A multichannel functional electrical stimulation (FES) system for the restoration of quadriplegic upper extremity function is described. The system is composed of a personal computer NEC PC-8801mkII, peripheral electronic circuits, CRT display and respiratory sensors for volitional control by the patient, and percutaneous electrodes. A C4 quadriplegic patient could drink canned tea by herself by using this FES system. Distinct features of the system are as follows: 1) Versatile volitional control was realized by controlling the memory allocation of the stored stimulation data by voluntary respiratory signals. 2) Sophisticated fine control of the fingers, wrists, and elbow was realized by creating the multichannel stimulation data from recorded myoelectric activities of normal subjects during movements of the upper limb.

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Activities of the elbow flexors (biceps brachii, BB; brachialis, B; brachioradialis, BR) and extensors (triceps brachii, TB) in a motion of forearm pronation/supination with maintenance of elbow flexion (PS-movement) in nine healthy human subjects were studied by electromyography (EMG). The subject performed the PS-movement slowly or quickly with or without a load extending the elbow. In the slow PS-movement, an increase and decrease of EMG activities during supination and pronation, respectively, were seen in BB and the reverse was in B. A clear increment of EMG activities in BB accompanied with a reduction of EMG activities in B and/or BR, and the reverse were often observed. The contraction level and gain with the forearm supine were higher and larger than those with the forearm prone, respectively, in BB and the reverse was in B and BR. In a series of the quick PS-movement, alternating increases of EMG activities between BB and the other flexors (B and BR) were seen. Since TB showed no EMG activities throughout the experiment, it is suggested that reciprocal contractions between BB and the other flexors, which produce a complementary force in flexion direction, enable motions of pronation/supination with maintenance of flexion. Contraction properties of the flexors were discussed.

Activities of the biceps brachii (long head: BiL, short head: BiS) on the elbow joint were studied using an electrical neuromuscular stimulation (ENS) and an electromyography (EMG). In ENS study, ENS to BiL or BiS was performed in seven volunteers. Before ENS, the volunteer relaxed the upper extremity on a table with the elbow extended and the forearm pronated. Then ENS-induced movements of the upper extremity were examined. Movements of elbow flexion and forearm Supination were induced simultaneously by ENS to BiS in all volunteer and by ENS to BiL in six volunteers. ENS to BiL of one volunteer resulted in only elbow flexion. In EMG study, averaged EMGs of BiL and BiS during a to-and-fro motion from prone to supine of the forearm with holding a load were analyzed in eight volunteers. The volunteer acted the movements with keeping the elbow joint in different angles. Although an increase and a decrease of EMG activities in BiL and BiS were observed accompanied by the degree of forearm supination, patterns of changes in quantities of EMG activities to changing elbow angles varied from individual to individual. These findings seem to indicate that each human subject has an individual use of the biceps brachii for supination movements, while the action of the muscle on the elbow joint is similar among the subjects. long (BiL) and short (BiS) heads of the biceps brachii; electrical neuromuscular stimulation (ENS); electromyography (EMG); forearm supination; elbow flexion

(EMG) Study of the Elbow Flexors during Supination and Pronation of the Forearm. Tohoku J. Exp. Med., 1995, 175 (4), [285][286][287][288] Activities of the elbow flexors during supination and pronation of the forearm in a normal human volunteer were studied by an electromyography (EMG). The volunteer performed the movement slowly or quickly holding elbow flexion at various angles with or without a load. The biceps brachii showed an increase and a decrease of EMG activities during supination and pronation, respectively. The brachialis and brachioradialis showed a reduction and an increment of EMU activities accompanied by an increase and a decrease of EMG activities in the biceps brachii, respectively. These findings seem to indicate that reciprocal contractions among the elbow flexors permit the biceps brachii to work for supination without an induction of elbow flexion. biceps brachii; brachialis; brachioradialis; supination and pronation; electromyography (EMU)The biceps brachii is acting as the elbow flexor and forearm supinator. We have confirmed that electrical activations of the muscle resulted in simultaneous inductions of flexion and supination in normal human volunteers and 04 quadriplegic patients (Naito et al. 1994a, b). On the other hand, our electromyographic (EMG) study of supination without any flexion indicated that activities of the biceps brachii increased with supinating the forearm (Naito et al. 1994a). Since these activities work for not only supination but also flexion, it seems that changes of the other muscles activities should occur to prevent an induction of flexion. In this study, we demonstrated clear reductions of the brachialis and brachioradialis activities accompanied with the increase of the biceps brachii activities using EMG.EMGs of the elbow flexors (long and short heads of the biceps brachii, the brachialis, the brachioradialis) were recorded from a human volunteer (female, 22 years of ages). Bipolar wire electrodes were implanted percutaneously into the muscles. Details of experimental procedures for EMG recording have been described previously (Naito et al. 1994a). EMGs were amplified, rectified and averaged for analysis.A movement tested was a to-and-fro motion from prone to supine position of the Received September 16, 1994; revision accepted for publication January 10, 1995. 285 286 A. Naito et al.forearm (PS-movement) while keeping the elbow joint in various angles of flexion (the maximum extension, 30, 60 and 90 degrees of flexion). In this study, the prone and supine positions indicated about 90 degrees of pronation and supination in the forearm, respectively. Thus the range of PS-movement was about 180 degrees (from 90 degrees of pronation to 90 degrees of supination). She performed the movement slowly or quickly with or without holding a load (a cylindrical object weighing of 1.2 kg) in the hand. In the slow movement, each motion of supination and pronation was started at an experimenter's call and finished in around 8 sec. When supination was ended she kept the fo...