title: A preliminary comparison of myoelectric and cyclic control of an implanted neuroprosthesis to modulate gait speed in incomplete SCI.
abstract: OBJECTIVE
  Explore whether electromyography (EMG) control of electrical stimulation for walking after incomplete spinal cord injury (SCI) can affect ability to modulate speed and alter gait spatial-temporal parameters compared to cyclic repetition of pre-programmed stimulation.
  
  
  METHODS
  Single case study with subject acting as own concurrent control. Setting Hospital-based biomechanics laboratory.
  
  
  METHODS
  Single subject with C6 AIS D SCI using an implanted neuroprosthesis for walking. Interventions Lower extremity muscle activation via an implanted system with two different control methods: (1) pre-programmed pattern of stimulation, and (2) EMG-controlled stimulation based on signals from the gastrocnemius and quadriceps.
  
  
  METHODS
  Gait speed, distance, and subjective rating of difficulty during 2-minute walks. Range of walking speeds and associated cadences, stride lengths, stride times, and double support times during quantitative gait analysis.
  
  
  RESULTS
  EMG control resulted in statistically significant increases in both walking speed and distance (P < 0.001) over cyclic stimulation during 2-minute walks. Maximum walking speed with EMG control (0.48 m/second) was significantly (P < 0.001) faster than the fastest automatic pattern (0.39 m/second), with increased cadence and decreased stride and double support times (P < 0.000) but no change in stride length (z = -0.085; P = 0.932). The slowest walking with EMG control (0.25 m/second) was virtually indistinguishable from the slowest with automatic cycling (z = -0.239; P = 0.811).
  
  
  CONCLUSIONS
  EMG control can increase the ability to modulate comfortable walking speed over pre-programmed cyclic stimulation. While control methods did not differ at the lowest speed, EMG-triggered stimulation allowed significantly faster walking than cyclic stimulation. The expanded range of available walking speeds could permit users to better avoid obstacles and naturally adapt to various environments. Further research is required to definitively determine the robustness, generalizability, and functional implications of these results.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Lombardo
authors.forename: Stephanie N
authors.initials: SN
authors.lastname: Bailey
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Foglyano
authors.forename: Michael E
authors.initials: ME
authors.lastname: Miller
authors.forename: Gilles
authors.initials: G
authors.lastname: Pinault
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Triolo
mesh_terms: D000328:Adult; D004576:Electromyography; D005684:Gait; D006801:Humans; D008297:Male; D058117:Neural Prostheses / Q000009:adverse effects*; D013119:Spinal Cord Injuries / Q000534:rehabilitation* / Q000601:surgery; D062187:Spinal Cord Stimulation / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*
keywords: Electromyography; Functional electrical stimulation; Gait training; Neural prosthesis; Rehabilitation; Spinal cord injury; Walking