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Characteristics of Power Wheelchair Use

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Studying the characteristics of power wheelchair use sheds some light onto how and why people use their power wheelchairs and if the devices are meeting their needs in everyday life. Gaining an understanding of actual power wheelchair use may provide guidance and direction in decision-making for the provision of power wheelchairs.

Table 16: Power Wheelchair Characteristics-Mobility Enhancement Robotic Wheelchair

Discussion

Cooper et al. (2002) examined the driving characteristics of two groups of people who used power wheelchairs and who live in the community. The two groups were 10 athletes competing in a local wheelchair games and seven people living in the community regularly using their power wheelchair. On average the athletic group travelled farther and faster than the regular use group, which the authors feel can be largely attributed to the amount of available activities, easily available transportation and social context of the competition. The study also found that most people charge the chair every night and the battery capacity was approximately five times that of what was actually being used. The authors also highlighted that wheelchair life expectancy was based on the hours of operation, distance travelled, and type of surface traversed including frequency of start and stops. It is worth noting that all participants in this study used rear wheel drive chairs with sealed lead acid batteries. Overall study findings indicated that the speed at which participants drove their wheelchairs most of the time, was much less than the available maximum speed, with full speed driving only for a few meters occasionally. This study found little variability in driving speed patterns across participants.

Sonenblum et al. (2008) found that bouts of mobility indoors occurred frequently but at slower speeds and shorter distances than bouts used outdoors. A bout was defined as transitional mobility between stationary activities. The average daily distance travelled was 1.9 kilometers; the distance that was travelled varied across participants as well as across days for the same person. The key finding from this study was that there was no typical pattern of power wheelchair use whether across people or across days for the same person.

Hastings et al. (2011) determined if differences existed between those who used power wheelchairs and those who used manual wheelchairs. The data was collected using questionnaires for self-esteem, function and participation. There were significant differences observed between manual and power wheelchair users, however, there were several confounding factors which the authors acknowledged as limitations but did not account for in the results. Of greatest concern is that the study did not account for varying motor function (e.g., complete versus incomplete injury, antigravity versus gravity-eliminated triceps function). The article suggests that people who sustained a C6-7 motor level injury are better able to maintain physical use of muscles above the injury, move around the environment more and attain employment in a manual wheelchair than power. Given these limitations the results should be interpreted carefully.

Hunt et al. (2004) surveyed 412 people with spinal cord injury who used a wheelchair for more than 40 hours a week from across 16 model spinal cord injury systems. The purpose of the survey was twofold: first to determine if a standard of care for wheelchairs provision exists (defined as 90% of respondents receiving wheelchairs with customizable features) and second to determine if disparity existed from this standard for those with a minority background or low socioeconomic status. The standard used in the study is that manual wheelchair users with SCI be provided with ultralight (<30 lb.) customizable wheelchairs and power wheelchair users be provided with programmable controls with customizable features. This standard was met across the 16 sites studied for 97% of manual wheelchairs users and 54% of power wheelchair users. There were significant differences between those that received the standard and those that did not. Those that did not were more likely to be a cultural minority, have low socioeconomic status, be less educated, have lower income, and have public sector health insurance. Additionally, for power wheelchairs users, they tended to be older and have paraplegia. Findings also indicated that 40% of manual wheelchair users had at least one additional chair with 73% being an additional manual wheelchair and 27% being power. 57% of power wheelchair users had at least one additional chair with 84% being manual and 16% being power.

Biering-Sorensen et al. (2004) examined mobility aids being used at least 10 years post injury based on data gathered from a larger follow up study. The study found that of the 85% of people who used a manual wheelchair there was with equal distribution across neurological level/ function classification groups. Power wheelchairs were used by 27% of people, with most in the tetraplegic functional class A-C. 32% of those people who used a manual wheelchair also had a power wheelchair or scooter. This paper highlighted the wide variety of mobility devices are used by people with SCI and that many have more than one device. The study did not account for possible influence of neurological or functional recovery on device use between initial injury and this follow up study. It also did not account for possible changes in mobility devices during the time period from initial injury to post injury 10-45 years later.

Daveler et al. (2015) completed a three-phase observational study to understand the conditions and barriers that users of electric powered wheelchairs (EPW) find difficult to drive in/over in the outdoor environment. The ultimate goal of this study was to develop a powered mobility device which addressed many of these issues/challenges. This review focused on the results as they relate to how power wheelchairs are used in the environment. In phase one participants (n=31) answered a questionnaire survey and rated 23 different driving scenarios by degree of difficulty; in phase two a prototype alternative mobility device was developed and in phase three the prototype was tried and evaluated using a questionnaire. The results of the survey in phase one indicated that the position of the drive wheel (FWD, RWD, and MWD) showed the greatest differences in driving difficulty especially in mud, gravel and cross slope conditions. Avoidance of these conditions when they were encountered was reported: 1) in mud 70% of RWD and MWD, 33% of FWD; 2) in gravel 54% of RWD, 31% of MWD, 17% of FWD and: 3) in cross slope conditions 31% of RWD, 50% of FWD and 62% of MWD. More than 50% of participants identified that the conditions such as uneven terrain, driving up and down steep hills, cross slopes, gravel, curb cuts, and ramps where particularly difficult to maneuver. In phase three, study participants (n=12) were asked to identify the top five obstacles that they encountered one to three times a week. The results of the questionnaire indicated that a small curb (n=6), cross slope (n=5), grass (n=5), dirt/mud (n=4), curbs (n=3) were the top driving conditions. The top five obstacles encountered greater than three times a week were curb cuts (n=11), door thresholds (n=11), concrete (n=11), carpet (n=10), traversing ramps (n=10). The top five obstacles that EPW users avoided were sand (n=12), curbs (n=8), gravel (n=6), dirt/mud (n=5), small curbs (n=4).

Conclusion

There is level 5 evidence (from one observational study; Hunt et al. 2004) that to meet full mobility needs, a wide variety of mobility devices are often used in conjunction with power wheelchairs.

There is level 5 evidence (from one observational study; Biering-Sorensen et al. 2004) that neurological level alone is not indicative of power versus manual wheelchair use.

There is level 5 evidence (from one observational study; Sonenblum et al. 2008) that there are no typical patterns of power wheelchair use in daily life but small bouts of movement were more frequently used.

There is level 5 evidence (from one observational study; Cooper et al. 2002) that power wheelchair users drive at high speeds for most movements but typically for short distances.

There is level 5 evidence (from one observation study; Daveler et al. 2015) to suggest that there are differences in how different power wheelchair drive wheel configurations are perceived to perform in commonly encountered driving situations which require climbing and/or traction control such as uneven terrain, curb cuts, gravel, and mud.

  • Considerations for how individuals use power wheelchairs should include more than distance and speed travelled, indoor/outdoor use and wheelchair occupancy.

    For the SCI population power wheelchair provision needs to include at a minimum customizable programmable controls.

    Consideration should be given to the potential provision of both power and manual wheelchairs to meet basic living needs for the SCI population.