Manual Wheelchair-Handling Skills by Caregivers Using New and Conventional Rear Anti-Tip Devices: A Randomized Controlled Trial

Article Outline

• Abstract
• Methods
  • Design
  • Participants
  • Ethical Issues
  • Recruitment and Screening
  • Inclusion and Exclusion Criteria
  • Group Allocation
  • Wheelchairs
  • Wheelchair Skills Training
  • Outcome Measures
    • Wheelchair Skills Test
    • Safety
    • Questionnaire
  • Procedure
  • Statistical Analysis
• Results
  • Demographic, Clinical, and Training Data
  • Wheelchair Skills Test Scores
  • Individual Skills
  • Safety
  • Questionnaire
• Discussion
  • Study Limitations
• Conclusions
• References
• Copyright

Abstract 

Kirby RL, Walker R, Smith C, Best K, MacLeod DA, Thompson K. Manual wheelchair-handling skills by caregivers using new and conventional rear anti-tip devices: a randomized controlled trial.

Objective

To test the hypothesis that, in comparison with caregivers handling manual wheelchairs equipped with conventional rear anti-tip devices (C-RADs), those using a new design (Arc-RADs) perform relevant wheelchair skills better and as safely.

Design

Randomized controlled trial.

Setting

Rehabilitation center.

Participants

Caregivers (n=16) and the wheelchair users (n=16) for whom they cared.

Intervention

Participants were trained in wheelchair-handling skills for an average of 54 minutes each.

Main Outcome Measures

Total percentage score on a set of 20 rear anti-tip device- and caregiver-relevant skills from the Wheelchair Skills Test, version 3.2, administered a minimum of 3 days after training.

Results

For the C-RAD and Arc-RAD groups, the mean ± SD Wheelchair Skills Test scores were 40%±0% and 98.8%±3.5%, respectively (P<.001). Skills that required the wheelchair to be tipped back extensively (eg, for ascending a 15cm curb) accounted for the differences between the groups. There were no adverse effects in either group.

Conclusions

The Arc-RAD design allows significantly better caregiver wheelchair-handling skills than the conventional design, without compromising safety.

Key Words: Caregivers, Rehabilitation, Safety, Wheelchairs

List of Abbreviations: Arc-RAD, new design for rear anti-tip device, C-RAD, conventional rear anti-tip device, RAD, rear anti-tip device, WST, Wheelchair Skills Test

MANY MANUAL wheelchairs are fitted with C-RADs to prevent rear tips. However, C-RADs can cause clearance issues (eg, at the bottom of inclines) and limit the extent to which the user can raise the casters to clear obstacles, climb curbs, maneuver in tight spaces, or negotiate rough terrain.¹ To circumvent these limitations, users often remove C-RADs or adjust them into inappropriate positions, leaving the wheelchair users susceptable to injury.¹

The limitations of C-RADs provided the incentive to design a new RAD that permits more rear tip without compromising safety.² The Arc-RAD consists of an adjustable-arc arm that self-deploys when needed. In the resting position, the Arc-RAD does not extend past the rearmost dimension of the rear wheel. When the wheelchair tips backward sufficiently, the lower end of the anti-tip arm contacts the ground, and the force of the tipping wheelchair deploys the anti-tip arm into a position that permits sufficient rear pitch for function (fig 1).

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• Fig 1. 

  Wheelchairs equipped with C-RADs (A) and Arc-RADs (B) tipped back to the extent possible, during attempts to ascend a 15m curb.

A variety of studies to date have confirmed the safety and effectiveness of the Arc-RAD in different settings.³, ⁴, ⁵, ⁶, ⁷, ⁸ Although caregivers play an important role in assisting with the mobility needs of wheelchair users,⁹, ¹⁰ only 1 study to date has dealt with the issue of Arc-RAD-equipped wheelchairs handled by caregivers.⁶ However, the focus of that study was on tilt-in-space wheelchairs. To our knowledge, there have been no Arc-RAD studies on conventional manual wheelchairs handled by caregivers.

The primary purpose of this study was to test the hypothesis that, in comparison with caregivers handling manual wheelchairs equipped with C-RADs, caregivers who use Arc-RADs perform relevant wheelchair skills better and as safely. Our secondary objectives were to obtain descriptive data on individual skills, training issues, and the perceptions of the participants.

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Methods 

Design 

This randomized controlled trial compared 2 groups of people who used wheelchairs equipped with either C-RADs or Arc-RADs.

Participants 

We enrolled 19 caregivers and the wheelchair users for whom they cared, a sample of convenience. We based the sample size on a power analysis, for which we used an α level of .05, a 2-sample t test, and a target power of .95. The effect size and variance assumptions were based on a pilot study of 20 pairs of able-bodied participants; for the C-RAD and Arc-RAD groups, the mean ± SD posttraining subtotal percentage RAD-relevant WST scores were 45.2%±5.1% and 97.0%±2.9%, respectively (P<.001).¹¹ The analysis indicated that a sample size of 5 participants per group would be adequate for the main objective related to total WST scores. We elected to oversample in case the pilot work assumptions were inaccurate and to provide more data to meet our secondary objectives.

From each caregiver participant, we recorded age, sex, weight, height, and the relationship to the wheelchair user. For each wheelchair user, we recorded age, sex, and the diagnosis accounting for wheelchair use.

Ethical Issues 

The Research Ethics Committee of the Capital District Health Authority approved the study. All participants provided informed consent.

Recruitment and Screening 

The clinical staff working with wheelchair users at the Nova Scotia Rehabilitation Center recruited potential participants. The investigators screened participants using data from self-report, chart review (for wheelchair users), and the wheelchair users' attending physicians.

Inclusion and Exclusion Criteria 

All participants were 18 years of age or older, able to provide informed consent, willing to participate, alert, and able to follow instructions. All wheelchair users had a body size that fit in the wheelchairs used (ie, without significant lateral pressure on the hips and thighs from the clothing guards), were inpatients at the Nova Scotia Rehabilitation Centre, had the permission of their attending physicians to participate in the study, and did not have any unstable medical or psychologic conditions. Caregiver participants provided at least part-time wheelchair-handling care for the wheelchair users in this study and did not report any medical conditions that might have caused them discomfort or endangered them when handling an occupied wheelchair.

Group Allocation 

We randomly assigned each pair of participants (caregiver and wheelchair user) to either the C-RAD or Arc-RAD groups by means of a randomization code and stratified the wheelchair users by broad diagnostic group (neurologic or musculoskeletal).

Wheelchairs 

Wheelchair type is known to affect performance.¹² To control variability, participants used 2 nearly identical lightweight manual wheelchairs^a for testing and training. The wheelchairs had folding frames. The front rigging was of the removable, swing-away type, with heel loops and flip-up footplates. The rear drive wheels were 61cm in diameter with treaded composite tires. For the C-RAD group, we fitted the wheelchair with the C-RADs originally supplied by the manufacturer. We adjusted the C-RADs to their most stable positions (as rearward as possible, consistent with the manufacturer's recommended clearance of 3.8cm). For the Arc-RAD group, we fitted the wheelchair with a pair of prototype Arc-RADs. For each participant, we adjusted the armrest height, to the extent possible, to support the elbow and forearm with the elbow in 90° of flexion. We adjusted the footrest height, to the extent possible, to support the thigh as fully as possible without undue pressure at the forward edge of the seat.

Wheelchair Skills Training 

Each caregiver was trained on any of the skills that he or she was unable to perform. The training was provided because we did not wish to assume that all of the caregivers recruited had already received such training.⁹ We carried out training using the principles and procedures of the standardized Wheelchair Skills Training Program, version 3.2.¹³ The Wheelchair Skills Training Program has been shown to be safe, practical, and efficacious for wheelchair users¹⁴, ¹⁵ and caregivers.⁶, ⁹ Up to 2 training sessions were permitted, at target intervals of 1 to 7 days. Training was considered complete when all of the skills had been mastered or no further progress was being made.

Outcome Measures 

The WST, version 3.2, designed for use in objectively assessing either wheelchair users or caregivers, was used as the principal outcome measure. The WST provides a pass/fail score for each skill. We calculated a total percentage RAD- and caregiver-relevant WST score (the percentage of skills passed). A trained tester administered the WST according to the Wheelchair Skills Program manual.¹³ We focused on 20 skills (listed later) that we defined as being relevant to both RADs and caregivers.⁵, ⁹ The measurement properties of the WST have been reported,¹² and a number of studies have been carried out using the WST as an outcome measure.⁴, ⁵, ⁶, ⁸, ⁹, ¹¹, ¹⁴, ¹⁵, ¹⁶ During testing, the tester asked the wheelchair user to refrain from providing physical or verbal assistance to the caregiver. We did not allow the caregivers to reposition or remove the RADs.

During testing, we recorded adverse incidents, which were defined as any injury, or significant spotter interventions to prevent injury.

After the WST, we asked both caregivers and wheelchair users whether they had found their participation in the study to be emotionally stressful (yes/no), physically stressful (yes/no), uncomfortable (yes/no), and useful (yes/no). Caregivers were also asked whether they perceived that the training that they received had improved their wheelchair-handling abilities (yes/no), how they perceived their overall level of exertion (using a 5-point Likert scale: 1 for none, 2 for mild, 3 for moderate, 4 for high, and 5 for extreme), and how they perceived that the anti-tip device they used had affected the safe performance of each skill (using a 3-point ordinal scale: 1 for hindered, 2 for no effect, and 3 for helped).

Procedure 

At the initial session, we obtained informed consent and carried out screening and randomization. We recorded demographic, clinical, and wheelchair-usage data. The caregivers underwent a pretraining assessment of their wheelchair-handling skills. Training occurred for any skills that the caregiver participant was unable to perform properly. A minimum of 3 days after training, we administered the WST and the questionnaire.

Statistical Analysis 

We entered data into a spreadsheet^b and used SAS statistical software^c for the analysis. Because the sample size was small, we elected to use nonparametric statistics. We calculated descriptive statistics. To assess the success of the randomization process, we compared the 2 groups from the perspectives of the demographic, clinical, and training parameters. For age, weight, height, and training time, we used the Wilcoxon rank-sum test. For sex and diagnostic group, we used the Fisher exact test. To compare the groups with respect to the principal outcome measure (the WST score), we used a Wilcoxon rank-sum test. For all statistical comparisons, we used 2-sample 2-sided tests and an α level of .05. Because we believed that the sample size would be too small to provide sufficient power for statistical comparisons, we elected to compare the success rates for the individual skills and questionnaire data descriptively; we used a difference between the groups of 30% or more as our conservative definition of clinical significance (to minimize the likelihood of a type I error, ie, concluding that there was a difference between the groups when there was not).

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Results 

Demographic, Clinical, and Training Data 

Sixteen pairs of caregivers and wheelchair users completed the study. There were 3 dropouts before data collection (2 as a result of scheduling difficulties and 1 as a result of an unrelated deterioration of the wheelchair user's health). Recruitment was slow because it was difficult to find caregivers who would be consistently available for the training and testing. Most of the caregivers visited the wheelchair users in the evenings and on weekends, when the research staff were not available. The consolidated standards of reporting trials diagram¹⁷ is shown in figure 2.

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• Fig 2. 

  Flowchart diagram for the wheelchair-using participants. During the 462-day recruitment period, there were a total of 711 inpatients admitted to the rehabilitation center.

Demographic, clinical, and training data are presented in table 1. There were no significant differences between the C-RAD and Arc-RAD groups when comparing the caregivers' age, sex, weight, and height, or the wheelchair users' age, sex, and diagnostic group. The specific diagnoses accounting for wheelchair use for the C-RAD group were amputation (n=3), paraplegia (n=3), multiple sclerosis (n=1), and encephalopathy (n=1). For the Arc-RAD group, the diagnoses were stroke (n=3), hip disease (n=2), amputation (n=2), and multiple sclerosis (n=1). In the C-RAD group, the relationship of the caregiver to the wheelchair user was that of spouse (n=3), parent (n=2), child (n=1), and other (n=2). In the Arc-RAD group, the relationship was that of spouse (n=5), child (n=1), and other (n=2). The mean ± SD total training time was 54.3±22.6 minutes (range, 10–95min), slightly longer for the Arc-RAD group, but not to a significant extent (P=.392).

Table 1. Participants' Demographic, Clinical, and Training Data

NOTE. Values are mean ± SD or as otherwise indicated.

Wheelchair Skills Test Scores 

We were unable to use an intent-to-treat analysis, including the 3 dropouts, because they had withdrawn before WST data had been collected. For the 16 pairs of participants who completed the study, the mean ± SD total WST percentage score for the C-RAD group was 40.0%±0%, significantly (P<.001) less than the Arc-RAD group value of 98.8%±3.5%.

Individual Skills 

The success rates on individual skills are shown in table 2. With 1 exception, all caregivers in the Arc-RAD group passed all skills. The single exception was that of a 68-year-old woman (weight, 75.0kg) handling the wheelchair occupied by her spouse, a 69-year-old male wheelchair user who had had a stroke (weight, 96.9kg). She failed 2 skills, the ascent and descent of the 15cm curb: she refused to perform them because of concern about the potential stress on her back. All caregivers in the C-RAD group failed the same skills—those that required the wheelchair to be tipped back to at least 15cm of caster clearance.

Table 2. Participants' Success Rates (%) for Individual Skills

Safety 

No adverse incidents occurred during training or testing for either group.

Questionnaire 

Most of the caregivers' and wheelchair users' responses are summarized in table 3. The sample size available for some parameters was reduced because some participants failed to answer all questions. There were no clinically significant differences between the groups. Generally, the training and testing were well tolerated. All caregivers (100%) and most wheelchair users (93%) perceived their experiences to have been useful. Most caregivers (94%) perceived that they had improved their skills. The mean perceived exertion levels were in the mild to moderate range for both groups, but slightly greater for the Arc-RAD group. Most of the caregivers in the C-RAD group perceived that the C-RADs had either no effect or had hindered their performance of most skills. For the Arc-RAD group, most of the caregivers perceived that the Arc-RADs had either no effect or had helped their performance of most skills.

Table 3. Questionnaire Results

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Discussion 

In this study, we corroborated the hypothesis that caregivers handling occupied wheelchairs equipped with Arc-RADs have significantly higher success rates on RAD- and caregiver-relevant skills and no less safety than a group handling wheelchairs equipped with C-RADs. The mean total WST score for the C-RAD group (40%) was much less than that of the Arc-RAD group (98.8%). These results are consistent with C-RAD versus Arc-RAD comparisons on wheelchair users (32.3% vs 85.1%)⁵ and the able-bodied pilot work for the current study (45.2% vs 97.0%).¹¹

The caregivers in the C-RAD group were only able to successfully perform 8 of the 20 skills. This was apparently due to the C-RADs preventing the caregiver from tipping the wheelchair back far enough. The caregivers in the Arc-RAD group scored perfectly on all skills except for 2 skills by 1 participant. The limiting factor in this case was fear of back pain, not the Arc-RAD design.

There were no adverse incidents recorded throughout the testing or training. Wheelchair handling was generally well tolerated. The slightly greater mean exertion level for the Arc-RAD group probably reflected the fact that the caregivers in this group performed over twice as many skills as those in the C-RAD group.

Regarding the training provided, the mean of 54 minutes was comparable to the approximately 50 minutes and 58 minutes provided in the 2 earlier studies in which caregivers were trained in wheelchair skills.⁶, ⁹ The mean training time for the Arc-RAD group in the current study was slightly longer than for the C-RAD group. Although this difference was not statistically significant, we interpret this difference as being due to the likelihood that the C-RADs prevented the performance of some skills, so further training was pointless. All caregivers in both groups thought that the training had been useful, and 94% thought that their abilities had improved. This suggests that caregiver training should be more routinely carried out than is currently the case.

Study Limitations 

There were a number of study limitations. The sample size was small but adequate for the primary purpose of the study. The sample used in this study was one of convenience, but it proved to be reasonably varied with respect to the participants' ages, sexes, range of diagnoses accounting for wheelchair use, and relationships between caregivers and wheelchair users. Three patients dropped out of the study, but the reasons for withdrawing were unrelated to the RAD type. The Arc-RADs used in this study were prototypes, and the design will likely undergo refinement before reaching the market. We used only a single wheelchair model, but it was reasonably representative of lightweight manual wheelchairs used in the community and in rehabilitation settings. This study constrained the caregivers from removing or repositioning the RADs in order to perform skills. For the purposes of this study, we considered this constraint to be appropriate to demonstrate the limitations of C-RADs in comparison with Arc-RADs. However, although it is usually time-consuming and awkward to do so, in everyday life, caregivers can reposition C-RADs as needed.

Future studies would be useful to address these limitations, including using a larger and more diverse sample of caregivers, wheelchair users, and wheelchairs, longer-term studies, and a broader range of outcome measures. Despite the study limitations and the need for future study, to our knowledge, this is the first study to document the effect of Arc-RADs on the performance of wheelchair-handling skills of caregivers who use conventional manual wheelchairs.

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Conclusions 

The Arc-RAD design allows caregivers to better handle conventional manual wheelchairs than when using C-RADs, without compromising safety.

Suppliers

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References 

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• a Quickie 2 model; Sunrise Medical Canada Inc, 237 Romina Dr, Concord, ON L4K 4V3 Canada.
• b Microsoft Excel; Microsoft Corp, 320 Matheson Blvd W, Mississauga, ON L5R 3R1 Canada.
• c SAS version 9.1; SAS Institute Inc, 100 SAS Campus Dr, Cary, NC 27513.