Force-pain relationship in functional magnetic and electrical stimulation of subjects with paresis and preserved sensation.
OBJECTIVE
Using "painless" magnetic stimulation (FMS) to support the cycling of paretic subjects with preserved sensation is possible and potentially superior to electrical stimulation (FES). We investigated the dependence of the torque and the pain evoked by FMS and FES on stimulation conditions in order to optimize magnetic stimulation.


METHODS
Torque and pain induced by quadriceps stimulation in 13 subjects with paresis and preserved sensation (due to multiple sclerosis) were compared under the conditions: (1) small vs large stimulated surfaces of the thigh, (2) varying contraction velocities of the muscle (isometric vs 15 and 30 rpm isokinetic speed), (3) FMS vs FES modalities, and (4) varying magnetic coil locations.


RESULTS
Torque and pain significantly depended on the amount of surface and location of stimulation during FMS, on the stimulation modality, and on the muscle contraction velocity during FES and FMS. FMS with a saddle-shaped coil produced more torque (p<0.05) than any other stimulation modality, even at 30 rpm velocity.


CONCLUSIONS
To support leg cycling of subjects with preserved sensation, the application of FMS stimulation with a large-surface saddle-shaped coil and the focusing of stimulation on the lateral-frontal surface of the thigh produces greater torque and less pain than FES.


CONCLUSIONS
Optimized magnetic stimulation is a superior alternative to electrical stimulation in the rehabilitation of subjects with preserved sensation.
Szecsi
J
J
Center for Sensorimotor Research, Department of Neurology, Ludwig-Maximilians University, Munich, Germany. Electronic address: jszecsi@nefo.med.uni-muenchen.de.
Götz
S
S
Technische Universität München, Munich, Germany.
Pöllmann
W
W
Marianne Strauss Therapy Center for Multiple Sclerosis, Kempfenhausen, Germany.
Straube
A
A
Center for Sensorimotor Research, Department of Neurology, Ludwig-Maximilians University, Munich, Germany.
D000328:Adult; D018450:Disease Progression; D004558:Electric Stimulation / Q000009:adverse effects* / Q000379:methods; D004576:Electromyography / Q000379:methods; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D055909:Magnetic Field Therapy / Q000009:adverse effects* / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications / Q000473:pathology; D018482:Muscle, Skeletal / Q000503:physiopathology*; D010146:Pain / Q000209:etiology*; D010291:Paresis / Q000503:physiopathology* / Q000628:therapy; D013119:Spinal Cord Injuries / Q000150:complications / Q000473:pathology; D013848:Thigh / Q000294:innervation / Q000503:physiopathology; D019415:Torque