In This Issue
Technologies for an Aging Population
March 1, 2009 Volume 39 Issue 1

Wheeled Mobility and Manipulation Technologies

Monday, March 16, 2009

Author: Rory A. Cooper

Elders can live more independently and safely in their homes with technologies that provide personal mobility and manipulation capabilities.

Technology can enhance the quality of life for older people, enable them to live safely in their homes, and enable them to participate in their communities as they age. Technology affects people with different levels of functioning in a variety of settings. In the home, technology may provide personal support and help for daily living. In a neighborhood, technological systems can enable a person to engage in community activities. In the larger community, technology may make it easier for an older person to commute to work and contribute to society through employment.

In each of these settings, technology may improve a person’s functionality by enhancing dexterity and mobility, helping with some home chores, reinforcing some kinds of memory, coaching for particular functions, either by providing information or by monitoring and intervening when necessary, and making it easier and safer for older people to drive. In other words, assistive technology may affect almost any aspect of daily life (Cooper et al., 2007).

Although the United States is in many ways an example for other countries in the world to follow, in the areas of assisting people with disabilities, rehabilitating people, and integrating older adults into our communities and culture we are losing ground. Ensuring the availability of assistive technol-ogy and accessible environments, providing sufficient support for research and development and adequate health care, and reaching consensus on a definition of disability are all issues we must address. If, as has been said, older people are the “canaries in the coal mine” of American society, the critical precursors of impending disaster, we must find a way to increase support for research, development, and education to create a basis for good decision making, invigorate translational science and engineering capacity for new technologies and services, improve our surveillance to get a better understanding of the problems facing older adults, and reform regulatory policy and legislation to meet their needs (IOM, 2007).

One problem facing every society, whether wealthy or poor, is integrating people with impairments and disabilities into the mainstream of life (Pearlman et al., 2008). The concept of “disability,” the interaction between a person’s impairment and attitudinal and environmental barriers that keep that person from full and effective participation in society, continues to evolve. Bringing the issues of disability, including the impairments of aging, into mainstream discussions is integral to the development of strategies for sustainable development and civil society. Older adults deserve to maintain their autonomy and independence, including the freedom to make their own choices, and they should have an opportunity to participate in decision making, especially when those decisions directly affect them.

Barriers to the Development and Use of Assistive Technologies
Although a plethora of assistive devices is available in the marketplace and a small research pipeline continues to make progress on assistive technologies, there are also notable individual, technical, policy, and societal challenges to be overcome.

Individual and Technical Barriers
The challenges faced by the individual cut across all other domains. These challenges include, but are not limited to, financial limitations, intellectual capacity, physical ability, sensory impairment, home environment, and the attitude toward technology (Albrecht et al., 2001). Technical barriers are largely defined by the complexity and intimacy of interactions between assistive technologies and older adults.

Human beings are extremely complex. Despite centuries of study, our depth of understanding about older people is still rudimentary. Assistive technology must be used by people with physical, sensory, or cognitive impairment, often a combination of all three. In addition, these technologies must function reliably day in and day out for months, if not years, with little maintenance, often in contact with or in close proximity to the person. An assistive device must function predictably and reliably, do no harm, and degrade or fail gracefully. The more one considers the environment and inter-actions between a device and its operating environment, the more complicated the design of the device becomes (Cooper et al., 2008a).

Policy Barriers
A few simple examples can illustrate the tremendous impact of public policy, such as Medicare policy, on the development, deployment, and use of assistive technologies by older adults. Most older people rely almost exclusively on Medicare for their primary health insurance.

Other insurance providers, led by Medicare, require that a person’s mobility be severely restricted before an electric-powered wheelchair (EPW) can be considered for coverage. Under Medicare, the patient and the rehabilitation team must prove that the person is unable to walk safely in the home. Commonly referred to as the “in-the-home-criterion,” older adults must be dependent on wheelchairs to meet their in-home mobility needs before Medicare will consider providing them with an EPW. Taken literally, this means that people must be imprisoned in their homes and no longer able to, for example, pay a social visit, shop, attend church, or go to a doctor’s office (Medicare Rights Center, 2005).

Figure 1 Cooper
Figure 1   iBOT transporter in use: (a) balance function for eye-level conversation; (b) standard function for washing hands; (c) remote function for loading in a van

This policy led to the ultimate demise of an assistive technology called the iBOT™ transporter (Figure 1), a unique wheelchair manufactured by Johnson & Johnson. The iBOT was an electric-powered chair with a revolutionary design that enabled individuals with impaired mobility to climb curbs, go up and down stairs, balance on two wheels to sit at eye level, and traverse uneven terrain such as sand (Cooper et al., 2004). With the iBOT, users could enter a garden, “stroll” through a park, or converse with a spouse eye-to-eye. These everyday activities, which we often take for granted, are dearly missed when they are lost. The iBOT provided much more mobility than traditional wheelchairs both inside and outside the home. However, their sophisticated design and concomitant higher cost were deemed a luxury by Medicare and were not fully covered.

Another example is hearing aids, another assistive technology not covered by Medicare, although they are regularly provided by the Department of Veterans Affairs (VA). Hearing loss, one of the most common impairments experienced by older adults, has a profound affect on a person’s ability to communicate and on personal safety.

Cultural and Social Barriers
In the simplest case, many cultures place a high value on the ability to walk. This may be entirely natural and intuitive, but it may have the inadvertent and possibly unintended consequence of devaluing people who use wheelchairs. It may also affect the allocation of resources to create an environment that is wheelchair accessible. One need only think of the difficulties and resentment aroused by the passage of the Americans with Disabilities Act (ADA), civil-rights legislation enforced by the U.S. Department of Justice.

Devices that Enhance Mobility and Manipulation
Mobility and manipulation are critical to living independently and are often strongly associated with the ability to continue to live safely in one’s home. Simple devices such as crutches, canes, walkers, and rollators (rolling walkers) can assist a person who has the endurance and strength to walk distances, but these devices must also provide some support or feedback to keep the person from losing their balance or enable the person to rest, when necessary. One of the challenges for engineers is matching an individual with the appropriate technology.

Transition to a wheelchair can be a significant personal hurdle for many people, although once the transition is made, it can be a liberating experience (Iezzoni et al., 2001). A common experience of older adults is the gradual contraction of their sphere of mobility; over time, they leave home less and less often. When the appropriate mobility technology, such as a wheelchair, is introduced, their sphere of mobility can once again expand (Hubbard-Winkler et al., 2008). Knowing when to introduce a new device requires assessing a person’s capabilities, home environment, and transportation.

Advances in Wheelchair Technology
Critical advances in wheelchairs have been made in the past decade. Manual wheelchairs now make more extensive use of titanium, carbon fiber, and medical-grade viscous fluids, which have resulted in chairs with a mass of less than 9 kilograms (Figure 2). Several studies have shown that reducing the mass of the wheelchair and user system reduces the strain on the arms and increases activity (Collinger et al., 2008).

Figure 2Figure 2 Ultralight manual wheelchair 
being driven over a mobility-skills course.

The greatest engineering challenges in manual wheelchair design are optimizing interaction between the user and the wheelchair, which requires knowledge of materials, biomechanics, ergonomics, anthropo-metrics, and human physiology, as well as motor learning to train the user in the skills necessary to achieve maximum mobility. User-mobility training involves virtual reality, machine learning, remote monitoring, and virtual coaching. In addition, technologies such as the SmartWheel (Figure 3), which was initially developed for research on wheelchair biomechanics, have become increasingly popular as clinical tools for selecting and fitting the manual wheelchair to the user (Asato et al., 1993; Cowan et al., 2008).Electric-powered mobility is critical to the lives of many older adults. The Segway, although not a medical device, is an attractive alternative to a wheelchair for some older adults who can stand for longer periods of time. It provides outdoor mobility and does not have the negative connotations of using a wheelchair.

Figure 3
Figure 3 SmartWheel.

EPWs, however, are extremely important sources of mobility for older adults with balance problems, cardiopulmonary restrictions, peripheral vascular disease, and a host of other health problems (Cooper et al., 2006). EPWs can provide comfortable, safe mobility both in the home and in the community.

Control-interface devices (Figure 4) for EPWs enable people to operate their chairs through proportional hand controls (e.g., joysticks, track pads, eraser joysticks), switches that can be operated by various parts of the body (e.g., hand, head, shoulder, foot, knee), and alternative controls that incorporate gyroscopes, accelerometers, and physiological signals (e.g., electro-myograms, electroencephalograms). Identifying the optimal interface, positioning it properly, and tuning it for the user provide substantial clinical challenges and opportunities for further research and development. Control algorithms are being investigated to provide traction control, anti-skid braking, anti-rollover capability, and navigational assistance (Simpson et al., 2008).

Figure 4Figure 4 Control interfaces for EPWs: (a and b) short-throw chin joystick, two views; (c) chin joystick with sip-and-puff switch.

Wheelchair seating is also extremely important. Researchers must take into account the dangers of pressure ulcers, venous pooling, spasticity, and contractures. EPW seats can be equipped with power functions that provide seat tilt (e.g., the user’s limbs maintain the same relative posture, but the seat rotates with respect to the gravity vector), recline, and elevation (Figure 5). These functions enable the user to change seated positions for comfort, to prevent injury, and to perform everyday activities.


Figure 5Figure 5 EPW: (a) seat in standard position; (b) seat in elevated position.

Quality-of-Life Technology Systems
An emerging area of technology development is to provide both mobility and manipulation. Some EPW users cannot retrieve a remote control, a book or magazine, or a drink unless it is placed in their immediate proximity. Frequently, older adults must ask family members or assistants to prepare their meals in advance and place them in the refrigerator, so they only require reheating or removing and eating.

Researchers are working on symbiotic systems that are efficient, safe, and reliable for retrieving real-life objects through user, remote, and autonomous devices. An essential feature of these systems is the seamless melding of robotics, with its approach to autonomous systems, with user-operated assistive technology to produce “quality-of-life technology” (QoLT) systems. QoLT systems create a symbiotic interaction of human and technology that maximizes human abilities and the capabilities of the technology in natural environments.

A QoLT that could remove a sealed plastic container from a refrigerator, place it in a microwave oven, heat it, open it, and place it where the user can eat it would be of great value to many older adults. One research project, the personal mobility and manipulation appliance (PerMMA), is being developed to provide these capabilities and more, both inside the home and in the community at large (Figure 6). PerMMA is not merely a wheelchair with “added intelligence” and arms. It is an integrated mobile robotic manipulator with full seating and EPW functions (Cooper et al., 2008b). A novel approach would be a remote caregiver who could provide assistance with operating a robotic device such as PerMMA to perform novel or difficult tasks. A remote operator could make robotic mobility and manipulation devices available quickly.

Figure 6
Figure 6 PerMMA, an appliance that provides independent capabilities inside and outside the home: (a) illustration showing use indoors; (b) photo of use outdoors.

 Motor Vehicles
Learning to drive is a defining moment in most of our lives. For young people, earning a driver’s license is a liberating experience, but for aging adults who lose that privilege, getting around can become a bewildering experience (Odenheimer, 2006). Many mainstream technologies, such as anti-lock braking systems, power steering, traction control, and global positioning systems, have enabled older adults to continue driving as they age. Intelligent-vehicle systems may make it possible for older adults to drive safely even longer as their skills decline.

At some point in the future, a fully autonomous vehicle may actually remove the driver from the control loop; however, many problems must be overcome before such vehicles become marketable. Semi-autonomous vehicles that learn from and provide support to the driver have great potential in the near-term for benefitting older adults. Currently, assistance with parallel parking is available from several manufacturers. In addition, systems that recognize driver alertness levels, adjust to lighting conditions, and present drivers with information on their driving performance are being investigated (Ayoob et al., 2003). For people with severe physical impairments, vehicles can be modified to be driven from a wheelchair, fitted with a driver’s seat that moves outside the vehicle to simplify ingress/egress, and equipped with alternative primary controls (e.g., hand controls, one-foot driving).

When a motor vehicle is modified, however, the safety of the vehicle may be compromised. For people unable to drive or people who prefer to use public transportation, the ADA requires that buses be accessible along all major routes. Thus buses are equipped with clearance low enough to extend a ramp to the curb so a wheelchair user can roll on and off or an older person can walk on or off without a having to negotiate a step. Because buses are considered low-acceleration environments, compartmentalization (a space or cubicle that confines the motion of a wheelchair) is used to reduce the risk of injury.

Engineers as Clinical Service Providers
The field of clinical-rehabilitation engineering provides not only technical challenges but also opportunities to help others. Engineers may work in medical rehabilitation, vocational, educational, or community-based settings. Clinical-rehabilitation engineers primarily provide assistive technology services to people with disabilities, including older adults. One of the most rewarding aspects for engineers is direct interaction with older adults in determining their needs, identifying or creating technological solutions, implementing and tuning the device or system, and training the older adult to use the device. Helping older adults maintain or regain independence and improve their quality of life can be personally gratifying.

Another feature of clinical-rehabilitation engineering is working as part of a team. Teams often include physicians (often physiatrists), physical therapists, occupational therapists, speech therapists, audiologists, prosthetists and orthotists, and rehabilitation counselors. Each professional has unique knowledge to contribute, but all of them share core values and a strong desire to help older adults.

An unfortunate challenge for clinical-rehabilitation engineers is reimbursement for their services. Most insurance providers do not recognize rehabilitation engineering as a health care profession. Therefore, payment for services must be incorporated into the cost of the technology or built into the overhead of the aggregate of assistive technology services provided by the medical rehabilitation team. Some state agencies (e.g., offices of vocational rehabilitation, agencies on aging) and federal agencies (e.g., VA) have fewer restrictions and may pay for clinical-rehabilitation engineering services. I expect that when clinical-rehabilitation engineering is recognized as a health care profession, the field will experience tremendous growth.

Transforming the Engineering Design Process
Teams of engineers, clinical scientists, social scientists, older adults, and caregivers must work together to relate psychological, physiological, physical, and cognitive function to the design of assistive and rehabilitative technologies. Ultimately, the result must be the creation of systems and devices that have a positive impact on quality of life of older adults. In part, this can be achieved by working closely with them and their caregivers throughout the design, development, test, and deployment phases to ensure that adoption, evaluation, and privacy concerns have been addressed. User involvement should be incorporated into engineering education and encouraged for practicing engineers.

Neither experts (clinicians or engineers) nor older adults and caregivers have complete critical knowledge. Accurate mapping and modeling of the abilities, opinions, experiences, and requirements of users can contribute to the development of successful assistive and rehabilitative technologies. A systematic approach to user involvement is characterized by: (1) the incorporation of universal design principals; (2) active involvement of all relevant parties and a clear understanding of the circumstances of the older adult and task requirements for the device; (3) multidisciplinary research, design, and development involving older adults, engineers, designers, marketers, clinicians, service deliverers, and social and health professionals; and (4) an inter-active development process.

A participatory action design (PAD) must include an understanding of the context in which the product will be used and the user’s cultural and organiza-tional requirements. Prototypes should be produced and designs evaluated according to the user’s criteria. The essence of PAD is a thorough understanding of policy, human assistance, assistive technology, and environmental interaction (the PHAATE model) (Cooper, et al., 2007).

Assistive technology is a cornerstone in the support structure that enables older adults to live independently, to participate in society, and to maintain their quality of life. Engineers continue to make important advances in technologies to assist older adults, and this can be a rewarding career path. Rehabilitation engineers are experts in understanding interactions between technology and people with disabilities in the performance of everyday activities.

Advances in engineering promise a brighter future for older adults. Rapid prototyping and manufacturing have reduced the time from conceptualization to product, and as virtual companies take advantage of flexible manufacturing, small, innovative companies are becoming competitive and earning sufficient revenue producing orphan products. As our understanding of the special needs of people with disabilities or infirmities improves, PAD processes and universal design processes will create crossover products that will help both older and younger people. If policy and societal hurdles can be overcome, robotics, machine learning, contextually aware systems, sensor integration, smart materials, and human-technology-activity modeling can transform assistive technologies.

Albrecht, G.L., K.D. Seelman, and M. Bury, editors. 2001. Handbook of Disability Studies. Thousand Oaks, Calif.: Sage Publications.

Asato, K.T., R.A. Cooper, R.N. Robertson, and J.F. Ster. 1993. SmartWheels: development and testing of a system for measuring manual wheelchair propulsion dynamics. IEEE Transactions on Biomedical Engineering 40(12): 1320–324.

Ayoob, E.M., R. Grace, and A. Steinfeld. 2003. A User-Centered Drowsy-Driver Detection and Warning System. Pp. 1–4 in Proceedings of the 2003 Conference on Designing for User Experiences, San Francisco, Calif., June 6–7, 2003. New York: Association for Computing Machinery.

Collinger, J.L., M.L. Boninger, A.M. Koontz, R. Price, S.A. Sisto, M. Tolerico, and R.A. Cooper. 2008. Shoulder biomechanics during the push phase of wheelchair propulsion: a multi-site study of persons with paraplegia. Archives of Physical Medicine and Rehabilitation 89(3): 667–676.

Cooper, R.A., M.L. Boninger, R. Cooper, S.G. Fitzgerald, and A. Dobson. 2004. Preliminary assessment of a prototype advanced mobility device in the work environment of veterans of spinal cord injury. Neurorehabilitation 19(2): 161–170.

Cooper, R.A., R. Cooper, M. Tolerico, S.F. Guo, D. Ding, and J. Pearlman. 2006. Advances in electric powered wheelchairs. Topics in Spinal Cord Injury Rehabilitation 11(4): 15–29.

Cooper, R.A., H. Ohnabe, and D.A. Hobson, eds. 2007. An Introduction to Rehabilitation Engineering. New York: Taylor & Francis.

Cooper, R.A., R. Cooper, and M.L. Boninger. 2008a. Trends and issues in wheelchair and seating technologies. Assistive Technology 20(2): 61–72.

Cooper, R.A., B.E. Dicianno, B. Brewer, E. LoPresti, D. Ding, R. Simpson, G. Grindle, H. Wang. 2008b. A perspective on intelligent devices and environments in medical rehabilitation. Medical Engineering and Physics 30(11): 1387–1398.

Cowan, R., M.L. Boninger, B.J. Sawatzky, B.D. Mazoyer, and R.A. Cooper. 2008. Preliminary outcomes of the SmartWheel users’ group database: a proposed framework for clinicians to objectively evaluate manual wheelchair
propulsion. Archives of Physical Medicine and Rehabilitation 89(2): 260–268.

Hubbard-Winkler, S.L., S.G. Fitzgerald, M.L. Boninger, and R.A. Cooper. 2008. Relationship between quality of wheelchair and quality of life. Topics in Geriatric Rehabilitation 24(3): 264–278.

Iezzoni, L., E. McCarthy, R. Davis, and H. Siebens. 2001. Mobility difficulties are not only a problem of old age. Journal of General Internal Medicine 16(4): 235–243.

IOM (Institute of Medicine). 2007. The Future of Disability in America. Washington, D.C.: National Academies Press.

Medicare Rights Center. 2005. Forcing isolation: Medicare’s “in the home” coverage standard for wheelchairs. Care Management Journal 6(1): 29–37.

Odenheimer, G. 2006. Driver safety in older adults: the physician’s role in assessing driving skills of older patients. Geriatrics 61(10): 14–21.

Pearlman, J., R.A. Cooper, M. Krizack, A. Lindsley, Y. Wu, K. Reisinger, W. Armstrong, H. Casanova, H.S. Chhabra, and J. Noon. 2008. Technical and clinical needs for successful transfer and uptake of lower-limb prosthetics and wheelchairs in low income countries. IEEE-EMBS Magazine (special Quality of Life Technology issue) 27(2): 12–22.

Simpson, R.C., E. LoPresti, and R.A. Cooper. 2008. How many people need a smart wheelchair? Journal of Rehabilitation Research and Development 45(1): 53–72.

About the Author:Rory A. Cooper is FISA Foundation Paralyzed Veterans of America Chair and Distinguished Professor at the University of Pittsburgh and director and senior career scientist of the Human Engineering Research Laboratories of the Rehabilitation Research and Development Service of the U.S. Department of Veterans Affairs.