Power wheelchairs are controlled by a variety of technologies, from conventional joysticks to head arrays and sip and puff systems. However, little research has been completed on the use or effectiveness of power wheelchair driving controllers, whether conventional or alternative. The following study examines a novel alternative power driving control which interfaces with a manual wheelchair.
This study by Lin et al. (2013) presents an alternative controller interface for driving power mobility devices. The study compares two groups, manual wheelchair users (MWCU) who all had a spinal cord injury and non-manual wheelchairs users (NMWCU), who were nondisabled. Performance measures of completion time and speed, and the muscle activation of the wrist and the forearm are tracked during forward propulsion over 5 metres and turning right and left for both the bimanual gilder and a conventional joystick. All participants had upper extremity strength graded as ‘good’ by manual muscle testing, and all MWCU had a thoracic spinal level injury with 7/11 being at the level of T11 or 12. Considerations for the impact of this level of strength and ability on the propulsion patterns and therefore the muscle recruitment were not noted in the article.
The authors reported that, based on study results, driving tasks using the bimanual glider controller interface took almost twice as long as using the conventional joystick. They also identified that different patterns of muscle recruitment were used for each controller, with the bimanual glider requiring less wrist flexion and extension but more triceps activation than the conventional joystick as well as requiring both upper extremities to operate instead of one with the conventional joystick. It is questioned why the authors chose this specific sub-population of people with SCI as they are not likely to use a power add on or alternate drive control interfaces and the injury level that may potentially benefit from this type of device would likely not have intact triceps muscles. The authors identify that study limitations included that the bimanual glider was not applied to a power wheelchair and they did not include participants who had experience driving power wheelchairs. Based on the findings in this study, it is difficult to surmise if the bimanual glider would be a viable option as an alternate controller interface for people with cervical level injuries or people with thoracic level injury with reduced strength for injury or overuse.
There is level 4 evidence (from one repeated measures study by Lin et al. 2013) that a bimanual power wheelchair controller may be an alternative to a power add on for manual wheelchairs.
There is limited evidence related to the benefit and use of conventional versus alternative driving controls.