title: Adaptation of postural responses during different standing perturbation conditions in individuals with incomplete spinal cord injury.
abstract: Incomplete spinal cord injury (ISCI) frequently disrupts afferent and efferent neural pathways underlying co-requisite voluntary and involuntary muscle activation required for functional standing and walking. To understand involuntary postural control mechanisms necessary for standing, we compared eight individuals with ISCI to eight controls with no impairment. The aim of this study was to investigate anticipatory and reactive balance responses in individuals with ISCI. The ability to adapt to changes in balance conditions was assessed by monitoring automatic postural responses (APRs) during a series of expected and unexpected changes in perturbation direction (backward translation versus toes-up rotation). Both groups were able to modulate appropriately within one or two trials following an unexpected change in condition. Onset times of anterior tibialis and medial gastrocnemius (MG) were significantly slower in the ISCI group during expected and unexpected conditions. These findings demonstrate that persons with mild to moderate lower extremity sensorimotor deficits are able to generate and adapt APRs to a rapid and unexpected contextual change during a simple standing balance task.
authors.affiliation: Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, FL 32608, United States. mthigpen@phhp.ufl.edu
authors.forename: Mary T
authors.initials: MT
authors.lastname: Thigpen
authors.forename: James
authors.initials: J
authors.lastname: Cauraugh
authors.forename: Gwen
authors.initials: G
authors.lastname: Creel
authors.forename: Kristin
authors.initials: K
authors.lastname: Day
authors.forename: Sheryl
authors.initials: S
authors.lastname: Flynn
authors.forename: Stacy
authors.initials: S
authors.lastname: Fritz
authors.forename: Shirley
authors.initials: S
authors.lastname: Frost
authors.forename: Robert
authors.initials: R
authors.lastname: Respess
authors.forename: Portia
authors.initials: P
authors.lastname: Gardner-Smith
authors.forename: Mia
authors.initials: M
authors.lastname: Brack
authors.forename: Andrea
authors.initials: A
authors.lastname: Behrman
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016022:Case-Control Studies; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D013119:Spinal Cord Injuries / Q000503:physiopathology*