title: Sensorimotor integration of vision and proprioception for obstacle crossing in ambulatory individuals with spinal cord injury.
abstract: Skilled walking, such as obstacle crossing, is an essential component of functional mobility. Sensorimotor integration of visual and proprioceptive inputs is important for successful obstacle crossing. The objective of this study was to understand how proprioceptive deficits affect obstacle-crossing strategies when controlling for variations in motor deficits in ambulatory individuals with spinal cord injury (SCI). Fifteen ambulatory individuals with SCI and 15 able-bodied controls were asked to step over an obstacle scaled to their motor abilities under full and obstructed vision conditions. An eye tracker was used to determine gaze behaviour and motion capture analysis was used to determine toe kinematics relative to the obstacle. Combined, bilateral hip and knee proprioceptive sense (joint position sense and movement detection sense) was assessed using the Lokomat and customized software controls. Combined, bilateral hip and knee proprioceptive sense in subjects with SCI varied and was significantly different from able-bodied subjects. Subjects with greater proprioceptive deficits stepped higher over the obstacle with their lead and trail limbs in the obstructed vision condition compared with full vision. Subjects with SCI also glanced at the obstacle more frequently and with longer fixation times compared with controls, but this was not related to proprioceptive sense. This study indicates that ambulatory individuals with SCI rely more heavily on vision to cross obstacles and show impairments in key gait parameters required for successful obstacle crossing. Our data suggest that proprioceptive deficits need to be considered in rehabilitation programs aimed at improving functional mobility in ambulatory individuals with SCI.
  
  
  
  This work is unique since it examines the contribution of combined, bilateral hip and knee proprioceptive sense on the recovery of skilled walking function, in addition to characterizing gaze behavior during a skilled walking task in people with motor-incomplete spinal cord injury.
authors.affiliation: School of Kinesiology and International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada raza.malik@alumni.ubc.ca.
authors.forename: Raza Naseem
authors.initials: RN
authors.lastname: Malik
authors.affiliation: School of Kinesiology and International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Rachel
authors.initials: R
authors.lastname: Cote
authors.affiliation: School of Kinesiology and International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Tania
authors.initials: T
authors.lastname: Lam
mesh_terms: D001696:Biomechanical Phenomena; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D005684:Gait / Q000502:physiology; D006615:Hip / Q000294:innervation; D006801:Humans; D007719:Knee Joint / Q000294:innervation; D008297:Male; D009068:Movement; D011434:Proprioception / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D013119:Spinal Cord Injuries / Q000503:physiopathology* / Q000534:rehabilitation*; D018709:Statistics, Nonparametric; D014785:Vision, Ocular / Q000502:physiology*; D016138:Walking
keywords: functional mobility; gaze behavior; obstacle crossing; proprioception; spinal cord injury