Advanced Platform Technology Center
APT CENTER RESEARCHERS PUBLISH STAND-TO-SIT AFTER PARALYSIS RESEARCH IN JRRD
Sitting down is not as easy as it looks. While standing, and stepping movements can be restored to people paralyzed as a result of spinal cord injury by contracting the paralyzed hip, knee, and ankle muscles with electrical stimulation, the stand-to-sit (STS) maneuver involves eccentric contractions of the quadriceps to control lowering of the body to the seated position. Such controlled eccentric contractions are difficult to achieve with stimulation alone and present unique challenges to the design and clinical application of lower-limb neuroprostheses and other assistive technologies.
Investigators with the Advanced Platform Technology (APT) Center of Excellence at the Louis Stokes Cleveland Veterans Affairs Medical Center (LSCVAMC) and Case Western Reserve University (CWRU) recently published an original study of how we manage to sit down without hurting ourselves in the Journal of Rehabilitative Research Development (JRRD). The paper entitled, “Understanding stand to-sit maneuver: Implications for motor system neuroprostheses after paralysis,” provides unique insight into how individuals with paralysis sit down with their implanted standing neuroprostheses compared to able-bodied controls. The results could improve the safety and cosmesis of future systems intended to restore standing and walking function after spinal cord injury.
The investigators examined the biomechanics of the STS maneuver in five nondisabled individuals and five users of an implanted neuroprosthesis. Neuroprosthesis users relied heavily on their upper limbs during STS, and exhibited an average vertical acceleration at the impact six times higher than that of the nondisabled subjects. Sitting with stimulation resulted in impact forces at initial contact with the seating surface representing an average of twice the impact forces of the nondisabled subjects. These results indicate a need for additional interventions to better control descent, minimize impact, and gently transition from standing to sitting to achieve a more natural movement and reduce the risk of injury.
“The current investigation demonstrated significantly greater peak values for upper-limb force, impact vertical acceleration, and impact force during the STS maneuver for neuroprosthesis users than for nondisabled subjects,” says Dr. Ronald Triolo, co-author of the study and Executive Director of the APT Center and Professor or Orthopaedics and Biomedical Engineering at Case. “Gravity always wins. It’s not sitting down itself that’s the problem. It’s the sudden stop at the end. What we’ve learned in this study will be invaluable for developing the new control systems or advanced bracing components that are needed to ensure a soft landing.”
Full text of the article can be viewed at:
http://www.rehab.research.va.gov/jour/2014/519/jrrd-2013-12-0264.html
Or downloaded from:
http://www.rehab.research.va.gov/jour/2014/519/pdf/jrrd-2013-12-0264.pdf
About the APT Center: The APT Center is one of 17 designated Centers of Excellence in the Rehabilitation Research and Development (RR&D) Service of the US Department of Veterans Affairs. Established in 2005 as a collaboration between the LSCDVAMC and CWRU, the APT Center focuses on applying the most recent advancements in microelectronics, material science, microfabrication, wireless communication and mechanical design to the pressing medical needs of disabled veterans, and translating them into viable clinical options. Investigators, project staff and support specialists associated with the Center concentrate their professional effort on translational research in the areas of: Prosthetics and Orthotics, Health Monitoring and Maintenance, Neural Interfacing, and Emerging Enabling Technologies. APT Center related activities have resulted in more than 60 invention disclosures and 15 patented or patent-pending concepts and prototypes that will serve the clinical needs of veterans with sensory, motor and cognitive deficits or limb loss. For additional information about the APT Center, please follow the link: http://www.aptcenter.research.va.gov/
JRRD is an open-access, international peer-reviewed rehabilitation journal, has been a leading research journal in the field of rehabilitation medicine and technology for more than 50 years. JRRD publishes original research articles, clinical studies, topical reviews, and editorials from U.S. and international researchers covering 31 rehabilitation disciplines. The journal is an official publication of VA's Rehabilitation Research and Development Service and is available to anyone with an Internet connection at www.rehab.research.va.gov/jrrd/index.html.
