Volume 89, Issue 10 , Pages 1958-1964, October 2008
Evaluation of a Stair-Climbing Power Wheelchair in 25 People With Tetraplegia
Article Outline
Abstract
Laffont I, Guillon B, Fermanian C, Pouillot S, Even-Schneider A, Boyer F, Ruquet M, Aegerter P, Dizien O, Lofaso F. Evaluation of a stair-climbing power wheelchair in 25 people with tetraplegia.
Objective
To compare the performance of a power wheelchair with stair-climbing capability (TopChair) and a conventional power wheelchair (Storm3).
Design
A single-center, open-label study.
Setting
A physical medicine and rehabilitation hospital.
Participants
Patients (N=25) who required power wheelchairs because of severe impairments affecting the upper and lower limbs.
Interventions
Indoor and outdoor driving trials with both devices. Curb-clearing and stair-climbing with TopChair.
Main Outcome Measures
Trial duration and Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) tool; number of failures during driving trials and ability to climb curbs and stairs.
Results
All 25 participants successfully completed the outdoor and indoor trials with both wheelchairs. Although differences in times to trial completion were statistically significant, they were less than 10%. QUEST scores were significantly better with the Storm3 than the TopChair for weight (P=.001), dimension (P=.006), and effectiveness (P=.04). Of the 25 participants, 23 cleared a 20-cm curb without help, and 20 climbed up and down 6 steps. Most participants felt these specific capabilities of the TopChair—for example, curb clearing and stair climbing—were easy to use (22/25 for curb, 21/25 for stairs) and helpful (24/25 and 23/25). A few participants felt insecure (4/25 and 6/25, respectively).
Conclusions
The TopChair is a promising mobility device that enables stair and curb climbing and warrants further study.
Key Words: Rehabilitation, Tetraplegia, Wheelchairs
List of Abbreviations: ANOVA, analysis of variance, ISO, International Organization for Standardization, QUEST, Quebec User Evaluation of Satisfaction with Assistive Technology, SCI, spinal cord injury
POWER WHEELCHAIRS ARE used by patients with a broad array of disorders including myopathy, SCI with tetraplegia, head injury, stroke, degenerative diseases (eg, multiple sclerosis), cerebral palsy, poliomyelitis, and age-related disability.1 The population of wheelchair users is growing throughout the world, and manufacturers are offering an expanding range of wheelchair options.2, 3
Overall, wheelchairs are perceived as the leading source of activity limitation among disabled persons, most notably those with SCI.4 Despite steady technologic advances and progress with levels of access, the independence of wheelchair users continues to be challenged1, 2 by stairs, curbs, uneven terrain, and loose ground coverings. A few systems for climbing stairs or clearing obstacles have been developed over the last 15 years.2, 5, 6, 7 With these new devices, half the users were able to climb stairs independently and felt that this capability was helpful. The remaining users were able to climb stairs with some assistance. All users agreed that such devices should be made available to war veterans who use wheelchairs.5, 7 The most advanced systems are the Explorera and the iBOT 4000.b Unfortunately, neither wheelchair is commercially available in France.
The TopChairc is a power wheelchair designed for indoor and outdoor use, including stair-climbing (fig 1). The chair combines wheels and a caterpillar track. When the climbing function is switched on, the wheels retract above the caterpillar track, allowing the chair to clear obstacles up to 20cm in height (eg, curbs) and to climb up or down stairs (see fig 1). The space required to use the TopChair can be described as follows: straight stairs must be at least 75cm wide, preferably 80cm, and the landing area must be at least 115cm long. An electromechanical device keeps the seat horizontal regardless of the slope of the terrain. Switching off the climbing function returns the device to its conventional wheelchair configuration.
Fig 1.
The TopChair power wheelchair.
Given that the electromechanic device and caterpillar track increase the bulk and weight of the wheelchair, stair-climbing capability might be associated with reduced maneuverability in the conventional wheelchair configuration. The bulk and weight of the TopChair are slightly greater than those of indoor or predominantly outdoor power wheelchairs available in France, such as Storm3d (table 1). However, whether these differences are clinically relevant remains unknown.
Table 1. Weight and Dimensions of the TopChair and Storm3
| Measure | Storm3 | TopChair |
|---|---|---|
| Width (cm) | 63.0 | 67.5 |
| Total length with footrest (cm) | 110.0 | 115.0 |
| Seat-to-floor distance with the Recaro seat (cm) | 50.0 | 62.0 |
| Weight with the batteries and Recaro seat (kg) | 135.0 | 150.0 |
The primary objective of this study was to determine whether the TopChair performed as well as the widely used, conventional, power wheelchair Storm3 for everyday indoor and outdoor use. To this end, we conducted a randomized, open-label trial. The secondary objectives were to evaluate ease of use and satisfaction with both devices and to evaluate use of the stair-climbing capabilities of the TopChair.
Methods
Participants
We conducted a single-center, randomized, open-label trial to compare the TopChair and Storm3. The study was performed at the Raymond Poincaré Hospital. Outpatients were screened for inclusion if they had been using a power wheelchair for at least 6 months to restore mobility because of severe disability affecting the upper and lower limbs, regardless of the cause (eg, SCI, myopathy, cerebral palsy, or other), with loss of ambulation. To be included in the study, participants had to be older than 18 years and able to use a joystick-controlled power wheelchair every day. Exclusion criteria were as follows: use of Storm3 as the primary wheelchair, inability to use a conventional joystick, and body weight greater than 75kg. Before beginning this clinical study, the TopChair had been successfully tested by the supplier with more than 100 people weighing between 50 and 120kg. To improve the security of the patients with tetraplegia who were involved in this study, we chose the 75-kg upper limit, which is below the real device capacity. When both inclusion criteria and none of the exclusion criteria were met, a clinician working with the patient suggested participation in the study. Patients willing to consider participation met with an investigator, who explained the study in detail.
The study was approved by the review board of our institution (Hôpital Ambroise Paré, Paris, France). Patients were included after they signed an informed consent document that explained the voluntary nature of study participation, the time commitment, the confidentiality of the results, and the use that would probably be made of the study data.
Test Procedure
Each participant evaluated both chairs, in random order. A balanced block design was used for randomization. One day was required for each participant. In the morning, the participants were included in the study and learned to use the 2 wheelchairs, with help from a physical therapist. Each participant practiced 90 minutes with each wheelchair. The afternoon was used for the driving trials and questionnaire completion.
Evaluation Criteria
Indoor and outdoor driving trialsThe outdoor circuit (fig 2) was a sequence of forward travel with the right-hand wheels on level ground and the left-hand wheels on a segment of a sphere (diameter, 3.10m; height at center, ≈15cm); forward travel over 3 ramps having slopes of 5%, 10%, and –15%, respectively; and forward travel up an 8% ramp with a 180° turn on a landing followed by forward travel down the ramp (–8%). The indoor circuit (see fig 2) involved traveling forward and backward in a hallway (width, 1.5m; length, 10m), then driving in a circle between 2 traffic cones placed 1.5m apart and between 2 traffic cones placed 90cm apart without touching the cones. Participants drove over each circuit twice with each of the 2 wheelchairs. Times needed to complete the indoor and outdoor trials were clocked using a standard manual chronometer. A successful trial was defined as a trial completed with no mistakes—for example, without touching any of the handrails or cones. Ability to complete both trials successfully was the primary evaluation criterion. Trial completion times were secondary evaluation criteria.
Fig 2.
Outdoor and indoor circuits. The solid lines indicate the path the participant has to follow, the dotted lines indicate handrails, and the black dots indicate cones the patient had to avoid hitting in order to complete the circuit successfully. The hatched areas indicate slopes.
Additional secondary evaluation criteria were scored on questionnaires for overall assessments of both wheelchairs and evaluation of the stair-climbing capability of the TopChair. Three questionnaires were used for overall assessments of the 2 wheelchairs. One was an ease-of-use questionnaire comprising a single item (Did you find the wheelchair: very easy to use, quite easy to use, quite difficult to use, or very difficult to use?). Satisfaction was assessed using the QUEST questionnaire,8, 9 which includes an 8-item section on the device and a 4-item section on services. In this study, the participants completed only the 8-item section, skipping the durability item, which was not relevant to our study. The items were dimensions, weight, adjustments, safety, simplicity of use, effectiveness, and comfort. Each item was scored from 1 to 5 (1, not satisfied at all; 2, not very satisfied; 3, more or less satisfied; 4, quite satisfied; 5, very satisfied). The third questionnaire consisted of a single item designed to determine which of the 2 wheelchairs the patients preferred.
Evaluation of the stair-climbing capability of the TopChairA task and a questionnaire were used. The task consisted in climbing up and down a 6-step tiled stairway having a 31° slope; width was 135cm, riser height was 16cm, tread depth was 28cm, and nosing radius was 14mm. The participant was asked to climb up and down twice. The investigator recorded each try as successful (with or without assistance from the physical therapist) or failed. Then, the participant was asked to clear a 20-cm step designed to simulate a curb. After completing the task, the patient completed a questionnaire on sense of security and ease of use of the wheelchair during the 2 tasks. Sense of security was scored as feeling secure or feeling insecure; ease of use was scored as very difficult, quite difficult, quite easy, or very easy.
Statistical Analysis
Normally distributed data were expressed as means ± SDs, which were compared between the 2 devices using parametric tests. Times to complete the indoor and outdoor circuits were evaluated by repeated-measures ANOVA with 2 within-patient factors (round number, wheelchair type). Comparisons of data with nonnormative distributions relied on nonparametric paired tests—namely, the Wilcoxon test for quantitative variables (QUEST) and the McNemar test for qualitative ones (questionnaires); the results were given as medians with the interquartile range. P values less than .05 were considered statistically significant. Statistical tests were run on StatView.e
Results
Participant Characteristics
From July 2005 through April 2006, 25 participants were included and randomized. All 25 patients completed the study. There were 14 women and 11 men with a mean age of 41±15.4 years (range, 19–67y). Anthropologic data were collected: patients' weight was 57.1±10.4kg (range, 38–74kg), and patients' height was 166.8±14.5cm (range, 122–187cm).
Diagnoses were as follows: tetraplegia after SCI (n=12), paraplegia with severe orthopedic abnormalities of the upper limbs (n=3), cerebral palsy (n=3), poliomyelitis (n=2), Charcot-Marie-Tooth disease (n=1), multiple sclerosis (n=1), polyneuropathy (n=1), spina bifida (n=1), and incomplete locked-in syndrome (n=1).
The 25 participants used 21 different wheelchairs, which we did not detail, but which included both indoor and outdoor devices. This variability did not allow the analysis of the usual devices' influence on the study results.
Indoor and Outdoor Driving Trials
All 25 participants successfully completed the outdoor and indoor trials with both devices. As shown in figure 3, round number and wheelchair type significantly influenced completion times for both the indoor trials (ANOVA; round number, P<.001; wheelchair device, P<.05; interaction between these 2 factors, P=.17) and the outdoor trials (ANOVA; round number, P<.001; wheelchair device, P<.05; interaction between these 2 factors, P=.17).
Fig 3.
Times needed to complete the (A) indoor and (B) outdoor circuits during the first and second rounds with the TopChair (solid gray bars) and the Storm3 (speckled bars). The box plot indicates mean values, quartiles and 5th and 95th. Both the round and the device exerted significant effects during the indoor trial (ANOVA; round effect, P<.001; device effect, P<.05; interaction, P=.17) and the outdoor trial (ANOVA; round effect, P<.001; device effect, P<.05; interaction, P=.17).
Questionnaires Used to Compare the 2 Wheelchairs
Use of Storm3 was rated very easy by 17 patients, quite easy by 7 participants, and quite difficult by 1 patient. Ratings for the TopChair were very easy for 12 participants, quite easy for 12 participants, and quite difficult for 1 participant. The difference was not statistically significant (McNemar, P=.33).
QUEST scores were significantly better for the Storm3 than for the TopChair regarding weight (Wilcoxon, P=.001), dimensions (Wilcoxon, P=.006), and effectiveness (Wilcoxon, P=.04). Scores on the other items of the QUEST did not differ significantly (fig 4).
Fig 4.
Scores on each item of the QUEST instrument with the TopChair (solid gray boxes) and Storm3 (speckled boxes). Boxplots showing the 10th, 25th, 50th, 75th, and 90th percentiles. *Significant differences between the TopChair and Storm3 (Wilcoxon, P=.05).
Of the 25 participants, 12 preferred Storm3, 10 preferred the TopChair, and 3 had no preference. The difference did not reach statistical significance (χ2, P=.57). Furthermore, 11 participants said they would purchase a TopChair whatever the cost of the device, and 6 said that they would purchase the chair for the price suggested by the manufacturer (€12,000).
Evaluation of Stair-Climbing With the TopChair
Climbing taskOf the 25 participants, 23 cleared the 20-cm simulated curb without help. One patient required minimal help for climbing up (hand replaced on the joystick). Another participant was unable to climb up the curb but climbed down with help.
The stair-climbing task was completed successfully by 20 (80%) of the 25 participants. Four participants required help on 1 of the 2 up-climbs or down-climbs. The remaining participant was unable to climb up the second time as a result of dysfunction of the automatic seat-tilt adjusting device.
QuestionnaireUse on the stairs was considered very easy or quite easy by 21 of the 25 participants. However, the 4 remaining participants, who rated ease of use quite difficult or very difficult, had performed the climbing task successfully. Use over the 20-cm step was considered very easy or quite easy by 22 participants; the remaining 3 participants gave a quite difficult rating but had completed the task successfully. Only 6 participants reported feeling insecure during the stair-climbing task and 4 during the 20-cm step-climbing task.
Adverse Events and Failures
No serious adverse events occurred during the stair-climbing and obstacle-clearing tasks. The evaluators intervened to prevent a fall on 2 occasions. In both cases, an underlying technical problem was identified and resolved. Similarly, nearly half of the failures recorded during the tasks were attributed to technical problems such as failure of the system for converting to stair-climbing mode, slipping of the tracks on the step-nosing because of an unfavorable attack angle or a faulty interface function, and faulty seat tilt adjustment in climbing mode. Unexpectedly, there were few failures related to apprehension or inappropriate use.
Discussion
Evaluation Method
The need to develop tests for evaluating wheelchairs, most notably power wheelchairs, has been obvious for many years.10, 11, 12, 13 The few reported tests are rarely used. Studies of the measurement properties of wheelchair tests have been published within the last few years.14, 15, 16, 17 Available wheelchair tests are designed to evaluate physical characteristics,18, 19 comfort and seating,20 the control interface,21, 22, 23, 24 specific capabilities, or innovative wheelchairs. In this last category, a power-assist system evaluated by Algood et al25 improved the functional capabilities of patients who used manual wheelchairs. Similarly, Lacoste et al26 evaluated a powered tilt and recline system.
We used these earlier studies as a foundation for developing the TopChair evaluation protocol. Our objective was to assess both performance and patient satisfaction when using this innovative device. Our selection of performance criteria was largely based on work by Kilkens et al14 and Holliday et al.27 The subjective evaluation relied chiefly on the QUEST scale, which has been validated for the assessment of assistive devices8, 9 and used previously in studies of wheelchairs.28
One of the main challenges raised by our study was related to the prototype status of the wheelchair, whose manufacturers needed a clinical evaluation and input from users to make decisions about final changes to their product. As a result, we encountered technical difficulties that would not have occurred with a finished product, such as power failures, inappropriate settings, or an unsatisfactory interface design. Although these problems were resolved by the technicians, they undoubtedly affected the results of the evaluation.
Currently Available Stair-Climbing Power Wheelchairs
Like the TopChair, Explorer is a stair-climbing wheelchair with wheels for level surfaces and tracks for climbing (dimensions, 63×113×93cm; weight, 118kg; see table 1 for TopChair dimensions). The seat automatically takes the right tilt when moving on the stairs. This wheelchair has 2 rear wheels but a single front wheel, limiting outdoor use. To our knowledge, no studies of Explorer have been published in the medical literature.
The iBOT Mobility System also can travel over uneven terrain and climb curbs and stairs (dimensions, 60×70×104cm; weight, 113kg; see table 1 for TopChair dimensions). It contains gyroscopes that serve as motion sensors to maintain balance automatically. The gyroscopes respond to motion by sending signals to built in computers, which use the information to control the motors in order to maintain stability. This system continuously realigns and adjusts the wheel position and seat orientation to keep the user upright and stable at all times, even when driving up and down steps. Stair-climbing is performed by rotating the 2 sets of powered wheels about each other; however, the user must either hold a handrail or receive help from an assistant to stabilize the wheelchair.
The iBOT was developed in the 1990s but obtained U.S. Food and Drug Administration approval only in 2003 because of safety concerns. It was put on the market in 2005 in the United States and the United Kingdom. In a 2003 study in 10 unimpaired nonwheelchair users and 4 wheelchair users with paraplegia, Cooper et al5 showed that the iBOT enhanced patient independence outdoors. The same group conducted a satisfaction study in 2004 in 4 men with SCI who used the chair to work in an office environment. Mean patient ratings on a 10-point visual analog scale were 6.7±1.8 for ease of getting around compared with their usual wheelchair and 6.0±2.8 for overall function at work. Cooper5 concluded that a larger study was needed. Uustal and Minkel7 asked 20 patients to compare the iBOT with their usual wheelchair in terms of safety and functional mobility. Of the 20 patients, 14 had a manual wheelchair and 6 had a power wheelchair. The patients used the test device at home and in the community environment for 2 weeks. The number of falls was similar with the 2 wheelchairs. With the iBOT, 10 patients were able to climb stairs independently and 10 with the help of 1 person. Scores on the Community Drive Test were significantly better with the iBOT.
Comparison of the TopChair and Storm3
The Storm3 power wheelchair was used for comparison because in a recent unpublished survey of 155 outpatients from our institution who used power wheelchairs, we found that Storm3 was the most widely used device (37% of patients). In addition, the Storm3 is a versatile wheelchair, although it was designed predominantly for outdoor use, with some indoor use. Because the climbing system adds to the weight and bulk of the TopChair, it was reasonable to compare it with an outdoor wheelchair that had similar weight, size, and characteristics rather than with a wheelchair designed predominantly for indoor use (see table 1).
Several QUEST item scores and maneuverability (as reflected by the time to complete the outdoor and indoor circuits) showed statistically significant differences in favor of the Storm3. Whether these differences were functionally significant, however, is not obvious. Thus, only 3 of the 7 QUEST items showed differences between the 2 devices, and the mean differences in circuit-completion times were less than 10%. Similarly, the preference ratings were only slightly in favor of the Storm3 (12 participants vs 10 preferring Storm3). These small differences against the TopChair may be considered a fair price to pay for the ability to climb curbs and steps. In keeping with this possibility, 6 patients (24%) of 25 said they were willing to purchase a TopChair despite its high price.
Evaluation of the Obstacle-Clearing and Stair-Climbing Capabilities of the TopChair
Unexpectedly, most of the failures recorded during the tasks were ascribed to technical problems. There were few failures related to apprehension or inappropriate use. These extremely encouraging results suggest that technical improvements will further enhance the performance of the TopChair. A similarly good safety profile has been reported for the iBOT.7 Two important points require further attention from the manufacturer. First, switching to climbing mode is achieved by pressing a button located near the joystick, which may be difficult for patients with motor impairments affecting finger function. A better switch could be developed and positioned according to the individual patient's capabilities. Second, an automated orientation system is needed to ensure that the tracks are exactly perpendicular to the stairs and to prevent slippage related to asynchronous function of the 2 tracks.
Overall, most of the participants felt that the stair-climbing and obstacle-clearing capabilities of the TopChair were potentially helpful and easy to use under the test conditions. These results are in line with those obtained by Cooper et al5 and Uustal and Minkel7 with the iBOT.
Results regarding perceived security were less favorable. Thus, slightly more than 20% of the participants felt insecure during the stair-climbing task. Several users, even among those who said they felt safe, believed the stair-climbing mode should be used only with an assistant. Similarly, in a study of the iBOT performed by Uustal and Minkel,7 only 10 of 20 participants were able to climb stairs independently. Importantly, the patients in the study by Uustal and Minkel7 had less extensive impairments than those in our study; thus, only 6 of the 20 subjects normally used a power wheelchair. It would be of interest to evaluate the TopChair for stair-climbing without the presence of an assistant and, subsequently, under real-life conditions.
Study Limitations
An important limitation of our study is that the TopChair was a prototype and therefore new to all the study patients. To avoid bias against Storm3 because of a new device effect, we excluded patients who were regular Storm3 users. Although we cannot exclude bias in favor of the TopChair because of the appeal usually associated with technologic novelty, several QUEST items and maneuverability (reflected by the time to complete the outdoor and indoor circuits) were significantly better with the Storm3 than with the TopChair.
We did not use previously validated protocols for the indoor and outdoor driving trials, because none were available at our hospital. However, the trial conditions reflected widespread testing practices and were effective in detecting differences between the 2 wheelchairs.
We did not test the TopChair on uneven terrain or loose ground coverings. However, the performance of the TopChair running on wheels over uneven terrain is probably similar to that of Storm3, because the 2 chairs have similar driving wheels and motors. The Storm3 has larger front wheels and may therefore be more comfortable in some situations. On sliding ground or gravel, the wheelchairs running on wheels can be stopped completely. With the TopChair, the driver can then switch to the caterpillar mode to get out of trouble without help.
The stairs used for our trials were tiled, and the landings at the bottom and top of the stairs measured only 2 × 2m. Such stairs are commonly found in hospitals, rehabilitation centers, public buildings, schools, and offices. The TopChair has recently obtained the Communauté Européenne label, as well as reimbursement by the French universal health insurance system. Because no accrediting bodies exist for climbing devices, the supplier recently tested the device. The results established compliance with ISO standard 7176-24:2004, which specifies requirements and testing methods for user-operated stair-climbing wheelchairs that climb backward up the stairs with the user facing downstairs and climb down the stairs in a forward position with the user facing downstairs. It also includes ergonomic, labeling, and disclosure requirements. The standard describes tests to demonstrate that the stair-climbing device performs safely on various types of stairs having at least 35° pitch. The supplier reported that the TopChair was able to climb straight stairs made of any material (including wood) and having a pitch of up to 35° (70%) and a step height of up to 20cm. The static stability test on a 42° slope showed no sliding. The straight stairs used in the tests were at least 75cm wide, and the length of the landing was at least 115cm. The caterpillar tracks on the TopChair are made of rubber, which causes no damage to the stair surface. The demonstration stairs used by the supplier are made of wood and show no evidence of damage after use by over 100 people (weighing 50–120kg) trying out the TopChair. The ISO standard requires postmarketing surveillance. To date, only 4 patients have purchased the device (1 in Belgium, 1 in Kazakhstan, 1 in the United States, 1 in France), and therefore, postmarketing surveillance has not yet started. Nevertheless, none of the 4 patients has contacted customer service for problems with the TopChair.
Conclusions
The TopChair showed acceptable performance when tested as a conventional indoor and outdoor power wheelchair. The simulated 20-cm curb task and the stair-climbing task were completed successfully without help by 92% and 80% of the patients, respectively. The device is now available in France. Postmarketing surveillance and long-term evaluations are needed to evaluate long-term safety, usefulness, and durability, as required by ISO standard 7176-24:2004.
Suppliers
References
- . Older people's use of powered wheelchairs for activity and participation. J Rehabil Med. 2004;36:70–77
- . Engineering manual and electric powered wheelchairs. Crit Rev Biomed Eng. 1999;27:27–73
- . Technological advances in powered wheelchairs. J Long Term Eff Med Implants. 2004;14:107–130
- . Assessing the influence of wheelchair technology on perception of participation in spinal cord injury. Arch Phys Med Rehabil. 2004;85:1854–1858
- . Preliminary assessment of a prototype advanced mobility device in the work environment of veterans with spinal cord injury. NeuroRehabilitation. 2004;19:161–170
- . Modeling of a stair-climbing wheelchair mechanism with high single-step capability. IEEE Trans Neural Syst Rehabil Eng. 2003;11:323–332
- . Study of the Independence IBOT 3000 Mobility System: an innovative power mobility device, during use in community environments. Arch Phys Med Rehabil. 2004;85:2002–2010
- . Stability and reproducibility of the Quebec User Evaluation of Satisfaction with Assistive Technology. Rehabil Outcomes Meas. 1999;3:45–52
- . Development of the Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST). Assist Technol. 1996;8:3–13
- . Testing of manually-propelled wheelchairs: the need for international standards. Prosthet Orthot Int. 1981;5:75–84
- . Evaluation of manual wheelchair skills: is objective testing necessary or would subjective estimates suffice?. Arch Phys Med Rehabil. 2002;83:1295–1299
- . Mobility of wheelchair users: a proposed performance assessment framework. Disabil Rehabil. 2003;25:19–34
- . Effect of visual perception, visual function, cognition, and personality on power wheelchair use in adults. Assist Technol. 2005;17:108–121
- . The wheelchair circuit: reliability of a test to assess mobility in persons with spinal cord injuries. Arch Phys Med Rehabil. 2002;83:1783–1788
- The wheelchair skills test (version 2.4): measurement properties. Arch Phys Med Rehabil. 2004;85:794–804
- . Development of a functional assessment measure for manual wheelchair users. J Rehabil Res Dev. 2003;40:301–307
- . Reliability and construct validity studies of an obstacle course assessment of wheelchair user performance. Int J Rehabil Res. 2005;28:49–56
- . Characterization of the dynamic stress response of manual and powered wheelchair frames. J Rehabil Res Dev. 1993;30:224–232
- . Assessment of wheelchair drag resistance using a coasting deceleration technique. Am J Phys Med Rehabil. 2003;82:880–889quiz 90-2
- . Development of a consumer-driven Wheelchair Seating Discomfort Assessment Tool (WcS-DAT). Int J Rehabil Res. 2004;27:85–90
- . Modular hand tiller system for joystick operation of powered wheelchairs. Arch Phys Med Rehabil. 1985;66:193–194
- Optimization of power wheelchair control for patients with severe Duchenne muscular dystrophy. Neuromuscul Disord. 2004;14:297–300
- . Integrating assistive technologies: current practices and future possibilities. Med Eng Phys. 1996;18:193–202
- . Skill evaluator and trainer for electrically operated devices: an evaluation of the SET. Arch Phys Med Rehabil. 1985;66:387–390
- . Effect of a pushrim-activated power-assist wheelchair on the functional capabilities of persons with tetraplegia. Arch Phys Med Rehabil. 2005;86:380–386
- . Powered tilt/recline systems: why and how are they used?. Assist Technol. 2003;15:58–68
- . Understanding and measuring powered wheelchair mobility and manoeuvrability, part I: reach in confined spaces. Disabil Rehabil. 2005;27:939–949
- . Client satisfaction with service delivery of assistive technology for outdoor mobility. Disabil Rehabil. 2002;24:550–557
- a TGR, Via Lombardia, 12, Ozzano dell'Emilia, Bologna, Italy 40064.
- b Independence Technology, PO Box 7338, Endicott, NY 13760.
- c HMC, info@topchair.net, Saint Germain en Laye, France.
- d Invacare, Route de St Roch, Fondettes, France F-37230.
- e Version 5; SAS Institute Inc, 100 SAS Campus Dr, Cary, NC 27513.
No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or on any organization with which the authors are associated.
PII: S0003-9993(08)00439-5
doi:10.1016/j.apmr.2008.03.008
© 2008 American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.
Volume 89, Issue 10 , Pages 1958-1964, October 2008
