Date Presented 4/21/2018
People with spinal cord injuries are at risk for integument injury and systemic illness arising from inadequate seating supports while participating in the occupation of work, especially when operating vehicles and machinery. This research is applicable to safety, health, and seating and mobility.
Primary Author and Speaker: Carla Wilhite
Contributing Authors: William E. Field
PURPOSE: The purpose of this grant-funded pilot research was to study the performance of wheelchair cushions as seating supports for vehicle and machinery operators with spinal cord injuries. The science is important to occupational therapy professionals providing services to people with disabilities in the arena of workplace safety and health, as well as seating and mobility.
METHOD: In this quasi-experimental design study with purposive sampling, participants were a heterogeneous group of adults with spinal cord injury, without an unstable decubitus ulcer, who were capable of driving vehicles, able to transfer to a testing rig, and able to give informed consent. Measures included the Braden Risk Scale for assessing decubitus ulcer risk, Vista Medical (Winnipeg, Manitoba) FSA pressure mapping system and software, and XSensor (Calgary, Alberta) pressure mapping system and software. Participants performed 20-min trials of simulated driving on a contour foam operator seat under dynamic conditions with five seating interventions: seat as is, 2-in. reticulated foam, and three air cushions of different heights. Analysis was descriptive (clinical analysis of images and raw system data: sensing area, peak pressure under bony prominences, dispersion index, and standard deviation) and explored potential statistical relationships (analyses of variance, t tests, and covariances). SAS/STAT (SAS Institute, Cary, NC) and statistician support were used to transform the data.
RESULTS: The as-is foam operator’s seat was rejected clinically and with statistical significance for all users, supporting the hypothesis that a foam operator’s seat would have higher peak pressures and dispersion index and smaller sensing area (body in contact with the support surface). The hypothesis that taller air bladder cushions would perform better than shorter air bladder cushions was not supported. The performance of a reticulated 2-in. foam cushion and three air bladder cushions as interventions varied by individual clinically and statistically.
CONCLUSION: Further research is necessary with larger samples of participants and intervention cushions. This pilot research indicates that people with spinal cord injuries who resume driving and work activities requiring seating in a machine operator’s station require a skilled assessment to identify appropriate seating supports. Also, problematically, aftermarket cushions change the orientation of the driver’s feet, hands, and posture in ways that affect safe control of vehicles and may enhance risk of acute injury and accumulation of musculoskeletal stress. These effects have not been studied in the literature.
IMPACT STATEMENT: As people with disabilities are enabled by technology to enter higher risk work environments, science must provide ample information to support interventions and solutions that fit within the design space and give consideration to variance in human factors. At the level of practice, occupational therapy experts in workplace safety and health, as well as seating and mobility, play a prominent role in designing solutions to protect vulnerable workers. Further, engineering, ergonomics, and industrial hygiene practices must give greater emphasis in designing for users with ergonomics of difference, but this will require changes of attitude and policy. These changes will not occur without science powerfully defining problems and proposing solutions.
Researchers in occupational therapy can illuminate the field of interrogation for the issues. This pilot study directly pertains to safety and injury prevention in the community and work space. There are secondary implications for improving health behaviors to prevent and manage chronic health conditions.
References
Braveman, B., & Page, J. J. (2012). Work: Promoting participation and productivity through occupational therapy. Philadelphia: F. A. Davis.
Kroemer, K. H. E. (2009). Fitting the human: Introduction to ergonomics (6th ed.). Boca Raton, FL: CRC Press.
Wilhite, C. S., Field, W. E., & Jaramillo, M. (2017). Tractor seating for operators with paraplegia. Assistive Technology, 29, 37–47. https://doi.org/10.1080/10400435.2016.1201171
Wilhite, C. S., Field, W. E., Jaramillo, M., & Sullivan, K. (2017). Comparisons of agricultural seating for paraplegia. Journal of Agricultural Safety and Health, 23, 23–37. https://doi.org/10.13031/jash.23.11640
