Re-education of upper limb function post-stroke, using iterative learning control (ILC) mediated by functional electrical stimulation (FES)

Re-education of upper limb function post stroke, using Iterative Learning Control (ILC) mediated by Functional Electrical Stimulation (FES) Introduction Current opinion in motor learning, reinforced by clinical evidence, supports the use of FES and robot therapy to improve motor control (i-iii). ILC is a technique applicable to processes which repeatedly perform a task with a view to sequentially improving accuracy such as trajectory following in robots. The aim of this project is to test the feasibility of applying ILC to neurological rehabilitation. Method 5 hemiplegic stroke subjects used a robotic workstation to track 2 dimensional trajectories, over 18 treatment sessions. ILC was used to govern the FES applied to their triceps muscles in terms of timing and amplitude to improve tracking performance, whilst encouraging a maximal voluntary contribution to the task. Results Differences in muscle activation patterns were observed between unimpaired and hemiplegic subjects. Improvements were recorded in isometric strength and unassisted performance of the tracking tasks in 4 out of the 5 hemiplegic subjects. Conclusion ILC mediated by FES enabled stroke subjects to accurately track a range of trajectories. Over time this related to an improvement in motor control reflected by increasing accuracy observed in unassisted tracking. References (i) De Kroon, J. R., van der Lee, J. H., Izerman, M. J., & Lankhorst, G. J. 2002, Clinical Rehabilitation, vol. 16, pp. 350-360. (ii) Schmidt, R. A. & Lee, T. D. Motor control and learning a behavioural emphasis. 3rd Edition. 261-285. 1999. Human Kinetics. (iii) Kwakkel, G., Kollen, B. J., & Krebs H.I 2008, Neurorehabilitation and Neural Repair, vol. 22, pp. 111-121.