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ASSISTIVE TECHNOLOGY: FROM THE PERSPECTIVE OF
REHABILITATION MEDICINE
Kavitha Raja and Saumen Gupta
Abstract: in the ICF framework of health and functioning, AT is recognized as an enabling
factor. AT covers gamut of devices and adjustments that help the differently abled to function
in society. A multifaceted assessment and involvement of the client in the decision making
process from start to finish is essential for AT to fulfill its role as an enabler. Design of AT is
a crucial factor in its acceptance by the target population. Some of the designs suggested are
universal design, cognitive design, affective design and participatory design. There is a large
body of research in AT, mainly on outcome evaluation. However, the quality of research is
inadequate resulting in less than optimum evidence. Optimum design, standard evaluation
tools and good quality outcome research are warranted in this area.
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Kavitha Raja
Professor, Department of Physiotherapy,
Manipal College of Allied Sciences, Manipal University
Manipal 576104, India
Saumen Gupta
Research Associate, Department of Physiotherapy,
Manipal College of Allied Sciences, Manipal University
Manipal 576104, India
In book: Advances in Therapeutic Engineering, Edition: 1st,
Chapter: Assistive Technology: From the Perspective of
Rehabilitation Medicine; Kavitha Raja and Saumen Gupta,
Publisher: CRC Press Taylor & Francis, Editors: Wenwei Yu;
Subhagata Chattopadhyay, Teik-Cheng Lim; U. Rajendra
Achary, pp.267-280
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List of abbreviations:
AT – Assistive technology
WHO – World Health Organization
ICF – International classification of functioning
CAT – Comprehensive Assistive Technology
MPT – Matching Person & Technology
SOTU – Survey of technology use
ATDPA – Assistive device predisposition assessment
HCTPA – Healthcare technology predisposition assessment
ATD – Assistive technology devices
GAS – Goal Attainment Scaling
QUEST – Quebec user evaluation of satisfaction with assistive technology
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1. Introduction: with improvements in medical care, mortality has been on the decline in
several diseases. The flip side of this is the increase in morbidity and more often in disability.
Disability can be physical or mental. Physical disability may be confined to one system or be
more pervasive affecting multiple systems. In order for the disabled or more correctly the
differently abled to function in a world designed for the able bodied or average individual,
many adjustments have to be made. Some of these include environmental modifications,
assistive devices and adaptive equipment. The term assistive technology (AT) is an umbrella
term that covers all forms of aids and appliances that allow a differently abled individual to
function in an optimum fashion in society.
Rehabilitation or habilitation is the process, by which a person with special needs, is
integrated into mainstream society such, that they can function with the least difficulty.
Technology is an integral part of this process, assisting people with disability in enhancing
social participation. The term assistive technology encompasses mobility devices, safety
devices, seating, communication devices, vision assists etc. according to the comprehensive
definition given by Gitlin, AT includes:
- Structural modifications (widening doors)
- Special equipment (grab bars/ rails)
- Assistive devices (wheelchairs, walkers)
- Adjustments to the non-permanent aspects of the environment (shifting furniture to
make room)
- Behavior modification in relation to the environment (breaking up tasks to conserve
energy)
The areas of application of AT are growing daily. As well as contributing to the
attainment of the highest possible level of functional independence, assistive technology has
been credited with the ability to enhance quality of life and fulfilment, to decrease handicap
and caregiver burden, and to “promote equal social status and access to competitive
employment”. Other authors have suggested that assistive technology which matches the
client’s needs has the potential, to “mitigate feelings of inadequacy and incompetence,”
provide a “feeling of accomplishment and self-mastery,” “decrease the effects of learned
helplessness,” and to “have a profound effect on the individual’s educational and
employment advancement” [1]
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Fig. 1 The interrelationships of domains to achieve independence
1.1 Modeling assistive technology systems: Traditionally AT has been referred to be based
on the level of technology. However the distinctions between these levels are often unclear.
Often there are systems that are hybrids of different levels of technology. There are also
situations where the same individual may require different levels of technology based on the
needs. For example, a high-level paraplegic may be quite comfortable using a manual
wheelchair at home but would require highly specialized mobility aids when outdoors. The
figure below illustrates the classification of AT based on amount of technology used.
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Fig. 2 Classification of AT based level of technology
Level of disability
WHO has classified rehabilitation into four levels. These are primordial prevention [2],
primary prevention, secondary and tertiary. [3,4,5] The role of AT in primary prevention is
many fold. These include prevention of secondary disabilities from occurring by
accommodation at an initial stage; prevention of disabilities from worsening, and
occasionally technology may assist in prevention of primary disability itself if one can
prognosticate. A simple example would be the use of a powered or electric wheelchair in
order to prevent overuse injuries of the shoulder in an individual with paraplegia.
Assistive Devices
Level of Technology
No technology
Low technology
High technology
Simple aids and
appliances for
activities of daily
living
Less complicated
electronic or
mechanical
devices, which are
simple to make
and are off the
shelf
Electronic and
computer assistive
aids usually custom
made
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Fig.3 Impact of assistive technology on disability
- Remediation: this refers to technology complementing or correcting disability. A
simple example is the use of glasses to correct vision
- Augmentation: refers to technology that can maximize on the patient’s potential. This
area is most commonly used in the communication devices domain.
- Substitution: technology taking over physiological function or compensating for an
anatomic structure would constitute substitution. This is most commonly seen in use
of prostheses.
However, it must be noted that often these functions are interchangeable. A particular
device can act in a remedial function for one group of patients but may act as substitutive in
others. For example, a person who has both of his legs amputated above the knees would
require a wheelchair for mobility outside the home. In this instance, the wheelchair serves a
remedial function. Take another case of an individual with one leg amputated below the level
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of the knee. The use of a wheelchair in this instance would serve as a substitution to his
prosthesis. This would be a matter of preference and not absolute need.
1.1.2 Function
Based on function, AT can be classified, as devices that enhance residual abilities be it in
locomotor, communication or sensory domains
Fig.4 Classification of assistive devices based on function
The objective of assistive devices, technology, and environments for people with
disabilities, is to improve the match between their capabilities and functional, occupational
and social demands in order to minimize dependence while enhancing performance and
social participation. These facilitators are described by a unified terminology and framework
of International classification of functioning (ICF). [6]
Assistive Devices
Functional Domains
Mobility aids
Communication aids
Safety aids
Aids for Basic activities of
daily living
Aids for extended
activities of daily living
Socialization/ recreation
aids
Walking aids, transfer aids,
wheeled mobility
Aids for hearing and visual
impaired
Fire alarms, gas alarms, drug
dispensers, fall alarms, bed safety
alarms etc.
Aids which assist in bathing,
toileting, grooming, eating
Aids which assist advanced
mobility like scooters, cooking,
writing, and housekeeping
Adapted recreational equipment,
computer aided facilities
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A recent model developed by Hersh and Johnson is the Comprehensive Assistive Technology
(CAT) modeling framework. [7] This is based not on the traditional medical model of
disability but on the current social model within the ICF framework. The ICF recognizes
technology as an enabler to overcome environmental barriers. The CAT model takes into
account the person, his physical characteristics, social context and belief systems. Further the
model considers the enablers and barriers in each of these domains. This model gives a
unified framework of AT across disabilities that is applicable worldwide. The CAT model is
flexible and easily understood. It can be represented in tabular format or a tree format. The
applicability includes
- Identification of needs in order to develop AT
- Analysis of existing AT
- Design and development of new AT
- Outcome evaluation of usability and design modification
The model can be used in all domains of ICF viz body structure, function and activities and
participation. The main advantages of this model are that it provides a single framework. This
enables the design of AT to be inclusive and avoid duplication. Moreover using the ICF
ensures that all contextual factors are taken into account like culture, beliefs, economics and
personal preferences. [8]
Mobility: the area of mobility is where AT has arguably the widest array of products both
custom built and off-the-shelf. Mobility devices include simple devices like the cane to
complicated devices like powered stair lifts and hoists.
Communication: devices used to enhance communication functions include technology to
help the hearing impaired and devices to assist individuals who have speech disability. This
category of AT ranges from the simple communication board to immersive environment
systems.
Cognitive functions: this area of AT is relatively new and has emerged out of the need for
older citizens to enjoy continuing independence. This category of AT is geared towards
assisting individuals with dementia to function in society. Products range from pill boxes to
electronic memory aids. Literature has reported several projects in this area in the past
decade. They include the Astrid project, ENABLE, Safe at Home etc. design requirements
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include an optimum mélange of user needs and requirements. Requirements as described by
Bjorneby must focus on enabling the individual without emphasis on the disability. This will
in turn give the person a feeling of independence and have a positive impact.[9]
User needs can be broadly grouped into 4 main categories
- Safety devices
- Cognitive and communication devices
- Multi-sensory stimuli
- Memory aids
Vision: visual disability includes both blind and low vision populations. AT products range
from collapsible sticks to magnifiers and Braille signs. Tactile aids are another group of AT
that fit into this category.
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Table showing indicative list of assistive devices [10]
Self-care
Mobility and seating
Hearing and speech and
communication
Vision
Recreation
No
technology
Reacher , sock aid, built up brush ,
bath mat, long handle brush ,long
handle shoe aids bath mat, grab
bars, bath stool / chair / bench and
lift, long brush, extended levers for
faucets, height of beds and chairs,
sliding boards, nonslip surfaces
Transfer boards , canes
,Wheelchairs, walkers,
ramp Vehicle and
driving adaptations
Ear trumpet, picture cards,
communication board
Reading/
magnifying glass,
Bright colored
objects, large
print, large no,
increased lighting
Built up handles on
racquets , floatation
devices
Low
technology
Electric toothbrush, electric
shavers, electronic adjustable toilet
tax
Light frame, foldable
wheel chairs, braces
Amplification aids, Braille
books, books on tape, guide
cane, screen reader for
computer, visual alerting
systems
Auditory alerts ,
alarms , braille
watch
Adapted tricycles,
adapted wheelchairs
High
technology
Sophisticated lifting hoists
Motorized wheel chair,
stair climber, elevator
amplification aids, assistive
listening devices, noise
reduction, sound systems,
telecommunication devices,
cochlear implant, augmentative
communication devices
Computer
applications Text
aloud, screen
magnifier
software
Adapted video games
with sensory haptic
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Prescribing assistive devices –
The most commonly used AT are mobility devices. Scherer [12, 13] suggested a shift in
AT focus from people in the 20th century to person in the 21st. this shift in focus from people
(who have a disability) to person (who has a unique combination of skills and needs) is in
keeping with the enabling model of ICF. This focus shift is also economically sound.
Example of prescription of assistive technology devices based on the problems
experienced by the consumer [11]
Problem
Potential assistive device
Musculo skeletal related problems
Difficulty walking, loss of leg
and lower body strength
Canes, walkers, wheelchairs, lifts, modified
vans, and power scooters
Muscle weakness and painful joints
Orthotics for the ankle and foot, built up
shoes
Loss of limb, hand or foot
Prosthetics including artificial limbs,
hands, and feet
Limited range of motion,
limited use of hands, fingers or
arms, limited strength
Communication and work related devices;
alternatives to the standard computer
keyboard used for typing in data; fist or
foot keyboards, switches, mouth controls,
joysticks, light pens, touch screens, and
breath activated switches
Vision enhancers
Low Vision
Eye glasses, large print playing cards, card
holders, screen magnifier for computer or
TV, large button telephone, bright colored
objects
Blind
Braille books, books on tape, guide cane,
screen reader for computer
Auditory Enhancers
Hard of hearing
Hearing aids, amplified telephones, visual
alerting systems, head phones for personal
control of sound on TV or stereo, or
concerts
Deafness
Written communication tools, visual
alerting systems, text telephone (TTY)
Environmental control units
Limited strength, limited
range of motion, limited reach
and mobility, low vision, hard
of hearing
Adaptations of timers, telephones, light
switches, switches which can be activated
by pressure, eyebrows, breath; text
telephones, control mechanisms with sonar
sensing devices, adaptations of existing
tools, personal pagers, alarm systems,
visual signalers
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Organizational and instructional devices
Forgetfulness, confused
thinking, memory loss
Pill dispensers, electronic calendars, timers,
specifically designed computer software
such as computer-assisted instructional
programs, information management and
record keeping programs
Home modifications – kitchens
Open flames and burners
Microwave, electric toaster oven, hot plate,
automatic shut-off crock pot
Difficulty reaching items
Adjustable height counters, cupboards; pull
out drawers, wall storage rack; reacher
Hard to turn on stove -
Lever-style faucet,"T" turning handle
Carrying items
Slide across counter, walker basket or tray,
bridge items surface to surface
Difficulty seeing
Adequate lighting, contracting colored
china, placemats, napkins, utensils with
brightly colored handles
Stove timer not audible
Timers that vibrate
Home modifications – Bathrooms
Getting on/off toilet
Raised seat, side safety bars, grab bars
Slippery or wet floors
Nonskid mat
Steps/Stairs
Cannot negotiate stairs
Stair glide, elevator, ramp
Note: the list above is an indicative list only. Prescription should follow the CAT model and
not a simplistic model of disability and device.
A useful model to use when prescribing AT is the MPT model suggested by Scherer. [12, 13]
This model consists of six steps.
- The first step is to identify the goals of independence, the way to achieve these goals
and the potential use of AT in this process.
- Step two consists of evaluating the history of AT use, satisfaction with previously
used AT and challenges faced in their use.
- Step three consists of an interview/ questionnaire that evaluates the consumer’s pre
disposition to using AT.
- Step four consists of a discussion between the consumer and the professional to sort
out differences in perspective
- Step five consists of the consumer and professional working together to solve the
problems.
- Step six consists of documentation of the final action plan.
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A number of instruments are used for the MPT model. Some of them are survey of
technology use (SOTU), assistive device predisposition assessment (ATDPA), healthcare
technology predisposition assessment (HCTPA). The role of AT as an integral part of
rehabilitation is unarguable. The question is on how best to incorporate AT to optimal
enablement of the user. [14]
3. Research: There is a large amount of AT outcomes research that can be accessed from
medical journals. These seek to identify the changes produced by AT interventions in the
lives of users in their environments for which the ATD have been prescribed. Conducting
meaningful research depends to a significant extent on studies that
(1) Employ technically sound measures of outcomes that are relevant to stakeholders,
(2) Use study designs resulting in persuasive evidence that AT interventions are actually
responsible for the ostensible outcomes, and
(3) Communicate the resulting information in ways that stakeholders can understand and use.
Doughty suggested that AT forced on consumers that do not meet their preferences are
likely to go unused. Others reasons for non-use have been identified as AT that set up barriers
to social interaction that are bulky and frightening or too complicated to use. Research in the
area of non-use is complicated due to the multifactorial nature of the subject. [15] Wessels et
al summarized the existing literature in the subject and identified the following qualifiers for
non-use [16]
- Device is never used/ used seldom
- Device is not used for the amount of time it is meant to be used/ not used for all
activities it is meant to be used for
- The device is not used voluntarily/ not used correctly
- The device was not being used at the time of questioning/ at a particular point in time
- The device was not used often/ much of the day
The authors cited Hocking to derive the lack of research into psychosocial aspects of
design except in the area of cosmesis and usability. Factors that influence non-use of AT have
been recognized as age, gender and diagnosis, client expectations from the AT. People with
acquired disabilities are less likely to accept AT than those with congenital disabilities.
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Apart from personal factors, contributing to non-use of AT factors related to the device have
also been cited as reasons for non-use. These reasons are poor quality, poor performance,
poor cosmetic appearance and difficulty of use.
Social factors that contribute to non-use are physical barriers, lack of opportunity to
use the AT and social reactions to use of AT. It has been documented that when users are
involved in informed decision-making and choice of AT the adherence is higher. Clear and
appropriate instructions and training, installation, service delivery and follow up are other
factors that influence use of AT.
In a study reported by Kaye et al from Independent living centres in California, USA,
certain trends in AT usage were reported. Usage increased markedly with age with women
being more likely to use AT. Usage increased with education and with income. People with
elderly onset disabilities were more likely to use low-tech devices and those with birth onset
disabilities were most likely to use high tech devices.
3.1 Outcome measures: The consortium on assistive technology outcomes research proposes
a chronological, spatial and developmental view of the disabled person’s interaction with AT.
This model fits the ICF framework. Wessels et al in their literature review identified Goal
Attainment Scaling (GAS) described in 1968 by Kiresuk and Sherman for mental health
treatment outcomes, as one of the most widely used outcome measures. This method consists
of a procedure to structure and evaluate the consumer in the service delivery system. [17]
Another widely used outcome tool for user satisfaction is QUEST (Quebec User Evaluation
of Satisfaction with assistive Technology). This tool specific to AT has undergone many
changes from its inception in 1996. [18]
Outcome evaluation of AT consists of efficacy, effectiveness and cost analysis. These are
challenges to research. Effectiveness and efficacy can be explored only as a comparison
between devices. This becomes difficult in the ICF model as it becomes difficult to match
individuals and situations. Cost can also be evaluated only when the devices being compared
are similar in function and other domains.
A recent systematic review of moderate quality by Jutai et al on the effectiveness of AT
for low vision rehabilitation did not find strong evidence for the effectiveness of AT for
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vision rehabilitation. These authors identified the dearth of effective and standardized
outcome measures to assess the quality of AT use. [19]
Even though there is a sub discipline of engineering-rehabilitation engineering that
primarily focuses on AT, there are various challenges to designing AT. The field of
rehabilitation engineering often treat designing for the disabled either as a short-term problem
solving task or adapt existing design to suit the disabled. However these approaches are
inadequate. The principle of universal design must be incorporated as these devices and the
individuals using them must interact with everyday situations and the average environment.
The concept of affective design must also be seriously incorporated into AT so that
acceptance is increased and use optimized. These are challenges that must be faced in a
multi-faceted approach involving engineers, allied health professionals, the disabled and
advocacy groups and funding agencies.
Another concept that is emerging in the field of design is “participatory” design. This
concept involves the client through all the stages of design. Yaagoubi and Edwards suggested
a term called “cognitive” design. [20] They conceptualized this in the framework of
participatory design. The process flows through the stags previously described in the
assessment procedure. Following the needs assessment where the client is involved, the
process of market assessment is undertaken. Following this, the problem is conceptualized
and a solution designed. The cognitive design framework identifies the following criteria for
evaluation of the technology. They are
- Safety
- Reliability
- Reinforcement
- Preference
4. Conclusion: All the models referenced in the previous sections emphasis the role of a
multi-disciplinary approach to the design and conceptualization of AT. The user must have an
active part in the whole process for the AT to be meaningful and pleasurable to use. There is
not enough evidence on the application of AT in improving the quality of life of the disabled.
The reasons are many but mainly there is a lack of high quality studies using standard tools.
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Research and development of AT must follow the same route as normal design so that there
is a seamless blending of mainstream and AT.
Fig. 5 Flowchart depicting the process of prescribing assistive technology
Disabled person
Personal factors, medical
factors, social factors,
environment and economic
needs and requirements,)
Set goals
Suitability assessment in a
trial period, assess
additional requirements/
modifications
Train and instruct, provide
ongoing support
Final AT
Follow up evaluation
/ outcome evaluation
Client satisfaction,
durability, usefulness,
achieving goals
Assessment
Client and provider
together
Selection of AT
Outcome
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References –
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