APPARATUS AND METHODS FOR STUDYING ARTIFICIAL FEEDBACK-CONTROL OF THEPLANTARFLEXORS IN PARAPLEGICS WITHOUT INTERFERENCE FROM THE BRAIN

Apparatus has been built to explore the practical feasibility of using automatic control with electrical stimulation of paralysed legs to re store function. The experiments are performed with paraplegics with th e aim of achieving a realistic postural task: to see whether the body may be maintained upright by stimulation of the plantarflexors when th e other joints are braced. Significantly, the intact upper body, under natural control of the brain, cannot interfere with the automatic con trol. The ''Wobbler'' apparatus allows measurement of the ankle muscle properties in isometric conditions or in sinusoidal motion. Using the biomechanical properties of the body, which are also measured, contro llers for stabilising the body can De designed. Controllers can be dyn amically tested, imitating anterior-posterior stony, while the body is held upright, before ''actual standing'' is attempted. (C) 1997 IPEM. Published by Elsevier Science Ltd.