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An Introduction to Functional Electrical Stimulation

An Introduction to Functional Electrical Stimulation. Presented by: Fereshteh Lagzi. Presentation Agenda. Introduct ion History of FES FES systems main components Electrodes Muscles, Neural and electrical stimulation Examples of Commercial systems. ES applications.

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An Introduction to Functional Electrical Stimulation

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  1. An Introduction to Functional Electrical Stimulation Presented by: Fereshteh Lagzi

  2. Presentation Agenda • Introduction • History of FES • FES systems main components • Electrodes • Muscles, Neural and electrical stimulation • Examples of Commercial systems

  3. ES applications

  4. اراده و هوشياري كاربر واسط كاربر- سيستم فرامين ارادي پردازش‌گر و كنترل‌گر فرامين فيدبك سيستم منبع تغذيه پارامترهاي تحريك تحريك كننده اتصالات الكترودها الكترودها تحريك حسگر نيرو انقباض عضلاني حركت حسگر موقعيت موقعيت مفصل FES system’s main components

  5. Nerve Muscle Pulse amplitude Pulse width Muscles neural ans electrical Stimulation • Skeletal Muscle fibers: Type I : red, slow, aerobic • Type II : white, fast, anaerobic • Alpha motor neurons: • small alpha motor neurons : innervate slow muscle fibers • large alpha motor neurons : innervate fast muscle fibers

  6. Muscles neural ans electrical Stimulation • Muscle contraction mechanisms: • recruitment : • activation of an increasing number of motor units within a • muscle on contraction • temporal summation : • increasing firing rate of active motor units • During voluntary activation, recruitment and temporal summation are two • mechanisms that regulate the strenght of muscle contraction, and usually • these mechanisms act simultaneously

  7. Polarizable electrodes: Ag Nonpolarizable electrodes: Ag_ AgCl Types of Electrodes

  8. Electrode- Tissue Behavior

  9. Electrode- Tissue Behavior

  10. Electrode Operating Characteristics

  11. Electrode Operating Characteristics

  12. Electrode Operating Characteristics

  13. Electrode Operating Characteristics

  14. Current wave forms

  15. Electrode Material • In choosing the material for an electrode the following factors are of importance: • (1) Passive compatibility of the material with tissue • (2) Extent of reversible behavior • (3) Mechanical compatibility with the tissue

  16. Electrode Placement • (1) (2) (3) (4) (5) • (1) Skin Surface Electrode • (2) Epimysial Electrode • (3) Nerve Cuff Electrode • (4) Percutaneous Intramuscular Electrode • (5) Intramuscular Electrode

  17. Electrodes • Nerve Cuff Electrode • Wrapped-around Electrode • Wrapped-around Electrode • Epimysial Electrode • Electrode • Electrode • Percutaneous Intramuscular Electrode

  18. The main goal of multilayer construction of the self_adhesive electrode is to provide a balanced most equally distributed stimulation current density over the whole electrode to prevent the skin from burns. Surface Electrode

  19. This automatic spiraling electrode is designed to form to the natural shape of the nerve. The cuff electrode has four contracts that can be grouped together to create a stimulation that will activate groups of muscles. Nerve Cuff Electrodes

  20. This electrode has a tandem conductor close coiled lead wire from the connector, covered with a silicone tube (“closed helix”). The epimysial electrode terminates in a Pt-10 Ir disk mounted in a silicone backing reinforced with dacron. Epimysial Electrodes

  21. The intramuscular electrode has a stainless steel stimulating area wound around the distal end of the lead. Percutaneous Intramuscular Electrodes

  22. Cuff Electrode

  23. Cuff Electrode

  24. Cuff Electrode

  25. Cuff Electrode

  26. Cuff Electrode

  27. Cuff Electrode

  28. Surface Electrode

  29. Surface Electrode

  30. Recruitment : Surface Electrode

  31. Recruitment : Surface Electrode

  32. ElectricFieldBetween a Positive and Negative Electode

  33. Nerve Excitation • Model of myelinated fiber

  34. Secondary Pulse Considerations

  35. Excitation of Myelinated Nerve • myelinated nerve fiber to a point source stimulation

  36. Excitation of Myelinated Nerve

  37. Excitation of Myelinated Nerve

  38. Excitation of Myelinated Nerve

  39. Motorresponse

  40. Recruitment Regimen

  41. Examples of: Commercial FES Systems

  42. HandMaster • Nathan • Israel • 1990 • Electrodes: Surface (5) • Commands: External • Lateral & Palmar Grasp • NESS Ltd. • Available commercially

  43. Bionic Glove (1996) • Prochazka • Univ. of Alberta • Canada • 1996 • tenodesis Bionic Glove is OFF • Bionic Glove is ON

  44. FreeHand • (?) Kilgore KL, Pekham PH • Case Western Reserve University • OH, USA • 1998 • Electrodes: (?) Epimysial • Sensors: (?) • Latera & Palmar Grasp • NeuroControl Corp.

  45. FreeHand (1999) • Case Western Reserve University

  46. FreeHand (2000) • Case Western Reserve University

  47. BION (USC-2000) • G. Loeb • Univ. Of Southern California • 2000 • Electrodes : Intramuscular • Weight: 0.75 grams • Dimentions: 3 mm x 28 mm • Advanced Bionic Corporation • (for investigation use only)

  48. BION (USC-2000)

  49. THANK YOU VERY MUCH For your Attention

  50. Nerve Trunk Anatomy

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