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IMAD FES Principles & Applications Chung-huang Yu Intelligent Mechatronic Assistive Device Lab Department of Physical Therapy and Assistive Technology.

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Presentation on theme: "IMAD FES Principles & Applications Chung-huang Yu Intelligent Mechatronic Assistive Device Lab Department of Physical Therapy and Assistive Technology."— Presentation transcript:

1 iMAD FES Principles & Applications Chung-huang Yu Intelligent Mechatronic Assistive Device Lab Department of Physical Therapy and Assistive Technology National Yang Ming University

2 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University What is Electrical Stimulation (ES)? Electrical Stimulation cause muscle contraction

3 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Can we make ES functional? Yes! (theoretically) Why, in theory? In body, very movement is actuated by muscle contraction. Why, in practice? Independence & Quality of Life Maintain muscle volume Improve physiological condition Psychological Benefit

4 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University The terms Functional Electrical Stimulation (FES) Functional Neuro-Muscular Electrical Stimulation (FNMES) A technique that utilizes patterned electrical stimulation of neural tissue with the purpose of restoring or enhancing a lost or diminished function

5 iMAD What have been done?

6 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University What muscle type have been targeted? skeletal distal muscles axial muscle (few - diaphragm) smooth bladder bow sexual organ cardiac (pacemaker)

7 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University What have been done on limb muscles? upper-limb hand grasping & release hand orientation (wrist, elbow, shoulder) whole upper-limb(s) -> not yet lower limb ankle (drop-foot - dorsiflexor) knee (standing - quadriceps) whole leg (standing, walking, cycling)

8 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Epilepsy control Tremor control Phrenic pacing Control of reaching and grasping Scoliosis control Muscles exercise Control of standing and walking Spasticity reduction Vision restoration Cochlear implant Cardiac pacing Bowel emptying Bladder empting and control of incontinence Wound healing Pain suppression Applications of Electrical Stimulation

9 iMAD Some examples

10 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University  The history of FES before 19th century

11 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Liberson, et al 1961 First registered FES work

12 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Parastep (Sigmedics Inc.)

13 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Parastep System Components

14 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University

15 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Freehand

16 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University

17 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Restoration of hand function in C5-6 tetraplegia and CVA Wrist movement must be preserved 3 channels self-adhesive electrodes over motor points Conductive panels in the glove make contact electrodes Control: wrist movements (tenodesis) sensed by a transducer Wrist flexed > extensors tension > hand opens Wrist extended > flexors tension > hand closes Independent Don-Doff Bionic Glove

18 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Lower Limb: Odstock foot drop stimulator One channel stimulator Stimulation: common peroneal nerve at head of fibula (TA) or popliteal fossa (withdrawal reflex) Heel switch trigger: Heel off > stimulation ON Heel on > stimulation OFF Rise and fall stimulation envelope can be adjusted Odstock 2 Channel Stimulator (O2CHS) for bilateral dropped foot

19 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Handmaster (NESS, Israel)

20 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University How can we make it functional? The key aspects Understand Human Sensory-Motor System Residual capacities Paralysis Define what “Normal” functions to restore How to meet the gap?

21 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Human Sensory-Motor System Visual Vestibular Skin: Touch, Pressure, Vibration Posture & Balance (Braim Stem) Reach & Fine Movement (Motor Cortex) Program Movement (Supplemental & Premotor) Planning, coordination (Cerebellum & Basal Ganglia) Golgi: Force Capsule: Extreme Angle Spindle: Length, Velocity Feed forward: 1. Synergistic 2. Antagonist Reflex (stretch, withdraw, inverse myotatic) Central Pattern Generator Motor Control CNS Muscles Motor Neuron Muscle Fibres Spinal Cord Corticospinal tract Sensory Nerve Sensory Feedback    

22 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University What are “normal” functions? Is it necessary to be “normal”?

23 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Types of Functions Functional Types Kinematically open Kinematically closed Functional Requirements State change Sit-to-stand, drop-foot Constant regulation Sit-to-stand, drop-foot Functional Joint Involved Single Joint v.s. Multiple Joint Single d.o.f. vs. Multiple d.o.f. Single limb v.s. Multiple limbs.

24 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University How can we make ES functional?

25 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Artificial Parts in an FES system Stimulator Controller Sensors

26 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Stimulator :The Physiological basics (1)? Why electrical stimulation cause contraction? What relations between muscle contraction and stimulation pattern? What stimulation parameter? Unipolar v.s. Bi-phasic Element waveform? Pulse width, height

27 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Stimulator: Physiological basics (2)? What stimulation parameter? Single pulse, doublet, triplet, etc. Frequency between elements Fixed v.s. Sweep Overall envelop Muscle Response threshold, saturation, in-between shape short term effect (fatigue) long term effect (muscle transfer, volume, etc.

28 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Problems/Difficulties of Paralyzed Muscle (1) Excitable? Spasiticity What is the response to stimulation? Stimulation Force

29 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Problems / Difficulties of Paralyzed Muscle (2) Individual motor unit (David Winter, 1990)

30 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Problems / Difficulties of Paralyzed Muscle (3) Muscle Group Selectivity Surface electrode (rough, limited muscle sites, high working power, don-doff, etc.) implant electrode (invasive, large number of electrodes, breakage) recruitment sequence size principle F voluntary >> F implant >> F surface F normal >> F paraplegic

31 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Problems / Difficulties of Paralyzed Muscle (4) Muscle Group Biarticular Muscle n-n & non-linear mapping between stimulation and response Muscle Itself Fatigue Time-Varying short-term long-term (muscle type change)

32 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University

33 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University

34 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University What do we want to control? stationary position withdraw trajectories accelerations joint moment joint stiffness contact forces Contact Slip reactions forces

35 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Control Strategies Functionally automatically triggered OpenDrop-foot (foot switch) CloseCycling (crank angle) Functionally automatically regulated CloseCHRELMS Artificially triggered Open Handmaster Close Demark (slip),

36 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Difficulties in Sensor system Why sensors in a FES system Feedback control Command controller Artificial sensors limited type limited number limited accuracy don-doff Natural sensors (Nerve cuff) Demark & Canada Group

37 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Three levels of concern Command Source Natural, subconscious Artificial, Volitional Command Type Trigger Regulation Artificial control Open-loop Close-loop (position, trajectory, force, slip, COG, etc.)

38 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Object of an FES system: Real- time and Patient Driven Real-time regulation Sensors position of joint contact forces Automatic Controller what algorithm Patient Driven What capacities to use? Command controller?

39 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Application of FES systems User capacity and paralysis Target function analysis Stimulation Patterns System Modeling Control Strategies Other considerations Safety, Economy, Cosmetic, Don-doff etc.

40 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Conclusions FES systems as orthosis based on superficial stimulation still have low acceptance due to practical reasons: long Don-Doff time, electrode positioning, braking parts, high EC/efficiency ratio, complicated to set and adjust -> Implants After periods of FES training patients show carry over effects -> FES devices can be used as therapeutic tool combined with conventional physiotherapy Functional Electrical Therapy (FET)

41 iMAD Design Example: CHRELMS Restoration of standing function to paraplegic by Functional Electrical Stimulation

42 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University FES standing/walking FESNormal Oxygen cost (ml/kg/m) Speed (m/min)6085 Heart Rate (beats/min)11895 Use of upper Extremities23%0% Cost (NT$500,000)

43 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Why FES walking at all? 8 Simple forward progressing only 8 Short distance, i.e. fatigue quickly 8 high energy 8 still wheel chair dependent 8 high cost 4 Cardiovascular 4 bone loading 4 muscle exercise Psychological Effect

44 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Long term Goals: Good standing Standing up: at will, trajectory, speed Standing: longer, more comfortable, maneuvers Sitting down: controlled descent Good walking long distance walk walk in community (different surface) different direction, step length, speed

45 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University But paraplegics do stand ! Supported Standing  Free-hand Standing Example: vertical back standing up

46 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Kinematics Analysis: controllable ? d.o.f. =3 (not 6)

47 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Kinetic Analysis: Force Balance

48 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Novel Concept: Deficit as control signals Leg moment produced from Upper-body u Upper-body Activities u Control Signals (later)

49 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Proposed Control System Deficits as error signals for artificial control Advantages: Patient driven natural error signals for each joint each axis no anthropometric data required less demanding of sensors handle reactions joint positions

50 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Theoretical Difficulties and Assumptions Leg Joints in alignment -> maneuver Mapping to desired muscle -> brain Bi-articulator muscles Muscle force change with length & velocity Muscle fatigue Static Indeterminacy -> (Discussed Later)

51 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University System Setup

52 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Software: controller

53 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Software (LabVIEW)

54 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University

55 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University

56 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University

57 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University The subject l Subject : TC (8 years after accident) l Gender: Male, Age: 49 l Height: 1.85 m, Weight: 85 kg l Lesion: T6 complete l FES standing user for 7 years l Asymmetry: left thigh is 5 cm shorter l Crooked Spine l Remarried during our experiment period

58 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Control Parameters Three channels each leg (i.e. gluteus, quadriceps, calf) Static Indeterminacy Conjugate Matrix Control Parameter Tuning I = 0.3, 1, 3

59 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University

60 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University CHRELMS : Standing Up Consistent timing -> enable to learn “Quick Knee Locking” Able to half-stand Asymmetry Better Control but not smaller force

61 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Standing maneuver Posture Switching- Prolong Standing Swaying Forward Swaying Backward Swaying Leftward Swaying Rightward Free-one hand Bending the knees

62 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University

63 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University CHRELMS : Sitting down “Knee moment reduction” strategy 40.2% Moment due to Body Weight 89.5% Rate of Moment Change “Release & Re-catch” Prefer

64 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Conclusion for the Controller Deficits provide 3D signals but 2D seems enough No preset mode/function Perform different tasks with the same control parameter Control of speed Feel of lower limbs with ability to correct posture

65 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University Conclusion of the Study Deficits: better understanding of paraplegic standing Control system simple & effective user preference potentially practical Supported Standing should be considered by overall system level

66 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University The future of an FES system? Advance of Electronic technique: System-on-Chip Micro Sensors Micro Stimulator Wireless System Collaboration of Multi-disciplines Engineers Clinical members Patients

67 iMAD Department of Physical Therapy and Assistive Technology (Institute of Rehabilitation Science & Technology), National Yang Ming University. National Yang Ming University FES clinic


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