Pushrim-Activated Power-Assist Wheelchairs
For many years, there were three main types of wheelchairs available to those individuals with disabilities: manual wheelchairs, scooters and electric powered wheelchairs. Pushrim-activated power-assist wheelchairs (PAPAW) have become an option for wheelchair users. The PAPAW is a combination of a manual wheelchair and electric powered wheelchair where a motor is linked to the pushrim by way of the rear hub to reduce the effort required to propel.
Summarized Level 5 Evidence Studies
The following level 5 evidence studies have been reviewed, and the overarching findings from the studies are highlighted in this section. As noted at the start of this chapter, these types of studies are not included in the discussion or in the conclusions.
In a qualitative study, Giacobbi et al. (2010) gathered reported experiences from participants before, during, and after use with a power assist wheelchair (PAW). 95 %of participants reported that PAWs allowed greater access to diverse terrains that included sand, gravel and grass and made wheeling up inclines easier. 80% of participants reported general decreases in fatigue after using the PAWs. Participants reported that PAWs helped to improve mood and help with independence with respect to mobility. 65% of participants (13/20) reported that the use of PAWs was linked to participation in novel activities or those that were “out of the ordinary”. Participants expressed that some of these were previous activities they couldn’t participate in, for example, going to the flea market and zooming around, or playing ball in the yard with their dog.
Discussion
There were three randomized control studies that explored PAPAW use. Giesbrecht et al. (2009) studied eight participants (mixed diagnoses) who used both a manual wheelchair and a power mobility device (dual users) in their everyday activities in determining if a PAPAW would be an alternative to a power wheelchair (PWC) for community-based activities. The study results suggested that after introducing PAPAW, study subjects remained as active in their community and spent similar amount of time using the PAPAW instead of their PWC. It was interesting to note that on the Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) Device subscale (outcome measure addressing activity level) the study participants rated four device subscale items higher for PAPAW use (weight, comfortable, dimensions, ease in adjusting) and four items higher for PWC use (durability, easy to use, safe and secure and effective). Study subjects identified that the PWC was preferred for outdoor activities and the PAPAW for tasks performed in a confined space. Only the self-esteem subscale (relates to emotional response and self-propulsion) on the Psychosocial Impact of Assistive Devices Scale (PIADS) was statistically significant between PWC and the PAPAW.
In the second RCT, Nash et al. (2008) tested the effects of PAPAW with respect to the energy needed and perceived effort required when wheeling a manual wheelchair for six minutes at a steady state and for twelve minutes with resisted wheeling at the study subject’s greatest attainable speed. During the six-minute steady state and 12-minute resistive propulsion trials there was a significant increase in oxygen uptake (VO2) at each time point for persons with paraplegia only. In addition, individuals with paraplegia travelled significantly farther than individuals with tetraplegia when using the PAPAW and both groups travelled farther with PAPAW than when using traditional wheels. Traditional wheels required greater energy cost than PAPAW and this increased the perceived exertion across all study subjects as the time component increased during the trials.
In the third RCT, Guillon et al. (2015) compared three different PAPAW (Servomatic A & B, and E-motion) to standard manual wheelchairs in a three phase study assessing wheelchair propulsion, indoor/outdoor use and ease of transferability in vehicles. Use of PAPAW resulted in greater decreases in oxygen consumption and heart rate compared to manual wheelchairs. But ease of transferability was greater when participants used manual wheelchairs compared to PAPAW. For the indoor and outdoor tests, the Servomatic PAPAW had better performance on completion time, pushrim frequency, and patient satisfaction compared to the E-motion PAPAW.
Corfman et al. (2003) examined the efficacy of the PAPAW in the reduction of upper extremity ROM and stroke frequency with nine individuals with paraplegia. When using the PAPAW upper extremity ROM was significantly reduced. The use of the PAPAW did not affect propulsion frequency. They suggest that the use of this device may reduce the frequency of upper limb injuries and allow an individual to use a manual wheelchair for a longer period of time.
Algood et al. (2005) compared the ability individuals to complete an obstacle course using a PAPAW and their own manual wheelchair. It was significantly easier for the subjects to propel on carpet, dimple strips, up a ramp as well as up curbs when using a PAPAW. Also, the mean heart rate was significantly lower. However, there was no significant difference in the time to complete the course, response to ergonomic questions or the amount of assistance required.
Cooper et al. (2001) compared the PAPAW to the subject’s own wheelchair on a dynamometer and also through an obstacle course. On the dynamometer, subjects had lower oxygen consumption and heart rate when using the PAPAW as compared to their own manual wheelchair. Oxygen consumption and heart rate, but not ventilation was significantly different when comparing chairs and speed. On the obstacle course the PAPAW had a higher ergonomic evaluation than the manual wheelchair. Subjects had faster completion times with the PAPAW and less difficulty going over the speed bump. The PAPAW had lower ratings on car transfer tasks of taking wheels off and putting them back on.
Algood et al. (2004) investigated the differences in metabolic demands, stroke frequency and upper extremity ROM when propelling the PAPAW as compared to a regular manual wheelchair. Individuals propelled their own manual wheelchair and a PAPAW through three different resistances on a wheelchair dynamometer. Ventilation, oxygen consumption and upper extremity ROM was significantly reduced when using the PAPAW. Stroke frequency was reduced at low resistances. They also found that the PAPAW has the potential to reduce metabolic energy expenditure.
Fitzgerald et al. (2003) followed individuals for a period of four weeks, two weeks using a PAPAW and two using their own personal wheelchair. No significant differences were found between the user’s own wheelchair and the PAPAW for average and total distance travelled, velocity, or the number of times leaving the house. However, the subjects reported that they were more apt to use the PAPAW when leaving their house. The subjects also reported that the PAPAW provided relief when fatigued and that the wheelchair went faster (perception) resulting in accomplishing more in the day. The subjects rated the PAPAW with higher comfort and easier propulsion as compared to their own wheelchair.
Conclusions
There is level 4 evidence (from one pre-post test study: Corfman et al. 2003) that the use of a PAPAW will reduce upper extremity ROM in individuals with paraplegia during wheelchair propulsion.
There is level 4 evidence (from three pre-post test studies: Algood et al. 2005; Cooper et al. 2001; Fitzgerald et al. 2003) that use of a PAPAW may improve the ability of individuals with tetraplegia to use their wheelchair in a variety of environments and for typical activities.
There is level 4 evidence (from one pre-post test study: Cooper et al. 2001) that the use of a PAPAW may reduce metabolic energy costs for individuals with paraplegia during propulsion and has higher ergonomic rating by users.
There is level 4 evidence (from one pre-post study: Algood et al. 2004) that the PAPAW reduces upper extremity ROM in individuals with tetraplegia during wheelchair propulsion. Metabolic energy expenditure and stroke frequency may be reduced.
There is level 2 evidence (from one low level RCT study: Guillon et al. 2015) that PAPAW results in decreased oxygen consumption and heart rate compared to manual wheelchairs.
There is level 1b evidence (from one randomized controlled trial: Nash et al. 2008) that the use of PAPAW allows individuals with a spinal cord injury (paraplegia and tetraplegia levels) who have long standing shoulder pain to propel their wheelchair further while decreasing energy costs and perceived exertion.
There is level 1b evidence (from one randomized controlled trial: Giesbrecht et al. 2009) that for individuals requiring power mobility, the pushrim-activated, power assisted wheelchair may provide an alternative to power wheelchair use.
