ABSTRACT
The paralyzed limbs of quadriplegic and paraplegic patients constitute one of the most intriguing challenges for applied neural control techniques. There are several general classes of techniques which are potential candidates for obtaining such somatosensory information from the functional neuromuscular stimulation (FNS) limb. Since the FNS patient already has a highly sophisticated array of force, length, and pressure transducers in his limb, i.e., the somatosensory mechanoreceptor neurons, it should be possible to avoid many of these engineering problems. The microelectrodes can be located in the most stable part of the trunk, the spinal canal, and draw on information conducted there by fibers from the most distal extremities. Perhaps the most obviously needed transducer in an FNS system is that for the force generated by the stimulated muscles. Although the naturally occurring transducers of length, strain, and pressure have obvious counterparts in electromechanical devices, they are not entirely characterizable by the usual engineering criteria.
