RERC: D-1 Decision-support Data Acquisition for Wheelchair Selection

D-1: Decision-support Data Acquisition for Wheelchair Selection

Task Leader: Rory A. Cooper, PhD (rehabilitation engineer, consumer)

Co-Investigators: Michael L. Boninger, MD (physiatrist); Mark Schmeler, MS, OT (occupational therapist), Shirley Fitzgerald, PhD, William Ammer (technical coordinator), Megan Vitek, David Algood, Andrew Rentschler, Eric Wolf (students)

Duration/Staging of Task: This task will be active over the full 60 months of the RERC grant cycle, commencing January 1st, 1999.

Rationale/Task Summary
Currently, clinicians rely heavily on past experience and the advice of durable medical equipment dealers (Cooper, 1996a). In many cases, the durable medical equipment dealer is the expert on reimbursement. In the current health care environment, it is becoming increasingly difficult to receive authorization for what many clinicians and consumers would consider the most appropriate wheelchair. This is because there is a paucity of data in the scientific literature related to the objective evaluation and comparison of wheelchairs. This creates a potentially serious problem for clinicians in an era of evidence-based practice. This task will develop comparative test data about the quality and cost-effectiveness of wheelchairs and disseminate that information to clinicians, consumers, payers, and manufacturers.
The impact of this study will be that consumers and clinicians will have more quantitative information about wheelchairs to assist them in the decision-making process. This will result in consumers receiving better wheelchairs that are more likely to improve mobility. It is also likely that funding agencies will be more apt to fund more appropriate wheelchairs as preliminary evidence shows that life-cycle costs are lower for higher quality wheelchairs than for lessor quality wheelchairs.

Photograph of double-drum wheelchair test machine.

Design of development activities

Objectives
The following assumptions will be investigated in the course of this product evaluation task:
1. The total equivalent number of cycles will be significantly different for the models of wheelchairs tested.
2. The cost per total equivalent cycle will be significantly different for the models of wheelchairs tested.
3. The static and dynamic stability results will be significantly different in any orientation for the models of wheelchairs tested.
4. The results of power and controls testing and environmental testing will be significantly different for the models of electric wheelchairs tested.

Progress Report (12/31/99)

Currently sections 01, 02, 03, 04, 05, 06, 07, 09, and 10 of the ANSI/RESNA Wheelchair Standards have been completed for all fifteen of the power wheelchairs. Static and impact strength have also been conducted on all of the wheelchairs. Seven of the fifteen wheelchairs have completed the fatigue strength tests as well. Only section 14 remains for these power wheelchairs. After the initial round of testing, each wheelchair will then be cycled through the fatigue strength tests until a Class III failure occurs.

Expected Outcomes
The primary products that will result from this study will be: (1) comparative data for consumers, clinicians, and payers to use when selecting wheelchairs; (2) information on the quality of products for manufacturers and designers of wheelchairs; and (3) enhanced mobility and safety for wheelchair users.
To be effective, it is essential to have a dissemination strategy that presents the comparative data in a manner that is meaningful to each constituent within the target population. We have previous experience disseminating information regarding our wheelchair evaluations to consumers, clinicians, manufacturers, and third-party providers. There will be four primary informative outcomes from this study: (1) articles for medical professionals in peer-reviewed journals; (2) articles in AT service delivery oriented "popular" publications (e.g., Team Rehab Report); (3) articles in consumer oriented magazines (e.g., Paraplegia News); and (4) postings on the WWW via WheelchairNet designed to reach all the target constituents on a world-wide scale.

Progress Report (12/31/00)

American National Standards Institute and the Rehabilitation Engineering and Assistive Technology Society of North America (ANSI/RESNA) have developed standards for wheelchairs, which give feedback about the effectiveness, durability, or performance of power wheelchairs. We have been testing 15 power wheelchairs using these standards. The following standards have been completed:
Determination of Static Stability (Section 1)
Determination of Dynamic Stability (Section 2)
Determination of Effectiveness of Brakes (Section 3)
Determination of Energy Consumption (Section 4)
Determination of Overall Dimensions, Mass, and Turning Space (Section 5)
Determination of Energy Consumption (Section 6)
Determination of Seating and Wheel Dimensions (Section 7)
Climatic Tests (Section 9)
Determination of Obstacle-Climbing Ability (Section 10)
Static, impact, and fatigue strength (Section 8) is complete for thirteen of the power wheelchairs. We are also working on the Testing of Power and Control Systems
(Section 14). Currently three wheelchairs are finished and the other twelve wheelchairs are eighty-percent finished.

After the wheelchairs have been tested for all of the standards, each wheelchair will be tested on the double-drum and the curb-drop until the wheelchair fails. We have already completed this task for the largest database of manual wheelchairs. We found that ultralight wheelchairs last significantly longer than depot and lightweight wheelchairs.

In addition, we are in the process of comparing the effects of vibrations on the seat and footrests of manual wheelchairs. We are comparing caster fork suspension systems to see if certain caster forks with a polymer based suspension system reduce the amount of vibrations experienced by wheelchair users.

Publications/Reports

"A Comparison of Power Wheelchair Stability Using ANSI/RESNA Standards" Rentschler A., Cooper R., Boninger M, Wolf E. In: RESNA '99- Spotlight on Technology; 1999, Long Beach, CA. Washington DC: RESNA Press, 1999.

"A Comparison of the Dynamic and Static Stability of Power Wheelchairs Versus Scooters" Rentschler A., Cooper R., In: Proceedings of the 21st Annual International Conference of the IEEE Engineering in Medicine and Biology Society; 1999, Atlanta, GA.

"Climatic Testing of Five Different Types of Power Wheelchairs" Rentschler A., Cooper R., Wolf E., Boninger M., Submitted to RESNA 2000 Conference.

"Comparison of Energy Consumption and Maximum Speed in Electric Powered Wheelchairs" Wolf E., Cooper R., Rentschler A., Fitzgerald S., Kortebek E., Submitted to RESNA 2000 Conference.

"Power and Control Testing of Five Different Types of Power Wheelchairs" Algood D., Cooper R.A., Vitek J.M., Ammer W.A., Wolf E.J. In: RESNA Conference; 2001, Reno, NV. Washington DC: RESNA Press, 2001. (Winner of the Whitaker Foundation Student Paper Award)

"Static, Impact, and Fatigue Testing of Five Different Types of Electric Powered Wheelchairs" Vitek J.M., Cooper R.A., Rentschler A.J., Algood D., Ammer W.A., Wolf E.J. In: RESNA Conference; 2001, Reno, NV. Washington DC: RESNA Press, 2001.

"Using Stability and Fatigue Strength When Choosing a Manual Wheelchair" Rentschler AJ, Cooper RA, Boninger ML, Fitzgerald SG. In: RESNA Conference; 2001, Reno, NV. Washington DC: RESNA Press, 2001.

"Comparison of Fatigue Life for Three Types of Manual Wheelchairs" Fitzgerald SG, Cooper RA, Boninger ML, Rentschler AJ, Archives of Physical Medicine & Rehabilitation, in press.

Progress Report (12/31/01)

Powered Wheelchair Study

Testing of the 15 power wheelchairs using all of the ANSI/RESNA standards is now complete. The wheelchairs are now being tested alternatively on the double-drum machine and the curb-drop machine until each wheelchair no longer is able to operate (Class 3 Failure). Currently 11 of the 15 wheelchairs have been tested until failure. Preliminary results show that Pride Healthcare Jazzy 1100 was the most durable and the most cost-effective, and the Permobil Chairman was the least durable and the cost-effective. The Everest & Jennings Lancer 2000 and the Invacare Action Arrow Storm are still being tested and were not used in these comparisons.

testiing formation, please contact task leader for additional information

Manual Wheelchair Suspension Study

In response to studies demonstrating the negative effects of whole-body vibrations, manufactures of manual wheelchairs have integrated rear suspension elements into their designs. By positioning suspension elements between the axle and the seat, they have intended to reduce the transmission of injurious vibrations to the user. The resulting designs have been brought to market; however, no data are available to assess their effectiveness. The purpose of this study is to determine whether suspension wheelchairs adequately reduce the transmission of whole-body vibrations and improve rider comfort.

Shock Evaluation

The study has been broken down into separate projects, each focusing on a different aspect of suspension wheelchairs. The purpose of the current study is to determine whether selected manual suspension wheelchairs reduce shock vibrations transmitted to users during curb descents as compared to folding x-brace and rigid frame wheelchairs. So far data has been collected from three manual suspension wheelchairs (Quickie XTR, Invacare A6S, and Colours Boing) and three folding x-brace wheelchairs (Invacare Xtra, E&J Epic, and Quickie 2). Data collected from a seat-plate accelerometer, consisting of a tri-axial accelerometer fitted onto an aluminum plate, was used to produce raw and frequency weighted peak-to-peak accelerations. Of all chairs tested, the Quickie XTR was the only chair that demonstrated shock reduction, however it shifted the frequencies of the accelerations (from the 150mm curb) into the range of natural frequencies of human oscillation (4-12 Hz). Analysis of the data showed that due to the sub-optimal alignment of the suspension units during curb descents, the suspension chairs failed to perform better than standard x-brace wheelchairs in reducing shock vibrations.

photo of person using a wheelchair, Please contact task leader for additional information

The next step in this study is to implement the same procedures for 6 more wheelchairs: 1 suspension (E&J Barracuda), 1 x-brace (Kuschall 1000) and 4 rigid frame wheelchairs (Quickie GP, TiSports, Kuschall 3000, and Invacare Action). Data from these additional tests will be used to establish a more comprehensive database from which to compare the performance of suspension wheelchairs with other manual wheelchairs.

Standards Testing

Another current project within the suspension study involves the testing of all included suspension wheelchairs against the established ANSI/RESNA standards for wheelchair performance. This section of the test is still in its early stages. The first stage of the testing (Section 7 ANSI/RESNA) includes taking complete wheelchair measurements. Every possible configuration is arranged, measured, and recorded to provide a quantitative account of the capabilities of each wheelchair.

Photo of a wheelchair fraim, Please contact task leader for additional information

Section 7 has begun on the first of the Colours Boing wheelchairs. The A-frame (wishbone style suspension frame) has been tested for adjustability and range of motion. The first chair was unable to perform the extended configuration due to inference from a support structure. It was determined that this interference was caused by imperfections in the manufacturing process. All records and results will be reported following conclusion of the testing. Section 7 of the standards testing should continue into next year and conclude by the end of January 2002.

Publications/Reports

"Comparison of Fatigue Life for 3 Types of Manual Wheelchairs" Fitzgerald S.G., Cooper R.A., Boninger M.L., Rentschler A.J., In: Archives of Physical Medicine and Rehabilitation, 82: 1484-1488, 2001.

"Durability and Value" Vitek J.M., Cooper R.A., Duncan J.P., Ammer W.A., Algood D., Fitzgerald S.G., Boninger M.L., Submitted to RESNA 2002 Conference.

"Analysis of Whole-Body Vibrations of Suspension Manual Wheelchairs: Utilization of the Absorbed Power Method" Wolf E., Cooper R.A., Kwarciak A., Submitted to RESNA 2002 Conference.

"Effectiveness of Rear Suspension in Reducing Shock Exposure to Manual Wheelchair Users during Curb Descents" Kwarciak A.M., Cooper R.A., Wolf E.J., Submitted to RESNA 2002 Conference.

Contact Person: Rory Cooper