Evaluation of Transfer Technologies to Preserve Shoulder Function in SCI

Abstract

This study investigated a series of independent unassisted and device-assisted transfers from a wheelchair to vehicle mock-up and vice versa while simultaneously capturing kinematic, kinetic and electromyographic (EMG) data of impaired volunteers. The study provides a venue for observation and evaluation of upper extremity (UE) joint stresses, muscular force and functional demands associated with transfers in persons with spinal cord injury (SCI) to ultimately prevent UE injury, minimize excessive stress, preserve functionality and limit pain. If people with SCI lose function of their UEs, due to pain and/or degeneration, they must then rely on others for everyday tasks.

Five paraplegic males from the Tampa Bay area were recruited to take part in the study. Participants were asked to perform a series of transfers using 4 commercially available devices or mock-ups of that device as well as an unassisted transfer, which permitted the use of no assistive device. Three data types were captured: kinematic data using motion capture, kinetic data using force transducers which were integrated into the vehicle mock-up and EMG of 5 bilateral muscle groups. Data collection took approximately 4 hours per subject.

Forces occurring during the unassisted transfers were found to be the highest. This is also supported by the EMG data. Performing level transfers lessened stresses at the UE versus non-level transfers. The highest moments of the UEs were found at the shoulders with high variability between subjects. It was also found that body mass index (BMI) had an affect on a subjects ability to perform transfers.

Ultimately this study found that using an assistive device is better than not using an assistive device. This is proven by EMG and force data, which were both found to be less with the use of an assistive device as opposed to transferring independently with no assistance. Performing level transfers, maintaining ones body mass and staying active are all factors that will limit stresses at the UEs during wheelchair transfers to and from a vehicle.