Riso R R, Ignagni A R, Keith M W
Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44109.
IEEE Trans Biomed Eng. 1991 Jan;38(1):29-38. doi: 10.1109/10.68206.
This paper describes the development of two sensory substitutions systems that provide cognitive feedback for FES hand grasp restoration neuroprostheses. One system uses an array of five electrodes to provide machine status information and a spatially encoded representation of the command signal that a quadriplegic individual generates to achieve proportional grasp control. Only one electrode site is active at any given instant, and a second informational channel is superimposed on the spatial position channel by modulating the frequency of the stimulus pulses. The frequency modulated feedback channel signals six levels of force developed at the finger tips during prehension activities. The second sensory system is an integral part of an implanted FES system and utilizes a single subdermally placed electrode to display machine status information and a five-level frequency code for feedback of the user generated grasp control signal. The multielectrode feedback system was implemented for laboratory studies using surface mounted electrodes, although its design will ultimately incorporate subdermal electrodes to provide a highly cosmetic and unencumbering system. An evaluation of the effectiveness of grasp force and command signal feedback provided by this multielectrode system in assisting an FES hand system user to regulate grasp force during a laboratory task, showed increased consistency of performance and an economy of grasp effort between 25 and 30%. Alternative strategies for feedback information and coding algorithms are discussed.
本文描述了两种感觉替代系统的开发，这两种系统为功能性电刺激（FES）手部抓握恢复神经假体提供认知反馈。一种系统使用由五个电极组成的阵列来提供机器状态信息以及四肢瘫痪个体为实现比例抓握控制而生成的命令信号的空间编码表示。在任何给定时刻，只有一个电极部位处于激活状态，并且通过调制刺激脉冲的频率，在空间位置通道上叠加了第二个信息通道。调频反馈通道信号表示在抓握活动期间指尖产生的六个力的级别。第二个感觉系统是植入式FES系统的一个组成部分，它利用单个皮下放置的电极来显示机器状态信息以及用于反馈用户生成的抓握控制信号的五级频率编码。多电极反馈系统通过使用表面安装电极来进行实验室研究，尽管其设计最终将采用皮下电极以提供高度美观且不妨碍活动的系统。对该多电极系统在实验室任务中为FES手部系统用户提供抓握力和命令信号反馈的有效性进行的评估表明，性能的一致性有所提高，抓握力节省了25%至30%。文中还讨论了反馈信息和编码算法的替代策略。
