Properties of auditory temporal integration revealed by mismatch negativity

2001 Proceedings of the 23rd Annual EMBS International Conference, October 25-28, Istanbul, Turke

Development of a Closed-loop FES System Using a 3-D Magnetic Position and Orientation Measurement System

Abstract — We have developed a closed-loop FES system using a magnetic 3-D position and orientation measurement system (FASTRAK, Polhemus Inc.). The purpose of this development was to resolve some experimental difficulties involved in our previous goniometer-based experimental system. The new system enabled us to perform FES control experiments on the multi-joint musculoskeletal system of the upper limbs including forearm pronation/supination. In this paper, we evaluated the system by some single-joint tracking tasks in order to compare its control performance with that of the previous system. Four muscles (ECRL(B), ECU, FCR, and FCU) of neurologically intact subjects were stimulated to control the wrist joint’s two degrees of freedom movement. Stimulation currents were determined by a multi-channel PID controller that was designed for a musculoskeletal system with redundancy (i.e. the number of muscles stimulated is more than that of the degree-of-freedom of the movement). The results showed that the system had sufficient control performance on tracking desired trajectories. Moreover, the system could compensate for unwanted external disturbances. Index Terms — Functional Electrical Stimulation (FES), closed-loop control, PID controller, magnetic sensor

Artificial Organs

Sensory supported electrical stimulation of the peroneal nerve during treadmill walking is proposed as a gait-training modality in incomplete spinal cord injury (SCI) patients. A multisensor device provides information on the tilt of the shank during gait. The information provided significantly improves the triggering instant of the electrical stimulation. Simultaneously, swing-phase estimation serves as a reference to determine the required motor augmentation support. Both approaches, as well as triggering using intensity control of the functional electrical stimulation were applied on a healthy person and on an incomplete C4--5 SCI patient. Key Words: Electrical stimulation---Sensors---Therapy---Incomplete---Spinal cord injury---Treadmill