RESNA 26th International Annual Confence

Technology & Disability: Research, Design, Practice & Policy

June 19 to June 23, 2003
Atlanta, Georgia

COMPARISON OF A PUSHRIM-ACTIVATED POWER-ASSISTED WHEELCHAIR AND A MANUAL WHEELCHAIR ON THE WHEELCHAIR SKILLS TEST

Krista L. Best, R. Lee Kirby, Cher Smith
Dalhousie University and Queen Elizabeth II Health Sciences Centre,
Halifax, Nova Scotia, Canada B3H 4K4

ABSTRACT

To compare the safety and efficacy of a pushrim-activated power-assisted wheelchair (PAPAW) with that of a manual wheelchair (MWC), both equipped with wheelie aids, 30 able-bodied subjects were trained in both types of chairs before completing the Wheelchair Skills Test (WST). There were no statistically significant differences between total WST scores, individual pass-fail success rates, or safety scores. Twenty-five percent of subjects felt the MWC was safer and 20% the PAPAW. Qualitative observations suggested that each wheelchair had advantages for particular skills. If given the choice, 85% of the subjects would choose the PAPAW for long-term use and 10% the MWC. The PAPAW holds promise and warrants further research and development.

BACKGROUND

Manual wheelchairs (MWCs) have proven to be a valuable rehabilitative tool, as they provide a generally effective and safe means of mobility. However, there are many wheelchair users (WCUs) who are unable to effectively propel a MWC (e.g., due to upper-extremity weakness, peripheral nerve injuries, or repetitive stress injuries). Powered wheelchairs provide many mobility options to such wheelchair users, but they are heavy, large, expensive, and may lead to deconditioning (1).

An intermediate alternative to these two traditional types of wheelchairs is the pushrim-activated power-assisted wheelchair (PAPAW). This new class of products is similar to a MWC, except that each rear wheel is equipped with a motor that assists with propulsion, in proportion to the forces applied to the pushrims by the WCU. The PAPAW is comparable to the MWC for measurements of stability, brake effectiveness, wheelchair dimensions, and evaluation of activities of daily living (2). The PAPAW also has lower metabolic demands for propulsion as it triples the user's power input and increases gross mechanical efficiency (3).

The PAPAW is a relatively new product about which little has been published to date, and long-range benefits have yet to be shown. The PAPAW has the theoretical potential to decrease the incidence of secondary injuries related to MWC use. It may also allow individuals to remain in manual wheelchairs for a longer period of time before transferring to a power chair, thus allowing the benefits of exercise. However, before the PAPAW can be widely recommended, its safety and efficacy in a wide range of environments must be determined.

RESEARCH QUESTION

The purpose of this study was to test the hypothesis that the PAPAW is as safe as the MWC and, for skills that require a high force on the pushrims, more efficacious.

RESULTS

There were no adverse incidents. Spotter intervention occurred for the high curb on two occasions, once in the PAPAW and once in the MWC. When asked to comment on the safety of both wheelchairs, 25% of subjects felt the MWC was safer and 20% the PAPAW. The wheelie aids functioned well with both wheelchairs. There were no statistically significant differences between total WST scores (Figure 1), individual pass-fail success rates, or safety scores for the PAPAW and the MWC.

Figure 1: Total percentage WST score for the MWC and PAPAW after training (n = 30).

Qualitative observations suggested that skills requiring a higher force on the pushrim (e.g., gravel, irregular surface and incline) were performed more easily with the PAPAW and skills requiring greater control of the wheelchair (e.g., 3-point turn, parallel parking, door and the wheelie skills) were performed more easily with the MWC. General comments from the subjects about the PAPAW included "needed less effort", "easier to push" and "changing gears makes it versatile for many situations". If given the choice, 85% of the subjects would choose the PAPAW over the MWC for long-term use, 10% would chose the MWC and 5% were undecided.

DISCUSSION

Overall, the safety and efficacy of the PAPAW and MWC devices studied were comparable in the WST setting. Qualitative observations suggested that the PAPAW is more effective than the MWC for skills that require a larger force on the pushrim, such as gravel, irregular surface, and incline ascent. However, subjects seemed to have more difficulty maneuvering the PAPAW for skills that required greater control, especially when the PAPAW was in the higher gain settings. Subjects found that performing and controlling a wheelie was easier in the MWC. In addition, obstacles such as the door and hallways were easier to negotiate in the MWC. The safety of the PAPAW was comparable to that of the MWC. The wheelie aids (4) appeared to enhance the safety and performance of both wheelchairs. The use of a small, able-bodied sample was a limitation of this study. A similar study design consisting of a larger sample of wheelchair users could provide valuable findings that could be generalized to the WCU population. The PAPAW holds promise and warrants further research and development.

1. van der Woude, L.H., Dallmeijer, A.J., Janssen, T.W., & Veeger, D. (2001). Alternative modes of manual wheelchair ambulation: an overview. Am J Phys Med Rehabil 80, 765-77.
2. Cooper, R.A., Fitzgerald, S.G., Boninger, M.L., Prins, K., Rentschler, A.J., Arva, J., & O'Connor TJ. (2001). Evaluation of a pushrim-activated, power assisted wheelchair. Arch Phys Med Rehabil 82, 702-8.
3. Arva, J., Fitzgerald, S.G., Cooper, R.A., & Boninger, M.L. (2001). Mechanical efficiency and user power requirement with a pushrim activated power assisted wheelchair. Med Eng Phys 23, 699-705.
4. Kirby, RL., Lugar, J.A., & Breckenridge, C. (2001). New wheelie aid for wheelchairs: Controlled trial of safety and efficacy. Arch Phys Med Rehabil 82, 380-90.
5. Kirby, R.L., Swuste, J., Dupuis, D.J., MacLeod, D.A., & Munroe, R. (2002). The wheelchair skills test: a pilot study of a new outcome measure. Arch Phys Med Rehabil 83, 10-18.