title: Modular control of gait after incomplete spinal cord injury: differences between sides.
abstract: METHODS
  This is an analytical descriptive study.
  
  
  OBJECTIVE
  The main goal of this study was to compare the modular organization of bilateral lower limb control in incomplete spinal cord injury (iSCI) patients during overground walking, using muscle synergies analysis. The secondary goal was to determine whether the similarity between the patients and control group correlate with clinical indicators of walking performance.
  
  
  METHODS
  This study was conducted in National Hospital for Spinal Cord Injury (Toledo, Spain).
  
  
  METHODS
  Eight iSCI patients and eight healthy subjects completed 10 walking trials at matched speed. For each trial, three-dimensional motion analysis and surface electromyography (sEMG) analysis of seven leg muscles from both limbs were performed. Muscle synergies were extracted from sEMG signals using a non-negative matrix factorization algorithm. The optimal number of synergies has been defined as the minimum number needed to obtain variability accounted for (VAF) ⩾90%.
  
  
  RESULTS
  When compared with healthy references, iSCI patients showed fewer muscle synergies in the most affected side and, in both sides, significant differences in the composition of synergy 2. The degree of similarity of these variables with the healthy reference, together with the composition of synergy 3 of the most affected side, presented significant correlations (P<0.05) with walking performance.
  
  
  CONCLUSIONS
  The analysis of muscle synergies shows potential to detect differences between the two sides in patients with iSCI. Specifically, the VAF may constitute a new neurophysiological metric to assess and monitor patients' condition throughout the gait recovery process.
authors.affiliation: Biomechanical and Technical Aids Department, National Hospital for Spinal Cord Injury, Toledo, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Pérez-Nombela
authors.affiliation: Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), Madrid, Spain.|Centre ALGORITMI, University of Minho, Azurém, Guimarães, Portugal.
authors.forename: F
authors.initials: F
authors.lastname: Barroso
authors.affiliation: Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), Madrid, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Torricelli
authors.affiliation: Biomechanical and Technical Aids Department, National Hospital for Spinal Cord Injury, Toledo, Spain.
authors.forename: A
authors.initials: A
authors.lastname: de Los Reyes-Guzmán
authors.affiliation: Biomechanical and Technical Aids Department, National Hospital for Spinal Cord Injury, Toledo, Spain.
authors.forename: A J
authors.initials: AJ
authors.lastname: Del-Ama
authors.affiliation: Sensoriomotor Function Group, National Hospital for Spinal Cord Injury, Toledo, Spain.|Toledo Physiotherapy Research Group (GIFTO). Nursing and Physical Therapy School, Castilla-La Mancha, Toledo, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Gómez-Soriano
authors.affiliation: Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), Madrid, Spain.
authors.forename: J L
authors.initials: JL
authors.lastname: Pons
authors.affiliation: Biomechanical and Technical Aids Department, National Hospital for Spinal Cord Injury, Toledo, Spain.
authors.forename: Á
authors.initials: Á
authors.lastname: Gil-Agudo
mesh_terms: D061725:Accelerometry; D000328:Adult; D000465:Algorithms; D001696:Biomechanical Phenomena; D004576:Electromyography; D005260:Female; D007839:Functional Laterality; D005684:Gait / Q000502:physiology*; D006801:Humans; D035002:Lower Extremity / Q000503:physiopathology*; D008297:Male; D018482:Muscle, Skeletal / Q000503:physiopathology*; D012815:Signal Processing, Computer-Assisted; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D016138:Walking / Q000502:physiology