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Reflex Mechanisms for Motor Impairment in Spinal Cord Injury

  • Brian D. Schmit
  • Ela N. Benz
  • William Z. Rymer
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 508)

Abstract

Spasticity is common feature of human spinal cord injury. It contributes to motor impairment and it also promotes joint deformity in patients who have sustained such injury. The classical definition of spasticity highlights the increased resistance of a joint to externally imposed motion. This resistance is attributable largely to changes in stretch reflex excitability, and it is manifested primarily in those muscles being stretched by the motion. Under this definition, there wouldbelittle activity in muscles crossing other joints. In spinal cord injury, however, muscles innervated from distal spinal segments often exhibit little hypertonia, yet patients report the occurrence of disabling spasms. These spasms appear as coordinated patterns of muscle activation throughout the limb, involving either limb flexors or extensors. These patterns are therefore quite different from those of classical spasticity. The receptor origins and neural pathways responsible for the spasms in spinal cord injury will be addressed.

Keywords

Spinal Cord Injury Chronic Spinal Cord Injury Flexion Torque Golgi Tendon Organ Spinal Cord Injured Patient 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Andersson, O., and Grillner, S., 1981, Peripheral Control of the Cat’s Step Cycle 1. Phase dependent effects of ramp-movements of the hip during “fictive locomotion”Acta Physiologica Scandinavica113, 89–101.PubMedCrossRefGoogle Scholar
  2. Baldissera, F., Hultborn, H., and Illert, M., 1981, Integration in spinal neuronal systems, in:Handbook of Physiology - The Nervous SystemBrookhart, J.M., and Mountcastle, V.B., eds., American Physiological Society, Baltimore, pp. 509–595.Google Scholar
  3. Cleland, C. L., Hayward, L., and Rymer, W. Z., 1990, Neural mechanisms underlying the clasp-knife reflex in the cat. II. Stretch-sensitive muscular-free nerve endingsJournal of Neurophysiology64, 1319–1330.PubMedGoogle Scholar
  4. Eccles, R.M., and Lundberg, A., 1959, Synaptic actions in motoneurones by afferents which may evoke the flexion reflexArchives Italiennes de Biologie9, 199–221.Google Scholar
  5. Grillner, S., and Rossignol, S., 1978, On the initiation of the swing phase of locomotion in chronic spinal catsBrain Research146, 269–277.PubMedCrossRefGoogle Scholar
  6. Hiebert, G. W., Whelan, P. J., Prochazka, A., and Pearson, K. G., 1996, Contribution of hind limb flexor muscle afferents to the timing of phase transitions in thecatstep cycleJournal of Neurophysiology75, 1126–1137.PubMedGoogle Scholar
  7. Houk, J. C., Crago, P. E., and Rymer, W. Z., 1980, Functional properties of the golgi tendon organs, in:Spinal and Supraspinal Mechanisms of Voluntary Motor Control and LocomotionDesmedt, J. E, ed., Basel, Karger, pp. 33–43.Google Scholar
  8. Kumazawa, T., and Mizumura, K., 1977, Thin-fibre receptors responding to mechanical, chemical, and thermal stimulation in the skeletal muscle of the dogJournal of Physiology273, 179–194.PubMedGoogle Scholar
  9. Lance, J. W., Pathophysiology of spasticity and clinical experience with baclofen, in:Spasticity: Disordered Motor ControlFeldman, R. G., Young, R. R., and Koella, W. P., eds., Year Book, Chicago, pp. 185–203.Google Scholar
  10. Mense, S., and Meyer, H., 1985, Different types of slowly conducting afferent units in cat skeletal muscle and tendonJournal of Physiology363, 403–417.PubMedGoogle Scholar
  11. Schmit, B. D., McKenna-Cole, A., and Rymer, W. Z., 2000, Flexor reflexes in chronic spinal cord injury triggered by imposed ankle rotationMuscle and Nerve23, 793–803.PubMedCrossRefGoogle Scholar
  12. Shahani, B. T., and Young, R. R., 1971, Human flexor reflexesJournal of Neurology Neurosurgery and Psychiatry34, 616–627.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2002

Authors and Affiliations

  • Brian D. Schmit
    • 1
  • Ela N. Benz
    • 2
  • William Z. Rymer
    • 2
  1. 1.Rehabilitation Institute of Chicago, and Department of Physical Medicine and Rehabilitation at NorthwesternUniversity Medical School, and the Department of Biomedical Engineering, Marquette UniversityMilwaukeeUSA
  2. 2.Rehabilitation Institute of Chicago, and Department of Physical Medicine and Rehabilitation at NorthwesternUniversity Medical SchoolUSA

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