education, and engineering. In 1993, NIDRR committed $38.6 million to support Rehabilitation Engineering Centers that would focus on the following areas: adaptive computers and information systems, augmentative and alternative communication devices, employability for persons with low back pain, hearing enhancement and assistive devices, prosthetics and orthotics,



quantification of physical performance, rehabilitation robotics, technology transfer and evaluation, improving wheelchair mobility, work site modifications and accommodations, geriatric assistive technology, personal licensed vehicles for disabled persons, rehabilitation technology services in vocational rehabilitation, technological aids for blindness and low vision, and technology for children with orthopedic disabilities. In fiscal year 1996, NIDRR funded 16 Rehabilitation Engineering Research Centers at a total cost of $11 million dollars and 45 Rehabilitation Research and Training Centers at a cost of $23 million dollars (NIDRR, 1999).


Sources of Information
Like any other emerging discipline, the knowledge base for rehabilitation engineering was scattered in disparate publications in the early years. Owing to its interdisciplinary nature, rehabilitation engineering research papers appeared in such diverse publications as the Archives of Physical Medicine & Rehabilitation, Human Factors, Annals of Biomedical Engineering, IEEE Transactions on Biomedical Engineering, and Biomechanics. Some of the papers were very practical and application specific, whereas others were fundamental and philosophical. In the early 1970s, many important papers were published by the Veterans Administration in its Bulletin of Prosthetic Research, a highly respected and widely disseminated peer-reviewed periodical. This journal was renamed the Journal of Rehabilitation R&D in 1983. In 1989, RESNA began Assistive Technology, a quarterly journal that focused on the interests of practitioners engaged in technological service delivery rather than the concerns of engineers engaged in research and development. The IEEE Engineering in Medicine and Biology Society founded the IEEE Transactions on Rehabilitation Engineering in 1993 to give scientifically based rehabilitation engineering research papers a much-needed home. This journal, which was renamed IEEE Transactions on Neural Systems and Rehabilitation Engineering, is published quarterly and covers the medical aspects of rehabilitation (rehabilitation medicine), its practical design concepts (rehabilitation technology), its scientific aspects (rehabilitation science), and neural systems.


Major Activities in Rehabilitation Engineering
The major activities in this field can be categorized in many ways. Perhaps the simplest way to grasp its breadth and depth is to categorize the main types of assistive technology that rehabilitation engineering has produced (Table 5.2). The development of these technological products required the contributions of mechanical, material, and electrical engineers, orthopedic surgeons, prosthetists and orthotists, allied health professionals, and computer professionals. For example, the use of voice in many assistive devices, as both inputs and outputs, depends on digital signal processing chips, memory chips, and sophisticated software developed by electrical and computer engineers. Figures 5.2 through 5.4 illustrate some of the assistive technologies currently available. As explained in subsequent sections of this chapter, the proper design, development, and application of assistive technology devices


TABLE 5.2 Categories of Assistive Devices
Prosthetics and Orthotics Artificial hand, wrist, and arms Artificial foot and legs Hand splints and upper limb braces Functional electrical stimulation orthoses
Assistive Devices for Persons with Severe Visual Impairments Devices to aid reading and writing (e.g., closed circuit TV magnifiers, electronic Braille, reading machines, talking calculators, auditory and tactile vision substitution systems) Devices to aid independent mobility (e.g., Laser cane, Binaural Ultrasonic Eyeglasses, Handheld Ultrasonic Torch, electronic enunciators, robotic guide dogs)
Assistive Devices for Persons with Severe Auditory Impairments Digital hearing aids Telephone aids (e.g., TDD and TTY) Lipreading aids Speech to text converters
Assistive Devices for Tactile Impairments Cushions Customized seating Sensory substitution Pressure relief pumps and alarms
Alternative and Augmentative Communication Devices Interface and keyboard emulation Specialized switches, sensors, and transducers Computer-based communication devices Linguistic tools and software
Manipulation and Mobility Aids Grabbers, feeders, mounting systems, and page turners Environmental controllers Robotic aids Manual and special-purpose wheelchairs Powered wheelchairs, scooters, and recliners Adaptive driving aids Modified personal licensed vehicles
Recreational Assistive Devices Arm-powered cycles Sports and racing wheelchairs Modified sit-down mono-ski

require the combined efforts of engineers, knowledgeable and competent clinicians, informed end users or consumers, and caregivers.
To knowledgeably apply engineering principles and fabricate devices that will help persons with disabling conditions, it is necessary to have a perspective on the



Figure 5.2 Add-on wheelchair system (from Church and Glennen, 1992).
Figure 5.3 Environmental control unit using radio frequency (RF) control (from Church and
Glennen, 1992).


human component and the consequence of various impairments. One way to view a human being is as a receptor, processor, and responder of information (Fig. 5.5). The human user of assistive technology perceives the environment via senses and responds or manipulates the environment via effectors. Interposed between the sensors and effectors are central processing functions that include perception, cognition, and movement control. Perception is the way in which the human being interprets the incoming sensory data. The mechanism of perception relies on the neural circuitry found in the peripheral nervous system and central psychological factors such as memory of previous sensory experiences. Cognition refers to activities that underlie problem solving, decision making, and language formation. Movement control utilizes the outcome of the processing functions described previously to form a motor pattern that is executed by the effectors (nerves, muscles, and joints). The impact of the effectors on the environment is then detected by the sensors, thereby providing feedback between the human and the environment. When something goes wrong in the information processing chain, disabilities often result. Table 5.3 lists the prevalence of various disabling conditions in terms of anatomic locations.
Interestingly, rehabilitation engineers have found a modicum of success when trauma or birth defects damage the input (sensory) end of this chain of information processing. When a sensory deficit is present in one of the three primary sensory channels (vision, hearing, and touch), assistive devices can detect important environmental information and present it via one or more of the other remaining senses. For example, sensory aids for severe visual impairments utilize tactile and/or auditory outputs to display important environmental information to the user. Examples of such sensory aids include laser canes, ultrasonic glasses, and robotic guide dogs. Rehabilitation engineers also have been modestly successful at replacing or augmenting some motoric (effector) disabilities (Fig. 5.6). As listed in Table 5.2, these include artificial arms and legs, wheelchairs of all types, environmental controllers, and, in the future, robotic assistants.
However, when dysfunction resides in the ‘‘higher information processing centers’’ of a human being, assistive technology has been much less successful in ameliorating the resultant limitations. For example, rehabilitation engineers and speech pathologists have been unsuccessful in enabling someone to communicate effectively when that person has difficulty formulating a message (aphasia) following a stroke. Despite the variety of modern and sophisticated alternative and augmentative communication devices that are available, none has been able to replace the volitional aspects of the human being. If the user is unable to cognitively formulate a message, an augmentative communication device is often powerless to help.
An awareness of the psychosocial adjustments to chronic disability is desirable because rehabilitation engineering and assistive technology seek to ameliorate the consequences of disabilities. Understanding the emotional and mental states of the person who is or becomes disabled is necessary so that offers of assistance and recommendations of solutions can be appropriate, timely, accepted, and, ultimately, used.
One of the biggest impacts of chronic disability is the minority status and socially devalued position that a disabled person experiences in society. Such loss of social
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