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Evaluation of two power assist systems for manual wheelchairs for usability, performance and mobility: a pilot study.

BACKGROUND
Power-assist devices for manual wheelchairs offer benefits, including increased community participation. Several power-assist devices are commercially available, but research on benefits and limitations of devices is limited.


OBJECTIVE
To compare the usability, performance, and mobility of two power-assist device systems for manual wheelchairs in indoor and outdoor environments.


METHODS
This mixed methods pilot study included 11 volunteers with limited wheelchair experience. Participants tested two different power-assist device configurations: (1) the Batec® and (2) the SmartDrive® + Freewheel®. Indoor & outdoor obstacle courses contained relevant skills from the Wheelchair Skills Test, Power Mobility Community Driving Assessment, and Power Mobility Indoor Driving Assessment. The NASA Task Load Index and System Usability Scale assessed participants' perceptions of cognitive demand and usability. A semi-structured interview was conducted to explore participants' experiences.


RESULTS
Substantial differences were found in the NASA Task Load Index, and System Usability Scale scores. Participant interviews and researcher observations revealed each device performed better on some obstacle course elements. Qualitative findings showed a general preference for using the Batec® for long trips outside and off-road terrains, primarily due to the Batec's® perceived better speed control, maximum speed, and simpler braking system. Conversely, the SmartDrive® + Freewheel® was deemed most useful indoors and in tight spaces; due to a smaller wheelchair footprint, better turning radius, and increased device portability.


CONCLUSION
Further studies are required to understand the usability, performance, and mobility of power-assist devices. Moving forward, these findings will inform end users and occupational therapists when procuring manual wheelchair power-assist devices.Implications for rehabilitationPower-assist devices (PADs) for manual wheelchairs increase the potential for community participation.Qualitative findings showed a general preference for using the Batec® for long trips outside and for off-road terrains, primarily due to the Batec's® perceived better speed control, maximum speed, and simpler braking system.The SmartDrive® + Freewheel® was deemed most useful indoors and in tight spaces; due to a smaller wheelchair footprint, better turning radius, and increased device portability.Increasing knowledge and research about PADs will support development of alternative options for manual or power wheelchairs users. PADs may allow manual wheelchair users (MWC) to delay moving to a power wheelchair (PWC), potentially reducing the perceived stigma associated with transitioning to a power wheelchair and impacting health outcomes.