9/14/2011. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 1 Development of Complex Curricula for Molecular Bionics and Infobionics Programs within a consortial* framework** Consortium leader PETER PAZMANY CATHOLIC UNIVERSITY Consortium members SEMMELWEIS UNIVERSITY, DIALOG CAMPUS PUBLISHER The Project has been realised with the support of the European Union and has been co-financed by the European Social Fund *** **Molekuláris bionika és Infobionika Szakok tananyagának komplex fejlesztése konzorciumi keretben ***A projekt az Európai Unió támogatásával, az Európai Szociális Alap társfinanszírozásával valósul meg. PETER PAZMANY CATHOLIC UNIVERSITY SEMMELWEIS UNIVERSITY sote_logo.jpg dk_fejlec.gif INFOBLOKK Peter Pazmany Catholic University Faculty of Information Technology www.itk.ppke.hu DOMONKOSHORVÁTH, BÁLINT PÉTER KEREKES and GYÖRGY KARMOS NEURAL INTERFACES AND PROSTHESES Neurális interfészek és protézisek LECTURE3 FUNCTIONAL MUSCLE AND NERVE STIMULATION (Funkcionális izom-és idegingerlés) NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) FUNCTIONAL ELECTRICAL STIMULATION • Definition: functional electrical stimulation is a technique that uses electrical currents to activate nerves innervating extremities affected by paralysis • Most common origins of paralysis:• Spinal cord injury • Head injury • Stroke • Other neurological disorders • Types of paralysis:• Paraplegia: both upper or both lower limbs are paralyzed • Tetraplegia: all four limbs are paralyzed • Hemiplegia: left or right side of the body is paralyzed 2011.09.14.. TÁMOP–4.1.2-08/2/A/KMR-2009-0006 3 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • Nerve stimulation: achieved by passing current between two or more electrodes implanted into the body or placed on the skin surface • Design: appropriate spatial and temporal patterns of stimulation must be determined in order to produce real functional nerve activation • Both nerve responses and stimulus properties must be understood for effective design 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 4 FUNCTIONAL ELECTRICALSTIMULATION(FES) NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) PROPERTIES OF ELECTRICAL STIMULATION • In FES, stimulation is extracellular, i. e. stimulating electrodes are placed outside the neurons and nerves 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 5 I0: single current point source placed at a distance hfrom a circular cylindrical fiber 2L: length of fiber a: radius of fiber .i: intracellular conductivity .e: extracellular conductivity z: fiber centerline axis .z: fiber element for numerical calculations http://www.ece.mcmaster.ca/~ibruce/courses/ECE795_2008/ECE795_lecture09.pdf NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • The effect of the point source can be described with the following equation: • .a: extracellular potential field • I0: current strength • .e: extracellular medium conductivity • r: distance from the source to an arbitrary field point • Effect of the fiber on the field is ignored. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 6 PROPERTIES OF ELECTRICAL STIMULATION NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • Transmembranecurrent induced by the stimulation must be equal tothe intrinsic ionic current plus the capacitive current of the membrane. • This can be fitted into the following equation: • ri: intrinsic membrane resistance • im: transmembrane current • .i: membrane potential • z: coordinate along the fiber centerline axis (see Slide 5) • See reformatted equation with ionic and capacitive membrane currents on next slide. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 7 PROPERTIES OF ELECTRICAL STIMULATION NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • Replacing .iby vm+.eand imby iion+cm.vm/.tin the previous equation gives the following: • At rest, vm=0 for all z • This means: .2vm/.z2=0 and iion=vm/rm • As a consequence, the first application of stimulus can be described as follows: 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 8 PROPERTIES OF ELECTRICAL STIMULATION NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • According to the previous equation, excitation is possible at the region where .2.e/.z2is positive because this makes .vm/.tinitially positive. • Thus, it is also true conversely that regions where .2.e/.z2is negative are hyperpolarized because this makes .vm/.tinitially negative. • Because of its role in the activation or inhibition of the membrane section, the function .2.e/.z2is called the activating function 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 9 PROPERTIES OF ELECTRICAL STIMULATION NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 10 PROPERTIES OF ELECTRICAL STIMULATION Neural_2_9.jpg Time evolution of induced transmembranevoltage along a fiber. Different curves represent different stimulus durations in milliseconds. Fiber structure is shown on Slide 5, h=0.02 cm. http://www.ece.mcmaster.ca/~ibruce/courses/ECE795_2008/ECE795_lecture09.pdf NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • Conclusion: a space clamped membrane patch and a whole fiber react differently on different durations of an external point stimulus • Space clamped membrane patch: threshold potential relatively independent of stimulus duration • Whole fiber: higher threshold for shorter stimulus duration. This effect is stronger when the source is close and weakens when the source is move further from the fiber. • These effects result from the hyperpolarized regions flanking the depolarized region. • The flanking hyperpolarized regions can block action potential generation along the fiber. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 11 PROPERTIES OF ELECTRICAL STIMULATION NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 12 TYPES OF ELECTRICAL NERVE STIMULATION Neural_2_13.jpg NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 13 EFFECTS OF ELECTRICAL STIMULATION Neural_2_14.jpg Current-force relation at nerve stimulation NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 14 EFFECTS OF ELECTRICAL STIMULATION Neural_2_13b.jpg Current-force relation at muscle stimulation NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 15 EFFECTS OF ELECTRICAL STIMULATION Charge production threshold for nerves and muscles: threshold is much lower in nerves than in muscles http://www.ece.mcmaster.ca/~ibruce/courses/EE3BA3_presentation04.pdf NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 16 EFFECTS OF ELECTRICAL STIMULATION Representation of current density at nerve stimulation Functional Electrical Stimulation: A Practical Clinical Guide (2nd Edition). Benton, Baker et al., 1981 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 17 EFFECTS OF ELECTRICAL STIMULATION Functional Electrical Stimulation: A Practical Clinical Guide (2nd Edition). Benton, Baker et al., 1981 Effect of stimulus frequency on fatigue NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) Neural_2_17a.jpg 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 18 STIMULUS WAVEFORMS Neural_2_17b.jpg Neural_2_17c.jpg Monophasic The monophasicwaveformstend to be asymmetric biphasic as the net charge built up in the body by the waveform discharges Biphasic charge balanced NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 19 UPPER LIMB FES SYSTEMS Neural_2_18a.jpg Schematicof a typical upper limb FES system http://www.rehab.research.va.gov/jour/02/39/3/Bhadraf1.jpg NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 20 UPPER LIMB FES SYSTEMS Different electrodes typically used in upper limb FES systems Sixteen channel implantable stimulator developed for upper and lower limb FES systems http://fescenter.org/images/stories/press/Report_to_the_Community_2010.pdf NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • Developed at Case Western Reserve University, Cleveland, Ohio in 1986 • Given FDA approval for general use in 1997 • System overview:• Shoulder position sensor implanted into non-injured shoulder • External control unit: receives shoulder position information and computes stimulation pattern based on it. • Implanted stimulator: receives stimulation pattern from external controller via a transmitting coil and stimulates implanted electrodes via electrode leads • Electrodes: implanted into arm and wrist muscles to stimulate them according to the pattern received from the stimulator • Programmable to six different movements, including palmarand lateral grasp 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 21 FREEHAND SYSTEM NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 22 FREEHAND SYSTEM http://www.sci-recovery.org/sci-therapies.htm Schematic of Freehand system components NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 23 FREEHAND SYSTEM X-ray pictures showing implanted Freehand system components NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 24 FREEHAND SYSTEM IN USE Patient applying make up with help of her implanted Freehand system NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • Developed by NESS Ltd., Israel in 2004 • Originally called Handmaster • Non-invasive prosthesis: no implanting operation needed • Two parts: orthosisand microprocessor • Orthosis: external stimulating device applied on forearm and wrist • Stimulates four different muscles in forearm wrist through the skin • Microprocessor: computes stimulation patterns for different tasks 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 25 NESS H200 SYSTEM NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 26 NESS H200 SYSTEM Orthosis Microprocessor Patient using her NESS H200 system http://www.ectron.co.uk/Neuro_Rehabilitation/ http://medgadget.com/2006/04/ness_h200_syste.html NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • Developed at the University of Alberta in 1996 • Non-invasive device • For patients with intact wrist moving capabilities • Electrodes placed on skin over wrist • Sensor records wrist movements, transmits the data to the microprocessor • Microprocessor computes finger stimulation patterns based on wrist movement data • Stimulator stimulates electrodes placed over wrist • The whole system can be worn on a glove on wrist 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 27 BIONIC GLOVE NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 28 BIONIC GLOVE http://www.ualberta.ca/~aprochaz/bgtemp.html Patient using his Bionic Glove NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • Developed at the Belgrade University in 2001 • Not only wrist and forearm but also elbow stimulation • Non-invasive, uses skin surface electrodes 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 29 BELGRADE GRASPING SYSTEM Patient using Belgrade Grasping System (left) and electrode placement for grasping function (right) NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • Developed at the Technical University of Zurich in 2000 • Restores hand grasping function • Patient controls the external control unit by hand 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 30 ETHZ-PARACARE NEUROPROSTHESIS ETHZ-Paracaresystem components (left) and Patient using ETHZ-Paracaresystem for grasping (right) NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • Developed by Advanced Bionics Corporation in 2005 • Implantable, battery powered microstimulator • Small enough to be able to be implanted into a muscle or near a nerve • Recharging and communication through a magnetic transmission coil • Several different uses: chronic pain, bladder function restoration, shoulder subluxationtreatment 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 31 BION MICROSTIMULATOR Demonstrating the size of a BION microstimulator NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 32 BION MICROSTIMULATOR Block diagram of BION 1, the first version of BION stimulators The latest version of BION stimulators NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • Shoulder subluxation: paralyzed shoulder joint (for example in stroke survivors) lets the humerusto leave the cotyleof shoulder which causes pain • Stimulation of shoulder joint keeps humerusin the cotyleand reduces pain • BION stimulator implanted into shoulder to provide stimulation • 6 hours/day stimulation 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 33 BION MICROSTIMULATOR FOR SHOULDER SUBLUXATION TREATMENT Shoulder subluxationtreatment (top) and electrode position in shoulder (bottom) NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • DevelopedattheRehabilitationInstitute of Chicago in2006 • Fullarmprosthesisforupperlimbamputees • Prosthesisattachedtotheshoulder • Looseendsof armmotor and sensorynervesre-innervatedintochestusingtechniquecalledtargetedre-innervating • Smartercontrolof prostheticarmpossiblewithregainingsenseoftouch: prostheticarmmovedwiththemovementofchestmusclesand armsensorynervesre-innervatedintochestsensorynerves • Twoveteransalreadyusethesystem 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 34 BIONIC ARM NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 35 BIONIC ARM Kuiken, TA; Miller, LA ; Lipschutz, RD ; Lock, BA; Stubblefield, K; Marasco, PD; Zhou, P; Dumanian, GA; Targeted reinnervationfor enhanced prosthetic arm function in a woman with a proximal amputation: a case study, LANCET, 369 (9559): 371-380 FEB 3 2007 Schematicof targetedmotoricre-innervation(top) and targetedsensoryre-innervation(bottom) NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 36 BIONIC ARM Kuiken, TA; Miller, LA ; Lipschutz, RD ; Lock, BA; Stubblefield, K; Marasco, PD; Zhou, P; Dumanian, GA; Targeted reinnervationfor enhanced prosthetic arm function in a woman with a proximal amputation: a case study, LANCET, 369 (9559): 371-380 FEB 3 2007 Mapsof surfaceelectromyogramamplitudeforfourdifferentmovements NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 37 BIONIC ARM www.ric.org PatientswearingtheirBionicArmprosthesis NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • European researchproject withinstitutionsfromItaly, Spain, Germany, Denmark • Led byScuolaSuperioreSant’Anna, Pontedera, Italy • Aimstodevelopa complexsystemimplementingseveralfunctions: • Efferentand afferentregeneration-typeelectrodes • Implantablesystemforneuralstimulationand recording • Efferentand afferenttelemetriclinks • "Biologically-inspired" mechatronichand • Biomimeticsensors • Externalunit fordecodingpatient'sintentionsand forprosthesiscontrol • System todeliverthecognitivefeedbacktothepatient 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 38 CYBERHAND PROJECT NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 39 CYBERHAND PROJECT Prototypeof CyberHand(left) and illustrationsof implementedfunctions(right) NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • DevelopedbyTouchBionicsInc. in2008 • Usesmyoelectricsignalsrecordedfromskinsurfacetocontrolhandand fingers • Firstupperlimbprosthesisthathas fiveindividuallypoweredfingers • Implementsfourdifferentgrippatternsand twograsps • Has differentcolourskin-likecoverings 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 40 I-LIMB HAND ilimbhand1.jpg ilimbhand2.jpg www.touchbionics.com NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 41 STIMUSTEP™ IMPLANTED DROPPED FOOTSTIMULATOR Strains the flexor muscles of the ankle when the foot is not on the floor. Developed by the University of TwenteandRoessinghResearch. & Development inHolland in collaboration with the UK based company, Finetech-Medical Ltd. sus1 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) FUNCTIONAL ELECTRIC STIMULATION OF A PARAPLEG PATIENT • 8 channel • stimulation pattern making for every individual person • changeable parameters:• Frequency: 1-200Hz (1Hz step) • Current: 0-130mA (1mA step) • Impulse width: 10us-1ms • Impulse type:• unipolar • bipolar • Data gathering to SD card 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 42 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) FES CYCLING 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 43 cicling NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) FES CYCLING Muscle contraction is an electrochemical process that is stimulated by an electric current and propagated through nerve and muscle cells. When an electrical potential is applied between two electrodes placed on the surface of the body electric current passes from one electrode to the other through the tissue. If the tissues contain any muscles they will contract during the passage of the electricity and relax when it stops. By controlling the timing of the electrical impulses and the positioning of the electrodes it is possible to create various patterns of muscle contraction and relaxations that can enable a paralysed limb to perform a function. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 44 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) http://www.ece.mcmaster.ca/~ibruce/courses/EE3BA3_presentation04.pdf 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 45 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 46 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) WALKING MOBILITY SYSTEM Implantable Reciever Stimulator External Control Unit Clinical Interface Target Muscles: Vastus lateralis Gluteus Maximus Semimembranosus Erector Spinae Tibialis Anterior Iliopsoas Sartorius TFL 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 47 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) IMPLANTED PATIENTS 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 48 jen_medium NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) SWISSFEDERALINSTITUTE OF TECHNOLOGYDept. of InformationTechnologyand ElectricalEngineering 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 49 http://control.ee.ethz.ch/~ncg/previous_projects/neuroprostheses.php FESRoller NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 50 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) ERIGO TILT TABLE WITH INTEGRATED ROBOTIC STEPPING SYSTEM Movementtherapyandloadingofthelegsareimportantelementsintherehabilitationofbed-riddenneurologicalpatients.Thedevelopmentofatilttablewithanintegratedsteppingsystemprovidesphysiciansandtherapistswiththeopportunitytodointensivemovementtherapyoflegscombinedwithverticalization.Accordingly,theErigoallowstwoapprovedformsoftherapytobeaccomplishedatthesametime.TheErigothereforesupportsandfacilitatesthemobilizationofbed-riddenpatients. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 51 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) Rehabilitation technique, to fortificate the muscles using the whole body. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 52 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) LOKOMAT BODY WEIGHT SUPPORTED TREADMILL TRAINING TheLokoliftisanelectronicallycontrolledbodyweightsupportsystemfortreadmilltrainingthatallowsaconstantandprecisebodyweightsupport.Theuser-friendlypatienthandlingthroughtheuserinterfaceallowsthetherapisttochangetheweightsupportofthepatientwithouthavingtostopthetraining.Basedonaclosedloopcontrol,theweightsupportismeasuredexactly,registeredbythecomputerandsenttothedrivesfortheadjustmentoftheweightsupport.Theintegrateddrivesprovidealow-inertiamovementandallowaphysiologicalgaitthatsupportsasuccessfulrehabilitationprocess. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 53 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) FUTURE DIRECTIONS LOWER EXTREMITY SYSTEMS • Ambulation • Closed loop control for balance and posture • New fundamental aproaches to interfacing with the nervous system • Incomplete spinal cord injury for ambulation • Combination therapies 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 54 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) REQUIREMENTS OF A PRACTICAL FES SYSTEM (electrical orthosis) 1.ShouldbeSimpletoputonandputoff(DonandDoff) Thisisvitalasitwilltoalargeextentdeterminetheamountofuseandhowmuchthepatientwillgetoutoftheirsystem.Thiswilllimitthenumberofconnectionsandleadsthatareexternaltothebody. 2.FunctionmustbeRelevanttotheUser Somefunctionsseemtohave'obvious'relevancetoanyone.Butevenafunctionlikestandingmaybeofverylittleusetoparaplegicinadaptedaccommodation. 3.SystemmustConsistentlyProvidetheDesiredFunction Theelectricalorthosismustprovidethedesiredfunctionunderarangeofworkingconditionsbothexternal,e.g.location,andinternal,e.g.electrodepositioning. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 55 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 4.TheSystemmustincludetheUser Theconditionoftheuser'smuscles,bones,ligamentsandcardiovascularperformanceareofvitalimportanceinensuringthattherequiredfunctioncanbeattainedsafelyandrepeatably. 5.UsermustbeAwareoftheLimitationsoftheSystem Itmustbeensuredthattheuserhasrealisticexpectations.Withopen-loopsystemstheusershouldunderstandtheproblemsthatmayoccur,egwithfatigue,andrealisehowthesewillaffecttheperformanceofthesystem. 6.UsermustUnderstandCommittmentRequiredtoMaximisetheBenefits Generallyalongtermcommitmenttoatrainingprogram(>3monthsfor"sittostand")isrequired. 7.SystemshouldIdeallybeFailSafe Atpresentthisisnotalwayspossible,e.g.howdoesonemakeanelectricalstimulationonlystandingsystemfailsafe!Withopen-loopsystemstheusershouldpossessthestrength/controltocopeintheeventofasystemsfailure.Thedegreetowhichfailureisdangerousdependsonthesystem-butthepossibilityoffailureneedstobecarefullyconsideredinprogrammingthestimulator. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 56 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) Apracticalelectricalorthosisconsistsoftwocomponents.First,areliableandadaptablesystemcapableofrespondingtochangingparameters.Second,atraineduserwiththenecessarymotivation. Bothpartsareofequalimportance! 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 57 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) Annualandcumulativecostsofbladderandbowelcareafterspinalcordinjuryarereducedaftercombinedsacraldorsalrootrhizotomyandimplantationofasacralanteriorrootstimulatorforbladderemptying.Cumulativecostsofbladderandbowelcareafterspinalcordinjury:comparisonoftraditionalandelectricalstimulationtreatment. Jezernik et al., Neurological Research, 2002, 24: 413-430. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 58 BOVELCONTROL NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 59 Systems Spinal segment Periferial descending Stimulus effect Parasympatic S2 -S4 Nervuspelvicus Bladder depleteing muscle contraction. Inner sphincter yielding (the bladder deplete). Sympatic Th11-L2 Nervus hypogastricus Bladder depleteing muscle yields. Urethra contraction. Inhibition of the parasimpatic ganglions (retention) Motoric S3 -S4 Nervus pudendalis Urethraspinchtercontraction. BLADDER INNERVATION NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • Whenthethoracicspinalcordisinjured(crosswiselesion),firstcompleteretention,andthenautomaticalbladderdevelops:thereisnoinvoluntarybladder,butthebladderautomaticallyeliminated,ifitreachesalimit,buttheexcretionisnotperfect. • Ifthesacralspinalcord(S2-S4)isdamaged,thewallofthebladderbecomesatonical,thereforeawideningofthebladderandurinaryretentiondevelops,withincontinence(autonomousbladder). • Ifthesensorypartofthesacralreflexarcisdamaged,thentheneedofurinationandthebladderreflexceases. • Thebladdersaturatesandincontinence(ischuriaparadoxa)develops. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 60 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) •Reflexincontinence:completespinalcordlesion,thereisnosensorystimulus • Pressureincontinence:Detrusorinstability, • Stressincontinence:pl.effectofcoughonsetofurination • Sacralanteriorrootstimulation(SARS):thickfiberstothebladdersphincter,thinpreganglionarparasympatheticfiberstothebladder. Solution:repetitivshortstimulusseries • Extraduralstimulation:mostlyafterposteriorrootcutoff • Neuromodulation:(MedtronicInterstim) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 61 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) REGULATE THE BLADDER OPERATIONOF INTERVENTION Bladder innervation, posterior rhizotomy site (transection of sacral dorsal roots to abolish bladder hyper-reflexia and detrusor–sphincter dyssynergia), and location of extradural electrodes for sacral anterior root stimulation to produce bladder contractions and bladder emptying. http://www.ece.mcmaster.ca/~ibruce/courses/ECE795_lecture10.pdf 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 62 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) Spinal reflex pathways controlling the lowerurinarytract. Electricalstimulationoflargepudendalafferentsinhibitsparasympatheticactivitytothebladder.Suchstimulationcanbeachievedbyimplantedelectrodes(sacralafferentstimulation)orbytranscutaneouselectricalstimulation(analandvaginalplugelectrodes,dorsalpenileorclitorialelectrodes). Jezernik et al., Neurological Research, 2002, 24: 413-430. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 63 THE SPINALREFLEXINFLUENCEWITH THE ELECTRICAL STIMULATION OF N.PUDENDALIS NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) REDUCED BLADDER CAPACITY DEMONSTRATED IN A CONTROL CYSTOMETROGRAM (CMG) OF A SPINAL CORD INJURED PERSON Jezernik et al., Neurological Research, 2002, 24: 413-430. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 64 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) REDUCED BLADDER CAPACITY DEMONSTRATED IN A CONTROL CYSTOMETROGRAM (CMG) OF A SPINAL CORD INJURED PERSON • A:Control, • B:Increaseinthebladdervolumeduringacystometryperformedduringacontinuouslyappliedelectricalstimulation(15Hzstimulationfrequency,200µsecpulsewidth). • C:Meanchangeinthebladdercapacityobtainedduringaseriesofcystometries.Cystometrogramsthatweremeasuredwithneuromodulationswitchedonareindicatedinthemiddleofthegraph.Thecarry-overeffectsofneuromodulationcanbeobserved. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 65 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) SCHEMATICS SHOWING THE PRINCIPLE FOR CONDITIONAL NEUROMODULATION Jezernik et al., Neurological Research, 2002, 24: 413-430. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 66 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) SCHEMATICS SHOWING THE PRINCIPLE FOR CONDITIONAL NEUROMODULATION • A:Bladderpressureissensedandthebladderpressuresignalusedtodetectbladdercontractionsandtotriggerpudendalafferentstimulationviadorsalpenileelectrodesonlywhenneeded,i.e.ifthereisnocontractionthereisnoneedforstimulation. • B:Toppanelshowsacystometrogramwithoutneuromodulation,andthebottompanelshowsacystometrogramduringaconditionalneuromodulation(switchedon/offbasedonthebladderpressuresignal).Urineleakageoccurredatahigherbladdervolumewhentheconditionalneuromodulationwasapplied. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 67 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) Nearthecathodebothsmallandlargefibersareexcitedtoproduceactionpotentials(APs)whichwillpropagatealongthefibers.Neartheanodethefibermembranesarehyperpolarized.Ifsufficientlyhyperpolarized,anAPcannotpassthehyperpolarizedzone,i.e.thefiberisblocked.Largefiberscanbeblockedatlowercurrentsthanrequiredtoblockthesmallerones,whichenablesaselectivefiberblockage. Jezerniketal.,NeurologicalResearch,2002,24:413-430. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 68 PRINCIPLE OF SELECTIVE SMALL FIBER ACTIVATION NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) SPINAL CORD STIMULATIONRESEARCH METHOD 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 69 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) MULTICONTACT ELECTRODE FOR SACRAL SPINAL CORD STIMULATION http://www.ninds.nih.gov/qpr/fes/N01-NS-1-2340QPR06.pdf 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 70 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) CAT BEFORE AND AFTER SPINAL CORD CUTOFF 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 71 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) STIMULATIONINDUCEDURINATION IN ALERT CATS WITH SPINAL CORD CUTOFF 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 72 Neuroprosthesis for afferent nervous activity Jezernik et al., Neurological Research, 2002, 24: 413-430. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 73 www.itk.ppke.hu NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) NEUROPROSTHESIS FOR AFFERENT NERVOUS ACTIVITY • A:Aneuralprosthesisthatwoulddetectoveractivebladdercontractionsbyrecordingandprocessingofthebladderafferentnervetraffic,andthatwouldafterdetectioninhibitthebladderandpreventhighbladderpressures.Thelattercouldbeachievedbyconditionalstimulationofthebladderinhibitorynerves. • B:Actualbladderafferentnervesignal(toppanel)recordedduringthreebladdercontractions(correspondingbladderpressureisshowninthebottompanel).BladdercontractionscanbedetectedfromtheincreasesintheENGsignal 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 74 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) •TheFinetechMedicalVOCAREBladderSystemconsistsofthefollowingsubsystems: • TheImplantedComponentsincludetheImplantableReceiver-StimulatorandExtraduralElectrodes. • TheExternalComponentsincludetheExternalController,ExternalTransmitter,ExternalCable,TransmitterTester,BatteryChargerandPowerCord. • TheSurgicalComponentsincludetheSurgicalStimulator,IntraduralSurgicalProbe,ExtraduralSurgicalProbe,ElectrodeTestCable,andSiliconeAdhesive 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 75 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 76 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) TheINTERSTIMBLADDERSYSTEMisaradiofrequencypoweredmotorcontrolneuroprosthesis,whichconsistsofbothimplantedandexternalcomponents. TheVOCAREBLADDERSYSTEMdeliverslowlevelsofelectricalstimulationtoaspinalcordinjuredpatient'sintactsacralspinalnerverootsinordertoelicitfunctionalcontractionofthemusclesinnervatedbythem. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 77 NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) MEDTRONIC INTERSTIM SYSTEM ProcedureandlocationofthepermanentwireelectrodeplacementfortheMedtronicInterstimsystem.TheelectrodeisusuallyplacedintothesacralforaminaS3. 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 78 www. medtronic.com NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) •BentonL.A.,BakerL.L.,BowmanB.R.,WatersR.L.,FunctionalElectricalStimulation:APracticalClinicalGuide(2ndEdition),RanchoRehabilitationEngineeringProgram.RanchoLosAmigosMedicalCentre,1981. • ChapinJ.K.,MoxonK.A.(eds.),NeuralProsthesesforRestorationofSensoryandMotorFunction,CRCPress,2001. • ZhouD.,GreenbaumE.(eds.),ImplantableNeuralProstheses1–DevicesandApplications,Springer,2009. • http://www.ece.mcmaster.ca/~ibruce/courses/EE3BA3_presentation04.pdf • http://www.ece.mcmaster.ca/~ibruce/courses/EE3BA3_2005/EE3BA3_presentation6.pdf • http://www.ece.mcmaster.ca/~ibruce/courses/ECE795_2008/ECE795_lecture09.pdf • http://www.ece.mcmaster.ca/~ibruce/courses/ECE795_2008/ECE795_lecture10.pdf 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 79 REFERENCES AND FURTHER READING NEURAL INTERFACES AND PROSTHESESFunctional Electrical Stimulation (FES) • What is functional electrical stimulation (FES)? • What are the most common origins of paralysis? • For which stimulation is charge production threshold higher: nerve or muscle stimulation? • What is the effect of stimulus frequency on fatigue? • List and characterize three upper limb FES systems! • List and characterize three lower limb FES systems! • What is body weight supported treadmill training? • What are the requirements of a practical FES system? • How do FES systems for bladder function restoration work? 9/14/2011 TÁMOP –4.1.2-08/2/A/KMR-2009-0006 80 REVIEW QUESTIONS