Optimizing Gait Rehabilitation: How Can Nervous System Plasticity Be Harnessed?   Jesse Dean 3.24.10
Introduction <ul><li>Restoration of functional mobility is a high ranking goal </li></ul><ul><li>Neurological injuries com...
Gait rehabilitation can improve function <ul><li>Therapist-Assisted </li></ul><ul><li>Powered Exoskeletons </li></ul><ul><...
Recovery is due to neural plasticity <ul><li>Nervous system connections are not hard-wired </li></ul>
Recovery is due to neural plasticity <ul><li>Nervous system connections are not hard-wired </li></ul><ul><ul><li>Multiple ...
Recovery is due to neural plasticity <ul><li>Nervous system connections are not hard-wired </li></ul><ul><ul><li>Multiple ...
Promoting plasticity for gait recovery <ul><li>To form/strengthen new functional circuits: </li></ul><ul><li>Descending co...
Promoting plasticity for gait recovery <ul><li>To form/strengthen new functional circuits: </li></ul><ul><li>Descending co...
Promoting plasticity for gait recovery <ul><li>To form/strengthen new functional circuits: </li></ul><ul><li>Descending co...
Proposed Interventions <ul><li>Mechanical </li></ul><ul><li>Physiological </li></ul><ul><li>To form/strengthen new functio...
Proposed Interventions <ul><li>Mechanical </li></ul><ul><ul><li>Goal: Drive walking motion with reduced muscle activation ...
Mechanical Intervention: Passive Exoskeleton <ul><li>Based on previous mechanical model simulations </li></ul><ul><li>Appr...
Proposed Interventions <ul><li>Mechanical </li></ul><ul><li>Physiological </li></ul><ul><li>To form/strengthen new functio...
Proposed Interventions <ul><li>Mechanical </li></ul><ul><li>Physiological </li></ul><ul><ul><li>Goal: Promote appropriate ...
Peripheral electrical stimulation can modulate motor pool excitability <ul><li>Non-invasive stimulation over a muscle or n...
Motor pool modulation during gait may promote plasticity <ul><li>Increased excitability will allow motor pool recruitment ...
Stimulation can be driven by mechanical feedback <ul><li>May be used either in combination with or independent from mechan...
Conclusions <ul><li>Gait rehabilitation outcomes may be improved through neural plasticity by: </li></ul><ul><ul><li>Mecha...
Optimizing Gait Rehabilitation: How Can Nervous System Plasticity Be Harnessed?   Jesse Dean 3.24.10
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Optimizing Gait Rehabilitation: How Can Nervous System Plasticity Be Harnessed, Jesse Dean, PhD

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Optimizing Gait Rehabilitation: How Can Nervous System Plasticity Be Harnessed, Jesse Dean, PhD

  1. 1. Optimizing Gait Rehabilitation: How Can Nervous System Plasticity Be Harnessed? Jesse Dean 3.24.10
  2. 2. Introduction <ul><li>Restoration of functional mobility is a high ranking goal </li></ul><ul><li>Neurological injuries commonly limit independent locomotion </li></ul><ul><ul><li>Stroke: 800,00 per year </li></ul></ul><ul><ul><li>Spinal cord injury: 12,000 per year </li></ul></ul>(Anderson, 2004)
  3. 3. Gait rehabilitation can improve function <ul><li>Therapist-Assisted </li></ul><ul><li>Powered Exoskeletons </li></ul><ul><li>By moving the legs through walking-like motions, patients can “relearn” how to walk </li></ul><ul><li>Treadmill training improves muscle activation patterns (Dietz et al., 1994), gait speed, and gait symmetry (Field-Fote, 2000) </li></ul>(Fritz et al., 2007) (Dietz et al., 1995)
  4. 4. Recovery is due to neural plasticity <ul><li>Nervous system connections are not hard-wired </li></ul>
  5. 5. Recovery is due to neural plasticity <ul><li>Nervous system connections are not hard-wired </li></ul><ul><ul><li>Multiple paths from one point to another </li></ul></ul>
  6. 6. Recovery is due to neural plasticity <ul><li>Nervous system connections are not hard-wired </li></ul><ul><ul><li>Multiple paths from one point to another </li></ul></ul><ul><li>Activity-dependent plasticity may create functionally relevant new connections </li></ul><ul><ul><li>“Fire together, wire together” </li></ul></ul>
  7. 7. Promoting plasticity for gait recovery <ul><li>To form/strengthen new functional circuits: </li></ul><ul><li>Descending commands must be present </li></ul>
  8. 8. Promoting plasticity for gait recovery <ul><li>To form/strengthen new functional circuits: </li></ul><ul><li>Descending commands must be present </li></ul><ul><li>Motor pools must be recruited at appropriate times </li></ul>
  9. 9. Promoting plasticity for gait recovery <ul><li>To form/strengthen new functional circuits: </li></ul><ul><li>Descending commands must be present </li></ul><ul><li>Motor pools must be recruited at appropriate times </li></ul><ul><li>Muscle contractions must drive movement, eliciting sensory feedback </li></ul>
  10. 10. Proposed Interventions <ul><li>Mechanical </li></ul><ul><li>Physiological </li></ul><ul><li>To form/strengthen new functional circuits: </li></ul><ul><li>Descending commands must be present </li></ul><ul><li>Motor pools must be recruited at appropriate times </li></ul><ul><li>Muscle contractions must drive movement, eliciting sensory feedback </li></ul>
  11. 11. Proposed Interventions <ul><li>Mechanical </li></ul><ul><ul><li>Goal: Drive walking motion with reduced muscle activation </li></ul></ul><ul><ul><li>Method: Use the principles of dynamic walking to essentially make walking easier </li></ul></ul><ul><li>Physiological </li></ul><ul><li>To form/strengthen new functional circuits: </li></ul><ul><li>Descending commands must be present </li></ul><ul><li>Motor pools must be recruited at appropriate times </li></ul><ul><li>Muscle contractions must drive movement, eliciting sensory feedback </li></ul>
  12. 12. Mechanical Intervention: Passive Exoskeleton <ul><li>Based on previous mechanical model simulations </li></ul><ul><li>Appropriate spring placement </li></ul><ul><ul><li>Reduces energetic cost by ~10% </li></ul></ul><ul><ul><li>Reduces swing phase muscle activity by up to 40% </li></ul></ul>(Dean, 2009)
  13. 13. Proposed Interventions <ul><li>Mechanical </li></ul><ul><li>Physiological </li></ul><ul><li>To form/strengthen new functional circuits: </li></ul><ul><li>Descending commands must be present </li></ul><ul><li>Motor pools must be recruited at appropriate times </li></ul><ul><li>Muscle contractions must drive movement, eliciting sensory feedback </li></ul>
  14. 14. Proposed Interventions <ul><li>Mechanical </li></ul><ul><li>Physiological </li></ul><ul><ul><li>Goal: Promote appropriate motor neuron firing in response to decreased excitatory input </li></ul></ul><ul><ul><li>Method: Increase excitability through motor neuron intrinsic properties </li></ul></ul><ul><li>To form/strengthen new functional circuits: </li></ul><ul><li>Descending commands must be present </li></ul><ul><li>Motor pools must be recruited at appropriate times </li></ul><ul><li>Muscle contractions must drive movement, eliciting sensory feedback </li></ul>
  15. 15. Peripheral electrical stimulation can modulate motor pool excitability <ul><li>Non-invasive stimulation over a muscle or nerve: </li></ul><ul><ul><li>Causes recruitment and continued activation of homonymous motor pool </li></ul></ul><ul><ul><li>Inhibits recruitment of the antagonist motor pool </li></ul></ul><ul><li>Likely due to modulation of persistent inward currents, an intrinsic property of neurons </li></ul>(Dean et al., 2008)
  16. 16. Motor pool modulation during gait may promote plasticity <ul><li>Increased excitability will allow motor pool recruitment with weaker descending commands (thus strengthening connections) </li></ul><ul><li>Decreased excitability will prevent strengthening of non-functional connections </li></ul>(Hof et al., 2002)
  17. 17. Stimulation can be driven by mechanical feedback <ul><li>May be used either in combination with or independent from mechanical intervention </li></ul>(Hof et al., 2002)
  18. 18. Conclusions <ul><li>Gait rehabilitation outcomes may be improved through neural plasticity by: </li></ul><ul><ul><li>Mechanical interventions allowing residual control to power walking </li></ul></ul><ul><ul><li>Physiological interventions promoting appropriately timed motor pool recruitment </li></ul></ul><ul><li>Anticipated issues: </li></ul><ul><ul><li>Ability of non-invasive techniques to form neural connections is limited </li></ul></ul><ul><ul><li>Application of these ideas to clinical populations </li></ul></ul>
  19. 19. Optimizing Gait Rehabilitation: How Can Nervous System Plasticity Be Harnessed? Jesse Dean 3.24.10

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