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A self-optimising portable FES system using an electrode array and movement sensors

By Ahmed Elsaify


A portable functional electrical stimulation system has been designed using embedded systems technology. The system, which was applied to patients suffering from foot drop, uses sensors to monitor foot movement and orientation in a unique way, uses sophisticated algorithms for feedback, and drives an array of surface electrodes for stimulation. This system meets British Standards and safety requirements for medical equipment.\ud A new technique was invented based on using the twitch response of muscles to optimise the configuration of the electrode array. This reduces the setup time in the clinic. Using feedback from the sensors, the optimum configuration of electrodes is chosen to produce correct stimulation and movement in real time. The instrument presents the patient with a ranked list of electrode combinations that are likely to be optimum; the patient can then choose a combination that is both effective and comfortable. The system is also able to vary the chosen pattern of electrodes and the stimulation signal parameters during the stimulation process. This may enable some problems associated with fatigue and skin irritation to be reduced. \ud Trials were carried on 30 controls and 12 patients to test the instrument and study and\ud develop the system optimisation and control algorithms. These preliminary clinical\ud trials showed that control of the stimulation during walking, based on the optimisation algorithms developed in this work, gives high quality correction of foot drop. This was shown by gait assessment analysis by the physiotherapists involved in the project and blind assessment using independent researchers. These trials prove that the concept of using the electrode array for stimulation has advantages over using a conventional 2-electrode system

Publisher: University of Leicester
Year: 2005
OAI identifier:

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  1. (1987). A comparative study of the functionality of the second generation of peroneal stimulators”,
  2. (1964). A Device for Polarity Alternation of Pulses for Biological Stimulation”,
  3. A four channel IBM PC/AT compatable Biphasic pulse generator for nerve stimulation”,
  4. (1990). A Functional Electric Stimulation System Using an Electrode Garment”,
  5. (1989). A Multichannel FES System for the Restoration of Motor Functions in High Spinal Cord Injury Patients: A Respiration Controlled System for Multijoint Upper Extremity”,
  6. (2004). A New Portable Device for Ambulatory Monitoring of Human Posture and Walking Velocity Using Miniature Accelerometers and Gyroscope”,
  7. A Portable FES System incorporating Electrode Array and feedback sensors”,
  8. (1999). A practical gait analysis system using gyroscopes”,
  9. (2002). A Review of Portable FESBased Neural Orthoses for the Correction of Drop Foot”,
  10. (2003). A system for MEAbased multisite stimulation”,
  11. ACTITRODE®: A new surface electrode-array for selective electrical stimulation”,
  12. (1999). Adaptive restriction rules Provide functional and safe Stimulation Pattern for Foot Drop Correction”,
  13. (1995). An Artificial Neural Systems for Closed Loop Control of Locomotion Produced via Neuromuscular Electrical Stimulation”,
  14. (1990). An Investigation into Electrical Stimulator Designs”, PhD thesis,
  15. (2004). An investigation of the effect of electrode size and electrode location on comfort during stimulation of the gastrocnemius muscle”, Medical Engineering and Physics,
  16. (1992). Application of a Programmable Dual Channel Adaptive Electrical Stimulation System for the Control and Analysis of Gait”,
  17. (1996). Application of tilt sensors in functional electrical stimulation”,
  18. (1989). Automatic detection of gait events: a case study using inductive learning techniques”,
  19. (1975). Biofeedback Treatment of Foot-Drop After Stroke Compared With Standard Rehabilitation Technique (Part 2): Effects on Nerve Conduction Velocity and Spasticity”,
  20. (1995). Biomechanical basis of human movement”,
  21. (1990). Biomechanics and Motor Control of Human Movement",
  22. (2004). Classification of basic daily movements using a triaxial accelerometer”,
  23. (1994). Clinical electrophysiology, electrotherapy and electrophysiologic testing”,
  24. (2000). Clinical neural prostheses beyond
  25. Compact Stimulator Using Integrated Circuits and Battery Power”,
  26. (1998). Comparison of foot-switch and hand switch triggered FES correction of foot drop”,
  27. (1987). Computer-controlled 22-channel stimulator for limb movement”, Acta Neurochir Suppl,
  28. (2000). Correction of drop foot using a fuzzy logic controlled miniature stimulator”,
  29. (1995). Cutaneous whole nerve recordings used for correction for footdrop in hemiplegic man”,
  30. (1992). Damage in Peripheral Nerve from Continuous Electrical Stimulation :
  31. (1998). Description and demonstration of a CMOS amplifier-based-system with measurement and stimulation capability for bioelectrical signal transduction”,
  32. (1996). Detection of static and dynamic activities using uniaxial accelerometers”,
  33. (1989). Development and Operation of Portable and Laboratory Electrical Stimulation Systems for Walking in Paraplegic Subjects”,
  34. (0873). Dynamics of Human Gait”, Human Kinetics,
  35. (2002). E “Improving the Quality of Life in Nerve Injured Subjects Using Functional Electrical Stimulation”,
  36. (1971). Effect of electrical stimulation on denervated muscle of rat”,
  37. (1994). Effect of gradually modulated electrical stimulation on the plasticity of artificially evoked movements”,
  38. (1988). Effects of duty cycle and frequency on muscle fatigue during isometric electrically stimulated quadriceps contractions”, Physical Therapy,
  39. (1994). Effects of electrode size on basic excitatory responses and on selected stimulus parameters”,
  40. (1988). Effects of joint angle, electrodes and waveform in electrical stimulation of the quadriceps and hamstrings”, Annals of Biomedical Engineering,
  41. (1984). Effects of stimulus pulse duration on comfort during controlled motor contractions”,
  42. (1985). Effects of waveform parameters on comfort during transcutaneous neuromuscular electrical stimulation,” Ann.
  43. (0387). Electrical nerve stimulation. Theory, experiments and applications”,
  44. (1992). Electrical stimulation and recording from cultured neurons using a planar electrode array”,
  45. (1463). Electrical stimulation of denervated muscle: is it worthwhile?” Med.Sci.Sports Exerc.2
  46. (1987). Electrical stimulation of paretic leg muscles in man, allowing feedback controlled movements to be generated from the wrist”,
  47. (2004). Electrical Stimulation of the finger flexors using ‘Virtual Electrodes’”,
  48. (1965). Electronic walking aids for patients with peroneal palsy”, in
  49. (1991). EMG and force values during sustained contraction in MS patients - implications for therapy”
  50. (2000). EMG during ambulation- clinical correlates and applications in functional electrical stimulation (FES) Rehabilitation in MS (RIMS)”, Annual Meeting Venice.
  51. (1999). Estimating orientation with gyroscopes and accelerometers”, in
  52. (1998). Evaluation of pattern stimulation for use in surface functional electrical stimulation systems”,
  53. (1997). Experience of clinical use of the Odstock Dropped Foot Stimulator”,
  54. (1975). Experimental Correction of Foot Drop by Electrical Stimulation of the Pcroncal Nerve”,
  55. (1962). Functional electrical stimulation for ambulation in hemiplegia,”
  56. (2003). Functional Electrical Stimulation Optimisation using an Electrode Array and Closed Loop Control” IPEM Annual Scientific Meeting,
  57. (1992). Functional Electrical Stimulation Systems for Restoration of Motor Function of Paralysed Muscles - Versatile Systems and a Portable System”,
  58. (1989). Functional electrical stimulation: standing and walking after spinal cord injury”,
  59. (1997). Functional Electrical Stimulation.
  60. (1961). Functional electrotherapy stimulation of the personal verve synchronised with the swing phase of the gait of hemiplegics patient”.
  61. (1989). Functional Neuromuscular Stimulation System Using an Implantable Hydroxyapatite Connector and a Microprocessor Based Portable Stimulator”,
  62. (1987). Gait Abnormalities in Hemiplegia, Their Correction by Ankle-Foot Orthoses”, Arch Phys Med Rehabil,
  63. (1991). Gait Analysis – An Introduction, Istedn”, 3rd edition Butterworm Heinmam,
  64. (1999). Gait control system for functional electrical stimulation using neural networks”,
  65. (1992). Gait Evaluation in Hemiparetic Patients Using Subcutaneous Peroneal Electrical Stimulation”,
  66. (2000). Gait event detection for FES using accelerometers and supervised machine learning”,
  67. (1984). Gait pattern behavior of hemiplegic patients under the influence of a six-channel microprocessor stimulator in a real environment”,
  68. (1999). Gait phase information provided by sensory nerve activity during walking: applicability as state controller feedback for FES”,
  69. (2002). Handbook of virtual environments: Design, implementation, and applications”, Mahwah, NJ: Lawrence Erlbaum Associates In,
  70. (1985). High voltage stimulation: effects of electrode size on basic excitatory responses”, Physical Therapy,
  71. (1989). Histologic and Physiologic Evaluation of Electrically Stimulated Peripheral Nerve: Consideration for the Selection of Parameters”,
  72. (1993). Human physiology, the mechanisms of body”,
  73. (2003). Improved Control of Ankle Movement using an Array of Mini-Electrodes”,
  74. (1971). Improvement in locomotion in hemiplegic patients with multichannel electrical stimulation”, Human Locomotor Engineering - A Review
  75. (1993). Improving limb flexion in FES gait using the flexion withdrawal response for the spinal cord injured person”,
  76. Interaction of array of finite electrodes with layered biological tissue: effect of electrode size and configuration”
  77. (1987). Interrater reliability of modified Ashworth scale of muscle spasticity”,
  78. (1995). Machine Learning in Control of Functional Electrical Stimulation Systems for Locomotion”,
  79. (2002). Mapping foot spatial measurements with small movements of FES electrode positions 2002”, FESNet
  80. (1989). Methods for Estimating Isometric Recruitment Curves of Electrically Stimulated Muscle”,
  81. (2001). microcontroller based electrical stimulation”, third year project report,
  82. (1988). Modelling the excitation of fibers under surface electrodes”,
  83. (2004). Multi-Field Surface Electrode for Selective Electrical Stimulation”,
  84. (1984). Multichannel electrical stimulation of gait in motor disabled patients”,
  85. (2002). Multiple Sclerosis: The Facts”.
  86. (1996). Multiple Sclerosis”,
  87. (1979). Muscle fatigue”,
  88. (1985). Muscles Alive”, Fifth edition,
  89. (1989). Muscles, Nerves and Movement:
  90. (1999). Natural versus artificial sensors applied in peroneal nerve stimulation”,
  91. (1088). Neural Network Control of Ncuromuscular Stimulation in Paraplegics for Independent Ambulalion”,
  92. (1993). Neuromuscular electrical stimulation: A practical guide”, Los Amigos Research and Education Institute, Rancho Los Amigos Medical Centre,
  93. Neuromuscular Parameters, Fatigue and Function
  94. (1996). New control strategies for neuroprosthetic systems”,
  95. (1975). Optimal stimulus parameters for minimum pain in the chronic stimulation of innervated muscle”,
  96. (1989). Paraplegic Standing Controlled by Functional Neuromuscular Stimulation: Part I - Computer Model and Control System Design”.
  97. (1983). Patient controlled electrical stimulation via EMG signature discrimination for providing certain paraplegics with primitive walking functions”,
  98. (1999). Patient’s perceptions of the Odstock Dropped Foot Stimulator (ODFS)”,
  99. (1996). Peroneal stimulator: evaluation for the correction of spastic drop foot in hemiplegia”,
  100. Physiology of Behavior”, Fifth Edition, Allyn and Bacon Publications,
  101. Portable FES System optimises Electrode Array using Twitch Response”,
  102. (1986). Postural switching for prolonging functional electrical stimulation in paraplegic patients", Paraplegia (Vol:24,
  103. (2001). Programmable and portable electrical stimulator for transcutaneous FES applications - Complex motion”, in
  104. (1979). Programmed six-channel electrical stimulator for complex stimulation of leg muscles during walking”,
  105. (1983). Rating neurologic impairment in multiple sclerosis: an expanded disability status scale
  106. (1988). Relationship Between Numbers and Frequencies of Stimuli in Human Muscle Fatigue".
  107. (1989). Restoration of Gait During Two to Three Weeks of Therapy with Multichannel Electrical Stimulation”, Physical Therapy,
  108. Restoration of Standing, WeightShift and Gait by Multichannel Electrical Stimulation in Hemiparetic Patients”,
  109. (1990). Restoring Unassisted Natural Gait to Paraplegics with Functional Neuromuscular Stimulation: A Computer Simulation Study”,
  110. (1989). Royal College of Physicians London “Stroke Towards better management ”A Report of the Royal College of Physicians London.
  111. (1989). Scoliosis Treatment in Children Using a Programmable, Totally Implantable Muscle Stimulator (ESI)”,
  112. Sealing cultured invertebrate neurons to embedded dish electrodes facilitates long-term stimulation and recording”,
  113. (1997). Self-optimising electrode arrays”,
  114. (1986). Sensors for use with functional neuromuscular stimulation”,
  115. Single motor unit and fibre action potentials during fatigue”,
  116. (1988). Stimulus Artifact Compensation Using Biphasic Stimulation.
  117. (1991). Stretch reflex inhibition using electrical stimulation in normal subjects and subjects with spasticity”,
  118. (1986). Study and Correction of Human Gait by Electrical Stimulation”, The American Surgeon,
  119. (1973). The Assessment of Muscle Denervation by Electrical Stimulation”,
  120. (1968). The Catch Properties of Ordinary Muscle”,
  121. The current requirements and the pain responses for various sizes of surface stimulation electrodes”,
  122. (1989). The Disability Status Scale for multiple sclerosis: apologia pro
  123. (1987). The effect of low-frequency electrical stimulation on denervation atrophy in man”,
  124. (1994). The effects of selected stimulus waveforms on pulse and phase characteristics at sensory and motor thresholds”,
  125. (1998). The incidence of drop foot following stroke in the St. Camillus’ Hospital catchment area within the Mid-Western Health Board”,
  126. (2001). The Neuron. Cell and Molecular Biology” Editors:
  127. (1997). The physiology of neuromuscular electrical stimulation”, Pediatric Physical Therapy,
  128. (2002). The sensitivity and selectivity of an implantable 2-channel peroneal nerve stimulator system for restoration of dropped-foot”,
  129. (2004). The Sensitivity and Selectivity of an Implantable TwoChannel Peroneal Nerve Stimulator System for Restoration of Dropped Foot”,
  130. (1994). The use of patterned neuromuscular stimulation to improve hand function following surgery for ulnar neuropathy”, J.Hand Surg.,
  131. (1987). Therapeutic effects of Mmultisite electric stimulation of gait in motor-disabled patients”,
  132. (2003). Three dimensional inertial sensing of foot movements for automatic tuning of a two-channel implantable foot drop stimulator”, Medical Engineering and Physics,
  133. (1994). Tibialis anterior surface EMG parameters change before force output in multiple sclerosis patients”, Clinical Rehabilitation
  134. (1986). Trigger switches for implantable gait stimulation”,
  135. Walking after stroke”,
  136. (1986). When are Actively Balanced Biphasic ('Lilly') Stimulating Pulses Necessary in a Neurological Prosthesis”, Historical Background; Pt Resting Potential;

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