CHANGES IN MUSCLE FORCE FOLLOWING THERAPEUTIC ELECTRICAL-STIMULATION IN PATIENTS WITH COMPLETE PARAPLEGIA

Changes in muscle force following therapeutic electrical stimulation ( TES) in 5 patients with complete paraplegia were evaluated by computed tomography, Cybex II, a strain-gauge transducer, and manual muscle te sting. The stimulation parameters included a frequency of 20 Hz, a pul se width of 0.2 ms, and an output voltage of -15 V. The cross-sectiona l areas of muscles, the muscle torques, and the muscle forces increase d after TES, though the increased ratio differed in each muscle. The r easons why it differed are as follows: (1) The possibility of peripher al nerve injury; (2) The different patterns of nerve distribution in t he muscles; (3) Implantation techniques; and (4) The possibility of br eakage, movement, or changes in the impedance of electrodes. This stud y demonstrates that TES increases muscle force during electrical stimu lation in paralyzed muscle, but that an initial TES-induced muscle for ce greater than a poor-minus level on manual muscle testing is necessa ry for practical use. TES treatment should be started as soon as possi ble after the onset of paralysis, in order to maintain muscle quality.