Experimental Brain Research

, Volume 154, Issue 3, pp 308–326 | Cite as

Initiating extension of the lower limbs in subjects with complete spinal cord injury by epidural lumbar cord stimulation

  • B. Jilge
  • K. Minassian
  • F. Rattay
  • M. M. Pinter
  • F. Gerstenbrand
  • H. Binder
  • M. R. DimitrijevicEmail author
Research Article


We provide evidence that the human spinal cord is able to respond to external afferent input and to generate a sustained extension of the lower extremities when isolated from brain control. The present study demonstrates that sustained, nonpatterned electrical stimulation of the lumbosacral cord—applied at a frequency in the range of 5–15 Hz and a strength above the thresholds for twitches in the thigh and leg muscles—can initiate and retain lower-limb extension in paraplegic subjects with a long history of complete spinal cord injury. We hypothesize that the induced extension is due to tonic input applied by the epidural stimulation to primary sensory afferents. The induced volleys elicit muscle twitches (posterior root muscle-reflex responses) at short and constant latency times and coactivate the configuration of the lumbosacral interneuronal network, presumably via collaterals of the primary sensory neurons and their connectivity with this network. We speculate that the volleys induced externally to the lumbosacral network at a frequency of 5–15 Hz initiate and retain an “extension pattern generator” organization. Once established, this organization would recruit a larger population of motor units in the hip and ankle extensor muscles as compared to the flexors, resulting in an extension movement of the lower limbs. In the electromyograms of the lower-limb muscle groups, such activity is reflected as a characteristic spatiotemporal pattern of compound motor-unit potentials.


Spinal cord injury Spinal cord stimulation Lower limb extension 





Compound motor-unit potential




Central nervous system


Electromyography, electromyographic






Mesencephalic locomotor region


Paraspinal muscles






Spinal cord injury, spinal cord-injured


Spinal cord stimulation




Tibialis anterior


Triceps surae



Special thanks are due to Ms. Auer, Ms. Preinfalk, and Ms. Alesch for their excellent technical support. This study was supported by the Austrian Science Fund (FWF), research project P15469; the Austrian Ministry of Transport, Innovation and Technology; and a grant from the Kent Waldrep National Paralysis Foundation in Addison, Texas, USA.


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Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • B. Jilge
    • 1
  • K. Minassian
    • 1
    • 2
  • F. Rattay
    • 1
  • M. M. Pinter
    • 3
  • F. Gerstenbrand
    • 4
  • H. Binder
    • 4
  • M. R. Dimitrijevic
    • 1
    • 4
    • 5
    • 6
    Email author
  1. 1.TU-BioMed—Association for Biomedical Engineering, Vienna University of TechnologyViennaAustria
  2. 2.Ludwig Boltzmann Institute for Electrical Stimulation and Physical RehabilitationViennaAustria
  3. 3.Neurological Rehabilitation Center RosenhügelViennaAustria
  4. 4.Ludwig Boltzmann Institute for Restorative Neurology and NeuromodulationViennaAustria
  5. 5.Department of Physical Medicine and RehabilitationBaylor College of MedicineHoustonUSA
  6. 6.University Institute of Clinical NeurophysiologyClinical CenterLjubljanaSlovenia

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