This article and any supplementary material should be cited as follows: Nataraj R, Audu ML, Triolo RJ. Center of mass acceleration feedback control of functional neuromuscular stimulation for standing in presence of internal postural perturbations. J Rehabil Res Dev. 2012;49(6):889–912. http://dx.doi.org/10.1682/JRRD.2011.07.0127
Slideshow ProjectDOI:10.1682/JRRD.2011.07.0127JSP
Center of mass acceleration feedback control of functional neuromuscular stimulation for
standing in presence of internal postural perturbations
Raviraj Nataraj; Musa L. Audu, PhD; Ronald J. Triolo, PhD
This article and any supplementary material should be cited as follows: Nataraj R, Audu ML, Triolo RJ. Center of mass acceleration feedback control of functional neuromuscular stimulation for standing in presence of internal postural perturbations. J Rehabil Res Dev. 2012;49(6):889–912. http://dx.doi.org/10.1682/JRRD.2011.07.0127
Slideshow ProjectDOI:10.1682/JRRD.2011.07.0127JSP
• Aim– Evaluate center of mass (COM) acceleration feedback
control of neuroprosthesis with functional neuromuscular stimulation (FNS) to restore standing balance to subject with spinal cord injury.
• Relevance– Neuroprosthesis users maintain balance by postural
corrections with upper-limb (UL) loads on assistive device or support surface (e.g., walker, countertop).
• This can compromise utility of standing with FNS by limiting functional use of hands and arms.
This article and any supplementary material should be cited as follows: Nataraj R, Audu ML, Triolo RJ. Center of mass acceleration feedback control of functional neuromuscular stimulation for standing in presence of internal postural perturbations. J Rehabil Res Dev. 2012;49(6):889–912. http://dx.doi.org/10.1682/JRRD.2011.07.0127
Slideshow ProjectDOI:10.1682/JRRD.2011.07.0127JSP
Methods• Created artificial neural network to map gain-
modulated changes in total body COM acceleration estimated from body-mounted sensors to optimal changes in stimulation required to maintain standing.
• Systematically tuned feedback gains to minimize UL loads applied by subject to instrumented support device during internally generated postural perturbations produced by volitional reaching and object manipulation.
This article and any supplementary material should be cited as follows: Nataraj R, Audu ML, Triolo RJ. Center of mass acceleration feedback control of functional neuromuscular stimulation for standing in presence of internal postural perturbations. J Rehabil Res Dev. 2012;49(6):889–912. http://dx.doi.org/10.1682/JRRD.2011.07.0127
Slideshow ProjectDOI:10.1682/JRRD.2011.07.0127JSP
Subject with spinal cord injury undergoing internal perturbations by volitionally moving object over level surface with one arm while stabilizing with other arm.
This article and any supplementary material should be cited as follows: Nataraj R, Audu ML, Triolo RJ. Center of mass acceleration feedback control of functional neuromuscular stimulation for standing in presence of internal postural perturbations. J Rehabil Res Dev. 2012;49(6):889–912. http://dx.doi.org/10.1682/JRRD.2011.07.0127
Slideshow ProjectDOI:10.1682/JRRD.2011.07.0127JSP
Results• Total body COM acceleration was accurately
estimated (>90% variance explained) from 3-D accelerometers mounted on pelvis and torso.
• Compared with clinical constant muscle stimulation, COM acceleration feedback control of stimulation improved standing performance by reducing UL loading required to resist internal postural disturbances by 27%.
This article and any supplementary material should be cited as follows: Nataraj R, Audu ML, Triolo RJ. Center of mass acceleration feedback control of functional neuromuscular stimulation for standing in presence of internal postural perturbations. J Rehabil Res Dev. 2012;49(6):889–912. http://dx.doi.org/10.1682/JRRD.2011.07.0127
Slideshow ProjectDOI:10.1682/JRRD.2011.07.0127JSP
Conclusions• This case study suggests that COM acceleration
feedback could be advantageous in standing neuroprosthesis.– Can be implemented with only a few feedback
parameters.– Requires minimal instrumentation for
comprehensive 3-D control of dynamic standing function.