Spinal Cord Lesion: Effects of and Perspectives for Treatment

[摘要] Following central motor lesions, two formsof adaptation can be observed which lead toimproved mobility: (1) the development of spasticmuscle tone, and (2) the activation of spinallocomotor centers induced by specific treadmilltraining. Tension development during spasticgait is different from that during normal gaitand appears to be independent of exaggeratedmonosynaptic stretch reflexes. Exaggeratedstretch reflexes are associated with an absenceor reduction of functionally essential polysynapticreflexes. When supraspinal control of spinalreflexes is impaired, the inhibition of monosynapticreflexes is missing in addition to areduced facilitation of polysynaptic reflexes.Therefore, overall leg muscle activity becomesreduced and less well modulated in patients withspasticity. Electrophysiologicai and histologicalstudies have shown that a transformation ofmotor units takes place following central motorlesions with the consequence that regulation ofmuscle tone is achieved at a lower level ofneuronal organization which in turn enables thepatient to walk. Based on observations of thelocomotor capacity of the spinal cat, recentstudies have indicated that spinal locomotorcenters can be activated and trained in patientswith complete or incomplete paraplegia whenthe body is partially unloaded. However, thelevel of electromyographic activity in thegastrocnemius (the main antigravity muscleduring gait) is considerably lower in the patientscompared to healthy subjects. During the courseof a daily locomotor training program, theamplitude of gastrocnemius, electromyographicactivity increases significantly during the stancephase, while inappropriate tibialis anterioractivation decreases. Patients with incompleteparaplegia benefit from such training programssuch that their walking ability on a stationarysurface improves. The pathophysiology andfunctional significance of spastic muscle tone andthe effects of treadmill training on the locomotorpattern underlying new attempts to improve themobility of patients with paraplegia are reviewed.

[学科分类] 精神健康和精神病学