The main objective of this study is to develop a closed-loop system for Functional Electrical Stimulation (FES), based on natural sensing and natural recruitment of paralysed muscles, as an improvement of current open-loop systems with superficial stimulation. Specifically, the system will be designed to bring about a safe, prolonged period of standing in paraplegic individuals. The objectives can be grouped as:
1) Selective recording of FES feedback signals from sensory nerves;
2) Development of a closed-loop control system for paraplegic standing;
3) Selective activation of muscles via selective stimulation of nerves;
4) Experimental evaluation of selective stimulation and recording in animals and humans.
Functional Electrical Stimulation (FES) has been investigated for several decades. FES can restore some mobility in spinal cord or brain injured patients who are otherwise confined to their wheelchairs. However, despite intense research efforts, present day FES has found limited application because of poor control systems, which are often open-loop. Moreover, the systems are difficult to handle for patients on a daily basis and hardly acceptable from a cosmetic point of view.
In this European Shared Cost RTD project, which includes seven Centres of Excellence, we seek to improve control schemes for FES systems by selective muscle recruitment via nerve stimulation and the inclusion of feedback information from the body's own sensory system. Natural sensors are abundantly available in the body and they are of paramount importance in the normal physiology of motor control. With the use of neural sensing and nerve stimulation the largest part of the FES system can be fully implantable, thus solving a part of the daily burden and acceptability for the patients.
Within the time frame of the BIOMED 2 Workprogramme we focus on a system for paraplegic standing. Paraplegic persons are not able to stand without assisting devices and are thus unable to perform trivial tasks, although by far the largest part of their neuromuscular system involved in standing-up, standing and sitting-down remains viable. We intend to design a system to bring about a safe and prolonged standing. It will consist of three parts: Sensing, Control and Stimulation. Signals are recorded with cuff electrodes placed around different peripheral nerves innervating the natural sensors of the foot sole and structures in and around the knee. The signal processing and control units will have inputs from the telemeter and outputs to the stimulator, which is connected to the stimulation nerve cuff electrodes.
Within the 36 months of the project a limited clinical evaluation will be carried out. By the end of the contract period the system should be ready for a Demonstration Project.
Funding SchemeCSC - Cost-sharing contracts
7500 AE Enschede
WC1E 6JA London