Title :
Paraplegic standing supported by FES-controlled ankle stiffness
Author :
Jaime, Ralf-Peter ; Matjacic, Zlatko ; Hunt, Kenneth J.
Author_Institution :
Centre for Syst. & Control, Univ. of Glasgow, Scotland, UK
Abstract :
The objective of this paper was to investigate whether a paraplegic subject is able to maintain balance during standing by means of voluntary and reflex activity of the upper body while being supported by closed loop controlled ankle stiffness using FES. The knees and hips of the subject were held in extended positions by a mechanical apparatus, which restricted movement to the sagittal plane. The subject underwent several training sessions where the appropriate level of stiffness around the ankles was maintained by the mechanical apparatus. This enabled the subject to learn how to use the upper body for balancing. After the subject gained adequate skills closed-loop FES was employed to regulate ankle stiffness, replacing the stiffness provided by the apparatus. A method to control antagonist muscle moment was implemented. In subsequent standing sessions, the subject had no difficulties in maintaining balance. When the FES support was withheld, the ability to balance was lost.
Keywords :
biocontrol; bioelectric phenomena; closed loop systems; handicapped aids; mechanoception; medical control systems; neuromuscular stimulation; orthotics; patient rehabilitation; FES-controlled ankle stiffness; adequate skills; ankles; antagonist muscle moment control; balance; balancing; closed loop controlled ankle stiffness; extended positions; functional electrical stimulation; hips; knees; mechanical apparatus; paraplegic subject; reflex activity; sagittal plane; spinal cord injury; standing; training sessions; upper body; voluntary activity; Biological system modeling; Bladder; Control systems; Fatigue; Hip; Knee; Muscles; Neuromuscular stimulation; Nonlinear dynamical systems; Spinal cord injury; Adult; Ankle Joint; Elasticity; Electric Stimulation Therapy; Equipment Design; Feedback; Humans; Lower Extremity; Male; Models, Biological; Muscles; Musculoskeletal Equilibrium; Orthotic Devices; Paraplegia; Posture; Reproducibility of Results; Sensitivity and Specificity; Spinal Cord Injuries; Thoracic Vertebrae; Volition;
Journal_Title :
Neural Systems and Rehabilitation Engineering, IEEE Transactions on
DOI :
10.1109/TNSRE.2002.806830